How to get a video flow with Elixir/HTTPoison or Hackney?

问题

I'm trying to get a stream from a cam using Elixir / HTTPoison and dump it into a file. Url is x.x.x.x/axis-cgi/mjpg/video.cgi?duration=1&resolution=320x240

Using the url in DHC (Chrome addon), i can have the following:

Response 200 OK

HEADERS Cache-Control: no-cache Pragma: no-cache Expires: Thu, 01 Dec 1994 16:00:00 GMT Connection: close Content-Type: multipart/x-mixed-replace; boundary=myboundary X-Time-Offset: 62044.312573 pretty COMPLETE REQUEST HEADERS Accept: / Accept-Encoding: gzip, deflate, sdch Accept-Language: fr-FR,fr;q=0.8,en-US;q=0.6,en;q=0.4 Content-Type: application/xml User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/52.0.2743.116 Safari/537.36 Note: XHR automatically adds headers like Accept, Accept-Language, Cookie, User-Agent, etc.

Raw formatting the body is showing me a lot of binary jpeg image separated by a --myboundary thing.

--myboundary

Content-Type: image/jpeg

Content-Length: 11848

��JFIF�� W�u]7W�u]7�� 2�̎TY"��C

Now, i want to try to get the same thing with Elixir.

  test "request headers from cam" do
    options = [hackney: [basic_auth: {"login","password"}]]
    {:ok, %HTTPoison.AsyncResponse{id: id}} = HTTPoison.get "http://x.x.x.x/axis-cgi/mjpg/video.cgi?duration=1&resolution=320x240",[], [stream_to: self, recv_timeout: :infinity, hackney: options]
    assert_receive %HTTPoison.AsyncStatus{id: ^id, code: 200}, 1_000
  end

I do have the following response,

  1) test request headers from cam (NewsequenceTest)
     test/newsequence_test.exs:9
     No message matching %HTTPoison.AsyncStatus{id: ^id, code: 200} after 1000ms.
     The following variables were pinned:
       id = #Reference<0.0.3.125>
     Process mailbox:
       %HTTPoison.AsyncStatus{code: 401, id: #Reference<0.0.3.125>}
       %HTTPoison.AsyncHeaders{headers: [{"Date", "Wed, 31 Aug 2016 06:47:00 GMT"}, {"Accept-Ranges", "bytes"}, {"Connection", "close"}, {"WWW-Authenticate", "Digest realm=\"AXIS_ACCC8E545922\", nonce=\"0000fa64Y50235919055a42f91d3dea744b10d2dab9653\", stale=FALSE, qop=\"auth\""}, {"WWW-Authenticate", "Basic realm=\"AXIS_ACCC8E545922\""}, {"Content-Length", "189"}, {"Content-Type", "text/html; charset=ISO-8859-1"}], id: #Reference<0.0.3.125>}
       %HTTPoison.AsyncChunk{chunk: "<HTML><HEAD><TITLE>401 Unauthorized</TITLE></HEAD>\n<BODY><H1>401 Unauthorized</H1>\nYour client does not have permission to get URL /axis-cgi/mjpg/video.cgi from this server.\n</BODY></HTML>\n", id: #Reference<0.0.3.125>}
       %HTTPoison.AsyncEnd{id: #Reference<0.0.3.125>}
     stacktrace:
       test/newsequence_test.exs:12: (test)

I did try without basic auth with the same result.

I don't understand yet what it's happening with this auth error. Sure i misunderstod something, can someone please enlighten me on this subject ?

Kind regards,

Pierre

回答1:

So the problem here was that the code was calling:

HTTPoison.get(..., [], [..., hackney: [hackney: [basic_auth: {"login","password"}]]])

instead of:

HTTPoison.get(..., [], [..., hackney: [basic_auth: {"login","password"}]])

which was causing hackney to ignore them as it was trying to fetch opts[:hackney][:basic_auth] etc which were all nil.

The fix is to replace:

options = [hackney: [basic_auth: {"login","password"}]]

with

options = [basic_auth: {"login","password"}]

来源：https://stackoverflow.com/questions/39243409/how-to-get-a-video-flow-with-elixir-httpoison-or-hackney

标签

elixir

multipart-mixed-replace

httpoison