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-rw-r--r--src/cowboy_constraints.erl175
-rw-r--r--src/cowboy_req.erl12
-rw-r--r--src/cowboy_router.erl12
3 files changed, 155 insertions, 44 deletions
diff --git a/src/cowboy_constraints.erl b/src/cowboy_constraints.erl
index 27c0e72..6b468fe 100644
--- a/src/cowboy_constraints.erl
+++ b/src/cowboy_constraints.erl
@@ -15,47 +15,160 @@
-module(cowboy_constraints).
-export([validate/2]).
+-export([reverse/2]).
+-export([format_error/1]).
-type constraint() :: int | nonempty | fun().
-export_type([constraint/0]).
--spec validate(binary(), [constraint()]) -> true | {true, any()} | false.
-validate(Value, [Constraint]) ->
- apply_constraint(Value, Constraint);
+-type reason() :: {constraint(), any(), any()}.
+-export_type([reason/0]).
+
+-spec validate(binary(), constraint() | [constraint()])
+ -> {ok, any()} | {error, reason()}.
validate(Value, Constraints) when is_list(Constraints) ->
- validate_list(Value, Constraints, original);
+ apply_list(forward, Value, Constraints);
validate(Value, Constraint) ->
- apply_constraint(Value, Constraint).
-
-validate_list(_, [], original) ->
- true;
-validate_list(Value, [], modified) ->
- {true, Value};
-validate_list(Value, [Constraint|Tail], State) ->
- case apply_constraint(Value, Constraint) of
- true ->
- validate_list(Value, Tail, State);
- {true, Value2} ->
- validate_list(Value2, Tail, modified);
- false ->
- false
+ apply_list(forward, Value, [Constraint]).
+
+-spec reverse(any(), constraint() | [constraint()])
+ -> {ok, binary()} | {error, reason()}.
+reverse(Value, Constraints) when is_list(Constraints) ->
+ apply_list(reverse, Value, Constraints);
+reverse(Value, Constraint) ->
+ apply_list(reverse, Value, [Constraint]).
+
+-spec format_error(reason()) -> iodata().
+format_error({Constraint, Reason, Value}) ->
+ apply_constraint(format_error, {Reason, Value}, Constraint).
+
+apply_list(_, Value, []) ->
+ {ok, Value};
+apply_list(Type, Value0, [Constraint|Tail]) ->
+ case apply_constraint(Type, Value0, Constraint) of
+ {ok, Value} ->
+ apply_list(Type, Value, Tail);
+ {error, Reason} ->
+ {error, {Constraint, Reason, Value0}}
end.
%% @todo {int, From, To}, etc.
-apply_constraint(Value, int) ->
- int(Value);
-apply_constraint(Value, nonempty) ->
- nonempty(Value);
-apply_constraint(Value, F) when is_function(F) ->
- F(Value).
+apply_constraint(Type, Value, int) ->
+ int(Type, Value);
+apply_constraint(Type, Value, nonempty) ->
+ nonempty(Type, Value);
+apply_constraint(Type, Value, F) when is_function(F) ->
+ F(Type, Value).
%% Constraint functions.
-int(Value) when is_binary(Value) ->
- try {true, binary_to_integer(Value)}
- catch _:_ -> false
- end.
+int(forward, Value) ->
+ try
+ {ok, binary_to_integer(Value)}
+ catch _:_ ->
+ {error, not_an_integer}
+ end;
+int(reverse, Value) ->
+ try
+ {ok, integer_to_binary(Value)}
+ catch _:_ ->
+ {error, not_an_integer}
+ end;
+int(format_error, {not_an_integer, Value}) ->
+ io_lib:format("The value ~p is not an integer.", [Value]).
+
+nonempty(Type, <<>>) when Type =/= format_error ->
+ {error, not_empty};
+nonempty(Type, Value) when Type =/= format_error, is_binary(Value) ->
+ {ok, Value};
+nonempty(format_error, {not_empty, Value}) ->
+ io_lib:format("The value ~p is not empty.", [Value]).
+
+-ifdef(TEST).
+
+validate_test() ->
+ F = fun(_, Value) ->
+ try
+ {ok, binary_to_atom(Value, latin1)}
+ catch _:_ ->
+ {error, not_a_binary}
+ end
+ end,
+ %% Value, Constraints, Result.
+ Tests = [
+ {<<>>, [], <<>>},
+ {<<"123">>, int, 123},
+ {<<"123">>, [int], 123},
+ {<<"123">>, [nonempty, int], 123},
+ {<<"123">>, [int, nonempty], 123},
+ {<<>>, nonempty, error},
+ {<<>>, [nonempty], error},
+ {<<"hello">>, F, hello},
+ {<<"hello">>, [F], hello},
+ {<<"123">>, [F, int], error},
+ {<<"123">>, [int, F], error},
+ {<<"hello">>, [nonempty, F], hello},
+ {<<"hello">>, [F, nonempty], hello}
+ ],
+ [{lists:flatten(io_lib:format("~p, ~p", [V, C])), fun() ->
+ case R of
+ error -> {error, _} = validate(V, C);
+ _ -> {ok, R} = validate(V, C)
+ end
+ end} || {V, C, R} <- Tests].
+
+reverse_test() ->
+ F = fun(_, Value) ->
+ try
+ {ok, atom_to_binary(Value, latin1)}
+ catch _:_ ->
+ {error, not_an_atom}
+ end
+ end,
+ %% Value, Constraints, Result.
+ Tests = [
+ {<<>>, [], <<>>},
+ {123, int, <<"123">>},
+ {123, [int], <<"123">>},
+ {123, [nonempty, int], <<"123">>},
+ {123, [int, nonempty], <<"123">>},
+ {<<>>, nonempty, error},
+ {<<>>, [nonempty], error},
+ {hello, F, <<"hello">>},
+ {hello, [F], <<"hello">>},
+ {123, [F, int], error},
+ {123, [int, F], error},
+ {hello, [nonempty, F], <<"hello">>},
+ {hello, [F, nonempty], <<"hello">>}
+ ],
+ [{lists:flatten(io_lib:format("~p, ~p", [V, C])), fun() ->
+ case R of
+ error -> {error, _} = reverse(V, C);
+ _ -> {ok, R} = reverse(V, C)
+ end
+ end} || {V, C, R} <- Tests].
+
+int_format_error_test() ->
+ {error, Reason} = validate(<<"string">>, int),
+ Bin = iolist_to_binary(format_error(Reason)),
+ true = is_binary(Bin),
+ ok.
+
+nonempty_format_error_test() ->
+ {error, Reason} = validate(<<>>, nonempty),
+ Bin = iolist_to_binary(format_error(Reason)),
+ true = is_binary(Bin),
+ ok.
+
+fun_format_error_test() ->
+ F = fun
+ (format_error, {test, <<"value">>}) ->
+ formatted;
+ (_, _) ->
+ {error, test}
+ end,
+ {error, Reason} = validate(<<"value">>, F),
+ formatted = format_error(Reason),
+ ok.
-nonempty(<<>>) -> false;
-nonempty(Value) when is_binary(Value) -> true.
-%% @todo Perhaps return true for any other type except empty list?
+-endif.
diff --git a/src/cowboy_req.erl b/src/cowboy_req.erl
index ab77a68..3eca379 100644
--- a/src/cowboy_req.erl
+++ b/src/cowboy_req.erl
@@ -780,10 +780,10 @@ filter([Key|Tail], Map) ->
true = maps:is_key(Key, Map),
filter(Tail, Map).
-filter_constraints(Tail, Map, Key, Value, Constraints) ->
- case cowboy_constraints:validate(Value, Constraints) of
- true ->
- filter(Tail, Map);
- {true, Value2} ->
- filter(Tail, Map#{Key => Value2})
+filter_constraints(Tail, Map, Key, Value0, Constraints) ->
+ case cowboy_constraints:validate(Value0, Constraints) of
+ {ok, Value} ->
+ filter(Tail, Map#{Key => Value});
+ {error, Reason} ->
+ exit(Reason)
end.
diff --git a/src/cowboy_router.erl b/src/cowboy_router.erl
index 7e70025..53ead4a 100644
--- a/src/cowboy_router.erl
+++ b/src/cowboy_router.erl
@@ -277,14 +277,12 @@ check_constraints([Field|Tail], Bindings) when is_atom(Field) ->
check_constraints([Field|Tail], Bindings) ->
Name = element(1, Field),
case Bindings of
- #{Name := Value} ->
+ #{Name := Value0} ->
Constraints = element(2, Field),
- case cowboy_constraints:validate(Value, Constraints) of
- true ->
- check_constraints(Tail, Bindings);
- {true, Value2} ->
- check_constraints(Tail, Bindings#{Name => Value2});
- false ->
+ case cowboy_constraints:validate(Value0, Constraints) of
+ {ok, Value} ->
+ check_constraints(Tail, Bindings#{Name => Value});
+ {error, _} ->
nomatch
end;
_ ->