eof hangs using websockets

[lucianolorenti]

Julia 1.2.0
HTTP.jl 0.8.6
MbedTLS.jl 0.7.0

Hello. I am having an issue using the eof function of the WebSockets.
Using the server provided in the Readme, and the following client:

julia> HTTP.WebSockets.open("ws://127.0.0.1:8081") do ws    
           @show eof(ws)
           write(ws, "Hello")           
           x = readavailable(ws)
           @show x
       end;

The client hangs.
But if I put the @show eof(ws) under the write(ws, "Hello") line, the code does not hang.

julia> HTTP.WebSockets.open("ws://127.0.0.1:8081") do ws    
           write(ws, "Hello") 
          @show eof(ws)          
           x = readavailable(ws)
           @show x
       end;

The issue happens also if the eof is called after readavailable(ws)
What am I missing?

[zhanglix]

It is due to eof(::TCPSocket) will hang if there is no data available to read.

eof(ws) will eventually call eof(::TCPSocket) then hang if there is no data available to read.

[quinnj]

@zhanglix is correct here and is one of the main reasons, in the newly merged overhaul of the websockets code on HTTP#master, I tried to move the WebSocket object and its API away from being IO-like. i.e. there's no eof(ws) method supported anymore because it's too easy to accidentally call this and it will just block forever waiting for a message to send. We now have a much more well-defined interface for how to work with a WebSocket object (check out the docs for ?WebSocket on HTTP#master!) which should lead to a much more predictable/convenient usage.