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Index › Programming Questions & Help › Other Libraries › Network Library - Client write
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Network Library - Client write (Read 1069 times)
joshuajnoble
Network Library - Client write
Mar 10th, 2009, 11:36pm  

Can anyone shed some light on what's going on with the Client library in this case:

I connect my client:

String req = "www.geoplugin.net";
String getReq = "/xml.gp?ip=12.215.42.19";

void setup() {
...
 c = new Client(this, req, 80); // Connect to server on port 80
}

then in the draw try once to do the following:

   c.write("GET "+getReq+" \n");
   c.write("Host: www.geoplugin.net\n");
   c.write("User-Agent: Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10.5; en-US; rv:1.9.0.7) Gecko/2009021906 Firefox/3.0.7\n");
   c.write("Accept: text/html,application/xhtml+xml,application/xml\n");
   c.write("Accept-Language: en-us,en;q=0.5\n");
   c.write("Accept-Encoding: gzip,deflate\n");
   c.write("Accept-Charset: ISO-8859-1,utf-8;q=0.7,*;q=0.7\n");
   c.write("Keep-Alive: 300\n");
   c.write("Connection: keep-alive\n");

This works fine in Telnet, in a little Python script I wrote up, i.e. I get:

HTTP/1.1 200 OK
Date: Tue, 10 Mar 2009 22:21:34 GMT
Server: Apache
Content-Length: 696
...

etc

but in my Processing app I always get back

<h2>Error 404</h2>

I think it's mangling something, but I can't figure out what's going on. Is this a weird Java string class problem? Any ideas would be sweet. Thanks!
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joshuajnoble
Re: Network Library - Client write
Reply #1 - Mar 11th, 2009, 12:01am  
Wierd...just as a heads up to people, you have to do:

c.write("GET http://www.geoplugin.net/xml.gp?ip=12.215.42.19 \n");

for the request. If anyone feels like explaining why that is, lemme know Smiley
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JohnG
Re: Network Library - Client write
Reply #2 - Mar 11th, 2009, 1:33pm  
It's because you're badly forming the request (and using the wrong line endings), your first line should actually be:
c.write("Get "+getReq+" HTTP/1.1\r\n");

Without the HTTP/1.1 definition the Host: field is ignored, since it'll default to HTTP/1.0.. or possibly even 0.9 hence having to put it in the first line for your workaround.
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PhiLho 
Re: Network Library - Client write
Reply #3 - Mar 11th, 2009, 3:09pm  
Uh, what JohnG said (I was about to make a similar answer).

I will add that the last write should send a double \r\n to mark the end of the request.
Just tried and got a nice XML file about Sugar Grove.

I suppose some servers has some tolerance, or perhaps Python fix the line endings on the fly, etc., but it is better to get things right... Smiley
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joshuajnoble
Re: Network Library - Client write
Reply #4 - Mar 11th, 2009, 3:13pm  
Wow, yeah I hadn't even noticed that I had accidentally dropped the HTTP/1.1 from the initial request. It was in there, and I know why it should be, but I think a long day had my head a little fuzzy. The "Get" versus "GET" is another one that I actually didn't know about, is that 1.0 vs 1.1? Or is it irrelevant?
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JohnG
Re: Network Library - Client write
Reply #5 - Mar 11th, 2009, 3:57pm  
Oops, it should be GET not Get.. that was my mistake.
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