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.

node.js http server concurrency issue

Whenever I try to to send rapid HTTP Post in succession, the server sometimes crashes (java.net.ConnectException: Connection refused: connect), sometimes freezes (no error, but cannot use it anymore), and sometimes works....
If I send HTTP Post to the server slowly, there seems to be no problems at all.
I have the simple code for an http server in node.js - My guess is that sometimes the NodeJS server will receive a request, then receive another request before it sends out the respond, thus causing all sorts of problem. How do I make my server able to accept multiple requests all at once?
var server = http.createServer(function (req, res) {
if (req.method != 'POST') {
res.end();
}
else {
req.on('data', function(chunk) {
//Do some stuff here
file1=JSON.parse(chunk.toString());
console.log("Hello World") ;
}
req.on('end', function() {
res.writeHead(200, "OK", {'Content-Type': 'text/html'});
res.end();
});
}
} server.listen(9000);
EDIT
Here is the java program sending the HTTP POSTS
public static String httpUrlRequest(String requestURL, String json) {
URL url;
String response = "";
HttpURLConnection connection = null;
InputStream is = null;
try {
url = new URL(requestURL);
connection = (HttpURLConnection) url.openConnection();
connection.setDoOutput(true);
connection.setRequestMethod("POST");
connection.getOutputStream().write(json.getBytes());
connection.getOutputStream().flush();
connection.getOutputStream().close();
int code = connection.getResponseCode();
System.out.println("code" + code);
} catch (Exception e) {
e.printStackTrace();
} finally {
connection.disconnect();
}
return response;
}
public static void main(String[] args) {
Date date = new Date();
Gson gson = new Gson();
Map<String, Object> tempMap = gson.fromJson(json, new TypeToken<Map<String, Object>>(){}.getType());
for(int i = 0; i < 10; i++){
date = new Date();
tempMap.put("GetOn", getDateString(date));
httpUrlRequest("http://111.111.11.111:9000" ,gson.toJson(tempMap));
}
}
UPDATE :
If I parse the JSON in the nodejs server, then sometimes I get the error where the connection is refused.
So when I parse the request data, for some reason, nodejs fails to receive the entire json file that was sent (5KB). Instead, it only receives half of it, and my Java console says connect error. And this problem occurs AFTER nodejs correctly parses about 3 to 5 requests. Then on the next request, everything goes wrong. How can I tell if the java breaks connection causing only half of the JSON to be sent, or if only half of the JSON is sent causing nodejs to crash, ultimately resulting in connect error.
If I comment out all the parsing, then I never get the errors anymore. I don't even understand why JSON.Parse in nodejs would induce a java connect error....

Your problem lies here:
req.on('data', function(chunk) {
//Do some stuff here
file1=JSON.parse(chunk.toString());
console.log("Hello World") ;
}
Since the body can be sent in multiple packets, you might receive more than 1 'data' event, thus attempting to parse an incomplete JSON. Try this instead:
var chunks = [];
req.on('data', function(chunk) {
chunks.push(chunk);
}
req.on('end', function () {
// assemble all chunks
var body = Buffer.concat(chunks).toString(),
file1 = JSON.parse(body);
res.writeHead(200, "OK", {'Content-Type': 'text/html'});
res.end();
});

during this kind of tests, it would be easy to hit max throughput via the connection port.
http://www.slideshare.net/sh1mmer/a-million-connections-and-beyond-nodejs-at-scale
https://groups.google.com/forum/#!topic/nodejs/cRRS7ZJkyzc
The simply solution is ulimit -n 100000 before your run your node.js. But never do this in the production, better consider cluster for really large connection if you need to handle it.

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();

URLConnection Error - java.io.IOException: Server returned HTTP response code: 400 for URL

I am trying to connect to a URL from a desktop app, and I get the error indicated in the Title of my question, but when I tried to connect to the same URL from servlet, all works fine. When I load the URL from browser, all works fine. I am using the same code in the servlet. The code was in a library, when it didn't work, I pulled the code out to a class in the current project, yet it didn't work.
The URL https://graph.facebook.com/me.
The Code fragment.
public static String post(String urlSpec, String data) throws Exception {
URL url = new URL(urlSpec);
URLConnection connection = url.openConnection();
connection.setDoOutput(true);
OutputStreamWriter writer = new OutputStreamWriter(connection.getOutputStream());
writer.write(data);
writer.flush();
BufferedReader reader = new BufferedReader(new InputStreamReader(connection.getInputStream()));
String line = "";
StringBuilder builder = new StringBuilder();
while((line = reader.readLine()) != null) {
builder.append(line);
}
return builder.toString();
}
I'm a little bit confused here, is there something that is present is a servlet that is not a normal desktop app?
Thanks.
FULL STACK TRACE
Feb 8, 2011 9:54:14 AM com.trinisoftinc.jiraffe.objects.FacebookAlbum create
SEVERE: null
java.io.IOException: Server returned HTTP response code: 400 for URL: https://graph.facebook.com/me
at sun.net.www.protocol.http.HttpURLConnection.getInputStream(HttpURLConnection.java:1313)
at sun.net.www.protocol.https.HttpsURLConnectionImpl.getInputStream(HttpsURLConnectionImpl.java:234)
at com.jiraffe.helpers.Util.post(Util.java:49)
at com.trinisoftinc.jiraffe.objects.FacebookAlbum.create(FacebookAlbum.java:211)
at com.trinisoftinc.jiraffe.objects.FacebookAlbum.main(FacebookAlbum.java:261)

EDIT: You need to find the exact error message that facebook is sending in the response
You can modify your code to get the message from the error stream like so:
HttpURLConnection httpConn = (HttpURLConnection)connection;
InputStream is;
if (httpConn.getResponseCode() >= 400) {
is = httpConn.getErrorStream();
} else {
is = httpConn.getInputStream();
}
Take a look at how you are passing the user context
Here's some information that could help you out:
Look at the error message behind the 400 response code:
"Facebook Platform" "invalid_request" "An active access token must be used to query information about the current user*
You'll find the solution here
HTTP/1.1 400 Bad Request
...
WWW-Authenticate: OAuth "Facebook Platform" "invalid_request" "An active access token must be used to query information about the current user."
...

I finally found the problem. Of course it's my code. One part of the code I didn't post is the value of data. data must contain only name and description but I am passing more than name and description.