request->params() returns 0 when used in custom handler

[docentYT]

Platform

ESP32

IDE / Tooling

PlatformIO

What happened?

request->params() returns 0 when used in void handleRequest(AsyncWebServerRequest *request) inside custom handler derived from AsyncWebHandler.

Stack Trace

Minimal Reproductible Example (MRE)

1. Create custom handler:

class CustomHandler: public AsyncWebHandler {
   public:
    CustomHandler() {}
    virtual ~CustomHandler() {}

    bool canHandle(__unused AsyncWebServerRequest *request) const override {
        return request->method() == HTTP_POST;
    }

    void handleRequest(AsyncWebServerRequest *request) {
       if (request->method() == HTTP_POST) {
            int params = request->params();
            Serial.println(params);
        }
    }
};

2. Add a handler to the server:

AsyncWebServer server(80);
int main() {
    server.addHandler(new CustomHandler());
    server.begin();
}

3. Send a POST request with some form data.

I confirm that:

• I have read the documentation.
• I have searched for similar discussions.
• I have searched for similar issues.
• I have looked at the examples.
• I have upgraded to the lasted version of ESPAsyncWebServer (and AsyncTCP for ESP32).

[mathieucarbou]

You miss that in your class:

    bool isRequestHandlerTrivial() const override {
        return false;
    }

This can be used as an optimization to avoid parsing bodies when not needed