$Web_Hdr_Parm
Value of request header field
$Web_Hdr_Parm retrieves the value of a request header field.
$Web_Hdr_Parm takes four arguments and returns a string, or null for any error condition.
Syntax
%string = $Web_Hdr_Parm( fieldname, occurrence, [start], [length] )
Syntax terms
| fieldname | The name of the header field, returned by $Web_Hdr_Name. Required argument if occurrence not specified, otherwise optional. |
|---|---|
| occurrence | The occurrence number of a header field, or the occurrence number of the header field matching fieldname, if fieldname is specified. Optional argument if fieldname is specified, otherwise it is required. |
| start | Starting position within the field. Optional argument which defaults to 1. |
| length | Length to return. This is an optional argument which defaults to the length of the header field. The length of a header field can be determined with $Web_Hdr_Len. |
Notes
- Even though "METHOD", "URL", "HTTP", and "ISINDEX" are not named HTTP header parameters, if requested with $web_hdr_parm, the following will be returned for these names:
METHOD The HTTP method associated with the request. URL The URL associated with the request. It will not contain the protocol (http or https) or host name for the request as these are not sent by the browser. The protocol (http vs. https) can be determined by the $Web_Secure function and the host name sent by the browser can usually be retrieved via the "HOST" header parameter. The "URL" value will also not include the query parameters (the part after a question mark) though these can be retrieved via the "ISINDEX" header parameter. ISINDEX The query parameters in the URL. This is the part of the URL that comes after a question mark and typically has a name=value&name=value... format. For URL parameters in this format the $web_isindex/$web_url_parm functions provide an easy way of getting the components of the URL parameters. HTTP The version of HTTP requested by the browser. This is currently almost always going to be "1.1".
Examples
The following example places the value of each header parameter into a User Language %variable of the same name.
* Stash the header values in matching fields. %METHOD = $Web_Hdr_Parm( 'METHOD' ) %URL = $Web_Hdr_Parm( 'URL' ) %VERSION = $Web_Hdr_Parm( 'VERSION' )