>
>Hi
>
>I've been playing with the sockets features in order to try and
>implement some client side http. I've been doing this because
>Metacard's built-in http support won't work with some URLs (something
>to do with the way aliasing is set up on the server, I think).
>
>The script below is a crude first attempt at this. It simply loads
>the data from the specified URL. (I've removed some stuff that was
>specific to my situation.) So far, it seems to work, even with
>previously unreachable URLs. Ideally, I'd like to be able to emulate
>the built-in http features of Metacard, but using sockets. (I've also
>had a go at the POST method, and it seems to work, but I need to make
>a more general solution than what I've done so far.)
>
>The scripts may be useful to anyone else wanting to do the same
>thing. More importantly, I'd appreciate any feedback from the sockets
>gurus about whether I'm going in the right direction.
>
>Two questions foremost on my mind:
>
>In order to show progress of the download (progress bar or whatever),
>is it necessary to do reads in short steps (as in the script below)
>or is there another way?
That's the way but when you get data it comes in chunks anyway.
Use repeat only if you have to.
>
>How to handle http proxies? Is this just a question of opening the
>socket to the proxy and carrying on as before, or is it, as I fear,
>more torturous?
Yes, take a look at my ftp client (http://www.cloud9.net/~undo) which handles proxy,
it should be the same.
It also shows you how I handled the progress bar and others.
>
>Any comments appreciated.
>
>Cheers
>Dave Cragg
>
>---------------------------------------------------------------
>local lcSocket, lcPath, lcData, lcHeader
>
>on httpLoad pURL
> ## remove initial "http://" if present
> if "http://" is char 1 to 7 of pURL then
> delete char 1 to 7 of pURL
> end if
> put offset("/",pURL) into tOff
> if tOff = 0 then
> put pURL into lcSocket
> put "" into lcPath
> else
> put char 1 to (tOff - 1) of pURL into lcSocket
> put char tOff to -1 of pURL into lcPath
> end if
>
> put numToChar(13) & numToChar(10) into CRLF
CRLF is built in you don't need to do the above.
>
> open socket to lcSocket
>
> put "GET" && lcPath && "HTTP/1.1" & CRLF into tString
> put "host:" & lcSocket & CRLF after tString
> put CRLF after tString ## blank line is necessary
Put an empty space between header item and value = host: host.com
>
> write tString to socket lcSocket
> read from socket lcSocket until CRLF ##line 1
> if word 2 of it = 200 then
> read from socket lcSocket until CRLF & CRLF ##get the header
> put it into lcHeader
> get lineOffset("Content-Length", lcHeader)
> if it <> 0 then
> put it into tLineNum
> put word 2 line tLineNum of lcHeader into tLength
> put 1024 into tStep
> end if
> put empty into lcData
> put 0 into tCount
> put tLength div tStep into tTimes
> ## read in small steps in order to show a progress bar or other indication
> repeat for tTimes
> add 1 to tCount
> read from socket lcSocket for tStep
> put it after lcData
> ## handle progress bar updating here
> end repeat
> read from socket lcSocket until empty ## catch last few dribbles
> put it after lcData
> close socket lcSocket
> ## do something with lcData here (cache it, return it, or whatever)
> else
> ## crude error handling
> put word 2 of it
> close socket lcSocket
> end if
>end httpLoad
>-------------------------------
>on socketError pSocket, pErr
> ##crude error handling
> put pSocket & ":" & pErr
>end socketError
>------------------------------
>on socketTimeout pSocket
> ##crude error handling
> put "Timed out"
> close socket pSocket
>end socketTimeout
>------------------------------
>_____________________________________________
>The LACS Centre (Business English Training Resources)
>mailto:[EMAIL PROTECTED]
>http://www.lacscentre.co.uk
>_____________________________________________
Regards, Andu
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