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Redirect (301) after POST re-reads file #9735

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auselen opened this issue Oct 14, 2022 · 2 comments

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HTTP

auselen commented Oct 14, 2022 •

edited

I did this

Some python3 code to imitate the server I was working with

import sys
from http.server import HTTPServer, BaseHTTPRequestHandler
class Redirect(BaseHTTPRequestHandler):
   def do_POST(self):
       post_data = self.rfile.read(1)
       self.send_response(301)
       self.send_header('Location', 'http://no.no')
       self.end_headers()
HTTPServer(("", 9000), Redirect).serve_forever()

$ python3 server.py

$ curl -v -F content=@<(echo hello) -L localhost:9000
...
curl: (65) Cannot rewind mime/post data

I expected the following

Reading https://everything.curl.dev/http/redirects, I wouldn't expect curl to try to rewind my input file (process substitution) when redirect is just a 301 and switches to GET.

curl/libcurl version

I tried with a local build and some prebuilt binary.

curl 7.86.0-DEV, 7.68.0

operating system

.

The text was updated successfully, but these errors were encountered:

bagder added the HTTP label

Contributor

dfandrich commented Oct 15, 2022 via email

The 301 doesn't come back until *after* the data is sent the first time. I think it might be possible to overcome this by forcing the 100-Continue logic which should send the redirect before the data is sent.

Member

bagder commented Oct 17, 2022

The problem is that curl considers and performs the rewind already when it sees the Location: header in the response to POST, before it has decided it should switch to GET...

bagder self-assigned this

bagder added a commit that referenced this issue


          lib: rewind BEFORE request instead of AFTER previous

07bef25

This makes a big difference for cases when the second request is not
actually performed (for exampel HTTP respons code 301 converts to GET)
and thererfore the rewind can be avoided. In particular for situations
when that rewind *fails*.

Reported-by: Ali Utku Selen

Fixes #9735
Closes #....

bagder added a commit that referenced this issue


          test1662: verify formpost, 302 redirect, no rewind possible

a33c480

Reproduces #9735 and verifies the subsequent fix. The original issue
uses a pipe that cannot be rewound, but this test case instead sets a
callback without rewind ability to get roughly the same properties but
being a much more portable test.

bagder added a commit that referenced this issue


          lib: rewind BEFORE request instead of AFTER previous

617373a

This makes a big difference for cases when the second request is not
actually performed (for example HTTP response code 301 converts to GET)
and therefore the rewind can be avoided. In particular for situations
when that rewind *fails*.

Reported-by: Ali Utku Selen

Fixes #9735
Closes #....

bagder added a commit that referenced this issue


          test1662: verify formpost, 301 redirect, no rewind possible

c632741

Reproduces #9735 and verifies the subsequent fix. The original issue
uses a pipe that cannot be rewound, but this test case instead sets a
callback without rewind ability to get roughly the same properties but
being a much more portable test.

bagder added a commit that referenced this issue


          lib: rewind BEFORE request instead of AFTER previous

445999a

This makes a big difference for cases when the second request is not
actually performed (for example HTTP response code 301 converts to GET)
and therefore the rewind can be avoided. In particular for situations
when that rewind *fails*.

Reported-by: Ali Utku Selen

Fixes #9735
Closes #9958

bagder added a commit that referenced this issue


          test1662: verify formpost, 301 redirect, no rewind possible

822c68b

Reproduces #9735 and verifies the subsequent fix. The original issue
uses a pipe that cannot be rewound, but this test case instead sets a
callback without rewind ability to get roughly the same properties but
being a much more portable test.

bagder added a commit that referenced this issue


          lib: rewind BEFORE request instead of AFTER previous

59c53a4

This makes a big difference for cases when the second request is not
actually performed (for example HTTP response code 301 converts to GET)
and therefore the rewind can be avoided. In particular for situations
when that rewind *fails*.

Reported-by: Ali Utku Selen

Fixes #9735
Closes #9958

bagder added a commit that referenced this issue


          test1662: verify formpost, 301 redirect, no rewind possible

1232c42

Reproduces #9735 and verifies the subsequent fix. The original issue
uses a pipe that cannot be rewound, but this test case instead sets a
callback without rewind ability to get roughly the same properties but
being a much more portable test.

bagder added a commit that referenced this issue


          lib: rewind BEFORE request instead of AFTER previous

77ee2d8

This makes a big difference for cases when the second request is not
actually performed (for example HTTP response code 301 converts to GET)
and therefore the rewind can be avoided. In particular for situations
when that rewind *fails*.

Reported-by: Ali Utku Selen

Fixes #9735
Closes #9958

bagder added a commit that referenced this issue


          test1662: verify formpost, 301 redirect, no rewind possible

2b3f62a

Reproduces #9735 and verifies the subsequent fix. The original issue
uses a pipe that cannot be rewound, but this test case instead sets a
callback without rewind ability to get roughly the same properties but
being a much more portable test.

bagder closed this as completed in

1b39731

bagder added a commit that referenced this issue


          test1662: verify formpost, 301 redirect, no rewind possible

cde8f28

Reproduces #9735 and verifies the subsequent fix. The original issue
uses a pipe that cannot be rewound, but this test case instead sets a
callback without rewind ability to get roughly the same properties but
being a much more portable test.

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