Using ajax to send back JSON to Android nanoHTTPd function

Question

Hey all I am trying to POST some json data to my android app via Jquery AJAX and using NanoHTTPd as the web server.

I can seem to call the correct url doing this:

var reqData = JSON.stringify({"AppName": "test", "Enabled": "yes" });

$.ajax('http://10.0.2.16:8765/data', {
   data: reqData,
   dataType: 'json',
   contentType: "application/json",
   async: false,
   type: 'POST',
   success: function (data, textStatus, jqXHR) {
      alert(data);
   },
   error: function (jqXHR, textStatus, errorThrown) {
      alert("error:" + errorThrown + ' ' + reqData);
   }
});

Once I fire off that call above it goes to this java/nanoHTTPd code:

if (uri.equals("/data")) {
   try {
      session.parseBody(new HashMap<String, String>());

      System.out.println( session.getMethod() + " " + session.getParms() );

      String postBody = session.getQueryParameterString();
      String postParameter = session.getParms().get("AppName");

      return newFixedLengthResponse(
          NanoHTTPD.Response.Status.OK, 
          MIME_PLAINTEXT, 
          "It was good!"
      );
   } catch (IOException e) {
      e.printStackTrace();
      return newFixedLengthResponse(Response.Status.NOT_FOUND,"","ERROR");
   } catch (ResponseException e) {
      e.printStackTrace();
      return newFixedLengthResponse(Response.Status.NOT_FOUND,"","ERROR");
   }
}

But I am getting null for the postBody? The System.out.println shows I/System.out: POST {}

The error alert for the ajax error part dispays like this:

What would I be missing here in order to get the post data ajax is sending?

Why are you doing this? If this is an app, there are easier ways to call native code in the same process from Javascript. If this is a unit test and you're mocking the server, you're better off running the http server on the host machine. Running an HTTP server on an Android device is never a good idea, there's always better ways to do it. — Gabe Sechan, Jul 25 '22 at 04:15

score 0 · Accepted Answer · answered Jul 27 '22 at 03:17

Well I figured it out finally. I needed to format my javascript code like this:

var reqData = JSON.stringify({ data: { AppName: "test", Enabled: "yes" }});

$.ajax({
   url        : "http://10.0.2.16:8765/data",
   data       : reqData,
   dataType   : "json",
   crossDomain: true,
   type       : "POST"
   headers    : {
       "Access-Control-Allow-Origin":"*"
   },             
   success    : function (data, textStatus, jqXHR) {
       $("#output").append("data: " + data.status);
   },
   error      : function (jqXHR, textStatus, errorThrown) {
       $("#output").append("error: " + errorThrown);
   }
});

And for the java code side using nanoHTTPd:

if (uri.equals("/data")) {
    try {
        if (session.getMethod().equals(Method.POST)) {
            session.parseBody(new HashMap<String, String>());
            JSONObject mainObject = new JSONObject(session.getQueryParameterString());
            JSONObject uniObject = mainObject.getJSONObject("data");
            String appname = uniObject.getString("AppName");
            String isEnabled = uniObject.getString("Enabled");

            Response R = newFixedLengthResponse(NanoHTTPD.Response.Status.OK, MIME_PLAINTEXT, "{\"status\":\"It was good!\"}");

            R.addHeader("Access-Control-Allow-Origin", "*");
            R.addHeader("Access-Control-Allow-Methods", "POST, GET");
            R.addHeader("Access-Control-Max-Age", "86400");

            return R;
        }
    } catch (IOException e) {
            e.printStackTrace();
            return newFixedLengthResponse(Response.Status.NOT_FOUND,"","ERROR");
    } catch (ResponseException e) {
            e.printStackTrace();
            return newFixedLengthResponse(Response.Status.NOT_FOUND,"","ERROR");
    } catch (JSONException e) {
            e.printStackTrace();
    }
}

return  null;

Using ajax to send back JSON to Android nanoHTTPd function

1 Answers1