Android Volley does not seem to post HTTP paramete

Question

I've seen a few of these questions on StackOverflow but I can't seem to work out why this code is not working for me.

public void postMethod(final String msg) {

    String url = "http://192.168.1.30/endpoint";

    RequestQueue queue = Volley.newRequestQueue(this);
    StringRequest sr = new StringRequest(Request.Method.POST, url, 
        new Response.Listener<String>() {

        @Override
        public void onResponse(String response) {
            // Handle response...
        }
    }, new Response.ErrorListener() {
        @Override
        public void onErrorResponse(VolleyError error) {
            // Handle error...
        }
    }){
        @Override
        protected Map<String,String> getParams(){
            Map<String,String> params = new HashMap<String, String>();
            params.put("msg", msg);

            return params;
        }

        @Override
        public Map<String, String> getHeaders() throws AuthFailureError {
            Map<String,String> params = new HashMap<String, String>();
            params.put("Content-Type","application/x-www-form-urlencoded");
            return params;
        }
    };
    queue.add(sr);
}

I'm trying to make a POST to my server which is running a python flask application. If I use a program to make HTTP Post requests my server application works fine. It will also work fine if I use an AsyncTask and do what Volley is trying to do for me.

From all of the examples I have seen this code should work fine but my flask server never receives any of the POST parameters. Any ideas what might be happening?

EDIT

Server Code:

from flask import Flask, request, abort
app = Flask(__name__)

@app.route('/endpoint', methods=['POST'])
def echo_msg():
    if request.method == 'POST':
        try:
            msg = request.form['msg']
            return msg

        except KeyError, e:
            # A required parameter is missing.
            abort(400)

Answer 1

Try using the body to pass your parameters, as it's done in JsonObjectRequest.

In JsonObjectRequest you can set a JSONObject as the body of the request. I'd suggest either switching you request type to this type, or overriding the getBody() method of your StringRequest similarly to the way it's done in JsonRequest (line 93).

Answer 2

Hope you've solved the problem. I faced a similar issue while implementing a code similar to yours. The code below actually worked for me. Thanks

public void postMethod(final String msg) {

String url = "http://192.168.1.30/endpoint";

Map<String,String> params = new HashMap<String, String>();
        params.put("msg", msg);

RequestQueue queue = Volley.newRequestQueue(this);
StringRequest sr = new StringRequest(Request.Method.POST, url, new JSONObject (params),
    new Response.Listener<String>() {

    @Override
    public void onResponse(String response) {
        // Handle response...
    }
}, new Response.ErrorListener() {
    @Override
    public void onErrorResponse(VolleyError error) {
        // Handle error...
    }
}){
    @Override
    public Map<String, String> getHeaders() throws AuthFailureError {
        Map<String,String> params = new HashMap<String, String>();
        params.put("Content-Type","application/x-www-form-urlencoded");
        return params;
    }
};
queue.add(sr);

}

Hope this helps anyone who ever faces such a problem. Thank you.

Answer 3

You can use encoded form application/x-www-form-urlencoded only this method

@Override
public String getBodyContentType() {
return "application/x-www-form-urlencoded";
}

Answer 4

You need to override getBodyContentType() and return "application/x-www-form-urlencoded; charset=UTF-8";

StringRequest jsonObjRequest = new StringRequest(Request.Method.POST,
            getResources().getString(R.string.base_url),
            new Response.Listener<String>() {
                @Override
                public void onResponse(String response) {

                    MyFunctions.toastShort(LoginActivity.this, response);
                }
            }, new Response.ErrorListener() {

                @Override
                public void onErrorResponse(VolleyError error) {
                    VolleyLog.d("volley", "Error: " + error.getMessage());
                    error.printStackTrace();
                    MyFunctions.croutonAlert(LoginActivity.this,
                            MyFunctions.parseVolleyError(error));
                    loading.setVisibility(View.GONE);
                }
            }) {

        @Override
        public String getBodyContentType() {
            return "application/x-www-form-urlencoded; charset=UTF-8";
        }

        @Override
        protected Map<String, String> getParams() throws AuthFailureError {
            Map<String, String> params = new HashMap<String, String>();
            params.put("username", etUname.getText().toString().trim());
            params.put("password", etPass.getText().toString().trim());
            return params;
        }

    };

    AppController.getInstance().addToRequestQueue(jsonObjRequest);