amos-pro-bsdsocket-extension/examples/HTTP Client Example.basic

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' This code shows how to make a non-blocking request with
' timeout to a remote HTTP server to retrieve a webpage
' and print it on the screen.
'
' This requires the BSD Socket Extension installed in Extension
' Slot 18.
'
' Copyright 2023 John Bintz
' Visit theindustriousrabbit.com for more info
' Licensed under the MIT License
LIB=Socket Library Open
If LIB<=0
Print "Unable to open bsdsocket.library!"
End
End If
SOCKET=Socket Create Inet Socket
' A lot of functions return debugging info. Assign that to
' some useless variable, unless you're trying to figure out
' an issue with the extension.
_=Socket Set Nonblocking(SOCKET,True)
HOST$="aminet.net"
Print "Trying to connect to "+HOST$
IP$=Dns Get Address By Name$(HOST$)
' When nonblocking sockets start to connect, they may or
' may not finish their connection before the function
' returns. If the socket doesn't connect, we have to wait
' for it to do so.
ALREADY_CONNECTED=Socket Connect(SOCKET To IP$,80)
Reserve As Work 30,1024
' Due to how AMOS takes over Ctrl-C handing, there's no way
' for the bsdsocket code to use Exec's Ctrl-C handling.
' This means we need to poll for network activity.
' However, the async functions will immediately return
' if they get appropriate data before the timeout ends.
' This is somewhat more CPU efficient.
For I=1 To 100
If ALREADY_CONNECTED=-1
' We can check a socket for writing if it's currently
' attempting to connect. Once it connects, we can stop
' checking for that status -- we're ready to communicate
' with the remote server.
RESULT=Socket Wait Async Writing(SOCKET,100)
If RESULT>0
ALREADY_CONNECTED=0
End If
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If RESULT=-3
Print "Unrecoverable error!"
Exit
End If
End If
If ALREADY_CONNECTED=0
Print "Connected to "+HOST$
HTTPGET$="GET / HTTP/1.0"+Chr$(10)+"Host: amiga"+Chr$(10)+Chr$(10)
Print "Making HTTP request to "+HOST$
_=Socket Send(SOCKET,Varptr(HTTPGET$),Len(HTTPGET$))
For J=1 To 100
RESULT=Socket Wait Async Reading(SOCKET,50)
If RESULT>0
Print "Receiving data"
' You can receive either to a block of memory...
'
'OUT=Socket Recv(SOCKET To Start(30),1024)
'For K=0 To OUT-1
' _DATA$=_DATA$+Chr$(Peek(Start(30)+K))
'Next K
'
' ...or to a string...
_DATA$=Socket Recv$(SOCKET,1024)
Print _DATA$
' If the amount read is less than the length of data,
' assume we're done. This is fine for HTTP.
If Len(_DATA$)<1024
Exit 2
End If
End If
Next J
Exit
End If
Next I
Socket Library Close