Develop Reference

Android HttpClient response

I'm trying to send json data to a php script from my Android application with HttpClient, and get the response.
Android Code
private void sendPurchase(String SKU) throws IOException{
Log.e("sendPurchase","Inside sendPurchase");
final SharedPreferences prefs = getGCMPreferences(getApplicationContext());
int pur_user = prefs.getInt("C_user", Integer.MIN_VALUE);
InputStream inputStream = null;
String result = "";
HttpClient httpclient = new DefaultHttpClient();
HttpPost httpPost = new HttpPost("http://www.*.com/includes/purchase.php");
JSONObject json = new JSONObject();
try {
json.put("PUR_sku", SKU);
json.put("PUR_user", pur_user);
} catch (JSONException e) { Log.e("SendPurchase","Problem with Json Object"); }
Log.i("JSONObject", json.toString());
StringEntity se = new StringEntity(json.toString(), HTTP.UTF_8);
httpPost.setEntity(se);
httpPost.setHeader("Accept", "application/json");
httpPost.setHeader("Content-type", "application/json");
HttpResponse httpResponse = httpclient.execute(httpPost);
inputStream = httpResponse.getEntity().getContent();
if(inputStream != null){ result = convertInputStreamToString(inputStream); }
else{result = "Did not work!"; }
Log.e("RESULT",result);
}
private static String convertInputStreamToString(InputStream inputStream) throws IOException{
BufferedReader bufferedReader = new BufferedReader( new InputStreamReader(inputStream));
String line = "";
String result = "";
while((line = bufferedReader.readLine()) != null)
result += line;
inputStream.close();
return result;
}
And the PHP script
<?
$auth=0;
require('./connexion.php');
$data = file_get_contents('php://input');
//$data = '{"PUR_sku":"singleone","PUR_user":"3"}';
$json = json_decode($data,true);
/* Some database stuff ... */
echo "Retour ".print_r($json)." et ".$json['PUR_sku']." et ".$json['PUR_user'];
?>
When i launch the app and execute sendPurchase function, it seems to be ok until the execution of the HttpPost. In the logcat i get all the logs with correct params, except the last log "RESULT" that does not appear.
That's why i guess something is going wrong with the HttpPost execution, but actually i don't know if the problem comes from the application side or the php script side...
When i execute the php script alone in a web browser, replacing first $data line by the second one, everything is ok. But when it comes from the application it's not ok...
The Json Object sent (i hope) to the script seems ok too : {"PUR_user":3,"PUR_sku":"singleone"}
(the sendPurchase function is executed in Background).
Any idea about what i'm doing wrong ? Thanks !
/EDIT/
Here is the logcat for #RyuZz solution.
My code is about purchasing an item, consume it and send new value to my database on a web server. The purchase & consume are ok, but i can't send the values to the web server.
And again, when i execute the php script alone in a web browser, replacing first $data line by the second one, everything is ok.
Note that i have another similar code to register user to GCM, using HttpClient, and that code works fine.
06-25 14:07:12.968: D/IabHelper(21833): Successfully consumed sku: singleconf
06-25 14:07:12.968: D/IabHelper(21833): Ending async operation: consume
06-25 14:07:12.979: D/CONSUME(21833): Consumption finished. Purchase: PurchaseInfo(type:inapp):{"orderId":"12999763169054705758.1353445524837889","packageName":"com.*.*","productId":"singleconf","purchaseTime":1435234296875,"purchaseState":0,"purchaseToken":"bohbcbiigcbidfficbikebnk.AO-J1OzuQ_SsNTG1h9MtUvbaPc3PeN9nBHG-qBOE82ao1rTDFNrgA7tYQcMdECxCVFrrZEn_QifQ28OcIupyesZI-5cjDILFODYpBEaeqMfE0wCAeMFkJLfNUK_TsKPMj7F2sBDdgOYx"}, result: IabResult: Successful consume of sku singleconf (response: 0:OK)
06-25 14:07:12.979: D/CONSUME(21833): You bought & consumed a single conf
06-25 14:07:12.979: D/CONSUME(21833): End consumption flow.
06-25 14:07:12.979: E/Purchase Background(21833): Inside doInBackground
06-25 14:07:12.979: E/sendPurchase(21833): Failed to send HTTP POST request due to: java.lang.NullPointerException

You can try the following instead of HttpClient which is anyway deprecated:
try{
int pur_user = prefs.getInt("C_user", Integer.MIN_VALUE);
URL url = new URL("http://www.*.com/includes/purchase.php");
HttpURLConnection connection = (HttpURLConnection) url.openConnection();
connection.setDoOutput(true);
connection.setDoInput(true);
connection.setRequestProperty("Content-Type", "application/json");
connection.setRequestProperty("Accept", "application/json");
connection.setRequestMethod("POST");
JSONObject jsonObject = new JSONObject();
jsonObject.put("PUR_sku", SKU);
jsonObject.put("PUR_user", pur_user);
//convert JSONObject to JSON to String
json = jsonObject.toString();
OutputStreamWriter writer = new OutputStreamWriter(connection.getOutputStream());
writer.write(json);
writer.close();
responseCode = connection.getResponseCode();
if(responseCode == 200) {
InputStream content = connection.getInputStream();
try {
BufferedReader reader = new BufferedReader(new InputStreamReader(content, "UTF-8"), 8);
StringBuilder sb = new StringBuilder();
String line;
while ((line = reader.readLine()) != null)
{
sb.append(line).append("\n");
}
result = sb.toString();
//TODO get your stuff from result
content.close();
} catch (Exception ex) {
Log.e(TAG, "Failed to parse JSON due to: " + ex);
} finally {
connection.disconnect();
}
} else {
Log.e(TAG, "Server responded with status code: " + responseCode);
}
} catch(Exception ex) {
Log.e(TAG, "Failed to send HTTP POST request due to: " + ex);
}
if this isn't working, please post the logcat.
Don't forget to implement the required permissions in your manifest:
<uses-permission
android:name="android.permission.INTERNET" />

How to handle 500 Internal Server Error when using JSON

I am relatively new to Android and I am using JSON to get data from a server. On the first loop at line 22, the StringBuilder contains, 500 Internal Server Error and then the jArray ends up coming back null. How can I handle this error?
public static JSONObject getJSON() {
String jsonString = "";
InputStream inStream = null;
//http post
JSONObject jArray = null;
try {
HttpClient httpClient = new DefaultHttpClient(new BasicHttpParams());
HttpPost httpPost = new HttpPost(WS_URL);
httpPost.setHeader("Content-type", "application/json");
HttpResponse response = httpClient.execute(httpPost);
HttpEntity entity = response.getEntity();
inStream = entity.getContent();
BufferedReader reader = new BufferedReader(new InputStreamReader(inStream, "UTF-8"), 8);
StringBuilder sb = new StringBuilder();
String line = null;
while ((line = reader.readLine()) != null) {
sb.append(line + "\n");
}
inStream.close();
jsonString = sb.toString();
jArray = new JSONObject(jsonString);
//outputTransactions(jArray);
} catch (IOException e) {
e.printStackTrace();
} catch (JSONException e) {
e.printStackTrace();
}
return jArray;
}

Though its a late reply but it might help others. You need to check the response status from the server before parsing it as JSON.
For ex.
int status_code=response.getStatusLine().getStatusCode();
if(status_code!=200){
Log.d("MYLOG","ERROR! Response status is"+status_code);
}
else{
inStream = entity.getContent();
BufferedReader reader = new BufferedReader(new InputStreamReader(inStream, "UTF-8"), 8);
StringBuilder sb = new StringBuilder();
String line = null;
while ((line = reader.readLine()) != null) {
sb.append(line + "\n");
}
inStream.close();
// Rest of your code......
}
or Optionally you can check the status code and display the error to the user
Like:
else if(status_code==404){
Log.d("MYLOG","Sorry! Page not found! Check the URL ");
}else if(status_code==500){
Log.d("MYLOG","Server is not responding! Sorry try again later..");
}
Hope it helps for newbies like you :-)

A "500 Internal Server" error means the server had a problem responding to your request. You are not getting a JSON string response.
Then when you try to create your jArray, the string is not valid JSON and the JSONObject cannot parse it - it returns "null" as you say.
You can parse the server response to see if it contains this string, and then create whatever jArray object you want, but you can't get a JSON object from a non-JSON string.

Take a look at this answer: https://stackoverflow.com/a/8148785/1974614
You should check the statusCode against 500

You should consider use a library to handle the REST requests like: http://square.github.io/retrofit/
If you use a library like that you can get an object from json when a success response is available and other when an error occur.
MyApi mylogin = restAdapter.create(MyApi.class); //this is how retrofit create your api
mylogin.login(username,password,new Callback<String>() {
#Override
public void success(String s, Response response) {
//process your response if login successfull you can call Intent and launch your main activity
}
#Override
public void failure(RetrofitError retrofitError) {
retrofitError.printStackTrace(); //to see if you have errors
}
});
}

I got the same problem like you and I solved it because I missed a part while adding GSON .jar files to adding my serverside project. I think you should carrefully add external libraries to your project too like me.With these links I could aware of problem .
LINK 1
LINK 2

Passing cookie with an HTTT GET

I am trying to get a list of user subreddits via the reddit api. Currently I am able to do a post for login which returns a cookie and modhash. Those are the parameters I'm passing to my method below. However each time I call the function I get an empty response:
"{}"
How can I pass a cookie and modhash via HTTPGET to get a valid response?
public void getUserSubreddits(String[] loginInfo){
HttpClient client = new DefaultHttpClient();
URL url = null;
try {
url = new URL("http://www.reddit.com/subreddits/mine/.json?limit=100");
HttpGet httpGet = new HttpGet(String.valueOf(url));
client.getParams().setParameter(CoreProtocolPNames.USER_AGENT, System.getProperty("http.agent"));
httpGet.addHeader("cookie", loginInfo[1]);
httpGet.addHeader("modhash", loginInfo[0]);
HttpResponse response = client.execute(httpGet);
HttpEntity ht = response.getEntity();
BufferedHttpEntity buf = new BufferedHttpEntity(ht);
InputStream is = buf.getContent();
BufferedReader r = new BufferedReader(new InputStreamReader(is));
StringBuilder total = new StringBuilder();
String line;
while ((line = r.readLine()) != null) {
total.append(line);
}
Log.d(TAG,total.toString());
} catch (Exception e) {
e.printStackTrace();
}
}

It was a simple mistake. To anyone in the future trying this I solved the problem by using Chrome to inspect the headers of an active session on http://www.reddit.com/subreddits/mine/.json?limit=100 url and found that the cookie header started with:
reddit_session
So I removed the modhash changed the my header parameter to read:
httpGet.addHeader("cookie", "reddit_session="+loginInfo[1]+";");
With this I got a valid response.

Memory leak with Android app?

I have a simple Android app that reads some JSON data from a php file on my local server. It's very simple and up until about an hour ago it was working fine. However, after a little break (I didn't even turn my PC off), it's suddenly struggling with what seems like a memory leak, although I'm no expert on the subject.
I'm not sure why all of a sudden this is happening, as I didn't change any code. But when I run the app my logcat slowly starts to fill with messages like this:
"GC_CONCURRENT freed, 910K, 53% free 3167K/6727K....."
The app eventually runs, but only after about 1-2 minutes of waiting. Anyway, I was wondering if someone could check my code or advise me what maybe causing this to happen.
public static JSONArray getJSONfromURL(String url) {
// initialize
InputStream is = null;
JSONArray jArray = null;
String result = "";
// http post
try {
HttpClient httpclient = new DefaultHttpClient();
HttpPost httppost = new HttpPost(url);
HttpResponse response = httpclient.execute(httppost);
HttpEntity entity = response.getEntity();
is = entity.getContent();
} catch (Exception e) {
Log.e("log_tag", "Error in http connection " + e.toString());
}
// convert response to string
try {
BufferedReader reader = new BufferedReader(new InputStreamReader(
is, "utf-8"), 8);
StringBuilder sb = new StringBuilder();
String line = null;
while ((line = reader.readLine()) != null) {
sb.append(line + "\n");
}
is.close();
result = sb.toString();
} catch (Exception e) {
Log.e("log_tag", "Error converting result " + e.toString());
}
// try parse the string to a JSON object
try {
jArray = new JSONArray(result);
} catch (JSONException e) {
Log.e("log_tag", "Error parsing data " + e.toString());
}
return jArray;
}
The JSON data isn't very large at all.
Thanks for any advice.

BufferedReader reader = new BufferedReader(new InputStreamReader(
is, "utf-8"), 8);
You've allocated a buffer size of 8 bytes. That is very small. Unless you really know what you're doing, just use the default size with the alternative single-argument constructor:
public BufferedReader(Reader in)

Well I changed the 'While' loop to this and performance increased dramatically:
int len;
char[] chars = new char[4*1024];
while((len = reader.read(chars))>=0) {
sb.append(chars, 0, len);
}
It's still slower than I'd like, but at least I'm heading in the right direction. I'm going to work on it some more. Thanks everyone.

How do I use the command: HttpEntity?

I wish to settle my long term problem by this question and hope you guys would help, but firstly; I have been having issues to connect to a HTTPS self-signed certificate server for almost 3 weeks. Despite the multiple solutions here, I cannot seem to resolve my problem. Probably I did not know how to use it properly or did not have some files or imported the correct libraries.
I came across some websites that requires me to download a certificate from the https site that I am trying to connect into, and when I did that. I have to do the some steps before I can use the certificate or keystore that I created. I got this solution from this website:
Android: Trusting SSL certificates
// Instantiate the custom HttpClient
DefaultHttpClient client = new MyHttpClient(getApplicationContext());
HttpGet get = new HttpGet("https://www.mydomain.ch/rest/contacts/23");
// Execute the GET call and obtain the response
HttpResponse getResponse = client.execute(get);
HttpEntity responseEntity = getResponse.getEntity();
I have a problem, after the last line, as stated above. What do I do with the responseEntity? How do I use it if I wish to display the https website on a WebView? Some help and explanation would be nice :)

If you want the content from the HttpEntity the correct way does not include calling HttpEntity#getContent() to retrieve a stream and doing tons of pointless stuff already available in the Android SDK.
Try this instead.
// Execute the GET call and obtain the response
HttpResponse getResponse = client.execute(get);
HttpEntity responseEntity = getResponse.getEntity();
// Retrieve a String from the response entity
String content = EntityUtils.toString(responseEntity);
// Now content will contain whatever the server responded with and you
// can pass it to your WebView using #loadDataWithBaseURL
Consider using WebView#loadDataWithBaseURL when displaying content - it behaves a lot nicer.

You need to call responseEntity.getContent() to get response in InputStream against your requested URL. Use that stream in your way to present data as you want. For example, if the expected data is String, so you may simply convert this stream into string with the following method:
/**
* Converts InputStream to String and closes the stream afterwards
* #param is Stream which needs to be converted to string
* #return String value out form stream or NULL if stream is null or invalid.
* Finally the stream is closed too.
*/
public static String streamToString(InputStream is) {
try {
StringBuilder sb = new StringBuilder();
BufferedReader tmp = new BufferedReader(new InputStreamReader(is),65728);
String line = null;
while ((line = tmp.readLine()) != null) {
sb.append(line);
}
//close stream
is.close();
return sb.toString();
}
catch (IOException e) { e.printStackTrace(); }
catch (Exception e) { e.printStackTrace(); }
return null;
}

InputStream is = responseEntity.getContent();
try{
BufferedReader reader = new BufferedReader(new InputStreamReader(is,"iso-8859-1"),8);
StringBuilder sb = new StringBuilder();
sb.append(reader.readLine() + "\n");
String line="0";
while ((line = reader.readLine()) != null) {
sb.append(line + "\n");
}
String result=sb.toString();
is.close();
}catch(Exception e){
Log.e("log_tag", "Error converting result "+e.toString());
}
you will have all the content in the String "result"