GoAhead WebServer URL Handlers

The GoAhead WebServer implements a flexible URL handler where the semantics of a URL may be interpreted at run-time by multiple URL handlers. URL handlers are given the URL and the option of accepting it for processing. If a handler accepts the URL, no further URL handlers will be called.

A URL handler specifies a path prefix, a processing function and a order option. The path prefix nominates the URLs of interest. Any URL that matches this URL prefix is given to the handler for processing. A match is deemed to occur if the URL exactly matches the prefix for the length of the prefix. If more than one handler matches, the longest matching URL handler will be called first and so-on in decreasing length order. For example, the following all match the prefix "/my":

/myCar?model= ford
/myPath/model/ford
/my/car/model/ford

A URL handler may supply the empty URL prefix "" and thus match all URLs. The order option enables a URL handler to specify that it wishes to be processed first or last regardless of the URL match. This is specified by the flagsparameter to the websUrlHandlerDefine API call. If multiple handlers may specify these flags, the order of evaluation for the handlers specifiying the same flag is undefined.

A URL handler is a C procedure according to the following prototype:

int myHandler(webs_t wp, char_t *url, char_t *path,
     char_t *query);

The url parameter contains the entire URL. The path parameter holds the URL portion after the hostname and port number. The query parameter holds any optional query. The URL handler must return 1 if it elects to process the URL. Otherwise it should return 0 to indicate that a later URL handler should process the URL.

A URL handler may modify the settings of a request but delay handling of the URL to another handler. The security handler is one example of this. Request settings, form variables and URL details may be modified by a handler to affect the processing by other handlers.

GoAhead WebServer URL Handlers

See Also