Python socket error in HTTP request

Question

I'm trying to exchange HTTP messages between a client and a server. The request contains HTTP/1.0, when I place this in the beginning of the request, it works fine.

client_socket.send("HTTP/1.0 400 Bad Request")

But When I place it at the end, it doesn't received on the other side and the program halts.

client_socket.send("GET 1.txt HTTP/1.0")

When I add an extra space to the request between HTTP and /1.0

client_socket.send("GET 1.txt HTTP/ 1.0")

It works fine and I receive the contents of the requested file.

I thinks the problem is with the forward slash, I want to omit it in order to make my client connect to another given server written in another language.

Are you fully aware of the HTTP protocol? The first message is usually sent from the server to the client, while the second one is sent from the client to the server. Which way are you trying to send this messages? — buc
– buc, Commented Sep 30, 2012 at 13:27
To begin with, all requests/response header fields should be terminated by a newline ('\r\n') and the whole header should be terminated by an empty line. To continue, see the comment from @buc. — Some programmer dude
– Some programmer dude, Commented Sep 30, 2012 at 13:27
...and GET requests should always be followed with a Host: HTTP-header. — buc
– buc, Commented Sep 30, 2012 at 13:28
Why use sockets? Generally, use that if you're protocol "savvy" and require low-level control (which I'm afraid from this post, you appear not to be). What is stopping you from using the urllib2 module (a Python stdlib) or the requests module? — Jon Clements
– Jon Clements, Commented Sep 30, 2012 at 13:31
Ok I know the first one is from the server and the second is from the client. I mean in a general case when replacing the two messages also the one with HTTP/1.0 is received while the other is not. — ABDELRAHMAN ADEL
– ABDELRAHMAN ADEL, Commented Sep 30, 2012 at 13:33

Antti Haapala · Accepted Answer · 2012-09-30 13:48:30Z

2

A HTTP 1.0 request at minimum is of following format:

GET /1.txt HTTP/1.0<CRLF>
Host: the.server.com<CRLF>
<CRLF>

That is, all line endings should be CR+LF (That is, ASCII characters 13 and 10 decimal, or "\015\012" in Python strings), and after the first line comes any number of additional headers, followed by an empty line. Though not strictly required, you should always provide the Host: header to aid with virtual hosts; many websites would not work without this. Do note, that the URI part after the GET verb must be an absolute one, and thus begin with a slash.

answered Sep 30, 2012 at 13:48

Antti Haapala

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4 Comments

ABDELRAHMAN ADEL Over a year ago

I'm working on a localhost, and I specified the port number and established a TCP connection before sending the request.

Dima Tisnek Over a year ago

Host: xxx is required in HTTP 1.1, not in HTTP 1.0; Most important is the double newline after the request. Strictly speaking it should be CRLFCRLF, but in practice most web servers understand "\n\n" too.

Antti Haapala Over a year ago

It is not required in HTTP1.0, yes, but many websites still wont work without virtual hosts.

ABDELRAHMAN ADEL Over a year ago

I still have the problem, it is a weird one. The problem occur when sending only over a socket, when there is /1.0 in the end middle of the string, it is not sent. When I separate with a space it is sent (i.e, / 1.0 or /1 .0). But when /1.0 is in the first word in the sentence it is O.K.

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