Httpoison get request with basic authorization -- "HTTP request failed: bad_request"

Questions & Help Questions
3

That error comes from the Hackney machinery responsible for parsing the response; the fact that it’s going down the {:error, HTTPoison.Error} path means it’s failing to parse the opening line of the response - things like missing headers etc would generally result in an HTTPoison.Response with a status_code of 400.

The code in Hackney suggests some possiblities:

https://github.com/benoitc/hackney/blob/d6d075f9edcbb7e0b5c9418dba5dd34f2c95bc21/src/hackney_http.erl#L194-L227

  • the server is sending too many blank lines before the HTTP/1.1 200 OK
  • the server is sending malformed line-endings which cause the binary:split on line 196 to not find two parts
  • the server is sending some other kind of mis-formatted value in the opening line (omitting the reason? Spelling HTTP wrong? Hard to tell)

The most reliable way to troubleshoot this is to capture the EXACT bytes the server is replying with, for instance with curl --trace:

Matts-MacBook-Pro-2:phoenix mattjones$ curl --trace - http://example.com
== Info: Rebuilt URL to: http://example.com/
== Info:   Trying 93.184.216.34...
== Info: TCP_NODELAY set
== Info: Connected to example.com (93.184.216.34) port 80 (#0)
=> Send header, 75 bytes (0x4b)
0000: 47 45 54 20 2f 20 48 54 54 50 2f 31 2e 31 0d 0a GET / HTTP/1.1..
0010: 48 6f 73 74 3a 20 65 78 61 6d 70 6c 65 2e 63 6f Host: example.co
0020: 6d 0d 0a 55 73 65 72 2d 41 67 65 6e 74 3a 20 63 m..User-Agent: c
0030: 75 72 6c 2f 37 2e 35 34 2e 30 0d 0a 41 63 63 65 url/7.54.0..Acce
0040: 70 74 3a 20 2a 2f 2a 0d 0a 0d 0a                pt: */*....
<= Recv header, 17 bytes (0x11)
0000: 48 54 54 50 2f 31 2e 31 20 32 30 30 20 4f 4b 0d HTTP/1.1 200 OK.
0010: 0a                                              .
<= Recv header, 13 bytes (0xd)
0000: 41 67 65 3a 20 35 30 31 35 34 32 0d 0a          Age: 501542..
<= Recv header, 31 bytes (0x1f)
0000: 43 61 63 68 65 2d 43 6f 6e 74 72 6f 6c 3a 20 6d Cache-Control: m
0010: 61 78 2d 61 67 65 3d 36 30 34 38 30 30 0d 0a    ax-age=604800..
<= Recv header, 40 bytes (0x28)
0000: 43 6f 6e 74 65 6e 74 2d 54 79 70 65 3a 20 74 65 Content-Type: te
0010: 78 74 2f 68 74 6d 6c 3b 20 63 68 61 72 73 65 74 xt/html; charset
0020: 3d 55 54 46 2d 38 0d 0a                         =UTF-8..
<= Recv header, 37 bytes (0x25)
0000: 44 61 74 65 3a 20 53 75 6e 2c 20 30 36 20 41 75 Date: Sun, 06 Au
0010: 67 20 32 30 32 33 20 32 30 3a 30 36 3a 35 35 20 g 2023 20:06:55 
0020: 47 4d 54 0d 0a                                  GMT..
<= Recv header, 26 bytes (0x1a)
...etcetcetc...