模式匹配HTTpoison響應Elixir

Question

有沒有什麼辦法可以模式匹配httpoison的錯誤響應？我這樣做

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 

但它並沒有趕上timeout，給了我誤差

** (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 

我覺得我在錯誤的方式做吧..有什麼建議？

Answer 1

HTTPoison.get!將raise異常，不返回一個，所以你需要使用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 

但是，這是不是因爲HTTPoison也有get返回{:ok, response}或{:error, error}它可以直接使用認爲好的代碼如下：

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