I have searched everywhere but I couldn't find my answer, is there a way to make a simple HTTP request? I want to request a PHP page / script on one of my websites but I don't want to show the webpage.
If possible I even want to do it in the background (in a BroadcastReceiver)
UPDATE
This is a very old answer. I definitely won't recommend Apache's client anymore. Instead use either:
Retrofit
OkHttp
Volley
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");
unless you have an explicit reason to choose the Apache HttpClient, you should prefer java.net.URLConnection. you can find plenty of examples of how to use it on the web.
we've also improved the Android documentation since your original post: http://developer.android.com/reference/java/net/HttpURLConnection.html
and we've talked about the trade-offs on the official blog: http://android-developers.blogspot.com/2011/09/androids-http-clients.html
Note: The Apache HTTP Client bundled with Android is now deprecated in favor of HttpURLConnection. Please see the Android Developers Blog for more details.
Add <uses-permission android:name="android.permission.INTERNET" /> to your manifest.
You would then retrieve a web page like so:
URL url = new URL("http://www.android.com/");
HttpURLConnection urlConnection = (HttpURLConnection) url.openConnection();
try {
InputStream in = new BufferedInputStream(urlConnection.getInputStream());
readStream(in);
}
finally {
urlConnection.disconnect();
}
I also suggest running it on a separate thread:
class RequestTask extends AsyncTask<String, String, String>{
#Override
protected String doInBackground(String... uri) {
String responseString = null;
try {
URL url = new URL(myurl);
HttpURLConnection conn = (HttpURLConnection) url.openConnection();
if(conn.getResponseCode() == HttpsURLConnection.HTTP_OK){
// Do normal input or output stream reading
}
else {
response = "FAILED"; // See documentation for more info on response handling
}
} 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..
}
}
See the documentation for more information on response handling and POST requests.
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.
Use Volley as suggested above. Add following into build.gradle (Module: app)
implementation 'com.android.volley:volley:1.1.1'
Add following into AndroidManifest.xml:
<uses-permission android:name="android.permission.INTERNET" />
And add following to you Activity code:
public void httpCall(String url) {
RequestQueue queue = Volley.newRequestQueue(this);
StringRequest stringRequest = new StringRequest(Request.Method.GET, url,
new Response.Listener<String>() {
#Override
public void onResponse(String response) {
// enjoy your response
}
}, new Response.ErrorListener() {
#Override
public void onErrorResponse(VolleyError error) {
// enjoy your error status
}
});
queue.add(stringRequest);
}
It replaces http client and it is very simple.
private String getToServer(String service) throws IOException {
HttpGet httpget = new HttpGet(service);
ResponseHandler<String> responseHandler = new BasicResponseHandler();
return new DefaultHttpClient().execute(httpget, responseHandler);
}
Regards
With a thread:
private class LoadingThread extends Thread {
Handler handler;
LoadingThread(Handler h) {
handler = h;
}
#Override
public void run() {
Message m = handler.obtainMessage();
try {
BufferedReader in =
new BufferedReader(new InputStreamReader(url.openStream()));
String page = "";
String inLine;
while ((inLine = in.readLine()) != null) {
page += inLine;
}
in.close();
Bundle b = new Bundle();
b.putString("result", page);
m.setData(b);
} catch (MalformedURLException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
handler.sendMessage(m);
}
}
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.
I made this for a webservice to requerst on URL, using a Gson lib:
Client:
public EstabelecimentoList getListaEstabelecimentoPorPromocao(){
EstabelecimentoList estabelecimentoList = new EstabelecimentoList();
try{
URL url = new URL("http://" + Conexao.getSERVIDOR()+ "/cardapio.online/rest/recursos/busca_estabelecimento_promocao_android");
HttpURLConnection con = (HttpURLConnection) url.openConnection();
if (con.getResponseCode() != 200) {
throw new RuntimeException("HTTP error code : "+ con.getResponseCode());
}
BufferedReader br = new BufferedReader(new InputStreamReader((con.getInputStream())));
estabelecimentoList = new Gson().fromJson(br, EstabelecimentoList.class);
con.disconnect();
} catch (IOException e) {
e.printStackTrace();
}
return estabelecimentoList;
}
Look at this awesome new library which is available via gradle :)
build.gradle: compile 'com.apptakk.http_request:http-request:0.1.2'
Usage:
new HttpRequestTask(
new HttpRequest("http://httpbin.org/post", HttpRequest.POST, "{ \"some\": \"data\" }"),
new HttpRequest.Handler() {
#Override
public void response(HttpResponse response) {
if (response.code == 200) {
Log.d(this.getClass().toString(), "Request successful!");
} else {
Log.e(this.getClass().toString(), "Request unsuccessful: " + response);
}
}
}).execute();
https://github.com/erf/http-request
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
}
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
I deploy the same war with jetty, a local tomcat and a remote tomcat.
For the same request :
With jetty and local tomcat everything is fine and I get a full response.
With remote tomcat response status is 200 but with empty body.
I don't know where to look at and why this difference.
If you can provide me another way to query an URL (which can be public or local to the network where the app is deployed), I'll be glad to hear it.
The code
private void get(String proxiedURIString, HttpServletResponse resp) throws IOException, ServletException {
HttpURLConnection connection = getHttpURLConnection(proxiedURIString, resp);
fillHeaders(resp, connection);
try {
IOUtils.copy(connection.getInputStream(), resp.getOutputStream());
} catch (IOException e) {
String message = String.format("Unable to parse response : %s", proxiedURIString);
LOGGER.error(message);
resp.sendError(500, message);
} finally {
resp.getOutputStream().flush();
connection.disconnect();
}
LOGGER.info("Successfully proxied URI : {}", proxiedURIString);
}
private static void fillHeaders(HttpServletResponse resp, HttpURLConnection connection) {
Map<String, List<String>> headers = connection.getHeaderFields();
for (String header : headers.keySet()) {
if(header == null || headers.get(header) == null) {
continue;
}
for (String headerValue : headers.get(header)) {
if(headerValue == null) {
continue;
}
resp.addHeader(header, headerValue);
}
}
}
private static HttpURLConnection getHttpURLConnection(String proxiedURIString, HttpServletResponse resp) throws ServletException, IOException {
HttpURLConnection connection = null;
try {
URL url = new URL(proxiedURIString);
connection = (HttpURLConnection) url.openConnection();
} catch (IOException e) {
String message = String.format("Unable to contact : %s", proxiedURIString);
LOGGER.error(message);
resp.sendError(404, message);
}
return connection;
}
Edit: Edit the code to only work with input/output streams. Also to provide further information, I contact the remote tomcat through an apache http server and the response body is big.
Edit2: Futher information. I mapped the proxied URI with one sending much less data and this time I get a full answer for every configuration.
I have a string that I am trying to send to a Parse.com cloud function. According to the REST API documentation (https://www.parse.com/docs/rest#general-requests), it must be in json format, so I made it into a json object and converted it to a string to append to the end of the http request url.
JSONObject jsonParam = new JSONObject();
jsonParam.put("emailId", emailId);
String urlParameters = jsonParam.toString();
Then I send the request as so, in my attempt to match their cURL code example as Java code:
con.setDoOutput(true);
DataOutputStream wr = null;
wr = new DataOutputStream(con.getOutputStream());
wr.writeBytes(urlParameters);
wr.flush();
wr.close();
Nonetheless, I receive a returned error code of 400 with error message "Bad Request", which I believe to be caused by unrecognizable parameters being sent to the cloud function. None of the other errors in my code trigger. Yet I verified through console logs that emailId is a normal string and the resulting JSON object, as well as its .toString() equivalent comes out as a proper string reading of a JSON object. Also this worked for another function I have in which I am creating an object in my Parse database. So why would it not work here?
Here is the full function for reference and context:
private void sendEmailWithParse(String emailId) throws IOException {
String url = "https://api.parse.com/1/functions/sendEmailNow";
URL obj = new URL(url);
HttpsURLConnection con = null;
try {
con = (HttpsURLConnection) obj.openConnection();
} catch (IOException e) {
System.out.println("Failed to connect to http link");
e.printStackTrace();
}
//add request header
try {
con.setRequestMethod("POST");
} catch (ProtocolException e) {
System.out.println("Failed to set to POST");
e.printStackTrace();
}
con.setRequestProperty("X-Parse-Application-Id", "**************************************");
con.setRequestProperty("X-Parse-REST-API-Key", "************************************************");
con.setRequestProperty("Content-Type", "application/json");
JSONObject jsonParam = new JSONObject();
jsonParam.put("emailId", emailId);
System.out.println("parameter being sent to cloud function: " + jsonParam);
System.out.println("parameter being sent to cloud function as string: " + jsonParam.toString());
String urlParameters = jsonParam.toString();
// Send post request
con.setDoOutput(true);
DataOutputStream wr = null;
try {
wr = new DataOutputStream(con.getOutputStream());
} catch (IOException e1) {
System.out.println("Failed to get output stream");
e1.printStackTrace();
}
try {
wr.writeBytes(urlParameters);
} catch (IOException e) {
System.out.println("Failed to connect to send over Parse object as parameter");
e.printStackTrace();
}
try {
wr.flush();
} catch (IOException e) {
e.printStackTrace();
}
try {
wr.close();
} catch (IOException e) {
System.out.println("Failed to connect to close datastream connection");
e.printStackTrace();
}
int responseCode = 0;
try {
responseCode = con.getResponseCode();
} catch (IOException e) {
System.out.println("Failed to connect to get response code");
e.printStackTrace();
}
System.out.println("\nSending 'POST' request to URL : " + url);
System.out.println("Post parameters : " + urlParameters);
System.out.println("Response Code : " + responseCode);
System.out.println("Response message: " + con.getResponseMessage());
}
I solved the problem by using the HttpRequest external library. It gave me better control of the request and made for easier debugging of the problem. The server was receiving the request just fine, the problem was with the JSON encoding. Rather than putting the JSON object as a parameter in the request, I inserted it into the body of the http request and encoded it in UTF-8.
In the end, this is the code that worked:
String url = "https://api.parse.com/1/functions/sendEmailNow";
URL obj = new URL(url);
//Attempt to use HttpRequest to send post request to parse cloud
HttpRequest request = HttpRequest.post(obj).contentType("application/json");
request.header("X-Parse-Application-Id", "**************************");
request.header("X-Parse-REST-API-Key", "********************");
JSONObject jsonParam = new JSONObject();
jsonParam.put("emailId", emailId);
request.send(jsonParam.toString().getBytes("UTF8"));
if (request.ok())
System.out.println("HttpRequest WORKED");
else
System.out.println("HttpRequest FAILED " + request.code() + request.body());
I try to learn rest webservice in java. I wrote a server jboss. I can get a list from server but I can't post a object to server. I try to post with restclient. This is successful. First block is get, second block is post and final block is request from client. Client project is normal java project. It is not web, jboss or it has not like jackson lib.
How can I post object as JSON for adding from Jax RS Client to server?
#GET
#Path("/categories")
#Produces(MediaType.APPLICATION_JSON)
public List<CategoryVO> getAllCategories(){
List<Category> cats = entityManager.createQuery("select c from Category c").getResultList();
ArrayList<CategoryVO> results = new ArrayList<CategoryVO>();
for (Category c : cats) {
results.add(new CategoryVO(c.getTitle(), c.getId()));
}
return results;
}
#POST
#Path("/categoryAdd")
#Consumes(MediaType.APPLICATION_JSON)
public void saveCategory(CategoryVO catVO){
System.out.println("Save Method is running");
Category cat = new Category(catVO.getTitle());
entityManager.persist(cat);
}
public static void main(String[] args) {
URL url = null;
HttpURLConnection con;
try {
url = new URL(
"http://localhost:8080/RestWS/rest/NetasRestWS/categories");
con = (HttpURLConnection) url.openConnection();
InputStreamReader reader = new InputStreamReader( con.getInputStream());
while(true){
int x =reader.read();
if(x==-1)
break;
System.out.print((char)x);
}
} catch (MalformedURLException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}
private void login() {
androidID = Secure.getString(MainActivity.this.getContentResolver(), Secure.ANDROID_ID);
String uP = androidID.concat(":ClientTrustedSecret");
byte[] authByteAry = null;
try {
authByteAry = uP.getBytes("UTF-8");
} catch (UnsupportedEncodingException e1) {
e1.printStackTrace();
}
String base64 = Base64.encodeToString(authByteAry, Base64.DEFAULT).trim();
client.addHeader("Authorization", "Basic ".concat(base64));
// Following format is required to post to OAuth
JSONObject jsonObject = new JSONObject();
try {
jsonObject.put("grant_type", "password");
jsonObject.put("username", "abc");
jsonObject.put("password", "abc");
} catch (JSONException e1) {
e1.printStackTrace();
}
String contentType = "application/json; charset=UTF-8";
StringEntity data = null;
try {
// Send the json to the server
data = new StringEntity(jsonObject.toString());
client.post(MainActivity.this, baseURL.concat("/tokens"), data, contentType, new AsyncHttpResponseHandler() {
#Override
public void onSuccess(String response) {
try {
JSONObject jsonObject = new JSONObject(response);
oauthAccessTokenString = jsonObject.get("access_token").toString();
} catch (JSONException e) {
e.printStackTrace();
}
}
#Override
public void onFailure(Throwable t, String err) {
System.out.println("login failed");
}
});
} catch (UnsupportedEncodingException e) {
e.printStackTrace();
}
}
The above is how I login. And when making another web serivce call I get the unauthorized. The unlock method requires the following headers.
http://i.imgur.com/EaWDO.png
private void unlock()
{
AsyncHttpClient asyncHttpClient = new AsyncHttpClient();
asyncHttpClient.addHeader("Locale", "en_US");
asyncHttpClient.addHeader("X-Originator-Type", "app");
asyncHttpClient.addHeader("Content-Type", "application/json");
// asyncHttpClient.addHeader("Connection", "Keep-Alive");
// asyncHttpClient.addHeader("X-Device-Id", androidID);
// asyncHttpClient.addHeader("X-via", deviceId);
// asyncHttpClient.addHeader("ClientID", "abc#abc.com");
asyncHttpClient.addHeader("Authorization", "Bearer ".concat(oauthAccessTokenString));
asyncHttpClient.get("host/users?loginName=abc#abc.com", new AsyncHttpResponseHandler() {
#Override
public void onSuccess(String response) {
System.out.println(response);
}
#Override
public void onFailure(Throwable t, String err) {
System.out.println("Unlock server call failed");
Log.d("printing error: ", err);
}
});
}
Above code throws 401 unauthorized exception. No references in documentation which I have, to call back url. I am providing the oauth access token just fine, but then why is it that I still get 401? Does the secret has anything to do with the second call? I am told is that I need to set up my headers that way. I am also told that "For https, the client needs to be able to handle the validation of the certificate. Does anyone knows how to solve it?
It was a wrong web service address :( There was no need to handle the validation of the certificate. There was nothing about call back url. The secret had nothing to do. But the documentation that I have is very poorly written, at one place they mentioned only the headers and then in another place they say body is required is well. So just make sure you go through the documents properly.