Router: 4. Request Processing Logic

1. RequestProcessor owerview

The RequestProcessor handles the processing of HTTP requests by coordinating with handlers and server configurations. It validates and normalizes request paths, executes appropriate handlers (e.g., for redirects, CGI, or static files), and generates error responses when needed.

2. Three stages: The snippet focuses on the three stages of processing after path validation and normalization:

void RequestProcessor::processRequest(const Request& req,
                                     const Handler* handler, Response& res, const Location* location) const {
    // validation stage

    // Stage 1: Execute handler if available
    if (handler) {
        if (executeHandler(handler, req, res, location)) {
            return;
        }
    }

    // Stage 2: Fallback: try to serve as static file
    if (tryServeAsStaticFile(req, res, method)) {
        return;
    }

    // Stage 3: All attempts failed - return 404
    router::utils::HttpResponseBuilder::setErrorResponse(res, http::NOT_FOUND_404);
}

Stage 1: call executeHandler(handler, req, res, location)

// Stage 1: Execute handler if available
if (handler) {
    if (executeHandler(handler, req, res, location)) {
        return;
    }
}

Attempts to process the request using the provided Handler (e.g., get, post, cgi, redirect, del), which is a callable object std::function<void(Request&, Response&)> retrieved from the Router’s _routes map.

Stage 2: call tryServeAsStaticFile(req, res, method)

// Stage 2: Fallback: try to serve as static file
if (tryServeAsStaticFile(req, res, method)) {
    return;
}

Attempts to serve the request as a static file (e.g., index.html, image.jpg) if no handler was provided or the handler failed. This is a fallback for requests that don’t match specific routes (e.g., GET requests for files).

Stage 3: call setErrorResponse(res, http::NOT_FOUND_404)

// Stage 3: All attempts failed - return 404
router::utils::HttpResponseBuilder::setErrorResponse(res, http::NOT_FOUND_404);

Generates a 404 Not Found response when both the handler and static file attempts fail, ensuring every request gets a response.