Arduino uno not writing to file

Question

I'd like the arduino to write to a file whenever an ajax call is made. The ajax works, but it doesn't write to the file. All other code inside the ajax handler does execute.

void handle_ajax() {
    int startUrlIndex = HTTP_req.indexOf("button");
    int endUrlIndex = HTTP_req.indexOf(" HTTP");
    String url = HTTP_req.substring(startUrlIndex, endUrlIndex);
    int startButtonIndex = url.indexOf("device-") + 7;// 7 is length of device-, I really just want the number.
    int endButtonIndex = url.indexOf("&");
    String button = url.substring(startButtonIndex, endButtonIndex);
    int startStateIndex = url.indexOf("state=") + 6; // 6 is length of state=, I really just want the number.
    String state = url.substring(startStateIndex);
    int device = button.toInt();
    int newState = state.toInt();
    dim_light(device, newState * 12);
    write_config("", "text");
}

bool write_config(String line, String text) {
    configFile = SD.open("config.ini", FILE_WRITE);

    if (configFile) {
        configFile.write("Dipshit");
    }

    configFile.close();
    Serial.println("Works.");
    return true;
}

Answer 1

You have run out of RAM. Consider moving string literals into flash with thr F() macro.