Request-Handling Process Overview

When Web Server first starts up, it performs some initialization tasks and then waits for an HTTP request from a client (such as a browser). When the server receives a request, it first selects a virtual server. The {{obj.conf}} file of the selected virtual server determines how the server handles a request.

The {{obj.conf}} file contains a series of instructions known as directives that tell the server what to do at each stage in the request-handling process. These directives are grouped inside {{Object}} tags. Each directive invokes a function with one or more arguments.

Each directive applies to a specific stage in the request-handling process. For example, a directive that applies during the authorization stage in the request-handling process is an {{AuthTrans}} directive.

h3. Stages in the Request-Handling Process

|| Stages || Description ||
|{{AuthTrans}} (authorization translation) |Verify the authorization information (such as name and password) sent in the request. |
|{{NameTrans}} (name translation) |Translate the logical URI into a local file system path. |
|{{PathCheck}} (path checking) |Check the local file system path for validity and check if the requestor has access privileges to the requested resource on the file system. |
|{{ObjectType}} (object typing) |Determine the Multipurpose Internet Mail Encoding (MIME) type of the requested resource (for example, {{text/html}}, {{image/gif}}, and so on), and establish other resource-specific settings. |
|{{Input}} (prepare to read input) |Select filters that will process incoming request data read by the {{Service}} step. |
|{{Output}} (prepare to send output) |Select filters that will process outgoing response data generated by the {{Service}} step. |
|{{Route}} (request routing) |Select the server to service the request. |
|{{Service}} (generate the response) |Generate and return the response to the client. |
|{{AddLog}} (adding log entries) |Add entries to log files. |
|{{Error}} (error handling) |Send an error message to the client and exit processing. This step is executed only if an error occurs in the previous steps. |