pattern match HTTpoison response Elixir

Question

Is there any way that we can pattern match the error response of httpoison ? I was doing this

case HTTPoison.get!(url, [], []) do
  %HTTPoison.Error{reason: reason} ->
    IO.inspect "Media: #{reason}!"
    :timer.sleep(:timer.seconds(3))
    do_loop(starting, ending, interval, camera_exid)
  response ->
    upload(response.status_code, response.body, starting, camera_exid)
    do_loop(starting + interval, ending, interval, camera_exid)
end

But It didn't catch the timeout and gave me error as

** (HTTPoison.Error) :timeout
    (httpoison) lib/httpoison.ex:66: HTTPoison.request!/5
    (extractor) lib/snapshot/snap_extractor.ex:67: Extractor.SnapExtractor.do_loop/4
       (elixir) lib/enum.ex:651: Enum."-each/2-lists^foreach/1-0-"/2
       (elixir) lib/enum.ex:651: Enum.each/2

I think am doing it in wrong way.. Any suggestions?

Dogbert Dogbert · Accepted Answer · 2016-10-24T11:39:30

HTTPoison.get! will raise an exception, not return one, so you need to use try ... rescue ...:

try do
  response = HTTPoison.get!(url, [], [])
  upload(response.status_code, response.body, starting, camera_exid)
  do_loop(starting + interval, ending, interval, camera_exid)
rescue
  %HTTPoison.Error{reason: reason} ->
    IO.inspect "Media: #{reason}!"
    :timer.sleep(:timer.seconds(3))
    do_loop(starting, ending, interval, camera_exid)
end

This is however not considered good code since HTTPoison also has get which returns {:ok, response} or {:error, error} which you can use as follows:

case HTTPoison.get(url, [], []) do
  {:ok, response} ->
    upload(response.status_code, response.body, starting, camera_exid)
    do_loop(starting + interval, ending, interval, camera_exid)
  {:error, %HTTPoison.Error{reason: reason}} ->
    IO.inspect "Media: #{reason}!"
    :timer.sleep(:timer.seconds(3))
    do_loop(starting, ending, interval, camera_exid)
end

pattern match HTTpoison response Elixir

1 Answers