I am creating an embedded web server using Mongoose. How can I get the parameters in the URL(looking for something like req.getparameter() in Java)

Question


void fn(struct mg_connection *c, int ev, void *ev_data, void *fn_data)
{

  
  if (ev == MG_EV_HTTP_MSG)
    {    
      struct mg_http_message *hm = (struct mg_http_message *) ev_data;

      if (mg_http_match_uri(hm, "/api/hello"))              // On /api/hello requests,
    {
      char html[1000];

      strcpy(html, "<!DOCTYPE html>"
    "<html>"
    "<head>"
    "</head>"

    "<body>"
        
         "<form action=\"sum\" method = \"GET\">"
            "<label> Number 1</label>"
            "<input type=\"text\" name=\"number1\"> <br>"
            "<label> Number 2</label>"
            "<input type=\"text\" name=\"number2\"><br>"

            "<input type=\"submit\" value=\"Add\">"
        "</form>"
    "</body>"
    "</html>");
      mg_http_reply(c, 200, "Content-Type: text/html\r\n", html);


    }
      else if(mg_http_match_uri(hm, "/api/sum"))
    {
     
      struct mg_str params = hm->body;
      
      double num1, num2;
      if(mg_json_get_num(params, "$[0]", &num1) &&
          mg_json_get_num(params,"$[1]", &num2))
        {         
          mg_http_reply(c, 200, "Content-Type: text/plain\r\n", "result:%g\n", num1 + num2);

        }
      else
        {
          mg_http_reply(c, 500, "NULL", "%s","Parameters Missing");
        }


    }
      else                                                 // For all other URIs,
    {
      mg_http_reply(c, 200, "Content-Type: text/plain\r\n", "%s\n", "Static Content");
      
    }


    }

}


void task1(void)
{

  struct mg_mgr mgr;
  mg_mgr_init(&mgr);                                       // Init manager
  mg_http_listen(&mgr, "http://10.0.0.6:8000", fn, &mgr);  // Setup listener
  for (;;) mg_mgr_poll(&mgr, 1000);                        // Event loop
}

In the code main.c calls task1(). When I type the URL "http://10.0.0.6:8000/api/hello" I am getting the html form. But on submitting the form I am not able to go to "http://10.0.0.6:8000/api/sum".

Tried

else if(mg_http_match_uri(hm, "/api/sum"))
    {
              mg_http_reply(c, 200, "Content-Type: text/plain\r\n", "%s\n", "Static Content");    
    }

and is working fine. I suspect the problem is in getting parameter values. In Java we have request.getparameter() for getting required parameters, Do we have something like that in mongoose.

So please tell me the correct way to get parameter values in a URL.

Answer 1

The problem is that you're submitting a form via GET, eg parameters are passed in the query string (in the URL). And you're getting parameters from the body.

There are two ways to fix your code.

Submit parameters in the HTTP body. To do that, change your form's method from GET to POST .
OR, get parameters from the query string. To do that, change struct mg_str params = hm->body; to struct mg_str params = hm->query;

Hope that helps.

I am creating an embedded web server using Mongoose. How can I get the parameters in the URL(looking for something like req.getparameter() in Java)

Question

1 answers

solution1
0 ACCPTED 2023-01-19 13:40:42

I am creating an embedded web server using Mongoose. How can I get the parameters in the URL(looking for something like req.getparameter() in Java)

Question

1 answers

solution1 0 ACCPTED 2023-01-19 13:40:42

solution1
0 ACCPTED 2023-01-19 13:40:42