Hi all, Not an Elixir problem per se but one with Erlang’s httpc module, that is getting me insane. I’m using it in one of my projects trying to avoid adding a dependency for a few http requests. I’m trying to get a payload at an address, and receive a redirect ({:redirect, false} added for demonstration purpose): iex(67)> :httpc.request(:get, {'https://mds2.fidoalliance.org/metadata/t3fyXjAh2Eu7EDsN4tQ6HL?token=[access_token_here]', []}, [{:verbose, :debug}, {:autoredirect, false}], []) 17:28:12.607 [info] [73, 110, 118, 97, 108, 105, 100, 32, 111, 112, 116, 105, 111, 110, 32, [123, ['verbose', 44, 'debug'], 125], 32, 105, 103, 110, 111, 114, 101, 100, 32, 10] {:ok, {{'HTTP/1.1', 301, 'MOVED PERMANENTLY'}, [ {'connection', 'keep-alive'}, {'date', 'Fri, 11 Jan 2019 14:28:13 GMT'}, {'location', 'https://mds2.fidoalliance.org/metadata/t3fyXjAh2Eu7EDsN4tQ6HL/?token=[access_token_here]'}, {'server', 'cloudflare'}, {'content-length', '441'}, {'content-type', 'text/html; charset=utf-8'}, {'set-cookie', '__cfduid=d88330cf7c6165a3dad6797c3cf5e8c171547216892; expires=Sat, 11-Jan-20 14:28:12 GMT; path=/; domain=.fidoalliance.org; HttpOnly'}, {'x-frame-options', 'SAMEORIGIN'}, {'x-xss-protection', '1; mode=block'}, {'expect-ct', 'max-age=604800, report-uri="https://report-uri.cloudflare.com/cdn-cgi/beacon/expect-ct"'}, {'cf-ray', '4978118b484e8ed9-DME'} ], '\nRedirecting...\n

Redirecting...

You should be redirected automatically to target URL: https://mds2.fidoalliance.org/metadata/t3fyXjAh2Eu7EDsN4tQ6HL/?token=d.... If not click the link.'}} Let’s try to make a new request from the value of the Location response header (the only difference is the '/' added before the '?'): iex(68)> :httpc.request(:get, {'https://mds2.fidoalliance.org/metadata/t3fyXjAh2Eu7EDsN4tQ6HL/?token=[access_token_here]', []}, [{:verbose, :debug}, {:autoredirect, false}], []) 17:30:19.542 [info] [73, 110, 118, 97, 108, 105, 100, 32, 111, 112, 116, 105, 111, 110, 32, [123, ['verbose', 44, 'debug'], 125], 32, 105, 103, 110, 111, 114, 101, 100, 32, 10] {:ok, {{'HTTP/1.1', 200, 'OK'}, [ {'cache-control', 'public, max-age=43200'}, {'connection', 'keep-alive'}, {'date', 'Fri, 11 Jan 2019 14:30:20 GMT'}, {'accept-ranges', 'bytes'}, {'etag', '"1547064685.0-7052-1005851543"'}, {'server', 'cloudflare'}, {'content-length', '7052'}, {'content-type', 'application/octet-stream'}, {'expires', 'Sat, 12 Jan 2019 02:30:20 GMT'}, {'last-modified', 'Wed, 09 Jan 2019 20:11:25 GMT'}, {'set-cookie', '__cfduid=d7e19909933a681371cf8aa0a1c490d191547217019; expires=Sat, 11-Jan-20 14:30:19 GMT; path=/; domain=.fidoalliance.org; HttpOnly'}, {'x-frame-options', 'SAMEORIGIN'}, {'content-disposition', 'attachment; filename=t3fyXjAh2Eu7EDsN4tQ6HL'}, {'x-xss-protection', '1; mode=block'}, {'expect-ct', 'max-age=604800, report-uri="https://report-uri.cloudflare.com/cdn-cgi/beacon/expect-ct"'}, {'cf-ray', '497814a48a104e54-DME'} ], 'eyJhc3NlcnRpb25TY2hlbWUiOiAiVTJGVjFCSU4iLCAiYXR0YW[...]' ++ ...}} Works fine. But now, when I reenable the auto-redirect (by not setting the :autoredirect option - default is true), I get a 404 error: iex(69)> :httpc.request(:get, {'https://mds2.fidoalliance.org/metadata/t3fyXjAh2Eu7EDsN4tQ6HL?token=...', []}, [{:verbose, :debug}], []) 17:33:29.843 [info] [73, 110, 118, 97, 108, 105, 100, 32, 111, 112, 116, 105, 111, 110, 32, [123, ['verbose', 44, 'debug'], 125], 32, 105, 103, 110, 111, 114, 101, 100, 32, 10] {:ok, {{'HTTP/1.1', 404, 'NOT FOUND'}, [ {'connection', 'keep-alive'}, {'date', 'Fri, 11 Jan 2019 14:33:31 GMT'}, {'server', 'cloudflare'}, {'content-length', '233'}, {'content-type', 'text/html'}, {'set-cookie', '__cfduid=db7e100503b6a9c7a64fcdb6f851aca681547217210; expires=Sat, 11-Jan-20 14:33:30 GMT; path=/; domain=.fidoalliance.org; HttpOnly'}, {'x-frame-options', 'SAMEORIGIN'}, {'x-xss-protection', '1; mode=block'}, {'expect-ct', 'max-age=604800, report-uri="https://report-uri.cloudflare.com/cdn-cgi/beacon/expect-ct"'}, {'cf-ray', '4978194eebbf8eeb-DME'} ], '\n404 Not Found\n

Not Found

The requested URL was not found on the server. If you entered the URL manually please check your spelling and try again.

\n'}} As you can see the :debug option is not much helpful. Any idea on why or other debugging solutions are welcome :slight_smile: Have a nice day

:httpc redirect issue