Adding and Removing Headers
The RWHttpClient classes automatically add Host and Content-Length headers when required by the HTTP protocol, but you can also add headers to the request or you can replace the defaults. RWHttpRequest takes an optional RWHttpHeaderList parameter that adds headers to the HTTP request, as shown in Example 16 .
Example 16 – Adding headers
RWHttpDateHeader date("Sun, 06 Nov 1994 08:49:37 GMT"); // 1
RWHttpHeaderList headerlist;
headerlist.addHeader(date); // 2
RWHttpRequest request(RWHttpRequest::Get, "/", headerlist); // 3
//1 Constructs an RWHttpDateHeader from a date string.
//2 Appends the header date to a header list.
//3 Adds headerlist to the RWHttpRequest request. The outgoing HTTP request contains each of the headers in headerlist.
When submitted to an HTTP server through an RWHttpClient connected to www.perforce.com, the request sends the following data:
GET / HTTP/1.1
Date: Sun, 06 Nov 1994 08:49:37 GMT
Host: www.perforce.com
The HTTP package also includes:
Helper classes for formatting and parsing specific HTTP headersA generic header class, RWHttpGenericHeader, for preparing any label-value pair for inclusion as a header in a HTTP requestFor more information about these helper classes, see the SourcePro API Reference Guide.
RWHttpAgent also enables you to specify additional headers. It has two member functions, addCustomHeader() and removeCustomHeader(), that you can use to add headers to outgoing HTTP requests:
Example 17 – Using RWHttpAgent to add headers
RWHttpFromHeader from("user@perforce.com"); // 1
agent.addCustomHeader(from); // 2
//1 Constructs an HTTP From header with the value user@perforce.com.
//2 Adds the header from to the agent.
Any requests using the agent in Example 17 would send an additional header line with each request identifying who the request is from.
You can remove headers using the RWHttpAgent::removeCustomHeader() member function.
NOTE: Once a header is associated with an RWHttpAgent object, all requests using that object send that header. If you add a custom header that should only be sent with a particular request, you need to remove it from the agent before issuing more requests.
