Develop Reference

ERROR 411 consuming API in java (POST METHOD)

I am working on a personal project to learn how to work with Rest web services.
I have an API web application in Visual, which is my controller and where the connection to Oracle is made, and a web application in JAVA and with a JSON library, in addition to trying to do it in layers according to what I learned in the institute.
When I make the GET request, I have no problem, they bring me the data, but when I make a POST request as a customer's registrar it is when the problems start and I get the error 411 in java.
I Read looking for the solution that some worked for them by placing the "Content-Length" I don't know if I put it right but I still have the problem.
public int insertarCliente(Cliente c){
globalURL += "?rut=" + c.getRut() + "&nom="+ c.getNombre() +"&app=" + c.getApellidoP() + "&apm=" + c.getApellidoM();
try {
HttpURLConnection conn = Conectar(globalURL);
conn.setRequestMethod("POST");
conn.setRequestProperty("ACCEPT", "application/json");
conn.setRequestProperty("Content-Length", "0");
if (conn.getResponseCode() == 200) {
//InputStreamReader in = new InputStreamReader(conn.getInputStream());
BufferedReader br = new BufferedReader(new InputStreamReader(conn.getInputStream()));
String resp = br.readLine();
JSONObject obj = new JSONObject(resp);
return obj.getInt("resp");
}
} catch (Exception e) {
Logger.getLogger(ClienteDAO.class.getName()).log(Level.SEVERE, null, e);
}
return 0;
}
The problem start in the IF.
And the error that shows me is the following:
Glook2 was successfully deployed in 227 milliseconds.
**Grave: java.lang.RuntimeException: Failed : HTTP Error code : 411**
at Controllers.ClienteDAO.insertarCliente(ClienteDAO.java:50)
at Services.cliente.registrar(cliente.java:104)
at Services.cliente.processRequest(cliente.java:46)
at Services.cliente.doPost(cliente.java:77)
I must emphasize that I have proven in the POSTMAN that the web services method works and correctly adds the data to the database.
String globalURL = "http://localhost:60367/api/Cliente";
HttpURLConnection conn;
public ClienteDAO() {
conn = Conectar(this.globalURL);
}
private HttpURLConnection Conectar(String urlRest) {
try {
URL url;
url = new URL(urlRest);
return (HttpURLConnection) url.openConnection();
} catch (Exception e) {
Logger.getLogger(ClienteDAO.class.getName()).log(Level.SEVERE, null, e);
}
return null;
}

Enable logging as shown here: How to enable wire logging for a java HttpURLConnection traffic?
You will then see1 that the Content-Length header is not sent:
FINE: sun.net.www.MessageHeader#4bf558aa5 pairs:
{POST / HTTP/1.1: null}
{ACCEPT: application/json}
{User-Agent: Java/13}
{Host: localhost:8080}
{Connection: keep-alive}
1: Sample log entry, wrapped for easier reading
That is because HttpURLConnection manages that header.
To send a Content-Length: 0 header, send no output, i.e. replace:
conn.setRequestProperty("Content-length", "0");
with:
conn.setDoOutput(true);
conn.getOutputStream().close();
Logging now shows the header:
FINE: sun.net.www.MessageHeader#5fa7e7ff7 pairs:
{POST / HTTP/1.1: null}
{ACCEPT: application/json}
{User-Agent: Java/13}
{Host: localhost:8080}
{Connection: keep-alive}
{Content-type: application/x-www-form-urlencoded}
{Content-Length: 0}
See also: JDK-6997628: HttpURLConnection strips Content-Length header on Post:
Affects Version/s: 6u22
Status: Open
Resolution: Unresolved
BT2:EVALUATION
The fix for CR 6961084 restricts the setting of some potentially security sensitive headers. Since these headers were allowed to be set in previous releases then of course compatibility is effected. A decision was made that compatibility was secondary to the security risk these headers posed. We understand that there may be valid apps out there that will be effected by this, so the sun.net.http.allowRestrictedHeaders property was added to revert to previous behavior.
BT2:WORK AROUND
Run with -Dsun.net.http.allowRestrictedHeaders=true
I would not recommend using that workaround.

Server to Firebase HTTP POST results in response message 200

Using Java code (scroll down to view) I am sending a notification message to my Android using FCM, when providing the correct server key token I receive the response message seen below.
The following response message is received from FCM after
Response: 200
Success Message: '{"multicast_id":-1,"success":0,"failure":1,"canonical_ids":0,"results":[{"error":"InvalidRegistration"}]}'
Error Message: ''
Process finished with exit code 0
This means the server key token is correct and there's some sort of authorization established with FCM. When I use incorrect server key token(s) I get a different error message. However, the message above although labeled "Success Message*" still states that the success value =0 and the failure value =1, error:InvalidRegistration. If this is indeed an error, does the error imply the notification was not received by FCM, or not by the endpoint Android application?
Android App
The Android application is able to receive notifications from FCM using the console. Does this mean the Android app is set to receive the same notifications from the Java server I wrote or does the app need additional code to process these notifications that are not sent from the console?
(Just for information purspose, code is clean and runs without errors, not all files of the project are shown below, just the relevant main function and HTTP POST file).
Java server
public class Sample {
private static String SERVER_KEY = "AAAA-NCJais:APA91b----CENSORED-------";
public static void main(String[] args) {
com.pushraven.Pushraven.setKey(SERVER_KEY);
// create Notification object
Notification raven = new Notification();
HashMap<String, Object> data = new HashMap<String, Object>();
data.put("Hello", "World!");
data.put("Rami", "Imar");
data.put("Test1", "Test2");
// build raven message using the builder pattern
raven.to("/topics/ALL")
.collapse_key("a_collapse_key")
.priority(1)
.delay_while_idle(true)
.time_to_live(100)
.restricted_package_name("com.example.******")
.dry_run(true)
.data(data)
.title("Testing")
.body("Hello World!");
// push the raven message
FcmResponse response = Pushraven.push(raven);
// alternatively set static notification first.
Pushraven.setNotification(raven);
response = Pushraven.push();
// prints response code and message
System.out.println(response);
}
}
--------------------------------- other file ------------------------------
public static FcmResponse push(Notification n) {
if(FIREBASE_SERVER_KEY == null){
System.err.println("No Server-Key has been defined.");
return null;
}
HttpsURLConnection con = null;
try{
String url = API_URL;
URL obj = new URL(url);
con = (HttpsURLConnection) obj.openConnection();
con.setRequestMethod("POST");
// Set POST headers
con.setRequestProperty("Authorization", "key="+FIREBASE_SERVER_KEY);
con.setRequestProperty("Content-Type", "application/json;charset=UTF-8");
// Send POST body
con.setDoOutput(true);
DataOutputStream wr = new DataOutputStream(con.getOutputStream());
BufferedWriter writer = new BufferedWriter(new OutputStreamWriter(wr, "UTF-8"));
writer.write(n.toJSON());
writer.close();
wr.close();
wr.flush();
wr.close();
con.getResponseCode();
}
catch(Exception e){
e.printStackTrace();
}
return new FcmResponse(con);
}

InvalidRegistration error means that the token you're sending the message to is invalid:
Check the format of the registration token you pass to the server. Make sure it matches the registration token the client app receives from registering with Firebase Notifications. Do not truncate or add additional characters.
Double check the value you're passing in your to parameter. In your code, I see that you're using news. If you were intending to send to a topic, you'll have to add the prefix /topics/. So it should be something like /topics/news/. See the Topic Messaging docs for more details.

Android HttpURLConnection receives HTTP 301 response code

I'm trying to do a HTTP GET using the HttpURLConnection object in Android.
UPDATE
I tried connection to a different server. This is also hosted within Cloud 9 (c9.io) and also returns a json response. This time I'm not getting a 301 redirect, but I am getting the actual response the server is supposed to send.
Since this means the problem is localised within the server, I've reorganized the following sections in order to focus reading onto the server-related information. Android related information has been moved to the end of the question.
Where I am connecting:
Development server on Cloud9
Using the Laravel Framework 5.2 (we cannot upgrade to 5.3 at this time, due to unsupported project dependencies)
The server should return a JSON answer
If I connect to the same URL through the browser I get the correct response (JSON string. Required HTTP Headers and a '200' HTTP Response Code)
Where I am connecting FROM
Android phone (Oneplus 3, on Android 6.0)
Compile SDK version: 23
Using Build Tools: "23.0.3"
Using Min SDK verion: 19
Using Target SDK version: 22
I'm connectiong using a HttpURLConnection object, using HTTP Method 'GET'
HTTP Response on Android
When I run my code I get the folling result from the server:
The HTTP response code is 301 but the message is null.
The new URL is exactly the same, but using HTTPS. It seems server is somehow forcing SSL/TSL encryption. Which does not happen when accessing HTTP from the browser.
HTTP Header (on Android):
date => Tue, 04 Oct 2016 05:56:26 GMT
location => https://domain.com/route/ (I modified this bit)
content-length => 382
content-type => text/html; charset=iso-8859-1
X-BACKEND => apps-proxy
X-Android-Selected-Protocol => http/1.1
X-Android-Sent-Millis => 1475560583894
X-Android-Received-Millis => 1475560585637
X-Android-Response-Source => NETWORK 301
null => HTTP/1.1 301
Other data
Since it seems the server wants Android to use HTTPS, I tried modifying the code to use HTTPS (HttpsURLConnection). This may or may not solve this problem, but I am unable to check it since I get an annoying SSL handshake failed error. Plus I have no need for encryption on this application, and therefore I'm reluctant to solve the problems coming with it.
This is all running within an AsyncTask object (since Android get moody when you try to use a network connection on the main thread).
Setting up a new server (outside of Cloud 9 and without any SSL/TSL) could be an option, but I'm reluctant to do this since it would be quite time consuming.
I tried connecting to another Cloud 9 server (which also returns a json response), using the exact same code, and everything works correctly. This suggests that the problem arises from the HTPP 301 error.
I will try to share with you any other information you may require to answer my question!
Native Android stuff (moved on UPDATE, see above)
The response content seems to be an incomplete JSON:
{ 'status':'ERROR'
Note I did NOT forget the closing } character, that's what the response actually containts. This is injected somewhere unknown (to me) during the workflow. When I capture the HTTP response (using Charles on my PC, which is set as a Proxy for my phone's Wi-Fi connection) it's content is (as expected) a simple HTML telling you to redirect (HTPP code 301) to a new route.
The invalid JSON code (above) isn't there, but a valid HTML is.
This would suggest that the invalid JSON appears somewhere internally to my code (not on the server, or transport). But there is no code on my app that generates a JSON string, let alone inject it into the response I'm processing.
Code for the HttpURLConnection
this.setURL(ruta); //gets correct url
HttpURLConnection cxn = (HttpURLConnection) this.getURL().openConnection(); //init
cxn.setRequestMethod("GET"); //use HTTP GET verb
cxn.setUseCaches(false); //no cache
cxn.setRequestProperty("Cache-Control", "no-cache"); //even less cache
cxn.setDoOutput(false); //only true in POST/PUT requests
cxn.setRequestProperty("Connection","keep-alive");
cxn.setRequestProperty("DNT", "1"); //TEMP
cxn.setInstanceFollowRedirects(true); //should follow redirects
cxn.setRequestProperty( "charset", "utf-8");
Code for the reading the result
int status_code = cxn.getResponseCode();
InputStream responseStream = new BufferedInputStream(cxn.getInputStream());
BufferedReader responseStreamReader = new BufferedReader(new InputStreamReader(responseStream));
String line = "";
StringBuilder stringBuilder = new StringBuilder();
while ((line = responseStreamReader.readLine()) != null) {
stringBuilder.append(line).append("\n");
}
responseStreamReader.close();
String response = stringBuilder.toString();
cxn.disconnect();

Remove the code you've used to create the HttpURLConnection and try with this one:
URL url;
HttpURLConnection urlConnection = null;
try {
url = new URL("http://www.domain.com/index.aspx?parameter1=X&parameter2=X"); //Use your url and add the GET parameters
urlConnection = (HttpURLConnection) url.openConnection();
urlConnection.setInstanceFollowRedirects(false); /* added line */
InputStream in = urlConnection.getInputStream();
InputStreamReader isw = new InputStreamReader(in);
int data = isw.read();
while (data != -1) {
char current = (char) data;
data = isw.read();
System.out.print(current);
}
} catch (Exception e) {
e.printStackTrace();
} finally {
if (urlConnection != null) {
urlConnection.disconnect();
}
}
This should be all you need to set for your GET request.
EDIT:
I've tested the webservice using Volley, here's the code I've used in order to retrieve the webservice response:
public class MainActivity extends AppCompatActivity {
public String response;
TextView textView;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
textView = (TextView) findViewById(R.id.rTextView);
RequestQueue queue = Volley.newRequestQueue(this);
String url = "yourWebserviceUrl";
// Request a string response from the provided URL.
StringRequest stringRequest = new StringRequest(Request.Method.GET, url,
new Response.Listener < String > () {
#Override
public void onResponse(String response) {
textView.setText("Response is: " + response);
}
}, new Response.ErrorListener() {
#Override
public void onErrorResponse(VolleyError error) {
textView.setText("That didn't work!");
}
});
// Add the request to the RequestQueue.
queue.add(stringRequest);
}
}
And this is the response I got:
{"status":"ok","found":false,"extra":"App\\Scanners"}

Changing the protocol to https worked for me.

I faced the same problem, and I fixed it after reading this source.
All we need to do is handling 3** errors like shown below
if(responseCode > 300 && responseCode < 400) {
String redirectHeader = conn.getHeaderField("Location");
if(TextUtils.isEmpty(redirectHeader)) {
return new JsonResponse(responseCode, "Failed to redirect");
}
JsonRequest newRequest = request;
newRequest.url = redirectHeader;
return getJsonFromUrl(newRequest);
}
Each 3** response should have a header with name Location which contains a redirect link which we should use.

Change the line :
HttpURLConnection cxn = (HttpURLConnection) this.getURL().openConnection();
with :
HttpsURLConnection cxn = (HttpsURLConnection) this.getURL().openConnection();
So you will able to handle https

google could message-"error":"MismatchSenderId"?

I am using gcm to push notifications to one or multiple devices, However I constantly get the error message: "mismatched sender ID".
Here is my code:
public static void post(String apiKey){
try{
// prepare JSON
JSONObject jGcmData = new JSONObject();
JSONObject jData = new JSONObject();
jData.put("message", "{good luck}");
jGcmData.put("to","token ID");
jGcmData.put("data", jData);
// Create connection to send GCM Message request.
URL url = new URL("https://android.googleapis.com/gcm/send");
HttpURLConnection conn = (HttpURLConnection) url.openConnection();
conn.setRequestProperty("Authorization", "key=" + apiKey);
conn.setRequestProperty("Content-Type", "application/json");
conn.setRequestMethod("POST");
conn.setDoOutput(true);
// Send GCM message content.
OutputStream outputStream = conn.getOutputStream();
outputStream.write(jGcmData.toString().getBytes());
// Read GCM response.
InputStream inputStream = conn.getInputStream();
String resp = IOUtils.toString(inputStream);
System.out.println(resp);
} catch (IOException e) {
System.out.println("Unable to send GCM message. "+e);
}
}
Also, when I used jGcmData.put("to","/topics/foo-bar");instead of jGcmData.put("to","token ID");, the notification can be sent successfully. However what I want is to push notification to selected devices.

For the mismatched sender ID:
Try uninstalling the app and run it again.This will clear any created keys of the App.
error:MismatchSenderId
A registration token is tied to a certain group of senders. When a client app registers for GCM, it must specify which senders are allowed to send messages. You should use one of those sender IDs when sending messages to the client app. If you switch to a different sender, the existing registration tokens won't work.
According to this SO answer, ""mismatchSenderId happens because the app within the same device have logged with different keys.""
For the Topic Subscription / Topic Sending
This may be related to this Subscribe to topics suddenly throws "java.io.IOException: InternalServerError", it says that "We identified an issue in our backed that affected a small percentage of the topic subscriptions during the last 24 hours. The issue has already been fixed, and the subscriptions should work correctly on all devices."
I hope this helps you.

FileNotFoundException while getting the InputStream object from HttpURLConnection

I am trying to send a post request to a url using HttpURLConnection (for using cUrl in java).
The content of the request is xml and at the end point, the application processes the xml and stores a record to the database and then sends back a response in form of xml string. The app is hosted on apache-tomcat locally.
When I execute this code from the terminal, a row gets added to the db as expected. But an exception is thrown as follows while getting the InputStream from the connection
java.io.FileNotFoundException: http://localhost:8080/myapp/service/generate
at sun.net.www.protocol.http.HttpURLConnection.getInputStream(HttpURLConnection.java:1401)
at org.kodeplay.helloworld.HttpCurl.main(HttpCurl.java:30)
Here is the code
public class HttpCurl {
public static void main(String [] args) {
HttpURLConnection con;
try {
con = (HttpURLConnection) new URL("http://localhost:8080/myapp/service/generate").openConnection();
con.setRequestMethod("POST");
con.setDoOutput(true);
con.setDoInput(true);
File xmlFile = new File("test.xml");
String xml = ReadWriteTextFile.getContents(xmlFile);
con.getOutputStream().write(xml.getBytes("UTF-8"));
InputStream response = con.getInputStream();
BufferedReader reader = new BufferedReader(new InputStreamReader(response));
for (String line ; (line = reader.readLine()) != null;) {
System.out.println(line);
}
reader.close();
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (MalformedURLException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}
}
Its confusing because the exception is traced to the line InputStream response = con.getInputStream(); and there doesn't seem to be any file involved for a FileNotFoundException.
When I try to open a connection to an xml file directly, it doesn't throw this exception.
The service app uses spring framework and Jaxb2Marshaller to create the response xml.
The class ReadWriteTextFile is taken from here
Thanks.
Edit:
Well it saves the data in the DB and sends back a 404 response status code at the same time.
I also tried doing a curl using php and print out the CURLINFO_HTTP_CODE which turns out to be 200.
Any ideas on how do I go about debugging this ? Both service and client are on the local server.
Resolved:
I could solve the problem after referring to an answer on SO itself.
It seems HttpURLConnection always returns 404 response when connecting to a url with a non standard port.
Adding these lines solved it
con.setRequestProperty("User-Agent","Mozilla/5.0 ( compatible ) ");
con.setRequestProperty("Accept","*/*");

I don't know about your Spring/JAXB combination, but the average REST webservice won't return a response body on POST/PUT, just a response status. You'd like to determine it instead of the body.
Replace
InputStream response = con.getInputStream();
by
int status = con.getResponseCode();
All available status codes and their meaning are available in the HTTP spec, as linked before. The webservice itself should also come along with some documentation which overviews all status codes supported by the webservice and their special meaning, if any.
If the status starts with 4nn or 5nn, you'd like to use getErrorStream() instead to read the response body which may contain the error details.
InputStream error = con.getErrorStream();

FileNotFound is just an unfortunate exception used to indicate that the web server returned a 404.

To anyone with this problem in the future, the reason is because the status code was a 404 (or in my case was a 500). It appears the InpuStream function will throw an error when the status code is not 200.
In my case I control my own server and was returning a 500 status code to indicate an error occurred. Despite me also sending a body with a string message detailing the error, the inputstream threw an error regardless of the body being completely readable.
If you control your server I suppose this can be handled by sending yourself a 200 status code and then handling whatever the string error response was.

For anybody else stumbling over this, the same happened to me while trying to send a SOAP request header to a SOAP service. The issue was a wrong order in the code, I requested the input stream first before sending the XML body. In the code snipped below, the line InputStream in = conn.getInputStream(); came immediately after ByteArrayOutputStream out = new ByteArrayOutputStream(); which is the incorrect order of things.
ByteArrayOutputStream out = new ByteArrayOutputStream();
// send SOAP request as part of HTTP body
byte[] data = request.getHttpBody().getBytes("UTF-8");
conn.getOutputStream().write(data);
if (conn.getResponseCode() != HttpURLConnection.HTTP_OK) {
Log.d(TAG, "http response code is " + conn.getResponseCode());
return null;
}
InputStream in = conn.getInputStream();
FileNotFound in this case was an unfortunate way to encode HTTP response code 400.

FileNotFound in this case means you got a 404 from your server - could it be that the server does not like "POST" requests?

FileNotFound in this case means you got a 404 from your server
You Have to Set the Request Content-Type Header Parameter
Set “content-type” request header to “application/json” to send the request content in JSON form.
This parameter has to be set to send the request body in JSON format.
Failing to do so, the server returns HTTP status code “400-bad request”.
con.setRequestProperty("Content-Type", "application/json; utf-8");
Full Script ->
public class SendDeviceDetails extends AsyncTask<String, Void, String> {
#Override
protected String doInBackground(String... params) {
String data = "";
String url = "";
HttpURLConnection con = null;
try {
// From the above URL object,
// we can invoke the openConnection method to get the HttpURLConnection object.
// We can't instantiate HttpURLConnection directly, as it's an abstract class:
con = (HttpURLConnection)new URL(url).openConnection();
//To send a POST request, we'll have to set the request method property to POST:
con.setRequestMethod("POST");
// Set the Request Content-Type Header Parameter
// Set “content-type” request header to “application/json” to send the request content in JSON form.
// This parameter has to be set to send the request body in JSON format.
//Failing to do so, the server returns HTTP status code “400-bad request”.
con.setRequestProperty("Content-Type", "application/json; utf-8");
//Set Response Format Type
//Set the “Accept” request header to “application/json” to read the response in the desired format:
con.setRequestProperty("Accept", "application/json");
//To send request content, let's enable the URLConnection object's doOutput property to true.
//Otherwise, we'll not be able to write content to the connection output stream:
con.setDoOutput(true);
//JSON String need to be constructed for the specific resource.
//We may construct complex JSON using any third-party JSON libraries such as jackson or org.json
String jsonInputString = params[0];
try(OutputStream os = con.getOutputStream()){
byte[] input = jsonInputString.getBytes("utf-8");
os.write(input, 0, input.length);
}
int code = con.getResponseCode();
System.out.println(code);
//Get the input stream to read the response content.
// Remember to use try-with-resources to close the response stream automatically.
try(BufferedReader br = new BufferedReader(new InputStreamReader(con.getInputStream(), "utf-8"))){
StringBuilder response = new StringBuilder();
String responseLine = null;
while ((responseLine = br.readLine()) != null) {
response.append(responseLine.trim());
}
System.out.println(response.toString());
}
} catch (Exception e) {
e.printStackTrace();
} finally {
if (con != null) {
con.disconnect();
}
}
return data;
}
#Override
protected void onPostExecute(String result) {
super.onPostExecute(result);
Log.e("TAG", result); // this is expecting a response code to be sent from your server upon receiving the POST data
}
and call it
new SendDeviceDetails().execute("");
you can find more details in this tutorial
https://www.baeldung.com/httpurlconnection-post

The solution:
just change localhost for the IP of your PC
if you want to know this: Windows+r > cmd > ipconfig
example: http://192.168.0.107/directory/service/program.php?action=sendSomething
just replace 192.168.0.107 for your own IP (don't try 127.0.0.1 because it's same as localhost)

Please change
con = (HttpURLConnection) new URL("http://localhost:8080/myapp/service/generate").openConnection();
To
con = (HttpURLConnection) new URL("http://YOUR_IP:8080/myapp/service/generate").openConnection();