Merge pull request #61 from alusco-scratch/strictjson

Add a strict version of JSON encoding

example/Gemfile.lock

@@ -1,18 +1,20 @@
 PATH
   remote: ..
   specs:
-    twirp (1.5.0)
+    twirp (1.7.0)
       faraday (< 2)
-      google-protobuf (~> 3.0, >= 3.0.0)
+      google-protobuf (~> 3.0, >= 3.7.0)
 
 GEM
   remote: https://rubygems.org/
   specs:
-    faraday (1.0.1)
+    faraday (1.1.0)
       multipart-post (>= 1.2, < 3)
-    google-protobuf (3.11.4)
+      ruby2_keywords
+    google-protobuf (3.13.0)
     multipart-post (2.1.1)
     rack (2.2.3)
+    ruby2_keywords (0.0.2)
 
 PLATFORMS
   ruby
@@ -22,4 +24,4 @@ DEPENDENCIES
   twirp!
 
 BUNDLED WITH
-   1.17.2
+   1.17.3

example/README.md

@@ -22,7 +22,7 @@ Now you can send `curl` requests from another terminal window:
 ```sh
 curl --request POST \
   --url http://localhost:8080/twirp/example.hello_world.HelloWorld/Hello \
-  --header 'Content-Type: application/json' \
+  --header 'Content-Type: application/json; strict=true' \
   --data '{"name": "World"}'
 ```
 

lib/twirp/encoding.rb

@@ -17,21 +17,27 @@ module Twirp
 
   module Encoding
     JSON = "application/json"
+    # An opt-in content type useful when curling or manually testing a twirp
+    # service.  This will fail if unknown fields are encountered. The return
+    # content type will be application/json.
+    JSON_STRICT = "application/json; strict=true"
     PROTO = "application/protobuf"
 
     class << self
 
       def decode(bytes, msg_class, content_type)
         case content_type
-        when JSON  then msg_class.decode_json(bytes, ignore_unknown_fields: true)
+        when JSON then msg_class.decode_json(bytes, ignore_unknown_fields: true)
+        when JSON_STRICT then msg_class.decode_json(bytes, ignore_unknown_fields: false)
         when PROTO then msg_class.decode(bytes)
         else raise ArgumentError.new("Invalid content_type")
         end
       end
 
       def encode(msg_obj, msg_class, content_type)
         case content_type
-        when JSON  then msg_class.encode_json(msg_obj, emit_defaults: true)
+        when JSON then msg_class.encode_json(msg_obj, emit_defaults: false)
+        when JSON_STRICT then msg_class.encode_json(msg_obj, emit_defaults: true)
         when PROTO then msg_class.encode(msg_obj)
         else raise ArgumentError.new("Invalid content_type")
         end
@@ -46,7 +52,7 @@ def decode_json(bytes)
       end
 
       def valid_content_type?(content_type)
-        content_type == JSON || content_type == PROTO
+        content_type == JSON || content_type == PROTO || content_type == JSON_STRICT
       end
 
       def valid_content_types

lib/twirp/version.rb

@@ -12,5 +12,5 @@
 # permissions and limitations under the License.
 
 module Twirp
-  VERSION = "1.7.0"
+  VERSION = "1.7.1"
 end

test/service_test.rb

@@ -65,12 +65,21 @@ def test_successful_json_request
   end
 
   def test_successful_json_request_emit_defaults
+    rack_env = json_strict_req "/example.Haberdasher/MakeHat", inches: 0 # default int value
+    status, headers, body = haberdasher_service.call(rack_env)
+
+    assert_equal 200, status
+    assert_equal 'application/json; strict=true', headers['Content-Type']
+    assert_equal({"inches" => 0, "color" => "white"}, JSON.parse(body[0]))
+  end
+
+  def test_successful_json_request_no_emit_defaults
     rack_env = json_req "/example.Haberdasher/MakeHat", inches: 0 # default int value
     status, headers, body = haberdasher_service.call(rack_env)
 
     assert_equal 200, status
     assert_equal 'application/json', headers['Content-Type']
-    assert_equal({"inches" => 0, "color" => "white"}, JSON.parse(body[0]))
+    assert_equal({"color" => "white"}, JSON.parse(body[0]))
   end
 
   def test_successful_proto_request
@@ -188,6 +197,20 @@ def test_json_request_ignores_unknown_fields
     assert_equal({"inches" => 10, "color" => "white"}, JSON.parse(body[0]))
   end
 
+  def test_json_strict_request_fails_unknown_fields
+    rack_env = json_strict_req "/example.Haberdasher/MakeHat", inches: 10, fake: 3
+    status, headers, body = haberdasher_service.call(rack_env)
+
+    assert_equal 400, status
+    assert_equal 'application/json', headers['Content-Type']
+    assert_equal({
+      "code" => 'malformed',
+      "msg"  => 'Invalid request body for rpc method "MakeHat" with Content-Type=application/json; strict=true: ' +
+                "Error occurred during parsing: No such field: fake",
+      "meta" => {"twirp_invalid_route" => "POST /example.Haberdasher/MakeHat"},
+    }, JSON.parse(body[0]))
+  end
+
   def test_bad_route_triggers_on_error_hooks
     svc = haberdasher_service
 
@@ -809,6 +832,12 @@ def json_req(path, attrs)
       "CONTENT_TYPE" => "application/json"
   end
 
+  def json_strict_req(path, attrs)
+    Rack::MockRequest.env_for path, method: "POST",
+      input: JSON.generate(attrs),
+      "CONTENT_TYPE" => "application/json; strict=true"
+  end
+
   def proto_req(path, proto_message)
     Rack::MockRequest.env_for path, method: "POST",
       input: proto_message.class.encode(proto_message),