Develop Reference

SocketIo EngineIOException cause: SSLException

I get this exception on Android using SocketIo, everytime when internet gets disconnected (I turn off wifi). I cant find the reason, please help :

This is exception is to be expected any time an SSLSocket read fails due to an unavailable network. Socket.IO clients may safely ignore it.
As you might expect, disabling a network while you are using it causes I/O errors. In Java, this produces an IOException of one kind or another. If you had been using "normal" sockets, this would have been a SocketException, and you would have seen the same sort of message ("software caused connection abort"). Since, in this case, you are using an HTTPS connection, the IOException is an SSLException (which wraps the error encountered by the lower-level TCP socket).
Any IOExceptions thrown by the TCP socket will cause SSLExceptions on the SSLSocket, at least until such time as the SSLSocket is properly closed.

SMTPTransport sendMessage stuck on connection loss

i am using javamail's SMTPTransport.sendMessage method to send emails in my android app and everything works fine... but when i start sending a message and in the middle, i disable my wifi, it gets stuck. I have waited for more than 1hour now and it is still stuck; no exception is thrown... any idea how to handle this situation?
edit:
i have added a timeout
props.put("mail.smtp.connectiontimeout", "3000");
props.put("mail.smtp.timeout", "3000");
does not seem to work ... i have simulated a connection loss and it's already 5mins now and it is still in sending state and has not timed out
edit2:
timeout/error(not even sure if it is a timeout) occurred after 16mins
06-30 18:47:27.722: I/System.out(15906): javax.net.ssl.SSLException: Write error: ssl=0xdf8268: I/O error during system call, Invalid argument
edit 3:
it does not always throw an exception... i have simulated a connection loss and after 1hr, still no exception... it is in sending state..... and have not return yet :(

The current version of JavaMail only handles timeouts for reads, because that's all the JDK supports. For the next JavaMail release I've added support for write timeouts. You can experiment with it using the 1.5.1-SNAPSHOT release of JavaMail available in the maven.java.net repository. You'll need to set the "mail.smtp.writetimeout" property. Don't know if this will help you on Android since it's not really Java...

Socket close timing

I have what appears to be a timing problem between a client (Galaxy Nexus) and a custom server since upgrading from Ice Cream Sandwich to Jelly Bean. Here is the general flow:
Client opens socket, issues HTTP get to server
Server accepts, starts new thread, responds with HTTP header and 200 OK.
Server writes (binary) file to socket.
Client reads data from socket and saves to a file.
After server thread writes all data, it closes the socket, and terminates
This has worked well over the past several months prior to the Jelly Bean update. Since the update the binary transfer succeeds about 70% of the time. The remaining 30% fails
when 'serverSocket.getInputStream().read' returns a -1 indicating the end of stream has been reached. No data has been read, no error exceptions raised, nothing in logcat.
The possibility of a timing problem arises when I change the server behavior in step #5. The thread was closing the socket after the write with the observed problems. If I remove the socket close, terminate the thread after the write, and let the OS eventually close the socket then it seems to work all the time.
I used tcpdump and WireShark to look at the packets in both the successful and failed cases. In the failed case a socket is closed in a few milli-seconds while in the successful case the socket is closed is a quarter or more of a second. The net of this is that any delay we cause in the socket closing improves our chances for success.
If anyone has any suggestions with what we may be doing to cause this problem or suggestions on how to narrow down the problem please feel free to respond. I can add code samples if required.

It looks like that when the server ask for the connection close, the socket is immediatly closed. Maybe the default ocket linger's time has changed between version ???
Try setting the socket linger's time using:
socket.setSoLinger(boolean on, int timeout);
to have the server waiting some time before close channel if some data still waiting to be sent.
If this doesn't solve, you can change your flow above to:
...
4.Client reads data from socket and saves to a file.
5.Client send confirmation to server.
6.Server close connection.
--EDITED--
A gracefull way to achive the above without additional TCP data packets traveling for the closing confirmation is:
when server finish writing to the socket calls:
socket.shutdownOutput();
when client socket.read() returns -1, client calls:
socket.close();
This ensures that client is informed that all data has been sent, and sender will wait for the socket closure protocol to complete.

Getting "SocketException : Connection reset by peer" in Android

My app needs to contact the same device it is working on, via http://127.0.0.1/... (a localhost url).
For some reason, about 50% of the times (and maybe exactly 50%) when I reach a website there with JSON content, I get the exception:
java.net.SocketException: recvfrom failed: ECONNRESET (Connection reset by peer)
For the other 50%, I get perfectly good results. I've tried to do polls (and even large delay between polls), but I keep getting the same weird results.
I've searched the internet and also here, and I'm not sure why it occurs. Does the peer mean that the client has caused it? Why does it happen, and how should i handle it?
Some websites say that it's a common thing, but I didn't find what's the best thing to do in such cases.

Ok, the answer was that it's the server's fault - it had to close the connection after each request.
It might be that Android keeps a pool of connections and use the old one or something like that.
Anyway , now it works.
EDIT: according to the API of HttpURLConnection, this can be solved on the client side too:
The input and output streams returned by this class are not buffered.
Most callers should wrap the returned streams with BufferedInputStream
or BufferedOutputStream. Callers that do only bulk reads or writes may
omit buffering. When transferring large amounts of data to or from a
server, use streams to limit how much data is in memory at once.
Unless you need the entire body to be in memory at once, process it as
a stream (rather than storing the complete body as a single byte array
or string).
To reduce latency, this class may reuse the same underlying Socket for
multiple request/response pairs. As a result, HTTP connections may be
held open longer than necessary. Calls to disconnect() may return the
socket to a pool of connected sockets. This behavior can be disabled
by setting the http.keepAlive system property to false before issuing
any HTTP requests. The http.maxConnections property may be used to
control how many idle connections to each server will be held.
Taken from:
developer.android.com/reference/java/net/HttpURLConnection.html

Try to set this property for your HttpURLConnection before connecting:
conn.setRequestProperty("connection", "close");
This will disable "keep-alive" property which is on by default.

This is an old thread i know. But this might help someone.
In my case this error was caused by the .NET WCF (soap) service. One of the objects in the returning result had a DataMember with get{} property but no set{} property.
For serialization to occur every DataMember should have both get{} & set{} available. I implemented an empty set{} (empty due to my business rules), and problem was solved.
My scenerio is a specific bad server implementation, but maybe it'll help someone saving time when troubleshooting.

I was having a lot of these Connection reset by peer when I was visiting certain web pages or downloading files (from my app or the Android browser).
Turned out it was my 3G carrier that blocked the connections (e.g. downloading an .exe file was forbidden).
Do you have the same problem on Wifi ?

in my situation the problem has been solved by cleaning the proxy address and port from APN which was produced by the operator.
as I have tested, using IP address of remote server instead of domain name also can solve the problem.

In our case the issue is in the Server side (Application Pool configuration in IIS). I resolved it by setting Maximum Worker Processes to 1. Setting it with value more than 1 will enable Web Garden which seems to be the issue.

Android TCP socket and Streaming. No Errors or exceptions when sending data after conectivty loss

Im trying to determine if data was successfully sent to the server through a TCP socket using the OutputStream object. for testing purposes i disable network communications in the phone and OutputStream.write(); doesn't throw an exception, all the methods in the socket class return as though the socket is active and working. Is there anything i'm doing wrong here?
is there any socket implementation or stream implementation i can use to get an exception or error when the stream / socket doesn't actually send the data in the buffer?
also setting SetSoTimeout() on the socket doesn't seem to do anything.
Thanks,
Totem

If you're using the emulator this is a known bug, data can still be sent after enabling airplane mode.