Change HTTP Attributes (CHGHTTPA)
| Where allowed to run: All environments (*ALL) Threadsafe: No |
Parameters Examples Error messages |
The Change HTTP Attributes (CHGHTTPA) command is used to change the configurable World Wide Web Hypertext Transfer Protocol (HTTP) server attributes. (This server is also known as the IBM HTTP Server).
When you change HTTP attributes using this command, the changes apply to all HTTP servers and HTTP server instances, with the following exceptions:
- Values specified on configuration and administration forms for a particular instance take precedence over the values specified with the CHGHTTPA command. For detailed information on how to use configuration and administration forms go to the HTTP web site at http://www.ibm.com/eserver/iseries/http.
- Values specified as "instance startup values" on the HTTPSVR parameter of the Start TCP/IP Server (STRTCPSVR) command take precedence over values specified anywhere else.
The changes take effect the next time the HTTP server is started either by the Start TCP/IP (STRTCP) command or by the Start TCP/IP Server (STRTCPSVR) command.
Restrictions
- You must have input/output system configuration (*IOSYSCFG) special authority to use this command.
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Parameters
| Keyword | Description | Choices | Notes |
|---|---|---|---|
| AUTOSTART | Autostart | *YES, *NO, *SAME | Optional |
| NBRSVR | Number of server threads | Element list | Optional |
| Element 1: Minimum | 1-9999, *SAME, *DFT | ||
| Element 2: Maximum | 1-9999, *SAME, *DFT, *NOMAX | ||
| CCSID | Coded character set identifier | 1-65533, *SAME, *DFT | Optional |
| TBLHTTPOUT | Server mapping tables | Single values: *SAME, *CCSID, *DFT Other values: Element list |
Optional |
| Element 1: Outgoing EBCDIC/ASCII table | Qualified object name | ||
| Qualifier 1: Outgoing EBCDIC/ASCII table | Name | ||
| Qualifier 2: Library | Name, *LIBL, *CURLIB | ||
| TBLHTTPIN | Single values: *SAME, *CCSID, *DFT Other values: Element list |
Optional | |
| Element 1: Incoming ASCII/EBCDIC table | Qualified object name | ||
| Qualifier 1: Incoming ASCII/EBCDIC table | Name | ||
| Qualifier 2: Library | Name, *LIBL, *CURLIB |
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Autostart (AUTOSTART)
Specifies whether to automatically start the HTTP server when TCP/IP is started by the STRTCP command. When HTTP is started by the STRTCPSVR command, the AUTOSTART parameter is ignored and the HTTP server is started regardless of the value of this parameter. If STRTCPSVR *HTTP is specified, and the HTTP server is already running, then the start request is denied.
- *SAME
- The AUTOSTART value does not change if it was previously set. Otherwise, *NO is used.
- *NO
- Do not start the HTTP server when the STRTCP command is issued. If you do not intend to use HTTP, set this parameter to *NO.
- *YES
- Start the HTTP server when the STRTCP command is issued.
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Number of server threads (NBRSVR)
Specifies the minimum and maximum number of HTTP server threads to start when HTTP is started by either the Start TCP/IP (STRTCP) command or the Start TCP/IP Server (STRTCPSVR) command.
Note: The value specified for the minimum number of server threads is ignored. The value has been left on the command for compatibility reasons.
Specifying a value of *NOMAX for the maximum number of server threads could have a negative impact on system performance because it affects all HTTP servers that do not explicitly specify a ThreadsPerChild directive. Be very cautious before specifying a value of *NOMAX.
The maximum number of server threads value is used as the default setting for the HTTP Server ThreadsPerChild directive. This value affects all HTTP servers that do not have a ThreadsPerChild configuration directive specified. A ThreadsPerChild directive specified in the HTTP server configuration file, or as a start up value, overrides this server attribute.
See the HTTP server documentation on the ThreadsPerChild directive for more information regarding the maximum number of server threads.
Element 1: Minimum
- *SAME
- The minimum number of server threads that was previously set does not change. Otherwise, 10 is used.
- *DFT
- The minimum number of server threads is set to the default value of 10.
- 1-9999
- Specify the minimum number of server threads requested to start.
Element 2: Maximum
- *SAME
- The maximum number of server threads previously set does not change. Otherwise, 40 is used.
- *NOMAX
- The *NOMAX option for the maximum number of server threads has been left on the command for compatibility reasons. Specifying a value of *NOMAX uses a maximum number of server threads value of 9999.
- *DFT
- The maximum number of server threads is set to the default value of 40. If you allow this parameter to default, the minimum number of server threads specified cannot be greater than 40.
- 1-9999
- Specify the maximum number of server threads that are allowed to start. This value must be greater than the value specified for the first element of this parameter.
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Coded character set identifier (CCSID)
If the character set and code page are not identified in the MIME header from the World Wide Web (WWW) browser, this value is used to determine the ASCII coded-character set identifier (CCSID) value to be used for translations when doing ASCII-to-EBCDIC and EBCDIC-to-ASCII mapping. Mapping is determined using the MIME header values or the specified ASCII CCSID and the EBCDIC default CCSID of the job.
Outgoing and incoming mapping can optionally be done with mapping tables defined in the TBLHTTPOUT and TBLHTTPIN parameters. Normally the TBLHTTPOUT and TBLHTTPIN parameters are set to the default of *CCSID or *DFT, with both indicating that the value used in the CCSID parameter is used for mapping.
If a mapping table is to be used for outgoing mapping, a table object can be specified in the TBLHTTPOUT parameter. Then this table object is used for outgoing mapping instead of the CCSID value.
Incoming mapping can be changed to use a mapping table in the same manner by specifying a table object in the TBLHTTPIN parameter. This mapping table then overrides the specified CCSID value and is used for incoming mapping.
- *SAME
- The CCSID value that was previously set does not change; otherwise, 00819 (ISO 8859-1 8-bit ASCII) is used.
- *DFT
- The CCSID value is 00819 (ISO 8859-1 8-bit ASCII).
- 1-65533
- Specify the CCSID to be used. This value is validated to ensure a valid ASCII CCSID has been requested.
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Server mapping tables (TBLHTTPOUT)
Specifies the table object that is to be used to map all outgoing server data in HTTP. Outgoing server data is mapped from EBCDIC to ASCII.
If a table object is specified for the TBLHTTPOUT parameter, the table object is used for outgoing mapping. Otherwise, the CCSID parameter is used to determine outgoing mapping.
Single values
- *SAME
- The TBLHTTPOUT value does not change if it was previously set; otherwise, *CCSID is used.
- *CCSID
- The CCSID parameter is used to determine outgoing mapping.
- *DFT
- The CCSID parameter is used to determine outgoing mapping.
Qualifier 1: Outgoing EBCDIC/ASCII table
- name
- Specify the name of the table object to be used for mapping the outgoing HTTP server data.
Qualifier 2: Library
- *LIBL
- All libraries in the job's library list are searched until the first match is found.
- *CURLIB
- The current library for the job is searched. If no library is specified as the current library for the job, the QGPL library is used.
- name
- Specify the name of the library to be searched.
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Library (TBLHTTPIN)
Specifies the table object that is used to map all incoming server data in HTTP. Incoming server data is mapped from ASCII to EBCDIC.
If a table object is specified for the TBLHTTPIN parameter, the table object is used for incoming mapping. Otherwise, the CCSID parameter is used to determine incoming mapping.
Single values
- *SAME
- The TBLHTTPIN value does not change if it was previously set; otherwise, *CCSID is used.
- *CCSID
- The CCSID parameter is used to determine incoming mapping.
- *DFT
- The CCSID parameter is used to determine incoming mapping.
Qualifier 1: Incoming ASCII/EBCDIC table
- name
- Specify the name of the table object to be used for mapping the incoming HTTP server data.
Qualifier 2: Library
- *LIBL
- All libraries in the job's library list are searched until the first match is found.
- *CURLIB
- The current library for the job is searched. If no library is specified as the current library for the job, the QGPL library is used.
- name
- Specify the name of the library to be searched.
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Examples
Example 1: Changing the HTTP Attributes to Automatically Start the Server When You Use the Start TCP/IP (STRTCP) CL Command.
CHGHTTPA AUTOSTART(*YES)
This command indicates that the server will automatically start up the next time that you use the STRTCP command. Server instances will start automatically if they do not have AUTOSTART overridden.
Example 2: Changing the Maximum Number of Server Threads.
CHGHTTPA NBRSVR(10 50)
This command indicates that a maximum of 50 server threads will be allowed to start to handle incoming HTTP requests. Note that the minimum number of server threads is allowed to be specified, but is ignored.
Example 3: Using the Server Mapping Tables
CHGHTTPA TBLHTTPOUT(*LIBL/TSTHTTPO)
TBLHTTPIN(*LIBL/TSTHTTPI)
This command indicates that the next time the server is started, the server will have the following characteristics:
- The ASCII-to-EBCDIC and EBCDIC-to-ASCII conversion is done using the outgoing and incoming mapping tables, rather than with a CCSID value.
- The server uses a copy of the information that you find in the TSTHTTPO table object for mapping outgoing data in HTTP. The table object is found by using the library list for the thread.
- The server uses a copy of the information that you find in the TSTHTTPI table object for mapping incoming data in HTTP. The table object is found by using the library list for the thread.
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