client-server question

Question

If i have a client that is connected to a server and if the server crashes, how can i determine, form my client, if the connection is off ? the idea is that if in my client's while i await to read a line from my server ( String a = sr.ReadLine(); ) and while the client is waiting to recieve that line , the server crashes , how do i close that thread that contains my while ?

Many have told me that in that while(alive) { .. } I should just change the alive value to true , but if my program is currently awaiting for a line to read, it won't get to exit the while because it will be trapped at sr.ReadLine() .

I was thinking that if i can't send a line to the server i should just close the client thread with .abort() . Any Ideas ?

score 2 · Accepted Answer · edited May 23 '17 at 12:04

2

Have a TimeOut parameter in ReadLine method which takes a TimeSpan value and times out after that interval if the response is not received..

public string ReadLine(TimeSpan timeout)
{
   // ..your logic.
)

For an example check these SO posts -

Implementing a timeout on a function returning a value

Implement C# Generic Timeout

edited May 23 '17 at 12:04

Community

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answered Dec 16 '10 at 20:22

Unmesh Kondolikar

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do you have an example at hand of this ? – Alex Dec 16 '10 at 20:35
See the updated answer, I just found some SO posts providing nice examples of it. – Unmesh Kondolikar Dec 17 '10 at 12:22

3Dave · Answer 2 · 2010-12-20T22:34:00.180

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Is the server app your own, or something off the shelf?

If it's yours, send a "heart beat" every couple of seconds to let the clients know that the connection and service are still alive. (This is a bit more reliable than just seeing if the connection is closed since it may be possible for the connection to remain open while the server app is locked.)

edited Dec 20 '10 at 22:34

answered Dec 16 '10 at 20:25

3Dave

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Did you mean "heart beat"? That's one of my boss's favorite buzz words/phase. – juharr Dec 16 '10 at 20:49

P.Brian.Mackey · Answer 3 · 2010-12-16T20:36:40.913

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If the server crashes I imagine you will have more problems than just fixing a while loop. Your program may enter an unstable state for other reasons. State should not be overlooked. That being said, a nice "server timed out" message may suffice. You could take it a step further and ping, then give a slightly more advanced message "server appears to be down".

edited Dec 16 '10 at 20:36

answered Dec 16 '10 at 20:26

P.Brian.Mackey

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score 0 · Answer 4 · answered Dec 16 '10 at 20:27

That the server crashes has nothing to do with your clients. There are several external factors that can make the connection go down: The client is one of them, internet/lan problems is another one.

It doesn't matter why something fails, the server should handle it anyway. Servers going down will make your users scream ;)

Regarding multi threading, I suggest that you look at the BeginXXX/EndXXX asynchronous methods. They give you much more power and a more robust solution.

score 0 · Answer 5 · answered Dec 16 '10 at 20:30

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Try to avoid any strategy that relies on thread abort(). If you cannot avoid it, make sure you understand the idiom for that mechanism, which involves having a separate appdomain and catching ThreadAbortException

answered Dec 16 '10 at 20:30

Brent Arias

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client-server question

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