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I am trying to receive information from a telnet connection in Lua using LuaSocket. I have all of that up and running except when I receive, if I receive anything less than the maximum number of bytes it takes 5 seconds. If I receive anything more than the number of bytes on the screen it takes upwards of half an hour.

My current idea for a solution is to try receiving for instance 750 bytes, then if that doesn't work within 6-7 seconds do 700 bytes, then 650 and so on until I can receive it very quickly. I need to parse the information and find two specific phrases, so if it's possible to do that inside of my telnet connection and just return that instead of the entire screen that would work as well. I also don't need ALL of it, but I need as much of the received information as possible to raise the chances that my information is in that block of it, hence why I'm only decrementing by 50 in my example.

I can't find any functions that allow you to start reading something (doing a function) and then quit it after a certain time interval. If anybody knows how to do this, or has any other solutions to my problem, let me know please! :) Thanks!

here is what I need repeated:

info = conn:receive(x)

with x decrementing each time it takes longer than 6 seconds to complete.

Collin Meaney
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  • Does `conn:settimeout(0, 'b')` help? Besides that, it seems like you trying to do buffered non-blocking io very wrong way. – user3125367 Jun 25 '15 at 21:42

1 Answers1

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The solution you are proposing looks a bit strange as there are more straightforward ways to deal with asynchronous communications. First of all, you can use settimeout to limit the amount of time that send and receive calls will wait for the results (be careful as receive may return partial results in this case). Second option is to use select which allows you to check if a socket has something to read/write before issuing a blocking command.

Paul Kulchenko
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