Java: how to use UrlConnection to post request with authorization?

Question

I would like to generate POST request to a server which requires authentication. I tried to use the following method:

private synchronized String CreateNewProductPOST (String urlString, String encodedString, String title, String content, Double price, String tags) {

    String data = "product[title]=" + URLEncoder.encode(title) +
                "&product[content]=" + URLEncoder.encode(content) + 
                "&product[price]=" + URLEncoder.encode(price.toString()) +
                "&tags=" + tags;
    try {
        URL url = new URL(urlString);
        URLConnection conn;
        conn = url.openConnection();
        conn.setRequestProperty ("Authorization", "Basic " + encodedString);
        conn.setDoOutput(true);
        conn.setDoInput(true);
        OutputStreamWriter wr = new OutputStreamWriter(conn.getOutputStream());
        wr.write(data);
        wr.flush(); 
        // Get the response 
        BufferedReader rd = new BufferedReader(new InputStreamReader(conn.getInputStream())); 
        String line; 
        while ((line = rd.readLine()) != null) { 
            // Process line... 
            } 
        wr.close(); 
        rd.close(); 
        return rd.toString();
    } catch (MalformedURLException e) {

        e.printStackTrace();
        return e.getMessage();
    }
    catch (IOException e) {

        e.printStackTrace();
        return e.getMessage();
    } 
}

but the server doesn't receive the authorization data. The line which is supposed to add authorization data is the following:

conn.setRequestProperty ("Authorization", "Basic " + encodedString);

and the line

BufferedReader rd = new BufferedReader(new InputStreamReader(conn.getInputStream())); 

also throws an IOException.

Anyway I would be very thankful if anyone could suggest any fix of the logic above in order to enable authorization using POST with UrlConnection.

but obviously it doesn't work as it is supposed to although if the same logic is used for GET request everything works fine.

Answer 1

A fine example found here. Powerlord got it right, below, for POST you need HttpURLConnection, instead.

Below is the code to do that,

    URL url = new URL(urlString);
    URLConnection conn = url.openConnection();
    conn.setDoOutput(true);
    conn.setRequestProperty ("Authorization", encodedCredentials);

    OutputStreamWriter writer = new OutputStreamWriter(conn.getOutputStream());

    writer.write(data);
    writer.flush();
    String line;
    BufferedReader reader = new BufferedReader(new 
                                     InputStreamReader(conn.getInputStream()));
    while ((line = reader.readLine()) != null) {
      System.out.println(line);
    }
    writer.close();
    reader.close();

Change URLConnection to HttpURLConnection, to make it POST request.

    HttpURLConnection conn = (HttpURLConnection) url.openConnection();
    conn.setRequestMethod("POST");

Suggestion (...in comments):

You might need to set these properties too,

conn.setRequestProperty( "Content-type", "application/x-www-form-urlencoded");
conn.setRequestProperty( "Accept", "*/*" );

Answer 2

I don't see anywhere in the code where you specify that this is a POST request. Then again, you need a java.net.HttpURLConnection to do that.

In fact, I highly recommend using HttpURLConnection instead of URLConnection, with conn.setRequestMethod("POST"); and see if it still gives you problems.

Answer 3

To do oAuth authentication to external app (INSTAGRAM) Step 3 "get the token after receiving the code" Only code below worked for me

Worth to state also that it worked for me using some localhost URL with a callback servlet configured with name "callback in web.xml and callback URL registered: e.g. localhost:8084/MyAPP/docs/insta/callback

BUT after successfully completed authentication steps, using same external site "INSTAGRAM" to do GET of Tags or MEDIA to retrieve JSON data using initial method didn't work. Inside my servlet to do GET using url like e.g. api.instagram.com/v1/tags/MYTAG/media/recent?access_token=MY_TOKEN only method found HERE worked

Thanks to all contributors

        URL url = new URL(httpurl);
        HashMap<String, String> params = new HashMap<String, String>();
        params.put("client_id", id);
        params.put("client_secret", secret);
        params.put("grant_type", "authorization_code");
        params.put("redirect_uri", redirect);
        params.put("code", code);  // your INSTAGRAM code received 
        Set set = params.entrySet();
        Iterator i = set.iterator();
        StringBuilder postData = new StringBuilder();
        for (Map.Entry<String, String> param : params.entrySet()) {
            if (postData.length() != 0) {
                postData.append('&');
            }
            postData.append(URLEncoder.encode(param.getKey(), "UTF-8"));
            postData.append('=');
            postData.append(URLEncoder.encode(String.valueOf(param.getValue()), "UTF-8"));
        }
        byte[] postDataBytes = postData.toString().getBytes("UTF-8");

        HttpsURLConnection conn = (HttpsURLConnection) url.openConnection();
        conn.setRequestMethod("POST");
        conn.setRequestProperty("Content-Type", "application/x-www-form-urlencoded");
        conn.setRequestProperty("Content-Length", String.valueOf(postDataBytes.length));
        conn.setDoOutput(true);
        conn.getOutputStream().write(postDataBytes);
        BufferedReader reader = new BufferedReader(new InputStreamReader(conn.getInputStream(), "UTF-8"));
        StringBuilder builder = new StringBuilder();
        for (String line = null; (line = reader.readLine()) != null;) {
            builder.append(line).append("\n");
        }
        reader.close();
        conn.disconnect();
        System.out.println("INSTAGRAM token returned: "+builder.toString());

Answer 4

To send a POST request call:

        connection.setDoOutput(true); // Triggers POST.

If you want to sent text in the request use:

        java.io.OutputStreamWriter wr = new java.io.OutputStreamWriter(connection.getOutputStream());
        wr.write(textToSend);
        wr.flush();

Answer 5

I ran into this problem today and none of the solutions posted here worked. However, the code posted here worked for a POST request:

// HTTP POST request
private void sendPost() throws Exception {

    String url = "https://selfsolve.apple.com/wcResults.do";
    URL obj = new URL(url);
    HttpsURLConnection con = (HttpsURLConnection) obj.openConnection();

    //add reuqest header
    con.setRequestMethod("POST");
    con.setRequestProperty("User-Agent", USER_AGENT);
    con.setRequestProperty("Accept-Language", "en-US,en;q=0.5");

    String urlParameters = "sn=C02G8416DRJM&cn=&locale=&caller=&num=12345";

    // Send post request
    con.setDoOutput(true);
    DataOutputStream wr = new DataOutputStream(con.getOutputStream());
    wr.writeBytes(urlParameters);
    wr.flush();
    wr.close();

    int responseCode = con.getResponseCode();
    System.out.println("\nSending 'POST' request to URL : " + url);
    System.out.println("Post parameters : " + urlParameters);
    System.out.println("Response Code : " + responseCode);

    BufferedReader in = new BufferedReader(
            new InputStreamReader(con.getInputStream()));
    String inputLine;
    StringBuffer response = new StringBuffer();

    while ((inputLine = in.readLine()) != null) {
        response.append(inputLine);
    }
    in.close();

    //print result
    System.out.println(response.toString());

}

It turns out that it's not the authorization that's the problem. In my case, it was an encoding problem. The content-type I needed was application/json but from the Java documentation:

static String encode(String s, String enc)
Translates a string into application/x-www-form-urlencoded format using a specific encoding scheme.

The encode function translates the string into application/x-www-form-urlencoded.

Now if you don't set a Content-Type, you may get a 415 Unsupported Media Type error. If you set it to application/json or anything that's not application/x-www-form-urlencoded, you get an IOException. To solve this, simply avoid the encode method.

For this particular scenario, the following should work:

String data = "product[title]=" + title +
                "&product[content]=" + content + 
                "&product[price]=" + price.toString() +
                "&tags=" + tags;

Another small piece of information that might be helpful as to why the code breaks when creating the buffered reader is because the POST request actually only gets executed when conn.getInputStream() is called.

Answer 6

On API 22 The Use Of BasicNamevalue Pair is depricated, instead use the HASMAP for that. To know more about the HasMap visit here more on hasmap developer.android

package com.yubraj.sample.datamanager;

import android.content.Context;
import android.os.AsyncTask;
import android.os.Bundle;
import android.text.TextUtils;
import android.util.Log;

import com.yubaraj.sample.utilities.GeneralUtilities;


import java.io.BufferedInputStream;
import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.io.UnsupportedEncodingException;
import java.net.HttpURLConnection;
import java.net.URL;
import java.net.URLEncoder;
import java.util.HashMap;
import java.util.Map;

import javax.net.ssl.HttpsURLConnection;

/**
 * Created by yubraj on 7/30/15.
 */
public class ServerRequestHandler {
    private static final String TAG = "Server Request";
    OnServerRequestComplete listener;

    public ServerRequestHandler (){

    }
    public void doServerRequest(HashMap<String, String> parameters, String url, int requestType, OnServerRequestComplete listener){

        debug("ServerRequest", "server request called, url  = " + url);
        if(listener != null){
            this.listener = listener;
        }
        try {
            new BackgroundDataSync(getPostDataString(parameters), url, requestType).execute();
            debug(TAG , " asnyc task called");
        } catch (Exception e) {
            e.printStackTrace();
        }

    }
    public void doServerRequest(HashMap<String, String> parameters, String url, int requestType){
        doServerRequest(parameters, url, requestType, null);
    }

    public interface OnServerRequestComplete{
        void onSucess(Bundle bundle);
        void onFailed(int status_code, String mesage, String url);
    }

    public void setOnServerRequestCompleteListener(OnServerRequestComplete listener){
        this.listener = listener;
    }

    private String getPostDataString(HashMap<String, String> params) throws UnsupportedEncodingException {
        StringBuilder result = new StringBuilder();
        boolean first = true;
        for(Map.Entry<String, String> entry : params.entrySet()){
            if (first)
                first = false;
            else
                result.append("&");

            result.append(URLEncoder.encode(entry.getKey(), "UTF-8"));
            result.append("=");
            result.append(URLEncoder.encode(entry.getValue(), "UTF-8"));
        }

        return result.toString();
    }

    class BackgroundDataSync extends AsyncTask<String, Void , String>{
        String params;
        String mUrl;
        int request_type;

        public BackgroundDataSync(String params, String url, int request_type){
            this.mUrl = url;
            this.params = params;
            this.request_type = request_type;
        }

        @Override
        protected void onPreExecute() {
            super.onPreExecute();
        }

        @Override
        protected String doInBackground(String... urls) {
            debug(TAG, "in Background, urls = " + urls.length);
            HttpURLConnection connection;
                debug(TAG, "in Background, url = " + mUrl);
                String response = "";
                switch (request_type) {
                    case 1:
                        try {
                            connection = iniitializeHTTPConnection(mUrl, "POST");
                            OutputStream os = connection.getOutputStream();
                            BufferedWriter writer = new BufferedWriter(
                                    new OutputStreamWriter(os, "UTF-8"));
                            writer.write(params);
                            writer.flush();
                            writer.close();
                            os.close();
                            int responseCode = connection.getResponseCode();
                            if (responseCode == HttpsURLConnection.HTTP_OK) {
                           /* String line;
                            BufferedReader br=new BufferedReader(new InputStreamReader(connection.getInputStream()));
                            while ((line=br.readLine()) != null) {
                                response+=line;
                            }*/
                                response = getDataFromInputStream(new InputStreamReader(connection.getInputStream()));
                            } else {
                                response = "";
                            }
                        } catch (IOException e) {
                            e.printStackTrace();
                        }
                        break;
                    case 0:
                        connection = iniitializeHTTPConnection(mUrl, "GET");

                        try {
                            if (connection.getResponseCode() == connection.HTTP_OK) {
                                response = getDataFromInputStream(new InputStreamReader(connection.getInputStream()));
                            }
                        } catch (Exception e) {
                            e.printStackTrace();
                            response = "";
                        }
                        break;
                }
                return response;


        }

        @Override
        protected void onPostExecute(String s) {
            super.onPostExecute(s);
            if(TextUtils.isEmpty(s) || s.length() == 0){
                listener.onFailed(DbConstants.NOT_FOUND, "Data not found", mUrl);
            }
            else{
                Bundle bundle = new Bundle();
                bundle.putInt(DbConstants.STATUS_CODE, DbConstants.HTTP_OK);
                bundle.putString(DbConstants.RESPONSE, s);
                bundle.putString(DbConstants.URL, mUrl);
                listener.onSucess(bundle);
            }
            //System.out.println("Data Obtained = " + s);
        }

        private HttpURLConnection iniitializeHTTPConnection(String url, String requestType) {
            try {
                debug("ServerRequest", "url = " + url + "requestType = " + requestType);
                URL link = new URL(url);
                HttpURLConnection conn = (HttpURLConnection) link.openConnection();
                conn.setRequestMethod(requestType);
                conn.setDoInput(true);
                conn.setDoOutput(true);
                return conn;
            }
            catch(Exception e){
                e.printStackTrace();
            }
            return null;
        }

    }
    private String getDataFromInputStream(InputStreamReader reader){
        String line;
        String response = "";
        try {

            BufferedReader br = new BufferedReader(reader);
            while ((line = br.readLine()) != null) {
                response += line;

                debug("ServerRequest", "response length = " + response.length());
            }
        }
        catch (Exception e){
            e.printStackTrace();
        }
        return response;
    }

    private void debug(String tag, String string) {
        Log.d(tag, string);
    }
}

and Just call the function when you needed to get the data from server either by post or get like this

HashMap<String, String>params = new HashMap<String, String>();
                    params.put("action", "request_sample");
                    params.put("name", uname);
                    params.put("message", umsg);
                    params.put("email", getEmailofUser());
                    params.put("type", "bio");
dq.doServerRequest(params, "your_url", DbConstants.METHOD_POST);
                    dq.setOnServerRequestCompleteListener(new ServerRequestHandler.OnServerRequestComplete() {
                        @Override
                        public void onSucess(Bundle bundle) {
                            debug("data", bundle.getString(DbConstants.RESPONSE));
                                                    }

                        @Override
                        public void onFailed(int status_code, String mesage, String url) {
                            debug("sample", mesage);

                        }
                    });

Now it is complete.Enjoy!!! Comment it if find any problem.