Re: 'POST' method leads to 411 Length Required
Dear Keary, Thank you for getting back to me. Some parts of the HTTP spec are ambiguous and left to implementation. In this specific case, error 411 means the server is saying that you are not sending a necessary content-length header, which is required for POSt requests whether there is any content or not. It may be that LWP doesn't provide the header if there is no content. Did you inspect the request to verify that the content-length header is indeed being sent? If the header is indeed being sent, the server might be choking on a 0 length. Send bogus data to see if that helps. Initially, I received www.google.com with GET, and 411 Length Required with POST. Subsequently, I tried providing header and content: $request = new HTTP::Request 'GET', 'http://www.google.com', [asdf = 'fdsa'], dummy content; and now with GET I see: 411 Length Required, and with POST: 405 Method Not Allowed. So, I am pretty baffled as to what the rules are, and how I can make this work. Thanx, Aaron -- Aaron (Aharon) Naiman Jerusalem College of Technology--Machon Lev nai...@math.jct.ac.il http://math.jct.ac.il/~naiman
RE: 'POST' method leads to 411 Length Required
Note that this 'expects' is fairly soft and does not go much further than
Applications SHOULD use this field to indicate the transfer-length of the
message-body, unless this is prohibited by the rules... with the transmission
rules (keep alive, chunked, etc) beeing the only exceptions overruling this for
POST (and related). This has always* been a messy problem.
But in general - this is a client bug (it should have been a bit more strict in
sending) - but arguably the server should (and can) be accomodating in what it
accepts. So I would try to fix both sides - starting with your own. E.g. a
simple content-length = $ENV{CONTENT_LENGTH} || 0 sort of thing :).
Thanks,
Dw.
*: 1998 http://arctic.org/~dean/apache/no-content-length/
-Original Message-
From: Bjoern Hoehrmann [mailto:derhoe...@gmx.net]
Sent: 21 April 2009 23:42
To: Aaron Naiman
Cc: libwww@perl.org
Subject: Re: 'POST' method leads to 411 Length Required
* Aaron Naiman wrote:
$request = new HTTP::Request 'POST', 'http://www.google.com';
$response = $ua-request($request);
You are using POST but are not posting any data, and
apparently the server ...
An Error Occurred 411 Length Required
... expects you to post some data when using POST.
--
Björn Höhrmann · mailto:bjo...@hoehrmann.de ·
http://bjoern.hoehrmann.de Am Badedeich 7 · Telefon:
+49(0)160/4415681 · http://www.bjoernsworld.de
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Re: 'POST' method leads to 411 Length Required
On Apr 22, 2009, at 3:11 AM, Aaron Naiman wrote: Thank you for getting back to me. Some parts of the HTTP spec are ambiguous and left to implementation. In this specific case, error 411 means the server is saying that you are not sending a necessary content-length header, which is required for POSt requests whether there is any content or not. It may be that LWP doesn't provide the header if there is no content. Did you inspect the request to verify that the content-length header is indeed being sent? If the header is indeed being sent, the server might be choking on a 0 length. Send bogus data to see if that helps. Initially, I received www.google.com with GET, and 411 Length Required with POST. Subsequently, I tried providing header and content: $request = new HTTP::Request 'GET', 'http://www.google.com', [asdf = 'fdsa'], dummy content; and now with GET I see: 411 Length Required, and with POST: 405 Method Not Allowed. So, I am pretty baffled as to what the rules are, and how I can make this work. I don't know about the first case, other than Google has been known to behave in nonstandard ways. a GET request shouldn't have an entity body, as I understand, and so shouldn't require a content length header. The second case--405 method not allowed--just means the site doesn't permit a POST request. A server is not required to accept POSTs, so this response is possible. It seems to me that the problems you are experiencing have more to do with your lack of understanding of the HTTP protocol, rather than the way LWP works. I suggest picking up a book on HTTP--I would recommend HTTP Developers Handbook by Chris Shiflett. I would also underscore to not base your understanding on how google behaves. Historically Google has been unfriendly towards any interaction with their servers not performed by well known web browsing software. Keary Suska
RE: 'POST' method leads to 411 Length Required
hey i'm not sure of your favorite browser... but if it's firefox, i would suggest you load a plugin called livehttpheaders (i think). this allows you to see exactly what's happening between the browser/server so you can see what's needed from the client side when you're attempting to create a client to interface with the server this process will tell you whether you're using get/post etc, and what the server is expecting, sending back to the client... you can also use a cmdline app like 'curl' to quickly see if what you think is required, works.. once you get to this point, coding in perl/php/python than becomes an easy process... good luck! -Original Message- From: Keary Suska [mailto:hieroph...@pcisys.net] Sent: Wednesday, April 22, 2009 7:16 AM To: Aaron Naiman Cc: Libwww Perl Subject: Re: 'POST' method leads to 411 Length Required On Apr 22, 2009, at 3:11 AM, Aaron Naiman wrote: Thank you for getting back to me. Some parts of the HTTP spec are ambiguous and left to implementation. In this specific case, error 411 means the server is saying that you are not sending a necessary content-length header, which is required for POSt requests whether there is any content or not. It may be that LWP doesn't provide the header if there is no content. Did you inspect the request to verify that the content-length header is indeed being sent? If the header is indeed being sent, the server might be choking on a 0 length. Send bogus data to see if that helps. Initially, I received www.google.com with GET, and 411 Length Required with POST. Subsequently, I tried providing header and content: $request = new HTTP::Request 'GET', 'http://www.google.com', [asdf = 'fdsa'], dummy content; and now with GET I see: 411 Length Required, and with POST: 405 Method Not Allowed. So, I am pretty baffled as to what the rules are, and how I can make this work. I don't know about the first case, other than Google has been known to behave in nonstandard ways. a GET request shouldn't have an entity body, as I understand, and so shouldn't require a content length header. The second case--405 method not allowed--just means the site doesn't permit a POST request. A server is not required to accept POSTs, so this response is possible. It seems to me that the problems you are experiencing have more to do with your lack of understanding of the HTTP protocol, rather than the way LWP works. I suggest picking up a book on HTTP--I would recommend HTTP Developers Handbook by Chris Shiflett. I would also underscore to not base your understanding on how google behaves. Historically Google has been unfriendly towards any interaction with their servers not performed by well known web browsing software. Keary Suska
Re: 'POST' method leads to 411 Length Required
* Aaron Naiman wrote: $request = new HTTP::Request 'POST', 'http://www.google.com'; $response = $ua-request($request); You are using POST but are not posting any data, and apparently the server ... An Error Occurred 411 Length Required ... expects you to post some data when using POST. -- Björn Höhrmann · mailto:bjo...@hoehrmann.de · http://bjoern.hoehrmann.de Am Badedeich 7 · Telefon: +49(0)160/4415681 · http://www.bjoernsworld.de 25899 Dagebüll · PGP Pub. KeyID: 0xA4357E78 · http://www.websitedev.de/
Re: 'POST' method leads to 411 Length Required
Dear Björn, Thank you for the quick result. * Aaron Naiman wrote: $request = new HTTP::Request 'POST', 'http://www.google.com'; $response = $ua-request($request); You are using POST but are not posting any data, and apparently the server ... An Error Occurred 411 Length Required ... expects you to post some data when using POST. But as can be seen from .../HTTP/Status.pm, this is a *client* error, and not a server error. Still stuck, Thanx, Aaron -- Aaron (Aharon) Naiman Jerusalem College of Technology--Machon Lev nai...@math.jct.ac.il http://math.jct.ac.il/~naiman
Re: 'POST' method leads to 411 Length Required
Dear Björn, Thank you again for your response. * Aaron Naiman wrote: You are using POST but are not posting any data, and apparently the server ... An Error Occurred 411 Length Required ... expects you to post some data when using POST. But as can be seen from .../HTTP/Status.pm, this is a *client* error, and not a server error. You're sending somebody who expects a letter from you an empty envelope. However, from all of the examples I have seen, one need not send anything in a POST. The only difference between GET and POST, is that the former sends the parameters in the URL, and the latter, as part of the header. N'est pas? Anyhow, I have tried sending header and content, and still get the same error. Were you able to succeed with sending content (filling in the envelope), and using the POST method? Thanx, Aaron -- Aaron (Aharon) Naiman Jerusalem College of Technology--Machon Lev nai...@math.jct.ac.il http://math.jct.ac.il/~naiman
Re: 'POST' method leads to 411 Length Required
On Apr 21, 2009, at 5:10 PM, Aaron Naiman wrote: Dear Björn, Thank you again for your response. * Aaron Naiman wrote: You are using POST but are not posting any data, and apparently the server ... An Error Occurred 411 Length Required ... expects you to post some data when using POST. But as can be seen from .../HTTP/Status.pm, this is a *client* error, and not a server error. You're sending somebody who expects a letter from you an empty envelope. However, from all of the examples I have seen, one need not send anything in a POST. Some parts of the HTTP spec are ambiguous and left to implementation. In this specific case, error 411 means the server is saying that you are not sending a necessary content-length header, which is required for POSt requests whether there is any content or not. It may be that LWP doesn't provide the header if there is no content. Did you inspect the request to verify that the content-length header is indeed being sent? If the header is indeed being sent, the server might be choking on a 0 length. Send bogus data to see if that helps. HTH, Keary Suska
