WEB CONVERSE

Description

The WEB CONVERSE command does not support chunked transfer-coding for the request, because this requires a sequence of send actions, and the WEB CONVERSE command provides a single send action. If you want to send a chunked message, use the WEB SEND command to send it, and the WEB RECEIVE command to receive it. If the server sends a chunked response, this can be received using the WEB CONVERSE command.

The WEB CONVERSE command cannot be used after the connection to the server has been closed. If you need to test whether the server has requested termination of the connection, use the WEB READ HTTPHEADER command to look for the Connection: close header in the last message from the server.

The WEB CONVERSE command performs a single send action and a single receive action, and it is designed to be used in place of a WEB SEND command and a WEB RECEIVE command. You may use WEB SEND and WEB RECEIVE commands, and WEB CONVERSE commands, in relation to the same connection (that is, with the same SESSTOKEN). However, if you are pipelining requests (that is, sending a sequence of requests without waiting for a response), you must not follow a WEB SEND command with a WEB CONVERSE command. CICS checks at program run time that each WEB SEND command has a subsequent WEB RECEIVE command before any WEB CONVERSE command is issued. For example, if you use the WEB SEND command three times to issue a pipelined sequence of requests, you must use the WEB RECEIVE command three times to receive the responses for those requests, before you can use the WEB CONVERSE command.

Options for sending the HTTP client request

ACTION(cvda)

This option is used to specify how the message should be sent out. The CVDA value is as follows:

EXPECT

Makes CICS send an Expect header along with the request line and headers for the request, and await a 100-Continue response before sending the message body to the server. If a response other than 100-Continue is received, CICS informs the application program and cancels the send. If no response is received after a period of waiting, CICS sends the message body anyway.

The Expect header is not supported by servers below HTTP/1.1. If CICS does not yet know the HTTP version of the server, CICS makes an additional request before sending your request, in order to determine the HTTP version of the server. If the Expect header would not be suitable, CICS sends your request without it.

This option must only be used if your request has a message body.

AUTHENTICATE(cvda)

This option allows you to specify user authentication details (credentials), to control access to restricted data. CVDA values are as follows:

NONE

Specifies that there are no restrictions on accessing this data, therefore no credentials are required. This is the default value for AUTHENTICATE.

BASICAUTH

Specifies that HTTP Basic Authentication credentials are required for this session. These details can be supplied within the command or by using the XWBAUTH global user exit.

CHANNEL(data-value)

Specifies the name of the channel to which the container belongs. The name of the channel can consist of up to 16 alphanumeric characters, including appropriate punctuation. Leading and embedded blanks are not permitted. If the name is less than 16 characters, it is padded with trailing blanks. You can specify the channel name DFHTRANSACTION to use the transaction channel.

If the CONTAINER option is specified, CHANNEL is optional.

If the CHANNEL option is not specified, CICS assumes the current channel.

CHARACTERSET(data-value)

Specifies a character set into which CICS translates the entity body of the item sent by the command before sending. The name of the character set can consist of up to 40 alphanumeric characters, including appropriate punctuation. CICS does not support all the character sets named by IANA. HTML coded character sets lists the IANA character sets that are supported by CICS for code page conversion.

To allow code page conversion of the entity body, the CLIENTCONV option must be set (or allowed to default) to CLICONVERT. If the NOCLICONVERT option is specified, code page conversion will not take place. If conversion is requested and CHARACTERSET is not specified, ISO-8859-1 is used as the default character set.

CLOSESTATUS(cvda)

Specifies whether or not a Connection header with the "close" connection option (Connection: close) should be included on the request. The default is that the header is not included. CVDA values are as follows:

CLOSE

Makes CICS write a Connection: close header for this request. The header notifies the server that the connection should be closed after the server has sent its response to the request. (For a server at HTTP/1.0 level, CICS achieves the same effect by omitting the Connection: Keep-Alive header.) Do not specify this option if you implemented connection pooling in the URIMAP resource for this connection, because a closed connection cannot be pooled for reuse. Only specify this option if this is your final request to the server and you are not using connection pooling.

NOCLOSE

Means that the Connection: close header is not used for this request. If the server is identified as HTTP/1.0, CICS sends a Connection header with the "Keep-Alive" connection option (Connection: Keep-Alive), to notify that a persistent connection is intended.

CONTAINER(data-value)

Specifies the name of the container where the HTTP body is held, before it is sent to the server. The name of the container can consist of up to 16 alphanumeric characters, including appropriate punctuation. Leading and embedded blanks are not permitted. If the name is shorter than 16 characters, it is padded with trailing blanks.

DOCSTATUS(cvda)

Indicates whether the document should be deleted or not deleted during processing of the WEB CONVERSE command. CVDA values are as follows:

DOCDELETE

CICS deletes the document after the document contents are saved for sending. Storage allocated for the document is released immediately. If you make subsequent requests for the document, these generate a TOKENERR response.

NODOCDELETE

CICS does not delete the document during processing of the WEB CONVERSE command. This is the default value for DOCSTATUS.

DOCTOKEN(data-value)

Specifies the 16-byte binary token of a document to be sent as the message body. The document must be created using the CICS Document interface, using the EXEC CICS DOCUMENT CREATE, INSERT, and SET commands. The FROM option provides an alternative way to create a message body.

FROM(data-area)

Specifies a buffer of data which holds the message body. The message body is built by the application program. When you specify the FROM option, use the FROMLENGTH option to specify the length of the buffer of data. The DOCTOKEN option provides an alternative way to create the message body.

There is no set maximum limit for the size of the data area, but its size is limited in practice by storage considerations. Producing an entity body for an HTTP message has more information about storage considerations.

FROMLENGTH(data-area)

Specifies the length, as a fullword binary value, of the buffer of data supplied on the FROM option (the message body). It is important to state this value correctly, because an incorrect data length can cause problems for the recipient of the message.

MEDIATYPE(data-area)

Specifies the data content of any message body provided, for example text/xml. You must specify a 56-byte area for MEDIATYPE. The media type is up to 56 alphanumeric characters, including appropriate punctuation, but not spaces. For more information on media types, see IANA media types and character sets . CICS checks that the format of the media type is correct, but does not check the validity of the media type against the data content. CICS uses this information to produce the Content-Type header for the message.

For requests that require a body, you must specify the MEDIATYPE option. There is no default. However, if the required Content-Type header needs to contain spaces or more than 56 characters, the application can provide it using the WEB WRITE HTTPHEADER command. In this case, do not specify the MEDIATYPE option.

The supplied media type is used to determine whether code page conversion is required under the following circumstances:

• If you are sending a message from a buffer, using the FROM option, and the CLIENTCONV and CHARACTERSET options are not specified.
• If you are sending a message from a document, using the DOCTOKEN option, and the CLIENTCONV and CHARACTERSET options are not specified.
• If you are sending a message from a named container, using the CONTAINER option, and either CLICONVERT is specified, or the CLIENTCONV and CHARACTERSET options are not specified.

If the supplied media type is text, the message is converted. If the supplied media type is nontext, the message is not converted.

The MEDIATYPE option is used for both the sending and receiving functions of the WEB CONVERSE command. If it is specified with a value, the value is used to construct the Content-Type header in the request, and the same field is used to receive the media type of the response that is returned by the server. If it is specified without a value, it is used only to receive the media type of the response.

METHOD(cvda)

Specifies the HTTP method for the request.

The GET, HEAD, POST, PUT, TRACE, OPTIONS, and DELETE methods are supported by this command. However, some HTTP servers, particularly HTTP/1.0 servers, might not implement all of these methods.

HTTP method reference for CICS Web support has more information about the correct use of methods, including the HTTP versions that apply to each.

CICS bars the sending of a message body for methods where it is inappropriate, and requires it for methods where it is appropriate.

CVDA values are as follows:

GET

Obtain a resource from the server. A request body is not allowed.

HEAD

Obtain the HTTP headers, but not the response body, for a resource. A request body is not allowed.

POST

Send data to a server. A request body is required.

PUT

Create or modify a resource on the server. A request body is required.

TRACE

Trace the route of your request to the server. A request body is not allowed.

OPTIONS

Obtain information about the server. A request body is allowed, but there is no defined purpose for the body. If you do use a request body, then you must specify a media type.

DELETE

Delete a resource on the server. A request body is not allowed.

PASSWORD(data-value)

Specifies the password associated with the user ID or logon name that is allowed access to this data. The PASSWORD option is required only if the USERNAME option is used. If the specified password is over 8 characters long, it is treated as a password phrase when it is sent to z/OS® systems.

PASSWORDLEN(data-value)

Specifies the buffer length supplied for the PASSWORD option as a fullword binary variable.

PATH(data-area)

Specifies the path information for the specific resource within the server that the application needs to access.

If the URIMAP option was used to specify an existing URIMAP definition on the WEB OPEN command for this connection, the path specified in that URIMAP definition is the default path for the WEB SEND command. In these circumstances, if you do not specify path information on the WEB SEND command, the path from the URIMAP definition is used. If you specify a different path from that given in the URIMAP definition, this overrides the path from the URIMAP definition.

If the URIMAP option was not used on the WEB OPEN command, there is no default path, and you must provide path information. Path information can be extracted from a known URL using the WEB PARSE URL command.

As an alternative to using the PATH option to provide the path information, you can use the URIMAP option on the WEB CONVERSE command to specify a URIMAP definition from which the path information is taken directly.

PATHLENGTH(data-value)

Specifies the length of the path, as a fullword binary value. If you are providing path information using the PATH option, you need to specify the PATHLENGTH option. Path length information is returned if you use the WEB PARSE URL command to parse a URL.

QUERYSTRING(data-area)

Specifies a query string that is to be supplied to the server as part of the request. You do not need to include a question mark (?) at the beginning of the query string; if you do not include it, CICS supplies it for you automatically when constructing the request. If you include escaped characters in the query string, CICS passes them to the server in their escaped format.

QUERYSTRLEN(data-value)

Specifies the length of the query string supplied on the QUERYSTRING option, as a fullword binary value.

SESSTOKEN(data-value)

Specifies the session token, an 8-byte binary value that uniquely identifies this connection between CICS and a server. This value is returned by a WEB OPEN command for CICS as an HTTP client. Session tokens explains the use of the session token.

URIMAP(data-value)

Specifies the name (up to 8 characters, in mixed case) of a URIMAP definition that provides the path information for the specific resource within the server that the application needs to access. The URIMAP definition must be for CICS as an HTTP client (with USAGE(CLIENT) specified). Its HOST attribute must be the same as the HOST attribute of the URIMAP definition that was specified on the WEB OPEN command for this connection, or the same as the host name specified in the HOST option on the WEB OPEN command for this connection. A URIMAP definition specified on the WEB CONVERSE command applies only to this request.

If the URIMAP option is specified, do not specify the PATH or PATHLENGTH options.

USERNAME(data-value)

Specifies the user ID or logon name that is allowed access to this data. If the USERNAME is specified, you also need to use the PASSWORD option.

USERNAMELEN(data-value)

Specifies the buffer length supplied for the USERNAME option as a fullword binary variable.

Options for receiving the server's response

BODYCHARSET(data-area)

Specifies the character set of the HTTP response body.

The name of the character set can consist of up to 40 alphanumeric characters, including appropriate punctuation.

If the HTTP body is received into an application buffer, the character set returned is as follows:

• If the INTO or SET option is specified, and the HTTP body is converted, CICS returns the character set of the HTTP body before conversion.
• If the INTO or SET option is specified, and the HTTP body is not converted, CICS returns the character set specified in the Content-Type header. If character set information is not available, blanks are returned.

If the HTTP body is received into a named container, the character set returned is as follows:

• If the container is a CHAR container, CICS returns the character set of the encoded data.
• If the container is a BIT container, CICS returns blanks.

If the value returned is more than 40 bytes, the data is truncated. If the value returned is less than 40 bytes, the data is padded to the right with blanks.

INTO(data-area)

Specifies the buffer that is to contain the data being received.

MAXLENGTH(data-value)

Specifies the maximum amount, as a fullword binary value, of data that CICS is to pass to the application. The MAXLENGTH option applies whether the INTO or the SET option is specified for receiving data. If the data has been sent using chunked transfer-coding, CICS assembles the chunks into a single message before passing it to the application, so the MAXLENGTH option applies to the total length of the chunked message, rather than to each individual chunk. The data is measured after any code page conversion has taken place.

If the length of data exceeds the value specified and the NOTRUNCATE option is not specified, the data is truncated to that value, and the remainder of the data is discarded.

If the length of data exceeds the value specified and the NOTRUNCATE option is specified, CICS retains the remaining data and can use it to satisfy subsequent RECEIVE commands.

MEDIATYPE(data-area)

Specifies a 56-character data area to receive the media type (that is, the type of data content) for the body, for example text/xml. See IANA media types and character sets for more information about media types.

The MEDIATYPE option is used for both the sending and receiving functions of the WEB CONVERSE command. If it is specified with a value, the value is used to construct the Content-Type header in the request, and the same field is used to receive the media type of the response that is returned by the server. If it is specified without a value, it is used only to receive the media type of the response.

NOTRUNCATE

Specifies that when the data available exceeds the length requested on the MAXLENGTH option, the remaining data is not to be discarded immediately but is to be retained for retrieval by subsequent RECEIVE commands. (If no further RECEIVE commands are issued, the data is discarded during transaction termination.)

A single RECEIVE command using the SET option and without the MAXLENGTH option receives all the remaining data, whatever its length. Alternatively, you can use a series of RECEIVE commands with the NOTRUNCATE option to receive the remaining data in appropriate chunks. Keep issuing the RECEIVE command until you are no longer getting a LENGERR response. Bear in mind that if you receive less than the length requested on the MAXLENGTH option, this does not necessarily indicate the end of the data; this could happen if CICS needs to avoid returning a partial character at the end of the data.

SET(ptr-ref)

Specifies a pointer reference that is to be set to the address of data received. The pointer reference is valid until the next RECEIVE command or the end of task.

STATUSCODE(data-area)

Specifies a data area to receive the HTTP status code sent by the server. The code is a binary halfword value. Examples are 200 (normal) or 404 (not found). Receiving the status code is optional, but you should always receive and check the status code in the following circumstances:

• If you intend to make an identical request to the server, now or during a future connection.
• If you intend to make further requests to the server using this connection.
• If your application is carrying out any further processing that depends on the information you receive in the response.

HTTP status code reference for CICS Web support has basic guidance on appropriate actions for an application to take in response to the status codes for HTTP/1.1.

STATUSLEN(data-value)

Specifies, as a fullword binary value, the length of the data area to receive any text returned by the server to describe the status code (the STATUSTEXT option). The text is known as a reason phrase. Most reason phrases recommended for HTTP are short, but a data-area length of 256 characters is suggested here, in case the server replaces the recommended reason phrase with more detailed information.

STATUSTEXT(data-area)

Specifies a data area to receive any text returned by the server to describe the status code. The text is known as a reason phrase. Examples are "OK" (accompanying a 200 status code), or "Bad Request" (accompanying a 400 status code). The STATUSLEN option gives the length allowed for the text.

TOCHANNEL(data-value)

Specifies the name of the channel that the container belongs to. The name of the channel can consist of up to 16 alphanumeric characters, including appropriate punctuation. The acceptable characters are A-Z a-z 0-9 $ @ # / % & ? ! : | " = , ; < > . - and _. Leading and embedded blanks are not permitted. If the name is less than 16 characters, it is padded with trailing blanks. If the channel does not exist, it is created. This new channel remains in scope until the link level changes. For more information about channel scope, see The scope of a channel.

If you plan to ship your channels between CICS regions, bear in mind that you should restrict your characters to standard alphanumeric characters (A-Z 0-9 & : = , ; <>. - _) to ensure they are represented in the same way by all EBCDIC code pages.

You can specify the channel name DFHTRANSACTION to use a transaction channel. A transaction channel does not go out of scope when the link level changes: it is always accessible in the transaction. For more information, see Channels and containers.

If the TOCHANNEL option is not specified, then CICS assumes the current channel.

TOCONTAINER(data-value)

Specifies the name of the container where the data is placed. The name of the container can consist of up to 16 alphanumeric characters, including appropriate punctuation. The acceptable characters are A-Z a-z 0-9 $ @ # / % & ? ! : | " = , ; < > . - and _. Leading and embedded blanks are not permitted. If the name is less than 16 characters, it is padded with trailing blanks.

If you plan to ship your containers between CICS regions, bear in mind that you should restrict your characters to standard alphanumeric characters (A-Z 0-9 & : = , ; <>. - _) to ensure they are represented in the same way by all EBCDIC code pages.

Do not use container names starting with "DFH", unless requested to do so by CICS.

TOLENGTH(data-area)

Specifies a fullword binary variable that is set to the amount of data that CICS has returned to the application. Note that this might be slightly less than the limit that you set using the MAXLENGTH option, especially if a double-byte or multi-byte character set is involved, because CICS does not return a partial character at the end of the data.

• If the NOTRUNCATE option is not specified, any further data present in the message is discarded. A LENGERR response with a RESP2 value of 57 is returned if further data was present.
• If the NOTRUNCATE option is specified, any additional data is retained. A LENGERR response with a RESP2 value of 36 is returned if additional data is available. The description for the NOTRUNCATE option tells you what to do in this case.

This option is the equivalent of the LENGTH option on the WEB RECEIVE command.

If you are using the TOCONTAINER option, do not specify the TOLENGTH option.

Options for converting items sent and received

CLIENTCONV(cvda)

Specifies whether or not CICS translates the entity body of the HTTP request before sending, and translates the entity body of the server's response. The default is that the entity body is converted both when the request is sent out, and when the response is received (CLICONVERT).

If you are receiving data into a named container (specified by the TOCONTAINER option), conversion does not take place.

• For the request body, you can use the CHARACTERSET option on this command to specify a character set that is suitable for the server. If conversion is requested (or happens as the default) but you do not specify a character set, the default is that CICS converts the entity body to the ISO-8859-1 character set.
• For the response body, you do not need to specify the character set used by the server. CICS identifies this by examining the Content-Type header of the message. If the header does not provide this information, or if the named character set is not supported by CICS for code page conversion, the ISO-8859-1 character set is used.
• For the application's code page, the default code page for the local CICS region (as specified in the LOCALCCSID system initialization parameter) is used, or an alternative EBCDIC code page that you specified on the WEB OPEN COMMAND.

CVDA values are as follows:

CLICONVERT

CICS converts the entity body of the request into the character set that you identify for the server, and converts the entity body of the response into a code page suitable for the application.

If the TOCONTAINER option is specified, conversion does not take place when the HTTP response is received. Instead, the media type of the HTTP response header determines whether the HTTP body is stored in a BIT or CHAR container. If the media type is a text media type, the body is stored in a CHAR container. If the media type is a non-text media type, the body is stored in a BIT container. If the HTTP response does not contain media type information, the default of text media type is assumed.

NOINCONVERT

CICS converts the entity body of the request into the character set that you identify for the server. However, CICS does not convert the entity body of the response, and it is passed to the application in the character set used by the server.

If the TOCONTAINER option is specified, conversion does not take place when the HTTP response is received. Instead, the media type of the HTTP response header determines whether the HTTP body is stored in a BIT or CHAR container. If the media type is a text media type, the body is stored in a CHAR container. If the media type is a non-text media type, the body is stored in a BIT container. If the HTTP response does not contain media type information, the default of text media type is assumed.

NOOUTCONVERT

CICS does not convert the entity body of the request, and it is sent to the server in the code page used by the application. However, CICS does convert the entity body of the response into a code page suitable for the application.

If the TOCONTAINER option is specified, conversion does not take place when the HTTP response is received. Instead, the media type of the HTTP response header determines whether the HTTP body is stored in a BIT or CHAR container. If the media type is a text media type, the body is stored in a CHAR container. If the media type is a non-text media type, the body is stored in a BIT container. If the HTTP response does not contain media type information, the default of text media type is assumed.

NOCLICONVERT

CICS does not convert the entity body of the request, and it is sent to the server in the code page used by the application. CICS does not convert the entity body of the response, and it is passed to the application in the character set used by the server.

If the TOCONTAINER option is specified, conversion does not take place when the HTTP response is received. Instead, the media type of the HTTP response header determines whether the HTTP body is stored in a BIT or CHAR container. If the media type is a text media type, the body is stored in a CHAR container. If the media type is a non-text media type, the body is stored in a BIT container. If the HTTP response does not contain media type information, the default of text media type is assumed.

Conditions

122 CHANNELERR

RESP2 values are:

1

The name specified by the TOCHANNEL option contains an illegal character or combination of characters.

2

The channel specified on the CHANNEL option could not be found.

110 CONTAINERERR

RESP2 values are:

1

The name specified by the TOCONTAINER option contains an illegal character or combination of characters.

2

The container specified by the CONTAINER option could not be found.

19 NOTOPEN

RESP2 values are:

27

Invalid session token.

16 INVREQ

RESP2 values are:

10

Invalid response header.

11

Action code invalid.

13

Close status invalid.

15

Code page conversion failure.

17

Expect-100 request was rejected by the server.

22

Invalid chunk size.

32

Media type invalid.

33

Method does not support a body.

34

Method requires a body.

41

The connection has been closed.

43

The DOCSTATUS value specified is invalid.

45

The character set specified is invalid.

46

The CLIENTCONV option is invalid.

49

The format of the path option is invalid.

54

The HTTP method is not valid.

63

URIMAP object disabled.

64

Host in URIMAP definition does not match host specified when this session was opened.

67

The content of the response does not conform to HTTP format. The error is generated because there is a syntax problem.

74

The connection has been closed (CICS sent a Connection: close header to the server, or the server may have timed out due to inactivity on this connection).

76

MEDIATYPE option required.

79

Pipelining is in progress. WEB CONVERSE command cannot be used.

80

CHARACTERSET cannot be specified with NOSRVCONVERT.

142

AUTHENTICATE is invalid. The CVDA is not NONE or BASICAUTH.

144

One or more of the Web command parameters is invalid.

145

Either CHANNEL was not specified with CONTAINER, or TOCHANNEL was not specified with TOCONTAINER (and there is no current channel).

146

The named container is a read-only container.

147

Internal conversion error.

150

Conversion requested, but data to be sent is in a DATATYPE BIT container.

157

The HTTP headers in the response are longer than 4k, and CICS is unable to process this HTTP response. The session is unusable, and a WEB CLOSE command is required.

22 LENGERR

RESP2 values are:

5

The PATHLENGTH option value was not greater than zero.

8

The QUERYSTRLEN option value was not greater than zero.

16

Invalid MAXLENGTH.

36

Partial response body returned. Use additional RECEIVEs to obtain remainder.

50

The FROMLENGTH option value was not greater than zero.

57

The response body exceeds the length specified, and the remainder of the body has been discarded.

58

The status text exceeds the length specified.

59

The STATUSLEN option value was not greater than zero.

139

USERNAMELEN is not positive.

140

PASSWORDLEN is not positive.

13 NOTFND

RESP2 values are:

61

The URIMAP object specified was not found.

112 TOKENERR

RESP2 values are:

47

The document token specified is invalid or the document has been deleted.

17 IOERR

RESP2 values are:

42

Socket error.

124 TIMEDOUT

RESP2 values are:

62

Timeout on socket receive.

156

Timeout on socket send.

70 NOTAUTH

RESP2 values are:

100

Path barred by security exit.

110

XWBAUTH error. The XWBAUTH global user exit has issued a UERCERR return code because the XWBAUTH exit is required but cannot return a valid response.

This error code is issued when the following are true: BASICAUTH is specified; USERNAME, PASSWORD, or both are omitted; XWBAUTH is inactive or returns a response of UERCERR.