How to customize the 404 page for all requests

[MJokar67]

I want to apply a custom general "Not Found" filter that will pass the filter if the path, page, method, or file is not found.

[palonza]

hi @MJokar67,

Create a controller to handle 404 requests for example NotFoundController.cc:

#include <drogon/HttpSimpleController.h>

using namespace drogon;

class NotFoundController : public HttpSimpleController<NotFoundController>
{
public:
    METHOD_LIST_BEGIN
    // Esta macro define el método de solicitud y la ruta a la que se vincula el controlador.
    // En este caso, cualquier ruta se vinculará a este controlador.
    ADD_METHOD_TO(NotFoundController::handleNotFound, "/", Get);
    METHOD_LIST_END

    void handleNotFound(const HttpRequestPtr &req, std::function<void(const HttpResponsePtr &)> &&callback)
    {
        // Aquí puedes personalizar la respuesta 404
        HttpResponsePtr resp = HttpResponse::newNotFoundResponse();
        resp->setBody("<h1>404 Not Found</h1>");
        callback(resp);
    }
};

In the config.json of your project add follow configuration for controller path:

{
  "http": {
    "routers": [
      {
        "name": "api",
        "useFilter": true,
        "filters": [],
        "routes": [
          {
            "path": "/(.*)",
            "controller": "NotFoundController"
          }
        ]
      }
    ]
  }
}

The above configuration states that any request matching the regular expression /(.*) will be sent to the NotFoundController. Make sure the path for the controller matches the setting in the NotFoundController::handleNotFound controller.

I hope it can help you as a guide. Regards, palonza

[MJokar67]

Hi dear @palonza. Thank you for your reply.
I haven't tested your code yet. It seems that your solution has improved the first part of my question to some extent, but I think there must be a better solution.
My question is how can I personalize some events.
For example, if a path is not found or a file does not exist, instead of showing the default 404 error page of Drogon, I will display the customized page. I understood from your solution that even the correct paths end up in this controller.
Is my understanding of your explanation correct?

[an-tao]

    /// Set custom 404 page
    /**
     * @param resp is the object set to 404 response
     * After calling this method, the resp object is returned
     * by the HttpResponse::newNotFoundResponse() method.
     * @param set404 if true, the status code of the resp will
     * be set to 404 automatically
     */
    virtual HttpAppFramework &setCustom404Page(const HttpResponsePtr &resp,
                                               bool set404 = true) = 0;