ESP32 httpd: Header fields are too long for the server to interpret

Question

I want to stream to WebView inside a Anrdoid App.

My code is:

WebView cam = (WebView) findViewById(R.id.Cam);
        cam.getSettings().setLoadWithOverviewMode(true);
        cam.getSettings().setUseWideViewPort(true);
        cam.getSettings().setBuiltInZoomControls(true);
        cam.getSettings().setPluginState(WebSettings.PluginState.ON);
        cam.getSettings().setPluginState(WebSettings.PluginState.ON);
        cam.loadUrl("http://192.168.0.10");

It works in emulator but if I install the App at smartphone it doesnt work. I get an error

Header fields are too long for the server to interpret

How do get rid of this error?

Answer 1

Edit sdkconfig and increase CONFIG_HTTPD_MAX_REQ_HDR_LEN e.g. like this:

CONFIG_HTTPD_MAX_REQ_HDR_LEN=1024

The default is 512. Don't set it too high to avoid wasting RAM, remember that ESP32 doesn't have much RAM.

Also it's best to set the User-Agent header in your WebView, otherwise a system-default User-Agent will be used, which can be longer or shorter depending on the actual Android device.

    cam.getSettings().setUserAgentString("Mozilla/5.0 (my app)");

The above might just fit within the default 512 bytes for the request length.