Android interacting with php - android

I have a problem! I have a connection with a php page to connect with database and the method works fine on Froyo, but doesn't work on newer versions of Android. What is the problem?
public static String interact(String request){
String result="test";
String site = "http://xxxx.net:nnn/xxx";
URL url = new URL(site);
HttpURLConnection connection = (HttpURLConnection) url.openConnection();
connection.setRequestMethod("POST");
connection.setDoOutput(true);
connection.connect();
OutputStreamWriter wr = new OutputStreamWriter(connection.getOutputStream());
wr.write(request);
wr.flush();
wr.close();
Scanner in = new Scanner(connection.getInputStream());
while(in.hasNextLine())
result+=in.nextLine();
connection.disconnect();
return result;
}
catch (UnknownHostException e) {
return e.getMessage();
} catch (IOException ex) {
return ex.getMessage();
}
catch (Exception ex){
return ex.getMessage();
}
}
I need to send data and get response, but it just gives me null on newer Android than 2.2.

you are running Network Request on main thread.
Android >=3.0 does not alow this. you need to use AsyncTask to call Network Request

Yes this is not allowed on version lower than 3.0. however you can override the rules by doing some setting bypass but at the very least don't do that as it might give app-crash to you.
I suggest to raise the level of your min-SDK level.

Related

HttpURlConnection not connecting

I am making a HttpUrlConnection with an Usgs API. This is my Url:
"https://earthquake.usgs.gov/fdsnws/event/1/queryformat=geojson&eventtype=earthquake&orderby=time&minmag=6&limit=10"
After thoroughly debugging, it seems that after connection.connect connection fails and jsonResponse is empty.
public static String makeHttprequest(URL url) throws IOException {
String jsonResponse = "";
HttpURLConnection connection = null;
InputStream stream = null;
try {
connection = (HttpURLConnection) url.openConnection();
connection.setRequestMethod("GET");
connection.setReadTimeout(1000000);
connection.setConnectTimeout(1500000);
connection.connect();
stream = connection.getInputStream();
jsonResponse = readfromstream(stream);
} catch (IOException e) {
Log.e("IOException", "Error while making request");
}
return jsonResponse;
}
This is Log
Everything looks good. It seems to me that you have no internet connection in your running devices. Probably you are using emulator in your computer which is not connected to internet.
Please try to run in real device. It is working perfect for me.
A bit advice, please try to use libraries such as Retrofit or OkHttp. They are very much easier and handier than these old ways.
If you insist using HttpURLConnection, try the following
URL url = new URL(yourUrlString);
HttpURLConnection urlConnection = (HttpURLConnection) url.openConnection();
try {
InputStream in = new BufferedInputStream(urlConnection.getInputStream());
readStream(in);
} finally {
urlConnection.disconnect();
}
Or for more formal use of HttpURLConnection, visit here. It shows several proper use of HttpURLConnection APIs.
https://developer.android.com/reference/java/net/HttpURLConnection
just tried my app on real device everything is working as expected there might be problem with emulator.

API call far faster on iOs and browser than on android

I have a trouble with my HttpsConnection on android.
First of all, no it is not a duplicate. I try almost all the solutions on SO, like changing the keep-alive option or the timeout ( and some of them indeed optimized a part of my code a little bit ) but it is still 5 to 10 times ( probably more ) slower on android than on iOS.
Sending a request to my server takes several seconds on android while it's almost instant on iOS and from a browser. I am sure that the server is not in cause. But it seems that getting the inputstream is terribly slow!
This line:
in=conn.getInputStream();
is the most delaying one, taking several seconds by itself.
My aim is to get a JSON from my server. My code is supposed to be technically as optimized as possible ( and it can probably help some people with HttpsConnection on the same time ):
protected String getContentUrl(String apiURL)
{
StringBuilder builder = new StringBuilder();
String line=null;
String result="";
HttpsURLConnection conn= null;
InputStream in= null;
try {
URL url;
// get URL content
url = new URL(apiURL);
System.setProperty("http.keepAlive", "false");
trustAllHosts();
conn = (HttpsURLConnection) url.openConnection();
conn.setHostnameVerifier(DO_NOT_VERIFY);
conn.setRequestMethod("GET");
conn.setRequestProperty(MainActivity.API_TOKEN, MainActivity.ENCRYPTED_TOKEN);
conn.setRequestProperty("Connection", "close");
conn.setConnectTimeout(1000);
in=conn.getInputStream();
// open the stream and put it into BufferedReader
BufferedReader br = new BufferedReader(new InputStreamReader(in));
while ((line=br.readLine())!= null) {
builder.append(line);
}
result=builder.toString();
//System.out.print(result);
br.close();
} catch (MalformedURLException e) {
result=null;
} catch (IOException e) {
result=null;
} catch (Exception e) {
result=null;
}
finally {
try {
in.close();
}catch(Exception e){}
try {
conn.disconnect();
}catch(Exception e){}
return result;
}
}
However, it keeps taking several seconds.
So I would like to know: is there a way to improve the speed of this API call? The problem is not the server or the JSON parsing but for sure the function above. Thanks a lot.

How to Connect Android Device with web serve using AsyncTask

I have this asynctask.I need to connect device with web server.Need to send a JSON Arry and receive JSON array. Can i use httpUrlConnection ? or httpClient. Does httpClient support latest versions of Android?
class background_thread extends AsyncTask<JSONArray, Void, Boolean> {
protected Boolean doInBackground(JSONArray... params) {
//connect with server side php script
String UR = "127.0.0.1/abc/index.php";
try {
URL url = new URL(UR);
try {
HttpURLConnection conn = (HttpURLConnection) url.openConnection();
json_array=json_encode();
conn.setDoOutput(true);
conn.setChunkedStreamingMode(0);
OutputStream out = new BufferedOutputStream(conn.getOutputStream());
writeStream(out);
} catch (IOException e) {
e.printStackTrace();
}
} catch (MalformedURLException e) {
e.printStackTrace();
}
return true;
}
You should use google's own volley library to make network calls and handle the response data in model classes. This is the most modular approach. Refer this link for official documentation.

HttpURLConnection: java.lang.IllegalStateException: Already connected

I'm trying to use HttpURLClient to send some POST data to a server using the HttpRestClient class shown below. When executing
conn.setDoInput(true);
I get
java.lang.IllegalStateException: Already connected
I uninstalled the app, and still get the same error.
In all the example I've seen openConnection is called before setDoInput. If, as its name suggests, openConnection opens a connection, it should never be used before `setDoInput, right? What am I missing?
Maybe at some point it crashed before executing disconnect. Could that be the reason? If so, how can I disconnect the old connection?
public class HttpRestClient {
static public int post(String urlStr, List<NameValuePair> data){
HttpURLConnection conn = null;
try {
URL url = new URL(urlStr);
conn = (HttpURLConnection) url.openConnection();
conn.setDoInput(true);
conn.setDoOutput(true);
conn.setRequestMethod("POST");
OutputStream os = conn.getOutputStream();
BufferedWriter writer = new BufferedWriter(
new OutputStreamWriter(os, "UTF-8"));
writer.write(getQuery(data));
writer.flush();
writer.close();
os.close();
InputStream is = conn.getInputStream();
String dude = readIt(is);
return 1;
} catch (MalformedURLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
return 0;
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
return 0;
}
finally {
if(conn!=null) conn.disconnect();
}
}
}
This might be due to watches while debugging in your IDE. See this answer.
It happened to me and was hard to discover.
You called both of conn.setDoInput(true); and conn.setDoOutput(true);. Use one of them:
setDoOutput(true) is used for POST and PUT requests.
setDoInput(true) is used for GET request.
The connection you made was confused, it can't decide which request should be used.
In your code:
static public int post(String urlStr, List<NameValuePair> data){
HttpURLConnection conn = null;
System.setProperty("http.keepAlive", "false"); // must be set
try {
...
conn.setDoOutput(true);
conn.setRequestMethod("POST");
// and connect to server, if needed
conn.connect();
...
}
....
It may be a misleading exception. See this defect for Jersey-2 https://java.net/jira/browse/JERSEY-2729
The link has been updated:
https://github.com/javaee/jersey/issues/3001
Basically the issue is jersey was throwing invalid exception. The real issue in my case was that the connection was refused from the server.

Android HttpURLConnection throwing EOFException

Here's the question in simplest way.
I create a HTTPS connection to my server through proxy using HttpUrlConnection Object.
My proxy closes the connection but my code still tries to reuse the same connection. And so I get EOFException.
How do I handle such cases?
I'd recommend disabling the http.keepalive system property. The performance section of the documentation indicates that socket connections will be reused when possible. It sounds like it is trying to reuse the connection, but the proxy has already closed it. On this post, Darrell also indicates that changing the system property solved his problem.
System.setProperty("http.keepAlive", "false");
Turns out they've fixed this issue in Android on Jan 8th [1]. The fix basically marks the old connection as recycled and internally retries the request.
To fix this for now, I would suggest retrying requests if an EOFException is encountered with a retry limit to prevent stackoverlows.
https://android.googlesource.com/platform/libcore/+/19aa40c81c48ff98ccc7272f2a3c41479b806376
I had this problem with normal HTTP connections as well. The first request went OK, the second failed with an EOFException.
Eventuelly I fixed it by removing...
urlConnection.setChunkedStreamingMode(0);
...from the HttpUrlConnection.
I could be that the webserver I'm calling can't handle chuncked data well. Don't know.
If you don't want to reuse the connection then release it.
finally {
urlConnection.disconnect();
}
You can use this method to pick data from server then you convert the inputs trim to string then you can parse for further use.`
public static InputStream getUrlData(final String url)
throws URISyntaxException, ClientProtocolException, IOException {
final DefaultHttpClient client = new DefaultHttpClient();
final HttpGet method = new HttpGet(new URI(url));
final HttpResponse res = client.execute(method);
return res.getEntity().getContent();
}
Maybe httpClient "has more bugs" and is deprecated, but this problem with JellyBean is a showstopper. I am using Ksoap2 so I tried all the suggested answers that I could.
System.setProperty("http.keepAlive", "false");
httpTransportSE.getServiceConnection().setRequestProperty("Connection", "close");
httpTransportSE.getServiceConnection().disconnect();
Nothing worked - my solution was to rollback the version of Ksoap2 I'm using from 3.1.1 to 2.6.5. Using 2.6.5 the problem is substantially reduced. Still testing but maybe even solved.
I found that retrying the connection fixes the issue as seen here: https://stackoverflow.com/a/20302767/2520390
Make sure you close off the connection before your recursive call.
Also, I added the following to the connection to close the connection, though I'm not sure if it helps:
if (retries > 0) {
connection.setRequestProperty("Connection", "close");
}
You shouldn't be attempting to reuse the same HttpURLConnection instance. The docs in the very bottom line of the "Class Overview" say
Each instance of HttpURLConnection may be used for one
request/response pair.
Keep-Alive connections work at a different level, see the disconnect docs:
http://developer.android.com/reference/java/net/HttpURLConnection.html#disconnect()
Unlike other Java implementations, this will not necessarily close
socket connections that can be reused. You can disable all connection
reuse by setting the http.keepAlive system property to false before
issuing any HTTP requests.
So you should always use a fresh HttpURLConnection and let the socket pool handle re-use.
There were apparently bugs with keep-alive connections pre-Froyo (2.2) so it is recommended to disable keep-alive on those old devices.
In my case the EOFException was caused by my server not sending a full response, see the details here: https://stackoverflow.com/a/27845172/2335025
You shouldn't be attempting to reuse the same HttpURLConnection instance. The docs in the very bottom line of the "Class Overview" say
Each instance of HttpURLConnection may be used for one
request/response pair.
Keep-Alive connections work at a different level, see the disconnect docs:
http://developer.android.com/reference/java/net/HttpURLConnection.html#disconnect()
Unlike other Java implementations, this will not necessarily close
socket connections that can be reused. You can disable all connection
reuse by setting the http.keepAlive system property to false before
issuing any HTTP requests.
So you should always use a fresh HttpURLConnection and let the socket pool handle re-use. There are perhaps issues if it tries to reuse a socket that has been closed by the server, which the answers to this question deal with: Android HttpUrlConnection EOFException
There were apparently bugs with keep-alive connections pre-Froyo (2.2) so it is recommended to disable keep-alive on those old devices.
In my case the EOFException was caused by my server not sending a full response, see the details here: https://stackoverflow.com/a/27845939/2335025
if (Build.VERSION.SDK != null
&& Build.VERSION.SDK_INT > 13) {
con.setRequestProperty("Connection", "close");
}
Try this code:`
Httppost method:
HttpParams httpParams = new BasicHttpParams();
HttpConnectionParams.setConnectionTimeout(httpParams, TIMEOUT_MILLISEC);
HttpConnectionParams.setSoTimeout(httpParams, TIMEOUT_MILLISEC);
HttpClient client = new DefaultHttpClient(httpParams);
HttpPost request = new HttpPost("put_url");
request.setHeader("Content-Type", "application/xml");
String file = resourceXml();
StringEntity se = null;
try {
se = new StringEntity(file);
} catch (UnsupportedEncodingException e1) {
e1.printStackTrace();
}
se.setContentEncoding("UTF-8");
se.setContentType("application/xml");
request.setEntity(se);
HttpResponse response = null;
try {
response = client.execute(request);
} catch (ClientProtocolException e1) {
e1.printStackTrace();
} catch (IOException e1) {
e1.printStackTrace();
}
HttpEntity entity = response.getEntity();
InputStream is = null;
try {
is = entity.getContent();
} catch (IllegalStateException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
String _response = convertStreamToString(is);
Log.i(TAG, "Response:" + _response);
// Check if server response is valid code
int res_code = response.getStatusLine().getStatusCode();
Log.i(TAG, "status_code" + res_code);
try {
is.close();
} catch (IOException e) {
e.printStackTrace();
}
`
to convert stream to string:`
private static String convertStreamToString(InputStream is) {
BufferedReader reader = new BufferedReader(new InputStreamReader(is),
8192);
StringBuilder sb = new StringBuilder();
String line = null;
try {
while ((line = reader.readLine()) != null) {
sb.append((line + "\n"));
}
} catch (IOException e) {
e.printStackTrace();
} finally {
try {
is.close();
} catch (IOException e) {
e.printStackTrace();
}
}
return sb.toString();
}`

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