Android - ErrnoException：套接字失败：发出 http 请求时的 EMFILE（打开的文件太多）

Question

In my app I am making http get and http post requests and after about making like 40-50 requests I get the following error exception. It looks like the http connection is keeping too many files open even after making the calls. I have added the HTTP Async handlers and their usages at the bottom. Any suggestions would be highly appreciated. Thanks for your time for reading this.

10-01 23:08:53.214  30139-30321/com.app W/System.err﹕ org.apache.http.conn.HttpHostConnectException: Connection to http://152.125.228.214:8080 refused
10-01 23:08:53.220  30139-30321/com.app W/System.err﹕ at org.apache.http.impl.conn.DefaultClientConnectionOperator.openConnection(DefaultClientConnectionOperator.java:188)

10-01 23:08:53.229  30139-30139/com.app E/SharedPreferencesImpl﹕ Couldn't create directory for SharedPreferences file /data/data/com.app/shared_prefs/MY_SHARED_PREF.xml
10-01 23:08:53.232  30139-30321/com.app W/System.err﹕ at org.apache.http.impl.conn.AbstractPoolEntry.open(AbstractPoolEntry.java:169)
10-01 23:08:53.232  30139-30321/com.app W/System.err﹕ at org.apache.http.impl.conn.AbstractPooledConnAdapter.open(AbstractPooledConnAdapter.java:124)
10-01 23:08:53.232  30139-30321/com.app W/System.err﹕ at org.apache.http.impl.client.DefaultRequestDirector.execute(DefaultRequestDirector.java:365)
10-01 23:08:53.232  30139-30321/com.app W/System.err﹕ at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:560)
10-01 23:08:53.232  30139-30321/com.app W/System.err﹕ at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:492)
10-01 23:08:53.233  30139-30321/com.app W/System.err﹕ at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:470)
10-01 23:08:53.233  30139-30321/com.app W/System.err﹕ at com.app.https.AsyncHttpTask.doInBackground(AsyncHttpTask.java:177)
10-01 23:08:53.233  30139-30321/com.app W/System.err﹕ at com.app.https.AsyncHttpTask.doInBackground(AsyncHttpTask.java:31)
10-01 23:08:53.233  30139-30321/com.app W/System.err﹕ at android.os.AsyncTask$2.call(AsyncTask.java:292)
10-01 23:08:53.233  30139-30321/com.app W/System.err﹕ at java.util.concurrent.FutureTask.run(FutureTask.java:237)
10-01 23:08:53.233  30139-30321/com.app W/System.err﹕ at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:231)
10-01 23:08:53.233  30139-30321/com.app W/System.err﹕ at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1112)
10-01 23:08:53.234  30139-30321/com.app W/System.err﹕ at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:587)
10-01 23:08:53.234  30139-30321/com.app W/System.err﹕ at java.lang.Thread.run(Thread.java:818)
10-01 23:08:53.234  30139-30321/com.app W/System.err﹕ Caused by: java.net.ConnectException: socket failed: EMFILE (Too many open files)
10-01 23:08:53.235  30139-30321/com.app W/System.err﹕ at org.apache.http.impl.conn.DefaultClientConnectionOperator.openConnection(DefaultClientConnectionOperator.java:186)
10-01 23:08:53.235  30139-30321/com.app W/System.err﹕ ... 14 more
10-01 23:08:53.235  30139-30321/com.app W/System.err﹕ Caused by: java.net.SocketException: socket failed: EMFILE (Too many open files)
10-01 23:08:53.239  30139-30321/com.app W/System.err﹕ at libcore.io.IoBridge.socket(IoBridge.java:623)
10-01 23:08:53.239  30139-30321/com.app W/System.err﹕ at java.net.PlainSocketImpl.create(PlainSocketImpl.java:198)
10-01 23:08:53.239  30139-30321/com.app W/System.err﹕ at java.net.Socket.checkOpenAndCreate(Socket.java:687)
10-01 23:08:53.240  30139-30321/com.app W/System.err﹕ at java.net.Socket.connect(Socket.java:847)
10-01 23:08:53.240  30139-30321/com.app W/System.err﹕ at org.apache.http.conn.scheme.PlainSocketFactory.connectSocket(PlainSocketFactory.java:124)
10-01 23:08:53.240  30139-30321/com.app W/System.err﹕ at org.apache.http.impl.conn.DefaultClientConnectionOperator.openConnection(DefaultClientConnectionOperator.java:149)
10-01 23:08:53.240  30139-30321/com.app W/System.err﹕ ... 14 more
10-01 23:08:53.240  30139-30321/com.app W/System.err﹕ Caused by: android.system.ErrnoException: socket failed: EMFILE (Too many open files)
10-01 23:08:53.241  30139-30321/com.app W/System.err﹕ at libcore.io.Posix.socket(Native Method)
10-01 23:08:53.241  30139-30321/com.app W/System.err﹕ at libcore.io.BlockGuardOs.socket(BlockGuardOs.java:282)
10-01 23:08:53.241  30139-30321/com.app W/System.err﹕ at libcore.io.IoBridge.socket(IoBridge.java:608)
10-01 23:08:53.241  30139-30321/com.app W/System.err﹕ ... 19 more
10-01 23:08:53.242  30139-30139/com.app D/com.app.util.JukeSpotUtils﹕ [ 10-01 23:08:54.556   191:  645 I/AudioFlinger ]
BUFFER TIMEOUT: remove(4101) from active list on thread 0xb5ae5008

Following is the code for making the HTTP requests.

public class AsyncHttpTask extends AsyncTask<String, Void, Response> {

    private HttpHandler httpHandler;

    private TaskCallback taskCallback;

    private HTTPType httpType;

    private String url;

    private String json;

    private NameValuePair[] headers;

    public static final MediaType JSON = MediaType.parse("application/json; charset=utf-8");

    public AsyncHttpTask(HttpHandler httpHandler, TaskCallback taskCallback, HTTPType httpType
        , String url, String json) {
        this.httpHandler = httpHandler;
        this.taskCallback = taskCallback;
        this.httpType = httpType;
        this.url = url;
        this.json = json;
    }

    @Override
    protected void onPreExecute() {
        if (taskCallback != null) {
            taskCallback.onPreExecute();
        }
    }

    @Override
    protected Response doInBackground(String... arg0) {
        InputStream inputStream = null;

        Response responseToReturn = new Response("", 500);
        try {
            Response response = null;
            HttpParams httpParameters = new BasicHttpParams();
            HttpConnectionParams.setConnectionTimeout(httpParameters, 5000);
            HttpConnectionParams.setSoTimeout(httpParameters, 10000);

            HttpClient httpclient = new DefaultHttpClient(httpParameters);

            HttpResponse httpResponse = httpclient.execute(httpHandler.getHttpRequestMethod());
            inputStream = httpResponse.getEntity().getContent();
            if (inputStream != null) {
                response = new Response(convertInputStreamToString(inputStream), httpResponse.getStatusLine().getStatusCode());
            } else {
                response = new Response("Did not work :(", httpResponse.getStatusLine().getStatusCode());
            }
            responseToReturn = response;
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            if(inputStream != null) {
                try {
                    inputStream.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }

       return responseToReturn;
    }

    @Override
    protected void onPostExecute(Response response) {
        if (taskCallback != null) {
            taskCallback.onPostExecute();
        }
        httpHandler.onResponse(response);
    }

    private String convertInputStreamToString(InputStream inputStream) throws IOException {
        BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(inputStream));
        String line = "";
        String result = "";
        while ((line = bufferedReader.readLine()) != null) {
            result += line;
        }

        return result;
    }
}

Following is an Abstract class which I use for defining my own implementation of HTTPGet objects and HTTPPost objects.

public abstract class HttpHandler {

    public abstract HttpUriRequest getHttpRequestMethod();

    public abstract void onResponse(Response result);

    public void execute(TaskCallback taskCallback, HTTPType httpType, String url, String json) {
        new AsyncHttpTask(this, taskCallback, httpType, url, json).execute();
    }
}

Following is the code for how I use my HttpHandler in the service I wrote.

new HttpHandler() {
    @Override
    public HttpUriRequest getHttpRequestMethod() {
        String refreshUrl = JukeSpotUtils.formRequestUrl(context,
                context.getString(R.string.refresh_token_api));
        HttpPost httpPost = new HttpPost(refreshUrl);
        try {
            JSONObject token = new JSONObject();
            token.put("refreshToken", getPreferenceValue(context, context.getString(R.string.refresh_token)));
            httpPost.setHeader("Content-Type", "application/json");

                httpPost.setEntity(new StringEntity(token.toString()));
        } catch (Exception e) {
            e.printStackTrace();
        }
        return httpPost;
    }

    @Override
    public void onResponse(Response response) {
        if (response != null && response.isSuccessful()) {
            try {
                flushOldToken(context, response.getResult());

                Log.d("ACCESS_TOKEN", getPreferenceValue(context, context.getString(R.string.access_token)));

                if (simpleCallback != null) {
                    simpleCallback.callBack();
                }
            } catch (Exception e) {
                e.printStackTrace();
            }
        }        
    }
}.execute(null, HTTPType.POST, true);

Answer 1

either your connections are not closing properly or you have executed many httpHandler simultaneously. You can try using threadPoolExecutor to start AsyncTask

Answer 2

Close your responses with response.close() .

We ran into this when doing multi-threaded networking and running into lots of 400 responses (intentional) during this.

What fixed it was ensuring that the response was being closed if it encountered an unsuccessful request, by doing:

response.close()

This must free up the socket immediately as opposed to waiting for some kind of timeout that can be too long and end up using all the file descriptors up before they have a chance to be let go automatically.

Read more here:

https://square.github.io/okhttp/4.x/okhttp/okhttp3/-response-body/