Make an HTTP request with android

Question

I have searched everywhere but I couldn't find my answer, is there a way to make an simple HTTP request? I want to request an PHP page / script on one of my website but I don't want to show the webpage.

If possible I even want to do it in the background (in an BroadcastReceiver)

Answer 1

The most simple way is using the Android lib called Volley

Volley offers the following benefits:

Automatic scheduling of network requests. Multiple concurrent network connections. Transparent disk and memory response caching with standard HTTP cache coherence. Support for request prioritization. Cancellation request API. You can cancel a single request, or you can set blocks or scopes of requests to cancel. Ease of customization, for example, for retry and backoff. Strong ordering that makes it easy to correctly populate your UI with data fetched asynchronously from the network. Debugging and tracing tools.

You can send a http/https request as simple as this:

        // Instantiate the RequestQueue.
        RequestQueue queue = Volley.newRequestQueue(this);
        String url ="http://www.yourapi.com";
        JsonObjectRequest request = new JsonObjectRequest(url, null,
            new Response.Listener<JSONObject>() {
                @Override
                public void onResponse(JSONObject response) {
                    if (null != response) {
                         try {
                             //handle your response
                         } catch (JSONException e) {
                             e.printStackTrace();
                         }
                    }
                }
            }, new Response.ErrorListener() {

            @Override
            public void onErrorResponse(VolleyError error) {

            }
        });
        queue.add(request);

In this case, you needn't consider "running in the background" or "using cache" yourself as all of these has already been done by Volley.

Answer 2

This is the new code for HTTP Get/POST request in android. HTTPClient is depricated and may not be available as it was in my case.

Firstly add the two dependencies in build.gradle:

compile 'org.apache.httpcomponents:httpcore:4.4.1'
compile 'org.apache.httpcomponents:httpclient:4.5'

Then write this code in ASyncTask in doBackground method.

 URL url = new URL("http://localhost:8080/web/get?key=value");
 HttpURLConnection urlConnection = (HttpURLConnection)url.openConnection();
 urlConnection.setRequestMethod("GET");
 int statusCode = urlConnection.getResponseCode();
 if (statusCode ==  200) {
      InputStream it = new BufferedInputStream(urlConnection.getInputStream());
      InputStreamReader read = new InputStreamReader(it);
      BufferedReader buff = new BufferedReader(read);
      StringBuilder dta = new StringBuilder();
      String chunks ;
      while((chunks = buff.readLine()) != null)
      {
         dta.append(chunks);
      }
 }
 else
 {
     //Handle else
 }

Answer 3

As none of the answers described a way to perform requests with OkHttp, which is very popular http client nowadays for Android and Java in general, I am going to provide a simple example:

//get an instance of the client
OkHttpClient client = new OkHttpClient();

//add parameters
HttpUrl.Builder urlBuilder = HttpUrl.parse("https://www.example.com").newBuilder();
urlBuilder.addQueryParameter("query", "stack-overflow");


String url = urlBuilder.build().toString();

//build the request
Request request = new Request.Builder().url(url).build();

//execute
Response response = client.newCall(request).execute();

The clear advantage of this library is that it abstracts us from some low level details, providing more friendly and secure ways to interact with them. The syntax is also simplified and permits to write nice code.

Answer 4

UPDATE

This is a very old answer. I definitely won't recommend Apache's client anymore. Instead use either:

• OkHttp
• HttpUrlConnection

Original Answer

First of all, request a permission to access network, add following to your manifest:

<uses-permission android:name="android.permission.INTERNET" />

Then the easiest way is to use Apache http client bundled with Android:

    HttpClient httpclient = new DefaultHttpClient();
    HttpResponse response = httpclient.execute(new HttpGet(URL));
    StatusLine statusLine = response.getStatusLine();
    if(statusLine.getStatusCode() == HttpStatus.SC_OK){
        ByteArrayOutputStream out = new ByteArrayOutputStream();
        response.getEntity().writeTo(out);
        String responseString = out.toString();
        out.close();
        //..more logic
    } else{
        //Closes the connection.
        response.getEntity().getContent().close();
        throw new IOException(statusLine.getReasonPhrase());
    }

If you want it to run on separate thread I'd recommend extending AsyncTask:

class RequestTask extends AsyncTask<String, String, String>{

    @Override
    protected String doInBackground(String... uri) {
        HttpClient httpclient = new DefaultHttpClient();
        HttpResponse response;
        String responseString = null;
        try {
            response = httpclient.execute(new HttpGet(uri[0]));
            StatusLine statusLine = response.getStatusLine();
            if(statusLine.getStatusCode() == HttpStatus.SC_OK){
                ByteArrayOutputStream out = new ByteArrayOutputStream();
                response.getEntity().writeTo(out);
                responseString = out.toString();
                out.close();
            } else{
                //Closes the connection.
                response.getEntity().getContent().close();
                throw new IOException(statusLine.getReasonPhrase());
            }
        } catch (ClientProtocolException e) {
            //TODO Handle problems..
        } catch (IOException e) {
            //TODO Handle problems..
        }
        return responseString;
    }

    @Override
    protected void onPostExecute(String result) {
        super.onPostExecute(result);
        //Do anything with response..
    }
}

You then can make a request by:

   new RequestTask().execute("http://stackoverflow.com");

Answer 5

private String getToServer(String service) throws IOException {
    HttpGet httpget = new HttpGet(service);
    ResponseHandler<String> responseHandler = new BasicResponseHandler();
    return new DefaultHttpClient().execute(httpget, responseHandler);

}

Regards

Answer 6

For me, the easiest way is using library called Retrofit2

We just need to create an Interface that contain our request method, parameters, and also we can make custom header for each request :

    public interface MyService {

      @GET("users/{user}/repos")
      Call<List<Repo>> listRepos(@Path("user") String user);

      @GET("user")
      Call<UserDetails> getUserDetails(@Header("Authorization") String   credentials);

      @POST("users/new")
      Call<User> createUser(@Body User user);

      @FormUrlEncoded
      @POST("user/edit")
      Call<User> updateUser(@Field("first_name") String first, 
                            @Field("last_name") String last);

      @Multipart
      @PUT("user/photo")
      Call<User> updateUser(@Part("photo") RequestBody photo, 
                            @Part("description") RequestBody description);

      @Headers({
        "Accept: application/vnd.github.v3.full+json",
        "User-Agent: Retrofit-Sample-App"
      })
      @GET("users/{username}")
      Call<User> getUser(@Path("username") String username);    

    }

And the best is, we can do it asynchronously easily using enqueue method