Merge pull request #1 from martinrehfeld/return-values

Use atoms in error return values

README.md

@@ -24,9 +24,9 @@ Req = "Z9Xn16Pdo5ac9YWDh5HD70aujhsZ9eCoyPMcpd2aaiM.eyJhbGdvcml0aG0iOiJITUFDLVN"
 
 
 % If the request is invalid the following return values are expected:
-{error, <<"Invalid format of signed request">>}
-{error, <<"Invalid Signature">>}
-{error, <<"Invalid Payload">>}
+{error, invalid_format}
+{error, invalid_signature}
+{error, invalid_payload}
 
 
 % Generate a signed request (useful for testing)

src/fb_signed_request.erl

@@ -28,28 +28,27 @@ generate(Payload, Secret) ->
 
 
 generate(Payload, Secret, [{return, binary}]) ->
-    erlang:list_to_binary(generate(Payload, Secret)).
+    list_to_binary(generate(Payload, Secret)).
 
 
 extract_signature_and_payload(Request) ->
-    try
-        re:split(Request, "\\.", [{return, list}])
-    catch
-        _:_ -> throw({fb_signed_request, <<"Invalid format of signed request">>})
+    case re:split(Request, "\\.", [{return, list}]) of
+        [Signature, Payload] -> [Signature, Payload];
+        _                    -> throw({fb_signed_request, invalid_format})
     end.
 
 
 decode_body(Payload) when is_binary(Payload) ->
-    decode_body( binary:bin_to_list(Payload) );
+    decode_body( binary_to_list(Payload) );
 
 
 decode_body(Payload) when is_list(Payload) ->
     try
-        erlang:list_to_binary(
+        list_to_binary(
             base64:decode_to_string( base64_pad(Payload) )
         )
     catch
-       _:_ -> throw({fb_signed_request, <<"Invalid Payload">>})
+       _:_ -> throw({fb_signed_request, invalid_payload})
     end.
 
 
@@ -59,7 +58,7 @@ validate_signature(Signature, Payload, Secret) ->
         ComputedSignature = create_signature(Payload, Secret),
         ComputedSignature = Signature
     catch
-        error:{badmatch,_} -> throw({fb_signed_request, <<"Invalid Signature">>})
+        error:{badmatch,_} -> throw({fb_signed_request, invalid_signature})
     end.
 
 
@@ -104,4 +103,4 @@ base64_pad( String ) ->
         0 -> 0;
         N -> 4 - N
     end,
-    string:left(String, Length + ToPad, $=).
+    string:left(String, Length + ToPad, $=).

test/fb_signed_request_test.erl

@@ -7,7 +7,9 @@
 
 -define(FB_SECRET, "897z956a2z7zzzzz5783z458zz3z7556").
 -define(VALID_REQ, "Z9Xn16Pdo5ac9YWDh5HD70aujhsZ9eCoyPMcpd2aaiM.eyJhbGdvcml0aG0iOiJITUFDLVNIQTI1NiIsImV4cGlyZXMiOjEzMDg5ODg4MDAsImlzc3VlZF9hdCI6MTMwODk4NTAxOCwib2F1dGhfdG9rZW4iOiIxMTExMTExMTExMTExMTF8Mi5BUUJBdHRSbExWbndxTlBaLjM2MDAuMTExMTExMTExMS4xLTExMTExMTExMTExMTExMXxUNDl3M0Jxb1pVZWd5cHJ1NTFHcmE3MGhFRDgiLCJ1c2VyIjp7ImFnZSI6eyJtaW4iOjIxfSwiY291bnRyeSI6ImRlIiwibG9jYWxlIjoiZW5fVVMifSwidXNlcl9pZCI6IjExMTExMTExMTExMTExMSJ9").
--define(INVALID_REQ, "umfudisP7mKhsi9nZboBg15yMZKhfQAARL9UoZtSE.eyJhbGdvcml0aG0iOiJITUFDLVNIQTI1NiIsImV4cGlyZXMiOjEzMDg5ODg4MDAsImlzc3VlZF9hdCI6MTMwODk4NTAxOCwib2F1dGhfdG9rZW4iOiIxMTExMTExMTExMTExMTF8Mi5BUUJBdHRSbExWbndxTlBaLjM2MDAuMTExMTExMTExMS4xLTExMTExMTExMTExMTExMXxUNDl3M0Jxb1pVZWd5cHJ1NTFHcmE3MGhFRDgiLCJ1c2VyIjp7ImNvdW50cnkiOiJkZSIsImxvY2FsZSI6ImVuX1VTIiwiYWdlIjp7Im1pbiI6MjF9fSwidXNlcl9pZCI6IjExMTExMTExMTExMTExMSJ9").
+-define(INVALID_REQ_FORMAT, "Z9Xn16Pdo5ac9YWDh5HD70aujhsZ9eCoyPMcpd2aaiM2eyJhbGdvcml0aG0iOiJITUFDLVNIQTI1NiIsImV4cGlyZXMiOjEzMDg5ODg4MDAsImlzc3VlZF9hdCI6MTMwODk4NTAxOCwib2F1dGhfdG9rZW4iOiIxMTExMTExMTExMTExMTF8Mi5BUUJBdHRSbExWbndxTlBaLjM2MDAuMTExMTExMTExMS4xLTExMTExMTExMTExMTExMXxUNDl3M0Jxb1pVZWd5cHJ1NTFHcmE3MGhFRDgiLCJ1c2VyIjp7ImFnZSI6eyJtaW4iOjIxfSwiY291bnRyeSI6ImRlIiwibG9jYWxlIjoiZW5fVVMifSwidXNlcl9pZCI6IjExMTExMTExMTExMTExMSJ9").
+-define(INVALID_REQ_PAYLOAD, "Z9Xn16Pdo5ac9YWDh5HD70aujhsZ9eCoyPMcpd2aaiM.*yJhbGdvcml0aG0iOiJITUFDLVNIQTI1NiIsImV4cGlyZXMiOjEzMDg5ODg4MDAsImlzc3VlZF9hdCI6MTMwODk4NTAxOCwib2F1dGhfdG9rZW4iOiIxMTExMTExMTExMTExMTF8Mi5BUUJBdHRSbExWbndxTlBaLjM2MDAuMTExMTExMTExMS4xLTExMTExMTExMTExMTExMXxUNDl3M0Jxb1pVZWd5cHJ1NTFHcmE3MGhFRDgiLCJ1c2VyIjp7ImFnZSI6eyJtaW4iOjIxfSwiY291bnRyeSI6ImRlIiwibG9jYWxlIjoiZW5fVVMifSwidXNlcl9pZCI6IjExMTExMTExMTExMTExMSJ9").
+-define(INVALID_REQ_SIGNATURE, "umfudisP7mKhsi9nZboBg15yMZKhfQAARL9UoZtSE.eyJhbGdvcml0aG0iOiJITUFDLVNIQTI1NiIsImV4cGlyZXMiOjEzMDg5ODg4MDAsImlzc3VlZF9hdCI6MTMwODk4NTAxOCwib2F1dGhfdG9rZW4iOiIxMTExMTExMTExMTExMTF8Mi5BUUJBdHRSbExWbndxTlBaLjM2MDAuMTExMTExMTExMS4xLTExMTExMTExMTExMTExMXxUNDl3M0Jxb1pVZWd5cHJ1NTFHcmE3MGhFRDgiLCJ1c2VyIjp7ImNvdW50cnkiOiJkZSIsImxvY2FsZSI6ImVuX1VTIiwiYWdlIjp7Im1pbiI6MjF9fSwidXNlcl9pZCI6IjExMTExMTExMTExMTExMSJ9").
 -define(EXPECTED_VALID_DATA, <<"{\"algorithm\":\"HMAC-SHA256\",\"expires\":1308988800,\"issued_at\":1308985018,\"oauth_token\":\"111111111111111|2.AQBAttRlLVnwqNPZ.3600.1111111111.1-111111111111111|T49w3BqoZUegypru51Gra70hED8\",\"user\":{\"age\":{\"min\":21},\"country\":\"de\",\"locale\":\"en_US\"},\"user_id\":\"111111111111111\"}">>).
 
 
@@ -16,9 +18,19 @@ test_parsing_a_valid_request() ->
     ?assert_equal({ok, ?EXPECTED_VALID_DATA}, Result).
 
 
-test_parsing_a_invalid_request() ->
-    Result = fb_signed_request:parse(?INVALID_REQ, ?FB_SECRET),
-    ?assert_equal({error, <<"Invalid Signature">>}, Result).
+test_parsing_a_request_with_invalid_format() ->
+    Result = fb_signed_request:parse(?INVALID_REQ_FORMAT, ?FB_SECRET),
+    ?assert_equal({error, invalid_format}, Result).
+
+
+test_parsing_a_request_with_invalid_payload() ->
+    Result = fb_signed_request:parse(?INVALID_REQ_PAYLOAD, ?FB_SECRET),
+    ?assert_equal({error, invalid_payload}, Result).
+
+
+test_parsing_a_request_with_invalid_signature() ->
+    Result = fb_signed_request:parse(?INVALID_REQ_SIGNATURE, ?FB_SECRET),
+    ?assert_equal({error, invalid_signature}, Result).
 
 
 test_generating_and_parsing_and_validating_a_request() ->
@@ -33,4 +45,4 @@ test_generate_signed_request_as_binary() ->
         ?EXPECTED_VALID_DATA, ?FB_SECRET, [{return, binary}]
     ),
 
-    ?assert_equal(erlang:list_to_binary(?VALID_REQ), SignedRequest).
+    ?assert_equal(erlang:list_to_binary(?VALID_REQ), SignedRequest).