Patch expm http.ex to pass http proxy settings to hackney

http.ex.patch

diff --git a/lib/repositories/http.ex b/lib/repositories/http.ex
index 2dae690..bdb1ece 100644
--- a/lib/repositories/http.ex
+++ b/lib/repositories/http.ex
@@ -9,7 +9,7 @@ defrecord Expm.Repository.HTTP, url: "https://expm.co", username: nil, password:
                  {"accept", "text/html"},
                  {"user-agent", "expm/#{Expm.version}"},                 
                 ],
-                "", [follow_redirect: true, force_redirect: true])
+                "", Expm.Repository.HTTP.Decoder.proxy(follow_redirect: true, force_redirect: true))
     {:ok, body, client} = H.body(client)
     H.close(client)
     body
@@ -21,6 +21,25 @@ end
 defmodule Expm.Repository.HTTP.Decoder do
   defexception SecurityException, message: nil
 
+  def proxy(options) do
+    case :os.getenv("https_proxy") do
+      false ->
+        case :os.getenv("HTTPS_PROXY") do
+          false ->
+            case :os.getenv("http_proxy") do
+              false ->
+                case :os.getenv("HTTP_PROXY") do
+                  false -> options
+                  proxy -> [ { :proxy, proxy } | options ]
+                end
+              proxy -> [ { :proxy, proxy } | options ]
+            end
+          proxy -> [ { :proxy, proxy } | options ]
+        end
+      proxy -> [ { :proxy, proxy } | options ]
+    end
+  end
+
   def decode({ :__block__, _, [b] }) when is_list(b) do
     decode_1(b)
   end
@@ -59,7 +78,7 @@ defimpl Expm.Repository, for: Expm.Repository.HTTP do
                  {"accept", "application/elixir"},
                  {"user-agent", "expm/#{Expm.version}"},
                 ],
-                "", [follow_redirect: true, force_redirect: true])
+                "", Expm.Repository.HTTP.Decoder.proxy(follow_redirect: true, force_redirect: true))
     {:ok, body, client} = H.body(client)
     H.close(client)
     case code do
@@ -77,7 +96,7 @@ defimpl Expm.Repository, for: Expm.Repository.HTTP do
                  {"accept", "application/elixir"},
                  {"user-agent", "expm/#{Expm.version}"},
                 ],
-                "", [follow_redirect: true, force_redirect: true])
+                "", Expm.Repository.HTTP.Decoder.proxy(follow_redirect: true, force_redirect: true))
     {:ok, body, client} = H.body(client)
     H.close(client)
     case code do
@@ -102,7 +121,7 @@ defimpl Expm.Repository, for: Expm.Repository.HTTP do
                  {"accept", "application/elixir"},
                  {"user-agent", "expm/#{Expm.version}"},              
                  ],
-                spec.encode, [follow_redirect: true, force_redirect: true])
+                spec.encode, Expm.Repository.HTTP.Decoder.proxy(follow_redirect: true, force_redirect: true))
     {:ok, body, client} = H.body(client)
     H.close(client)
     case code do
@@ -120,7 +139,7 @@ defimpl Expm.Repository, for: Expm.Repository.HTTP do
                  {"accept", "application/elixir"},
                  {"user-agent", "expm/#{Expm.version}"},          
                  ],
-                "", [follow_redirect: true, force_redirect: true])
+                "", Expm.Repository.HTTP.Decoder.proxy(follow_redirect: true, force_redirect: true))
     {:ok, body, client} = H.body(client)
     H.close(client)
     case code do
@@ -138,7 +157,7 @@ defimpl Expm.Repository, for: Expm.Repository.HTTP do
                  {"accept", "application/elixir"},
                  {"user-agent", "expm/#{Expm.version}"},         
                  ],
-                filter.encode, [follow_redirect: true, force_redirect: true])
+                filter.encode, Expm.Repository.HTTP.Decoder.proxy(follow_redirect: true, force_redirect: true))
     {:ok, body, client} = H.body(client)
     H.close(client)
     case code do 
@@ -149,4 +168,4 @@ defimpl Expm.Repository, for: Expm.Repository.HTTP do
     end
   end
 
-end
\ No newline at end of file
+end