This function returns the value of the named HTTP request header field, or NULL if it does not exist or if it is not called
from an HTTP service. It is used when processing an HTTP request via a web service.
Some headers that may be of interest when processing an HTTP web service request include the following:
The cookie value(s), if any, stored by the client, that are associated with the requested URI.
The URL of the page that contained the link to the requested URI.
The name or IP of the host that submitted the request.
The name of the client application.
A list of encodings for the response that are acceptable to the client application.
When used within a stored procedure that is called by an HTTP web service, the following example gets the Cookie header value:
SET cookie_value = HTTP_HEADER( 'Cookie' );
When used within a stored procedure that is called by an HTTP web service, the following example displays the name and values
of the HTTP request headers in the database server messages window.
declare header_name long varchar;
declare header_value long varchar;
set header_name = NULL;
SET header_name = NEXT_HTTP_HEADER( header_name );
IF header_name IS NULL THEN
SET header_value = HTTP_HEADER( header_name );
MESSAGE 'HEADER: ', header_name, '=',
header_value TO CONSOLE;