Drogon contains the following common filters:

  • drogon::LocalHostFilter: allow HTTP requests from 127.0.0.1 or ::1 only, or return the 404 page.

Of course, users can customize the filter, you need to inherit the HttpFilter class template, the template type is the subclass type, for example, if you want to create a LoginFilter, you could define it as follows:

You need to override the doFilter virtual function of the parent class to implement the filter logic;

This virtual function has three parameters, which are:

  • req: http request;
  • fcb: filter callback function, the function type is void (HttpResponsePtr), when the filter determines that the request is not valid, the specific response is returned to the browser through this callback;

The registration of filters is always accompanied by the registration of controllers.the macros (PATH_ADD, METHOD_ADD, etc.) mentioned earlier can add the name of one or more filters at the end; for example, we change the registration line of the previous getInfo method to the following form:

After the path is successfully matched, the getInfo method will be called only when the following conditions were met:

  1. The request must be an HTTP Get request;
  2. The requesting party must have logged in;

Note: If the filter is defined in the namespace, you must write the namespace completely when you register the filter.

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