221 UTL_HTTP

Using UTL_HTTP

This section contains topics which relate to using the UTL_HTTP package.

• Overview

• Security Model

• Constants

• Datatypes

• Operational Notes

• Exceptions

• Examples

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Overview

With the UTL_HTTP package, you can write PL/SQL programs that communicate with Web (HTTP) servers. And UTL_HTTP contains a function that can be used in SQL queries.

The package supports HTTP over the Secured Socket Layer protocol (SSL), also known as HTTPS. It also supports SSL client authentication by sending the client-certificate in a wallet to authenticate with the remote Web server.

Other Internet-related data-access protocols (such as the File Transfer Protocol (FTP) or the Gopher protocol) are also supported using an HTTP proxy server that supports those protocols.

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Security Model

This package is an invoker's rights package and the invoking user will need the connect privilege granted in the access control list assigned to the remote network host to which he wants to connect, as well as the use-client-certificates or the use-passwords privilege to authenticate himself with the remote Web server using the credentials stored in an Oracle wallet.

---

Constants

The UTL_HTTP package uses the constants shown in following tables.

• UTL_HTTP Constants - HTTP Versions

• UTL_HTTP Constants - Default Ports

• UTL_HTTP Constants - HTTP 1.1 Status Codes

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Datatypes

• REQ Type

• RESP Type

• COOKIE and COOKIE_TABLE Types

• CONNECTION Type

• REQUEST_CONTEXT_KEY Type

REQ Type

Use this PL/SQL record type to represent an HTTP request.

Syntax

TYPE req IS RECORD (
   url           VARCHAR2(32767),
   method        VARCHAR2(64),
   http_version  VARCHAR2(64));

Parameters

Usage Notes

The information returned in REQ from the interface begin_request is for read-only. Changing the field values in the record has no effect on the request.

There are other fields in REQ record type whose names begin with the prefix private_. The fields are private and are intended for use by implementation of the UTL_HTTP package. You should not modify the fields.

REQUEST_CONTEXT_KEY Type

This type is used to represent the key to a request context. A request context is a context that holds a private wallet and cookie table to make a HTTP request. This private wallet and cookie table, unlike the session-wide ones maintained in the package, will not be shared with other HTTP requests within the database session.

Syntax

SUBTYPE request_context_key IS PLS_INTEGER;

Usage Notes

To provide enhanced security, UTL_HTTP allows PL/SQL programs to create request contexts. A request context is a private context that holds a wallet and a cookie table that will not be shared with other programs in the same database session when making HTTP requests and receiving HTTP responses. PL/SQL programs should use request contexts when they need to use wallets or cookies that contain sensitive information such as authentication credentials.

RESP Type

This PL/SQL record type is used to represent an HTTP response.

Syntax

TYPE resp IS RECORD (
   status_code    PLS_INTEGER,
   reason_phrase  VARCHAR2(256),
   http_version   VARCHAR2(64));

Parameters

Usage Notes

The information returned in RESP from the interface GET_RESPONSE is read-only. There are other fields in the RESP record type whose names begin with the prefix private_. The fields are private and are intended for use by implementation of the UTL_HTTP package. You should not modify the fields.

COOKIE and COOKIE_TABLE Types

The COOKIE type is the PL/SQL record type that represents an HTTP cookie. The COOKIE_TABLE type is a PL/SQL index-by-table type that represents a collection of HTTP cookies.

Syntax

TYPE cookie IS RECORD (
   name  VARCHAR2(256),
   value  VARCHAR2(1024),
   domain  VARCHAR2(256),
   expire  TIMESTAMP WITH TIME ZONE,
   path  VARCHAR2(1024),
   secure  BOOLEAN,
   version  PLS_INTEGER,
   comment  VARCHAR2(1024));

TYPE cookie_table IS TABLE OF cookie INDEX BY binary_integer;

Fields of COOKIE Record Type

Table 221-6 shows the fields for the COOKIE and COOKIE_TABLE record types.

Usage Notes

PL/SQL programs do not usually examine or change the cookie information stored in the UTL_HTTP package. The cookies are maintained by the package transparently. They are maintained inside the UTL_HTTP package, and they last for the duration of the database session only. PL/SQL applications that require cookies to be maintained beyond the lifetime of a database session can read the cookies using GET_COOKIES, store them persistently in a database table, and re-store the cookies back in the package using ADD_COOKIES in the next database session. All the fields in the cookie record, except for the comment field, must be stored. Do not alter the cookie information, which can result in an application error in the Web server or compromise the security of the PL/SQL and the Web server applications. See "Retrieving and Restoring Cookies".

CONNECTION Type

Use the PL/SQL record type to represent the remote hosts and TCP/IP ports of a network connection that is kept persistent after an HTTP request is completed, according to the HTTP 1.1 protocol specification. The persistent network connection may be reused by a subsequent HTTP request to the same host and port. The subsequent HTTP request may be completed faster because the network connection latency is avoided. connection_table is a PL/SQL table of connection.

For a direct HTTP persistent connection to a Web server, the host and port fields contain the host name and TCP/IP port number of the Web server. The proxy_host and proxy_port fields are not set. For an HTTP persistent connection that was previously used to connect to a Web server using a proxy, the proxy_host and proxy_port fields contain the host name and TCP/IP port number of the proxy server. The host and port fields are not set, which indicates that the persistent connection, while connected to a proxy server, is not bound to any particular target Web server. An HTTP persistent connection to a proxy server can be used to access any target Web server that is using a proxy.

The SSL field indicates if Secured Socket Layer (SSL) is being used in an HTTP persistent connection. An HTTPS request is an HTTP request made over SSL. For an HTTPS (SSL) persistent connection connected using a proxy, the host and port fields contain the host name and TCP/IP port number of the target HTTPS Web server and the fields will always be set. An HTTPS persistent connection to an HTTPS Web server using a proxy server can only be reused to make another request to the same target Web server.

Syntax

TYPE connection IS RECORD (
   host  VARCHAR2(256),
   port  PLS_INTEGER,
   proxy_host  VARCHAR2(256),
   proxy_port  PLS_INTEGER,
   ssl  BOOLEAN);

TYPE connection_table IS TABLE OF connection INDEX BY BINARY_INTEGER;

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Operational Notes

• Operational Flow

• Simple HTTP Fetches

• HTTP Requests

• HTTP Responses

• HTTP Persistent Connections

• Error Conditions

• Session Settings

• Request Context

• External Password Store

Operational Flow

The UTL_HTTP package provides access to the HTTP protocol. The interfaces must be called in the order shown in Figure 221-1, or an exception will be raised.

The following can be called at any time:

• Non-protocol interfaces that manipulate cookies

  • GET_COOKIE_COUNT

  • GET_COOKIES

  • ADD_COOKIES

  • CLEAR_COOKIES

• Persistent connections

  • GET_PERSISTENT_CONN_COUNT

  • GET_PERSISTENT_CONNS

  • CLOSE_PERSISTENT_CONN

  • CLOSE_PERSISTENT_CONNS

• Interfaces that manipulate attributes and configurations of the UTL_HTTP package in the current session

  • SET_PROXY

  • GET_PROXY

  • SET_COOKIE_SUPPORT

  • GET_COOKIE_SUPPORT

  • SET_FOLLOW_REDIRECT

  • GET_FOLLOW_REDIRECT

  • SET_BODY_CHARSET

  • GET_BODY_CHARSET

  • SET_PERSISTENT_CONN_SUPPORT

  • GET_PERSISTENT_CONN_SUPPORT

  • SET_DETAILED_EXCP_SUPPORT

  • GET_DETAILED_EXCP_SUPPORT

  • SET_WALLET

  • SET_TRANSFER_TIMEOUT

  • GET_TRANSFER_TIMEOUT

• Interfaces that retrieve the last detailed exception code and message UTL_HTTP package in the current session

  • GET_DETAILED_SQLCODE

  • GET_DETAILED_SQLERRM

    NOTE:

    Some of the request and response interfaces bear the same name as the interface that manipulates the attributes and configurations of the package in the current session. They are overloaded versions of the interface that manipulate a request or a response.

Simple HTTP Fetches

REQUEST and REQUEST_PIECES take a string uniform resource locator (URL), contact that site, and return the data (typically HTML) obtained from that site.

You should not expect REQUEST or REQUEST_PIECES to succeed in contacting a URL unless you can contact that URL by using a browser on the same machine (and with the same privileges, environment variables, and so on.)

If REQUEST or REQUEST_PIECES fails (for example, if it raises an exception, or if it returns an HTML-formatted error message, but you believe that the URL argument is correct), then try contacting that same URL with a browser to verify network availability from your machine. You may have a proxy server set in your browser that needs to be set with each REQUEST or REQUEST_PIECES call using the optional proxy parameter.

HTTP Requests

The HTTP Requests group of subprograms begin an HTTP request, manipulate attributes, and send the request information to the Web server. When a request is created, it inherits the default settings of the HTTP cookie support, follow-redirect, body character set, persistent-connection support, and transfer timeout of the current session. The settings can be changed by calling the request interface.

HTTP Responses

The HTTP Responses group of subprograms manipulate an HTTP response obtained from GET_RESPONSE and receive response information from the Web server. When a response is created for a request, it inherits settings of the HTTP cookie support, follow-redirect, body character set, persistent-connection support, and transfer timeout from the request. Only the body character set can be changed by calling the response interface.

HTTP Cookies

The UTL_HTTP package provides subprograms to manipulate HTTP cookies.

HTTP Persistent Connections

The UTL_HTTP package provides subprograms to manipulate persistent connections.

Error Conditions

The UTL_HTTP package provides subprograms to retrieve error information.

Session Settings

Session settings manipulate the configuration and default behavior of UTL_HTTP when HTTP requests are executed within a database user session. When a request is created, it inherits the default settings of the HTTP cookie support, follow-redirect, body character set, persistent-connection support, and transfer timeout of the current session. Those settings can be changed later by calling the request interface. When a response is created for a request, it inherits those settings from the request. Only the body character set can be changed later by calling the response interface.

Request Context

The UTL_HTTP package maintains a common wallet and cookie table within the database session that all HTTP requests and responses share. This makes it easy for users to share the wallet or to maintain application state in the cookies within the session. However, if an application stores private information in the wallet or in the cookies that it does not want to share with other applications in the same database session, it may define a request context to hold its own wallet and cookie table and use this request context to make HTTP requests.

External Password Store

The UTL_HTTP package allows HTTP password credentials to be stored in an Oracle wallet's external password store. The external password store provides an easy but secure storage for passwords and frees the application developers from the need to maintain their own storage.

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Exceptions

Table 221-7 lists the exceptions that the UTL_HTTP package interface can raise. By default, UTL_HTTP raises the exception request_failed when a request fails to execute. If the package is set to raise a detailed exception by set_detailed_excp_support, the rest of the exceptions will be raised directly (except for the exception end_of_body, which will be raised by READ_TEXT, READ_LINE, and READ_RAW regardless of the setting).

For REQUEST and REQUEST_PIECES, the request_failed exception is raised when any exception occurs and detailed_exception is disabled.

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Examples

The following examples demonstrate how to use UTL_HTTP.

• General Usage

• Retrieving HTTP Response Headers

• Handling HTTP Authentication

• Retrieving and Restoring Cookies

• Making HTTP Request with Private Wallet and Cookie Table

General Usage

SET SERVEROUTPUT ON SIZE 40000
  
DECLARE
  req   UTL_HTTP.REQ;
  resp  UTL_HTTP.RESP;
  value VARCHAR2(1024);
BEGIN
  UTL_HTTP.SET_PROXY('proxy.my-company.com', 'corp.my-company.com');
  req := UTL_HTTP.BEGIN_REQUEST('http://www-hr.corp.my-company.com');
  UTL_HTTP.SET_HEADER(req, 'User-Agent', 'Mozilla/4.0');
  resp := UTL_HTTP.GET_RESPONSE(req);
  LOOP
    UTL_HTTP.READ_LINE(resp, value, TRUE);
    DBMS_OUTPUT.PUT_LINE(value);
  END LOOP;
  UTL_HTTP.END_RESPONSE(resp);
EXCEPTION
  WHEN UTL_HTTP.END_OF_BODY THEN
    UTL_HTTP.END_RESPONSE(resp);
END;

Retrieving HTTP Response Headers

SET SERVEROUTPUT ON SIZE 40000
  
DECLARE
  req   UTL_HTTP.REQ;
  resp  UTL_HTTP.RESP;
  name  VARCHAR2(256);
  value VARCHAR2(1024);
BEGIN
  UTL_HTTP.SET_PROXY('proxy.my-company.com', 'corp.my-company.com');
  req := UTL_HTTP.BEGIN_REQUEST('http://www-hr.corp.my-company.com');
  UTL_HTTP.SET_HEADER(req, 'User-Agent', 'Mozilla/4.0');
  resp := UTL_HTTP.GET_RESPONSE(req);
  DBMS_OUTPUT.PUT_LINE('HTTP response status code: ' || resp.status_code);
  DBMS_OUTPUT.PUT_LINE('HTTP response reason phrase: ' || resp.reason_phrase);
  FOR i IN 1..UTL_HTTP.GET_HEADER_COUNT(resp) LOOP
    UTL_HTTP.GET_HEADER(resp, i, name, value);
    DBMS_OUTPUT.PUT_LINE(name || ': ' || value);
  END LOOP;
  UTL_HTTP.END_RESPONSE(resp);
END;

Handling HTTP Authentication

SET serveroutput ON SIZE 40000
  
CREATE OR REPLACE PROCEDURE get_page (url      IN VARCHAR2,
                                      username IN VARCHAR2 DEFAULT NULL,
                                      password IN VARCHAR2 DEFAULT NULL,
                                      realm    IN VARCHAR2 DEFAULT NULL) AS
  req       UTL_HTTP.REQ;
  resp      UTL_HTTP.RESP;
  my_scheme VARCHAR2(256);
  my_realm  VARCHAR2(256);
  my_proxy  BOOLEAN;
BEGIN
  -- Turn off checking of status code. We will check it by ourselves.
  UTL_HTTP.HTTP_RESPONSE_ERROR_CHECK(FALSE);
  req := UTL_HTTP.BEGIN_REQUEST(url);
  IF (username IS NOT NULL) THEN
    UTL_HTTP.SET_AUTHENTICATION(req, username, password); -- Use HTTP Basic Authen. Scheme
  END IF;
  resp := UTL_HTTP.GET_RESPONSE(req);
  IF (resp.status_code = UTL_HTTP.HTTP_UNAUTHORIZED) THEN
    UTL_HTTP.GET_AUTHENTICATION(resp, my_scheme, my_realm, my_proxy);
    IF (my_proxy) THEN
       DBMS_OUTPUT.PUT_LINE('Web proxy server is protected.');
       DBMS_OUTPUT.PUT('Please supplied the required ' || my_scheme || ' authentication username/password for realm ' || my_realm || ' for the proxy server.');
    ELSE
      DBMS_OUTPUT.PUT_LINE('Web page ' || url || ' is protected.');
      DBMS_OUTPUT.PUT('Please supplied the required ' || my_scheme || ' authentication username/password for realm ' || my_realm || ' for the Web page.');
    END IF;
    UTL_HTTP.END_RESPONSE(resp);
    RETURN;
  END IF;
  FOR i IN 1..UTL_HTTP.GET_HEADER_COUNT(resp) LOOP
    UTL_HTTP.GET_HEADER(resp, i, name, value);
    DBMS_OUTPUT.PUT_LINE(name || ': ' || value);
  END LOOP;
  UTL_HTTP.END_RESPONSE(resp);
END;

Retrieving and Restoring Cookies

CREATE TABLE my_cookies (
    session_id  INTEGER,
    name        VARCHAR2(256),
    value       VARCHAR2(1024),
    domain      VARCHAR2(256),
    expire      DATE,
    path        VARCHAR2(1024),
    secure      VARCHAR2(1),
    version     INTEGER);

CREATE SEQUENCE session_id;
SET SERVEROUTPUT ON SIZE 40000

REM Retrieve cookies from UTL_HTTP
CREATE OR REPLACE FUNCTION save_cookies RETURN PLS_INTEGER AS
  cookies        UTL_HTTP.COOKIE_TABLE;
  my_session_id  PLS_INTEGER;
  secure         VARCHAR2(1);
BEGIN
  /* assume that some cookies have been set in previous HTTP requests. */
  UTL_HTTP.GET_COOKIES(cookies);
  SELECT session_id.nextval INTO my_session_id FROM DUAL;
  FOR i in 1..cookies.count LOOP
    IF (cookies(i).secure) THEN
      secure := 'Y';
    ELSE
      secure := 'N';
    END IF;
    INSERT INTO my_cookies
    VALUES (my_session_id, cookies(i).name, cookies(i).value,
            cookies(i).domain,
            cookies(i).expire, cookies(i).path, secure, cookies(i).version);
  END LOOP;
  RETURN my_session_id;
END;
/

REM Retrieve cookies from UTL_HTTP
CREATE OR REPLACE PROCEDURE restore_cookies (this_session_id IN PLS_INTEGER)
AS
  cookies        UTL_HTTP.COOKIE_TABLE;
  cookie         UTL_HTTP.COOKIE;
  i              PLS_INTEGER := 0;
  CURSOR c (c_session_id PLS_INTEGER) IS
    SELECT * FROM my_cookies WHERE session_id = c_session_id;
BEGIN
  FOR r IN c(this_session_id) LOOP
    i := i + 1;
    cookie.name     := r.name;
    cookie.value    := r.value;
    cookie.domain   := r.domain;
    cookie.expire   := r.expire;
    cookie.path     := r.path;
    IF (r.secure = 'Y') THEN
      cookie.secure := TRUE;
    ELSE
      cookie.secure := FALSE;
    END IF;
    cookie.version := r.version;
    cookies(i) := cookie;
  END LOOP;
  UTL_HTTP.CLEAR_COOKIES;
  UTL_HTTP.ADD_COOKIES(cookies);
END;
/

Making HTTP Request with Private Wallet and Cookie Table

SET SERVEROUTPUT ON SIZE 40000
 
CREATE OR REPLACE PROCEDURE DISPLAY_PAGE(url IN VARCHAR2) AS
  request_context UTL_HTPT.REQUEST_CONTEXT_KEY;
  req             UTL_HTTP.REQ;
  resp            UTL_HTTP.RESP;
  data            VARCHAR2(1024);
 
BEGIN

  -- Create a request context with its wallet and cookie table
  request_context := UTL_HTTP.CREATE_REQUEST_CONTEXT(
                       wallet_path          => 'file:/oracle/wallets/test/wallet',
                       wallet_password      => '******',
                       enable_cookies       => TRUE,
                       max_cookies          => 300,
                       max_cookies_per_site => 20);
 
  -- Make a HTTP request using the private wallet and cookie
  -- table in the request context
  req := UTL_HTTP.BEGIN_REQUEST(
           url             => url,
           request_context => request_context);
  resp := UTL_HTTP.GET_RESPONSE(req);
 
  BEGIN
    LOOP
       UTL_HTTP.READ_TEXT(resp, data);
       DBMS_OUTPUT.PUT(data);
    END LOOP;
  EXCEPTION
      WHEN UTL_HTTP.END_OF_BODY THEN
         UTL_HTTP.END_RESPONSE(resp); 
  END;
 
  -- Destroy the request context
  UTL_HTTP.DESTROY_REQUEST_CONTEXT(request_context);
 
END;
 
BEGIN
  DISPLAY_PAGE('https://www.example.com/');
END;
/

Subprogram Groups

UTL_HTTP subprograms are grouped by function:

• Simple HTTP Fetches in a Single Call Subprograms

• Session Settings Subprograms

• HTTP Requests Subprograms

• HTTP Request Contexts Subprograms

• HTTP Responses Subprograms

• HTTP Cookies Subprograms

• HTTP Persistent Connections Subprograms

• Error Conditions Subprograms

---

Simple HTTP Fetches in a Single Call Subprograms

REQUEST and REQUEST_PIECES take a string uniform resource locator (URL), contact that site, and return the data (typically HTML) obtained from that site.

---

Session Settings Subprograms

---

HTTP Requests Subprograms

---

HTTP Request Contexts Subprograms

---

HTTP Responses Subprograms

---

HTTP Cookies Subprograms

---

HTTP Persistent Connections Subprograms

---

Error Conditions Subprograms

Summary of UTL_HTTP Subprograms

---

ADD_COOKIES Procedure

This procedure adds the cookies either to a request context or to the UTL_HTTP package's session state.

Syntax

UTL_HTTP.ADD_COOKIES (
   cookies          IN  cookie_table,
   request_context  IN  request_context_key DEFAULT NULL);

Parameters

Usage Notes

The cookies that the package currently maintains are not cleared before new cookies are added.

---

BEGIN_REQUEST Function

This functions begins a new HTTP request. UTL_HTTP establishes the network connection to the target Web server or the proxy server and sends the HTTP request line. The PL/SQL program continues the request by calling some other interface to complete the request. The URL may contain the username and password needed to authenticate the request to the server. The format is

scheme://[user[:password]@]host[:port]/[...]

Syntax

UTL_HTTP.BEGIN_REQUEST (
   url               IN  VARCHAR2,
   method            IN  VARCHAR2 DEFAULT 'GET',
   http_version      IN  VARCHAR2 DEFAULT NULL,
   request_context   IN  request_context_key DEFAULT NULL)
RETURN req;

Parameters

Usage Notes

• The URL passed as an argument to this function is not examined for illegal characters, such as spaces, according to URL specification RFC 2396. You should escape those characters with the UTL_URL package to return illegal and reserved characters. URLs should consist of US-ASCII characters only. See Chapter 235, "UTL_URL" for a list of legal characters in URLs. Note that URLs should consist of US-ASCII characters only. The use of non-US-ASCII characters in a URL is generally unsafe.

• BEGIN_REQUEST can send a URL whose length is up to 32767 bytes. However, different Web servers impose different limits on the length of the URL they can accept. This limit is often about 4000 bytes. If this limit is exceeded, the outcome will depend on the Web server. For example, a Web server might simply drop the HTTP connection without returning a response of any kind. If this happens, a subsequent invocation of the GET_RESPONSE Function will raise the PROTOCOL_ERROR exception.

  A URL will be long when its QUERY_STRING (that is, the information that follows the question mark (?)) is long. In general, it is better to send this parameterization in the body of the request using the POST method.

  req := UTL_HTTP.BEGIN_REQUEST (url=>the_url, method=>'POST');
  UTL_HTTP.SET_HEADER (r      =>  req, 
                       name   =>  'Content-Type',   
                       value  =>  'application/x-www-form-urlencoded');
  UTL_HTTP.SET_HEADER (r      =>   req, 
                       name   =>   'Content-Length', 
                       value  =>'  <length of data posted in bytes>');
  UTL_HTTP.WRITE_TEXT (r      =>   req, 
                       data   =>   'p1 = value1&p2=value2...');
  resp := UTL_HTTP.GET_RESPONSE 
                       (r     =>   req);
  ...
  

  The programmer must determine whether a particular Web server may, or may not, accept data provided in this way.

• An Oracle wallet must be set before accessing Web servers over HTTPS. See the SET_WALLET Procedure procedure on how to set up an Oracle wallet. To use SSL client authentication, the client certificate should be stored in the wallet and the caller must have the use-client-certificates privilege on the wallet. See "Managing Fine-grained Access to External Network Services" in the Oracle Database Security Guide to grant the privilege.

• To connect to the remote Web server directly, or indirectly through a HTTP proxy, the UTL_HTTP must have the connect ACL privilege to the remote Web server host or the proxy host respectively.

---

CLEAR_COOKIES Procedure

This procedure clears all the cookies maintained either in a request context or in the UTL_HTTP package's session state.

Syntax

UTL_HTTP.CLEAR_COOKIES (
   request_context  IN  request_context_key DEFAULT NULL);

Parameters

---

CLOSE_PERSISTENT_CONN Procedure

This procedure closes an HTTP persistent connection maintained by the UTL_HTTP package in the current database session.

Syntax

UTL_HTTP.CLOSE_PERSISTENT_CONN (
   conn  IN connection);

Parameters

---

CLOSE_PERSISTENT_CONNS Procedure

This procedure closes a group of HTTP persistent connections maintained by the UTL_HTTP package in the current database session. This procedure uses a pattern-match approach to decide which persistent connections to close.

To close a group of HTTP persistent connection that share a common property (for example, all connections to a particular host, or all SSL connections), set the particular parameters and leave the rest of the parameters NULL. If a particular parameter is set to NULL when this procedure is called, that parameter will not be used to decide which connections to close.

For example, the following call to the procedure closes all persistent connections to foobar:

UTL_HTTP.CLOSE_PERSISTENT_CONNS(host => 'foobar');

And the following call to the procedure closes all persistent connections through the proxy www-proxy at TCP/IP port 80:

UTL_HTTP.CLOSE_PERSISTENT_CONNS(proxy_host => 'foobar',
                                proxy_port => 80);

And the following call to the procedure closes all persistent connections:

UTL_HTTP.CLOSE_PERSISTENT_CONNS;

Syntax

UTL_HTTP.CLOSE_PERSISTENT_CONNS (
   host        IN VARCHAR2 DEFAULT NULL,
   port        IN PLS_INTEGER DEFAULT NULL,
   proxy_host  IN VARCHAR2 DEFAULT NULL,
   proxy_port  IN PLS_INTEGER DEFAULT NULL,
   ssl         IN BOOLEAN DEFAULT NULL);

Parameters

Usage Notes

Connections to the same Web server at different TCP/IP ports are counted individually. The host names of the Web servers are identified as specified in the URL of the original HTTP requests. Therefore, fully qualified host names with domain names will be counted differently from the host names without domain names.

Note that the use of a NULL value in a parameter when this procedure is called means that the caller does not care about its value when the package decides which persistent connection to close. If you want a NULL value in a parameter to match only a NULL value of the parameter of a persistent connection (which is when you want to close a specific persistent connection), you should use the CLOSE_PERSISTENT_CONN procedure that closes a specific persistent connection.

---

CREATE_REQUEST_CONTEXT Function

This function creates a request context. A request context is a context that holds a wallet and a cookie for private use in making a HTTP request. This allows the HTTP request to use a wallet and a cookie table that will not be shared with other applications making HTTP requests in the same database session.

Syntax

UTL_HTTP.CREATE_REQUEST_CONTEXT (
 wallet_path          IN VARCHAR2 DEFAULT NULL,
 wallet_password      IN VARCHAR2 DEFAULT NULL,
 enable_cookies       IN BOOLEAN  DEFAULT TRUE,
 max_cookies          IN PLS_INTEGER DEFAULT 300,
 max_cookies_per_site IN PLS_INTEGER DEFAULT 20)
RETURN request_context_key;

Parameters

Return Values

The request context created.

Examples

DECLARE
  request_context  UTL_HTTP.REQUEST_CONTEXT_KEY;
  req              utl_http.req;
BEGIN
  request_context := UTL_HTTP.CREATE_REQUEST_CONTEXT(
       wallet_path          => 'file:/oracle/wallets/test_wallets',
       wallet_password      => NULL,
       enable_cookies       => TRUE,
       max_cookies          => 300,
       max_cookies_per_site => 20);
  req := UTL_HTTP.BEGIN_REQUEST(
       url                  => 'http://www.example.com/',
       request_context      => request_context);
END;

---

DESTROY_REQUEST_CONTEXT Procedure

This procedure destroys a request context in UTL_HTTP. A request context cannot be destroyed when it is in use by a HTTP request or response.

Syntax

UTL_HTTP.DESTROY_REQUEST_CONTEXT (
   request_context    request_context_key);

Parameters

Examples

DECLARE
  request_context  UTL_HTTP.REQUEST_CONTEXT_KEY;
BEGIN
  request_context := UTL_HTTP.CREATE_REQUEST_CONTEXT(…);
  …
  UTL_HTTP.DESTROY_REQUEST_CONTEXT(request_context);
END;

---

END_REQUEST Procedure

This procedure ends the HTTP request. To terminate the HTTP request without completing the request and waiting for the response, the program can call this procedure. Otherwise, the program should go through the normal sequence of beginning a request, getting the response, and closing the response. The network connection will always be closed and will not be reused.

Syntax

UTL_HTTP.END_REQUEST (
   r  IN OUT NOCOPY req);

Parameters

---

END_RESPONSE Procedure

This procedure ends the HTTP response. It completes the HTTP request and response. Unless HTTP 1.1 persistent connection is used in this request, the network connection is also closed.

Syntax

UTL_HTTP.END_RESPONSE (
   r  IN OUT NOCOPY resp);

Parameters

---

GET_AUTHENTICATION Procedure

This procedure retrieves the HTTP authentication information needed for the request to be accepted by the Web server as indicated in the HTTP response header.

Syntax

UTL_HTTP.GET_AUTHENTICATION(
   r          IN OUT NOCOPY resp,
   scheme     OUT VARCHAR2,
   realm      OUT VARCHAR2,
   for_proxy  IN BOOLEAN  DEFAULT FALSE);

Parameters

Usage Notes

When a Web client is unaware that a document is protected, at least two HTTP requests are required for the document to be retrieved. In the first HTTP request, the Web client makes the request without supplying required authentication information; so the request is denied. The Web client can determine the authentication information required for the request to be authorized by calling GET_AUTHENTICATION. The Web client makes the second request and supplies the required authentication information with SET_AUTHORIZATION. If the authentication information can be verified by the Web server, the request will succeed and the requested document is returned. Before making the request, if the Web client knows that authentication information is required, it can supply the required authentication information in the first request, thus saving an extra request.

---

GET_BODY_CHARSET Procedure

This procedure retrieves the default character set of the body of all future HTTP requests.

Syntax

UTL_HTTP.GET_BODY_CHARSET (
   charset  OUT NOCOPY VARCHAR2);

Parameters

---

GET_COOKIE_COUNT Function

This function returns the number of cookies maintained either in a request context or in the UTL_HTTP package's session state.

Syntax

UTL_HTTP.GET_COOKIE_COUNT (
   request_context  IN  request_context_key DEFAULT NULL) 
 RETURN PLS_INTEGER;

Parameters

---

GET_COOKIE_SUPPORT Procedure

This procedure retrieves the current cookie support settings.

Syntax

UTL_HTTP.GET_COOKIE_SUPPORT (
   enable                OUT BOOLEAN,
   max_cookies           OUT PLS_INTEGER,
   max_cookies_per_site  OUT PLS_INTEGER);

Parameters

---

GET_COOKIES Function

This function returns all the cookies maintained either in a request context or in the UTL_HTTP package's session state.

Syntax

UTL_HTTP.GET_COOKIES (
   cookies          IN  OUT NOCOPY cookie_table,
   request_context  IN             request_context_key DEFAULT NULL);

Parameters

---

GET_DETAILED_EXCP_SUPPORT Procedure

This procedure checks if the UTL_HTTP package will raise a detailed exception or not.

Syntax

UTL_HTTP.GET_DETAILED_EXCP_SUPPORT (
   enable  OUT BOOLEAN);

Parameters

---

GET_DETAILED_SQLCODE Function

This function retrieves the detailed SQLCODE of the last exception raised.

Syntax

UTL_HTTP.GET_DETAILED_SQLCODE 
RETURN PLS_INTEGER;

---

GET_DETAILED_SQLERRM Function

This function retrieves the detailed SQLERRM of the last exception raised.

Syntax

UTL_HTTP.GET_DETAILED_SQLERRM 
RETURN VARCHAR2;

---

GET_FOLLOW_REDIRECT Procedure

This procedure retrieves the follow-redirect setting in the current session

Syntax

UTL_HTTP.GET_FOLLOW_REDIRECT (
   max_redirects  OUT PLS_INTEGER);

Parameters

---

GET_HEADER Procedure

This procedure returns the n^th HTTP response header name and value returned in the response.

Syntax

UTL_HTTP.GET_HEADER (
   r      IN OUT NOCOPY resp,
   n      IN PLS_INTEGER,
   name   OUT NOCOPY VARCHAR2,
   value  OUT NOCOPY VARCHAR2);

Parameters

Usage Notes

If the response body returned by the remote Web server is encoded in chunked transfer encoding format, the trailer headers that are returned at the end of the response body will be added to the response, and the response header count will be updated. You can retrieve the additional headers after the end of the response body is reached and before you end the response.

---

GET_HEADER_BY_NAME Procedure

This procedure returns the HTTP response header value returned in the response given the name of the header.

Syntax

UTL_HTTP.GET_HEADER_BY_NAME(
   r      IN OUT NOCOPY resp,
   name   IN VARCHAR2,
   value  OUT NOCOPY VARCHAR2,
   n      IN PLS_INTEGER DEFAULT 1);

Parameters

Usage Notes

If the response body returned by the remote Web server is encoded in chunked transfer encoding format, the trailer headers that are returned at the end of the response body will be added to the response, and the response header count will be updated. You can retrieve the additional headers after the end of the response body is reached and before you end the response.

---

GET_HEADER_COUNT Function

This function returns the number of HTTP response headers returned in the response.

Syntax

UTL_HTTP.GET_HEADER_COUNT (
   r  IN OUT NOCOPY resp) 
RETURN PLS_INTEGER;

Parameters

Usage Notes

If the response body returned by the remote Web server is encoded in chunked transfer encoding format, the trailer headers that are returned at the end of the response body will be added to the response, and the response header count will be updated. You can retrieve the additional headers after the end of the response body is reached and before you end the response.

---

GET_PERSISTENT_CONN_COUNT Function

This function returns the number of network connections currently kept persistent by the UTL_HTTP package to the Web servers.

Syntax

UTL_HTTP.GET_PERSISTENT_CONN_COUNT 
RETURN PLS_INTEGER;

Usage Notes

Connections to the same Web server at different TCP/IP ports are counted individually. The host names of the Web servers are identified as specified in the URL of the original HTTP requests. Therefore, fully qualified host names with domain names will be counted differently from the host names without domain names.

---

GET_PERSISTENT_CONN_SUPPORT Procedure

This procedure checks:

• If the persistent connection support is enabled

• Gets the maximum number of persistent connections in the current session

  See Also:

  Session Settings and Session Settings Subprograms

Syntax

UTL_HTTP.GET_PERSISTENT_CONN_SUPPORT (
   enable     OUT BOOLEAN,
   max_conns  OUT PLS_INTEGER);

Parameters

---

GET_PERSISTENT_CONNS Procedure

This procedure returns all the network connections currently kept persistent by the UTL_HTTP package to the Web servers.

Syntax

UTL_HTTP.get_persistent_conns (
   connections  IN OUT NOCOPY connection_table);

Parameters

Usage Notes

Connections to the same Web server at different TCP/IP ports are counted individually. The host names of the Web servers are identified as specified in the URL of the original HTTP requests. Therefore, fully qualified host names with domain names will be counted differently from the host names without domain names.

---

GET_PROXY Procedure

This procedure retrieves the current proxy settings.

Syntax

UTL_HTTP.GET_PROXY (
   proxy             OUT NOCOPY VARCHAR2, 
   no_proxy_domains  OUT NOCOPY VARCHAR2);

Parameters

---

GET_RESPONSE Function

This function reads the HTTP response. When the function returns, the status line and the HTTP response headers have been read and processed. The status code, reason phrase, and the HTTP protocol version are stored in the response record. This function completes the HTTP headers section.

Syntax

UTL_HTTP.GET_RESPONSE (
   r  IN OUT NOCOPY req) 
RETURN resp;

Parameters

---

GET_RESPONSE_ERROR_CHECK Procedure

This procedure checks if the response error check is set or not.

Syntax

UTL_HTTP.GET_RESPONSE_ERROR_CHECK (
   enable  OUT BOOLEAN);

Parameters

---

GET_TRANSFER_TIMEOUT Procedure

This procedure retrieves the default timeout value for all future HTTP requests.

Syntax

UTL_HTTP.GET_TRANSFER_TIMEOUT (
   timeout  OUT PLS_INTEGER);

Parameters

---

READ_LINE Procedure

This procedure reads the HTTP response body in text form until the end of line is reached and returns the output in the caller-supplied buffer. The end of line is as defined in the function read_line of UTL_TCP. The end_of_body exception will be raised if the end of the HTTP response body is reached. Text data is automatically converted from the response body character set to the database character set.

Syntax

UTL_HTTP.READ_LINE(
   r            IN OUT NOCOPY resp,
   data         OUT NOCOPY  VARCHAR2 CHARACTER SET ANY_CS,
   remove_crlf  IN  BOOLEAN DEFAULT FALSE);

Parameters

Usage Notes

The UTL_HTTP package supports HTTP 1.1 chunked transfer-encoding. When the response body is returned in chunked transfer-encoding format as indicated in the response header, the package automatically decodes the chunks and returns the response body in de-chunked format.

If transfer timeout is set in the request of this response, read_line waits for each data packet to be ready to read until timeout occurs. If it occurs, this procedure stops reading and returns all the data read successfully. If no data is read successfully, the transfer_timeout exception is raised. The exception can be handled and the read operation can be retried later.

If a partial multibyte character is found at the end of the response body, read_line stops reading and returns all the complete multibyte characters read successfully. If no complete character is read successfully, the partial_multibyte_char exception is raised. The exception can be handled and the bytes of that partial multibyte character can be read as binary by the read_raw procedure. If a partial multibyte character is seen in the middle of the response body because the remaining bytes of the character have not arrived and read timeout occurs, the transfer_timeout exception is raised instead. The exception can be handled and the read operation can be retried later.

When the Content-Type response header specifies the character set of the response body and the character set is unknown or unsupported by Oracle, the "ORA-01482: unsupported character set" exception is raised if you try to read the response body as text. You can either read the response body as binary using the READ_RAW procedure, or set the character set of the response body explicitly using the SET_BODY_CHARSET procedure and read the response body as text again.

---

READ_RAW Procedure

This procedure reads the HTTP response body in binary form and returns the output in the caller-supplied buffer. The end_of_body exception will be raised if the end of the HTTP response body is reached.

Syntax

UTL_HTTP.READ_RAW(
   r     IN OUT NOCOPY resp,
   data  OUT NOCOPY RAW,
   len   IN PLS_INTEGER DEFAULT NULL);

Parameters

Usage Notes

The UTL_HTTP package supports HTTP 1.1 chunked transfer-encoding. When the response body is returned in chunked transfer-encoding format as indicated in the response header, the package automatically decodes the chunks and returns the response body in de-chunked format.

If transfer timeout is set in the request of this response, read_raw waits for each data packet to be ready to read until timeout occurs. If it occurs, read_raw stops reading and returns all the data read successfully. If no data is read successfully, the transfer_timeout exception is raised. The exception can be handled and the read operation can be retried later.

---

READ_TEXT Procedure

This procedure reads the HTTP response body in text form and returns the output in the caller-supplied buffer. The end_of_body exception will be raised if the end of the HTTP response body is reached. Text data is automatically converted from the response body character set to the database character set.

Syntax

UTL_HTTP.READ_TEXT(
   r     IN OUT NOCOPY resp,
   data  OUT NOCOPY VARCHAR2 CHARACTER SET ANY_CS,
   len   IN PLS_INTEGER DEFAULT NULL);

Parameters

Usage Notes

The UTL_HTTP package supports HTTP 1.1 chunked transfer-encoding. When the response body is returned in chunked transfer-encoding format as indicated in the response header, the package automatically decodes the chunks and returns the response body in de-chunked format.

If transfer timeout is set in the request of this response, read_text waits for each data packet to be ready to read until timeout occurs. If it occurs, this procedure stops reading and returns all the data read successfully. If no data is read successfully, the transfer_timeout exception is raised. The exception can be handled and the read operation can be retried later.

If a partial multibyte character is found at the end of the response body, read_text stops reading and returns all the complete multibyte characters read successfully. If no complete character is read successfully, the partial_multibyte_char exception is raised. The exception can be handled and the bytes of that partial multibyte character can be read as binary by the read_raw procedure. If a partial multibyte character is seen in the middle of the response body because the remaining bytes of the character have not arrived and read timeout occurs, the transfer_timeout exception is raised instead. The exception can be handled and the read operation can be retried later.

When the Content-Type response header specifies the character set of the response body and the character set is unknown or unsupported by Oracle, the "ORA-01482: unsupported character set" exception is raised if you try to read the response body as text. You can either read the response body as binary using the READ_RAW procedure, or set the character set of the response body explicitly using the SET_BODY_CHARSET procedure and read the response body as text again.

---

REQUEST Function

This function returns up to the first 2000 bytes of data retrieved from the given URL. This function can be used directly in SQL queries. The URL may contain the username and password needed to authenticate the request to the server. The format is

scheme://[user[:password]@]host[:port]/[...]

You can define a username/password for the proxy to be specified in the proxy string. The format is

[http://][user[:password]@]host[:port][/]

Syntax

UTL_HTTP.REQUEST (
   url              IN VARCHAR2,
   proxy            IN VARCHAR2 DEFAULT NULL, 
   wallet_path      IN VARCHAR2 DEFAULT NULL,
   wallet_password  IN VARCHAR2 DEFAULT NULL)
RETURN VARCHAR2;

Pragmas

pragma restrict_references (request, wnds, rnds, wnps, rnps);

Parameters

Return Values

The return type is a string of length 2000 or less, which contains up to the first 2000 bytes of the HTML result returned from the HTTP request to the argument URL.

Exceptions

INIT_FAILED
REQUEST_FAILED

Usage Notes

The URL passed as an argument to this function is not examined for illegal characters, for example, spaces, according to URL specification RFC 2396. The caller should escape those characters with the UTL_URL package. See the comments of the package for the list of legal characters in URLs. Note that URLs should consist of US-ASCII characters only. The use of non-US-ASCII characters in a URL is generally unsafe.

Please see the documentation of the function SET_WALLET on the use of an Oracle wallet, which is required for accessing HTTPS Web servers.

Unless response error check is turned on, this function does not raise an exception when a 4xx or 5xx response is received from the Web server. Instead, it returns the formatted error message from the Web server:

<HTML> 
<HEAD> 
<TITLE>Error Message</TITLE> 
</HEAD> 
<BODY> 
<H1>Fatal Error 500</H1> 
Can't Access Document:  http://home.nothing.comm. 
<P> 
<B>Reason:</B> Can't locate remote host:  home.nothing.comm. 
<P> 
<P><HR> 
<ADDRESS><A HREF="http://www.w3.org"> 
CERN-HTTPD3.0A</A></ADDRESS> 
</BODY> 
</HTML> 

Examples

SQL> SELECT UTL_HTTP.REQUEST('http://www.my-company.com/') FROM DUAL;
UTL_HTTP.REQUEST('HTTP://WWW.MY-COMPANY.COM/')                         
<html>
<head><title>My Company Home Page</title>
<!--changed Jan. 16, 19
1 row selected.

If you are behind a firewall, include the proxy parameter. For example, from within the Oracle firewall, where there might be a proxy server named www-proxy.my-company.com:

SQLPLUS> SELECT 
UTL_HTTP.REQUEST('http://www.my-company.com', 'www-proxy.us.my-company.com') FROM DUAL;

---

REQUEST_PIECES Function

This function returns a PL/SQL table of 2000-byte pieces of the data retrieved from the given URL. You can define a username/password for the proxy to be specified in the proxy string. The format is

[http://][user[:password]@]host[:port][/] 

Syntax

TYPE html_pieces IS TABLE OF VARCHAR2(2000) INDEX BY BINARY_INTEGER;

UTL_HTTP.REQUEST_PIECES (
   url             IN VARCHAR2,
   max_pieces      IN NATURAL DEFAULT 32767,
   proxy           IN VARCHAR2 DEFAULT NULL,
   wallet_path     IN VARCHAR2 DEFAULT NULL,
   wallet_password IN VARCHAR2 DEFAULT NULL)
RETURN html_pieces;

Pragmas

PRAGMA RESTRICT_REFERENCES (request_pieces, WNDS, RNDS, WNPS, RNPS);

Parameters

Return Values

REQUEST_PIECES returns a PL/SQL table of type UTL_HTTP.HTML_PIECES. Each element of that PL/SQL table is a string of maximum length 2000. The elements of the PL/SQL table returned by REQUEST_PIECES are successive pieces of the data obtained from the HTTP request to that URL.

Exceptions

INIT_FAILED
REQUEST_FAILED

Usage Notes

The URL passed as an argument to this function will not be examined for illegal characters, for example, spaces, according to URL specification RFC 2396. The caller should escape those characters with the UTL_URL package. See the comments of the package for the list of legal characters in URLs. Note that URLs should consist of US-ASCII characters only. The use of non-US-ASCII characters in a URL is generally unsafe.

Each entry of the PL/SQL table (the "pieces") returned by this function may not be filled to their fullest capacity. The function may start filling the data in the next piece before the previous "piece" is totally full.

Please see the documentation of the function SET_WALLET on the use of an Oracle wallet, which is required for accessing HTTPS Web servers.

Unless response error check is turned on, this function does not raise an exception when a 4xx or 5xx response is received from the Web server. Instead, it returns the formatted error message from the Web server:

<HTML> 
<HEAD> 
<TITLE>Error Message</TITLE> 
</HEAD> 
<BODY> 
<H1>Fatal Error 500</H1> 
Can't Access Document:  http://home.nothing.comm. 
<P> 
<B>Reason:</B> Can't locate remote host:  home.nothing.comm. 
<P> 
<P><HR> 
<ADDRESS><A HREF="http://www.w3.org"> 
CERN-HTTPD3.0A</A></ADDRESS> 
</BODY> 
</HTML>

Examples

SET SERVEROUTPUT ON 

DECLARE 
   x   UTL_HTTP.HTML_PIECES; 
   len PLS_INTEGER; 
BEGIN 
   x := UTL_HTTP.REQUEST_PIECES('http://www.oracle.com/', 100); 
   DBMS_OUTPUT.PUT_LINE(x.count || ' pieces were retrieved.'); 
   DBMS_OUTPUT.PUT_LINE('with total length '); 
   IF x.count < 1 THEN 
      DBMS_OUTPUT.PUT_LINE('0'); 
  ELSE 
   len := 0; 
   FOR i in 1..x.count LOOP 
      len := len + length(x(i)); 
   END LOOP; 
   DBMS_OUTPUT.PUT_LINE(i); 
  END IF; 
END; 
/ 
-- Output 
Statement processed. 
4 pieces were retrieved. 
with total length 
7687 

---

SET_AUTHENTICATION Procedure

This procedure sets HTTP authentication information in the HTTP request header. The Web server needs this information to authorize the request.

Syntax

UTL_HTTP.SET_AUTHENTICATION(
   r         IN OUT NOCOPY req,
   username  IN VARCHAR2,
   password  IN VARCHAR2,
   scheme    IN VARCHAR2 DEFAULT 'Basic',
   for_proxy IN BOOLEAN  DEFAULT FALSE);

Parameters

Usage Notes

The supported authentication schemes are HTTP basic and Amazon S3 authentication.

---

SET_AUTHENTICATION_FROM_WALLET Procedure

This procedure sets the HTTP authentication information in the HTTP request header needed for the request to be authorized by the Web server using the username and password credential stored in the Oracle wallet.

Syntax

UTL_HTTP.SET_AUTHENTICATION_FROM_WALLET(
   r         IN OUT NOCOPY req,
   alias     IN VARCHAR2,
   scheme    IN VARCHAR2 DEFAULT 'Basic',
   for_proxy IN BOOLEAN  DEFAULT FALSE);

Parameters

Usage Notes

• To use the password credentials in a wallet, the UTL_HTTP user must have the use-passwords privilege on the wallet.

• The supported authentication schemes are HTTP basic and Amazon S3 authentication schemes.

Examples

Creating a wallet and entering username and password in the wallet

> mkstore -wrl /oracle/wallets/test_wallet -create
Enter password: ******
Enter password again: ******
> mkstore –wrl /oracle/wallets/test_wallet –createCredential hr-access jsmith 
Your secret/Password is missing in the command line
Enter your secret/Password: ****
Re-enter your secret/Password: ****
Enter wallet password: ******

Granting the use-passwords privilege on the wallet to a user by the database administrator

BEGIN
  DBMS_NETWORK_ACL_ADMIN.CREATE_ACL(
    acl         => 'wallet-acl.xml', 
    description => 'Wallet ACL',
    principal   => 'SCOTT',
    is_grant    => TRUE,
    privilege   => 'use-passwords');
  DBMS_NETWORK_ACL_ADMIN.ASSIGN_WALLET_acl(
      acl          => 'wallet-acl.xml', 
      wallet_path  => 'file: /oracle/wallets/test_wallet');
END;

Using username and password from the wallet

DECLARE
  req  UTL_HTTP.req;
BEGIN
  UTL_HTTP.SET_WALLET(path => 'file:/oracle/wallets/test_wallet');
  req := UTL_HTTP.BEGIN_REQUEST(…);
  UTL_HTTP.SET_AUTHENTICATION_FROM_WALLET(req, 'hr-access');
  …
END;

---

SET_BODY_CHARSET Procedures

This procedure is overloaded. The description of different functionality is located alongside the syntax declarations.

Syntax

Sets the default character set of the body of all future HTTP requests when the media type is text and the character set is not specified in the Content-Type header. Following the HTTP protocol standard specification, if the media type of a request or a response is text, but the character set information is missing in the Content-Type header, the character set of the request or response body should default to ISO-8859-1. A response created for a request inherits the default body character set of the request instead of the body character set of the current session. The default body character set is ISO-8859-1 in a database user session. The default body character set setting affects only future requests and has no effect on existing requests. After a request is created, the body character set can be changed by using the other SET_BODY_CHARSET procedure that operates on a request:

UTL_HTTP.SET_BODY_CHARSET (
   charset  IN VARCHAR2 DEFAULT NULL);

Sets the character set of the request body when the media type is text but the character set is not specified in the Content-Type header. According to the HTTP protocol standard specification, if the media type of a request or a response is "text" but the character set information is missing in the Content-Type header, the character set of the request or response body should default to "ISO-8859-1". Use this procedure to change the default body character set a request inherits from the session default setting:

UTL_HTTP.SET_BODY_CHARSET(
   r        IN OUT NOCOPY req,
   charset  IN VARCHAR2 DEFAULT NULL);

Sets the character set of the response body when the media type is "text" but the character set is not specified in the Content-Type header. For each the HTTP protocol standard specification, if the media type of a request or a response is "text" but the character set information is missing in the Content-Type header, the character set of the request or response body should default to "ISO-8859-1". Use this procedure to change the default body character set a response inherits from the request:

UTL_HTTP.SET_BODY_CHARSET(
   r        IN OUT NOCOPY resp,
   charset  IN VARCHAR2 DEFAULT NULL);

Parameters

---

SET_COOKIE_SUPPORT Procedures

This procedure is overloaded. The description of different functionality is located alongside the syntax declarations.

This procedure

Syntax

Enables or disables support for the HTTP cookies in the request. Use this procedure to change the cookie support setting a request inherits from the session default setting:

UTL_HTTP.SET_COOKIE_SUPPORT(
   r       IN OUT NOCOPY REQ,
   enable  IN BOOLEAN DEFAULT TRUE);

Sets whether or not future HTTP requests will support HTTP cookies, and the maximum number of cookies maintained in the current database user session:

UTL_HTTP.SET_COOKIE_SUPPORT (
   enable       IN BOOLEAN,
   max_cookies  IN PLS_INTEGER DEFAULT 300,
   max_cookies_per_site  IN PLS_INTEGER DEFAULT 20);

Parameters

Usage Notes

If cookie support is enabled for an HTTP request, all cookies saved in the current session and applicable to the request are returned to the Web server in the request in accordance with HTTP cookie specification standards. Cookies set in the response to the request are saved in the current session for return to the Web server in the subsequent requests if cookie support is enabled for those requests. If the cookie support is disabled for an HTTP request, no cookies are returned to the Web server in the request and the cookies set in the response to the request are not saved in the current session, although the Set-Cookie HTTP headers can still be retrieved from the response.

Cookie support is enabled by default for all HTTP requests in a database user session. The default setting of the cookie support (enabled versus disabled) affects only the future requests and has no effect on the existing ones. After your request is created, the cookie support setting may be changed by using the other SET_COOKIE_SUPPORT procedure that operates on a request.

The default maximum number of cookies saved in the current session is 20 for each site and 300 total.

If you lower the maximum total number of cookies or the maximum number of cookies for each Web site, the oldest cookies will be purged first to reduce the number of cookies to the lowered maximum. HTTP cookies saved in the current session last for the duration of the database session only; there is no persistent storage for the cookies. Cookies saved in the current session are not cleared if you disable cookie support.

See "Examples" for how to use GET_COOKIES and ADD_COOKIES to retrieve, save, and restore cookies.

---

SET_DETAILED_EXCP_SUPPORT Procedure

This procedure sets the UTL_HTTP package to raise a detailed exception. By default, UTL_HTTP raises the request_failed exception when an HTTP request fails. Use GET_DETAILED_SQLCODE and GET_DETAILED_SQLEERM for more detailed information about the error.

Syntax

UTL_HTTP.SET_DETAILED_EXCP_SUPPORT (
   enable  IN BOOLEAN DEFAULT FALSE);

Parameters

---

SET_FOLLOW_REDIRECT Procedures

This procedure sets the maximum number of times UTL_HTTP follows the HTTP redirect instruction in the HTTP response to this request, or future requests, in the GET_RESPONSE function.

Syntax

Use this procedure to set the maximum number of redirections:

UTL_HTTP.SET_FOLLOW_REDIRECT (
   max_redirects  IN PLS_INTEGER DEFAULT 3);

Use this procedure to change the maximum number of redirections a request inherits from the session default setting:

UTL_HTTP.SET_FOLLOW_REDIRECT(
   r              IN OUT NOCOPY req,
   max_redirects  IN PLS_INTEGER DEFAULT 3);

Parameters

Usage Notes

If max_redirects is set to a positive number, the GET_RESPONSE Function will automatically follow the redirected URL for the HTTP response status code 301, 302, and 307 for the HTTP HEAD and GET methods, and 303 for all HTTP methods, and retry the HTTP request (the request method will be changed to HTTP GET for the status code 303) at the new location. It follows the redirection until the final, non-redirect location is reached, or an error occurs, or the maximum number of redirections has been reached (to prevent an infinite loop). The URL and method fields in the REQ record will be updated to the last redirected URL and the method used to access the URL. Set the maximum number of redirects to zero to disable automatic redirection.

While it is set not to follow redirect automatically in the current session, it is possible to specify individual HTTP requests to follow redirect instructions the function FOLLOW_REDIRECT and vice versa.

The default maximum number of redirections in a database user session is 3. The default value affects only future requests and has no effect on existing requests.

The SET_FOLLOW_REDIRECT procedure must be called before GET_RESPONSE for any redirection to take effect.

---

SET_HEADER Procedure

This procedure sets an HTTP request header. The request header is sent to the Web server as soon as it is set.

Syntax

UTL_HTTP.SET_HEADER (
   r      IN OUT NOCOPY req,
   name   IN VARCHAR2,
   value  IN VARCHAR2);

Parameters

Usage Notes

Multiple HTTP headers with the same name are allowed in the HTTP protocol standard. Therefore, setting a header does not replace a prior header with the same name.

If the request is made using HTTP 1.1, UTL_HTTP sets the Host header automatically for you.

When you set the Content-Type header with this procedure, UTL_HTTP looks for the character set information in the header value. If the character set information is present, it is set as the character set of the request body. It can be overridden later by using the SET_BODY_CHARSET procedure.

When you set the Transfer-Encoding header with the value chunked, UTL_HTTP automatically encodes the request body written by the WRITE_TEXT, WRITE_LINE and WRITE_RAW procedures. Note that some HTTP-1.1-based Web servers or CGI programs do not support or accept the request body encoding in the HTTP 1.1 chunked transfer-encoding format.

---

SET_PERSISTENT_CONN_SUPPORT Procedure

This procedure enables or disables support for the HTTP 1.1 persistent-connection in the request.

Syntax

UTL_HTTP.SET_PERSISTENT_CONN_SUPPORT(
   r       IN OUT NOCOPY req,
   enable  IN BOOLEAN DEFAULT FALSE);

Parameters

Usage Notes

If the persistent-connection support is enabled for an HTTP request, the package will keep the network connections to a Web server or the proxy server open in the package after the request is completed properly for a subsequent request to the same server to reuse for each HTTP 1.1 protocol specification. With the persistent connection support, subsequent HTTP requests may be completed faster because the network connection latency is avoided. If the persistent-connection support is disabled for a request, the package will always send the HTTP header "Connection: close" automatically in the HTTP request and close the network connection when the request is completed. This setting has no effect on HTTP requests that follows HTTP 1.0 protocol, for which the network connections will always be closed after the requests are completed.

When a request is being made, the package attempts to reuse an existing persistent connection to the target Web server (or proxy server) if one is available. If none is available, a new network connection will be initiated. The persistent-connection support setting for a request affects only whether the network connection should be closed after a request completes.

Use this procedure to change the persistent-connection support setting a request inherits from the session default setting.

Users should note that while the use of persistent connections in UTL_HTTP may reduce the time it takes to fetch multiple Web pages from the same server, it consumes precious system resources (network connections) in the database server. Also, excessive use of persistent connections may reduce the scalability of the database server when too many network connections are kept open in the database server. Network connections should be kept open only if they will be used immediately by subsequent requests and should be closed immediately when they are no longer needed. Set the default persistent connection support as disabled in the session, and enable persistent connection in individual HTTP requests as shown in "Examples".

The default value of the maximum number of persistent connections in a database session is zero. To truly enable persistent connections, you must also set the maximum number of persistent connections to a positive value or no connections will be kept persistent.

Examples

Using SET_PERSISTENT_CONN_SUPPORT in HTTP Requests

DECLARE
  TYPE vc2_table IS TABLE OF VARCHAR2(256) INDEX BY BINARY_INTEGER;
  paths VC2_TABLE;

UTL_HTTP.fetch_pages(paths IN vc2_table) AS
    url_prefix   VARCHAR2(256) := 'http://www.my-company.com/';
    req          UTL_HTTP.REQ;
    resp         UTL_HTTP.RESP;
    data  VARCHAR2(1024);
  BEGIN
    FOR i IN 1..paths.count LOOP
      req := UTL_HTTP.BEGIN_REQUEST(url_prefix || paths(i));
      -- Use persistent connection except for the last request
      IF (i < paths.count) THEN
        UTL_HTTP.SET_PERSISTENT_CONN_SUPPORT(req, TRUE);
      END IF;
      resp := UTL_HTTP.GET_RESPONSE(req);
      BEGIN
        LOOP
          UTL_HTTP.READ_TEXT(resp, data);
          -- do something with the data
        END LOOP;
      EXCEPTION
        WHEN UTL_HTTP.END_OF_BODY THEN
          NULL;
      END;
      UTL_HTTP.END_RESPONSE(resp);
    END LOOP;
  END;

BEGIN
  UTL_HTTP.SET_PERSISTENT_CONN_SUPPORT(FALSE, 1);
  paths(1) := '...';
  paths(2) := '...';
  ...   
  fetch_pages(paths);
END;

---

SET_PROXY Procedure

This procedure sets the proxy to be used for requests of the HTTP or other protocols, excluding those for hosts that belong to the domain specified in no_proxy_domains.no_proxy_domains is a comma-, semi-colon-, or space-separated list of domains or hosts for which HTTP requests should be sent directly to the destination HTTP server instead of going through a proxy server.

Syntax

UTL_HTTP.SET_PROXY (
   proxy             IN VARCHAR2,
   no_proxy_domains  IN VARCHAR2);

Parameters

Usage Notes

The proxy may include an optional TCP/IP port number at which the proxy server listens. The syntax is [http://]host[:port][/], for example, www-proxy.my-company.com:80. If the port is not specified for the proxy, port 80 is assumed.

Optionally, a port number can be specified for each domain or host. If the port number is specified, the no-proxy restriction is only applied to the request at the port of the particular domain or host, for example, corp.my-company.com, eng.my-company.com:80. When no_proxy_domains is NULL and the proxy is set, all requests go through the proxy. When the proxy is not set, UTL_HTTP sends requests to the target Web servers directly.

You can define a username/password for the proxy to be specified in the proxy string. The format is

[http://][user[:password]@]host[:port][/]

If proxy settings are set when the database server instance is started, the proxy settings in the environment variables http_proxy and no_proxy are assumed. Proxy settings set by this procedure override the initial settings.

---

SET_RESPONSE_ERROR_CHECK Procedure

This procedure sets whether or not GET_RESPONSE raises an exception when the Web server returns a status code that indicates an error—a status code in the 4xx or 5xx ranges. For example, when the requested URL is not found in the destination Web server, a 404 (document not found) response status code is returned.

Syntax

UTL_HTTP.SET_RESPONSE_ERROR_CHECK (
   enable  IN BOOLEAN DEFAULT FALSE);

Parameters

Usage Notes

If the status code indicates an error—a 4xx or 5xx code—and this procedure is enabled, GET_RESPONSE will raise the HTTP_CLIENT_ERROR or HTTP_SERVER_ERROR exception. If SET_RESPONSE_ERROR_CHECK is set to FALSE, GET_RESPONSE will not raise an exception when the status code indicates an error.

Response error check is turned off by default.

The GET_RESPONSE function can raise other exceptions when SET_RESPONSE_ERROR_CHECK is set to FALSE.

---

SET_TRANSFER_TIMEOUT Procedure

This procedure sets the default time out value for all future HTTP requests that the UTL_HTTP package should attempt while reading the HTTP response from the Web server or proxy server. This time out value may be used to avoid the PL/SQL programs from being blocked by busy Web servers or heavy network traffic while retrieving Web pages from the Web servers.

Syntax

UTL_HTTP.SET_TRANSFER_TIMEOUT (
   timeout  IN PLS_INTEGER DEFAULT 60);

Parameters

Usage Notes

The default value of the time out is 60 seconds.

---

SET_WALLET Procedure

This procedure sets the Oracle wallet used for all HTTP requests over Secured Socket Layer (SSL), namely HTTPS. When the UTL_HTTP package communicates with an HTTP server over SSL, the HTTP server presents its digital certificate, which is signed by a certificate authority, to the UTL_HTTP package for identification purpose. The Oracle wallet contains the list of certificate authorities that are trusted by the user of the UTL_HTTP package. An Oracle wallet is required to make an HTTPS request.

Syntax

UTL_HTTP.SET_WALLET (
   path      IN VARCHAR2,
   password  IN VARCHAR2 DEFAULT NULL);

Parameters

Usage Notes

To set up an Oracle wallet, use the Oracle Wallet Manager to create a wallet. In order for the HTTPS request to succeed, the certificate authority that signs the certificate of the remote HTTPS Web server must be a trust point set in the wallet.

When a wallet is created, it is populated with a set of well-known certificate authorities as trust points. If the certificate authority that signs the certificate of the remote HTTPS Web server is not among the trust points, or the certificate authority has new root certificates, you should obtain the root certificate of that certificate authority and install it as a trust point in the wallet using Oracle Wallet Manager

---

WRITE_LINE Procedure

This procedure writes a text line in the HTTP request body and ends the line with new-line characters (CRLF as defined in UTL_TCP). As soon as some data is sent as the HTTP request body, the HTTP request headers section is completed. Text data is automatically converted from the database character set to the request body character set.

Syntax

UTL_HTTP.WRITE_LINE(
   r     IN OUT NOCOPY req,
   data  IN VARCHAR2 CHARACTER SET ANY_CS);

Parameters

Usage Notes

An HTTP client must always let the remote Web server know the length of the request body it is sending. If the amount of data is known beforehand, you can set the Content-Length header in the request, where the length of the content is measured in bytes instead of characters. If the length of the request body is not known beforehand, you can send the request body using the HTTP 1.1 chunked transfer-encoding format. The request body is sent in chunks, where the length of each chunk is sent before the chunk is sent. The UTL_HTTP package performs chunked transfer-encoding on the request body transparently when the Transfer-Encoding: chunked header is set. Note that some HTTP-1.1-based Web servers or CGI programs do not support or accept the request body encoding in the HTTP 1.1 chunked transfer-encoding format. See the SET_HEADER procedure for details.

If you send the Content-Length header, you should note that the length specified in the header should be the byte-length of the textual request body after it is converted from the database character set to the request body character set. When either one of the two character sets is a multibyte character set, the precise byte-length of the request body in the request body character set cannot be known beforehand. In this case, you can perform the character set conversion explicitly, determine the byte-length of the results, send the Content-Length header, and the results using the WRITE_RAW procedure to avoid the automatic character set conversion. Or, if the remove Web server or CGI programs allow, you can send the request body using the HTTP 1.1 chunked transfer-encoding format, where UTL_HTTP handles the length of the chunks transparently.

---

WRITE_RAW Procedure

This procedure writes some binary data in the HTTP request body. As soon as some data is sent as the HTTP request body, the HTTP request headers section is completed.

Syntax

UTL_HTTP.WRITE_RAW(
   r     IN OUT NOCOPY REQ,
   data  IN            RAW);

Parameters

Usage Notes

An HTTP client must always let the remote Web server know the length of the request body it is sending. If the amount of data is known beforehand, you can set the Content-Length header in the request, where the length of the content is measured in bytes instead of characters. If the length of the request body is not known beforehand, you can send the request body using the HTTP 1.1 chunked transfer-encoding format. The request body is sent in chunks, where the length of each chunk is sent before the chunk is sent. UTL_HTTP performs chunked transfer-encoding on the request body transparently when the Transfer-Encoding:chunked header is set. Note that some HTTP-1.1-based Web servers or CGI programs do not support or accept the request body encoding in the HTTP 1.1 chunked transfer-encoding format. See the SET_HEADER procedure for details.

---

WRITE_TEXT Procedure

This procedure writes some text data in the HTTP request body. As soon as some data is sent as the HTTP request body, the HTTP request headers section is completed. Text data is automatically converted from the database character set to the request body character set.

Syntax

UTL_HTTP.WRITE_TEXT(
   r     IN OUT NOCOPY REQ,
   data  IN            VARCHAR2 CHARACTER SET ANY_CS);

Parameters

Usage Notes

An HTTP client must always let the remote Web server know the length of the request body it is sending. If the amount of data is known beforehand, you can set the Content-Length header in the request, where the length of the content is measured in bytes instead of characters. If the length of the request body is not known beforehand, you can send the request body using the HTTP 1.1 chunked transfer-encoding format. The request body is sent in chunks, where the length of each chunk is sent before the chunk is sent. UTL_HTTP performs chunked transfer-encoding on the request body transparently when the Transfer-Encoding: chunked header is set. Note that some HTTP-1.1-based Web servers or CGI programs do not support or accept the request body encoding in the HTTP 1.1 chunked transfer-encoding format. See the SET_HEADER procedure for details.

If you send the Content-Length header, you should note that the length specified in the header should be the byte-length of the textual request body after it is converted from the database character set to the request body character set. When either one of the two character sets is a multibyte character set, the precise byte-length of the request body in the request body character set cannot be known beforehand. In this case, you can perform the character set conversion explicitly, determine the byte-length of the results, send the Content-Length header, and the results using the WRITE_RAW procedure to avoid the automatic character set conversion. Or, if the remove Web server or CGI programs allow, you can send the request body using the HTTP 1.1 chunked transfer-encoding format, where UTL_HTTP handles the length of the chunks transparently.