feat(router/builder): string bodies should support "text/plain" mime

any route who can accept a string as the body should support "text/plain" mime so the request doesn't need to be JSON encoded

Author: stakach

shard.yml

@@ -1,5 +1,5 @@
 name: action-controller
-version: 7.5.3
+version: 7.6.0
 crystal: ">= 1.9.0"
 
 dependencies:

spec/open_api_spec.cr

@@ -9,7 +9,7 @@ describe ActionController::OpenAPI do
   it "generates openapi docs" do
     result = ActionController::OpenAPI.generate_open_api_docs("title", "version", description: "desc")
     result[:openapi].should eq "3.0.3"
-    result[:paths].size.should eq 25
+    result[:paths].size.should eq 26
     result[:info][:description].should eq "desc"
   end
 end

spec/route_builder_spec.cr

@@ -114,6 +114,17 @@ describe AC::Route::Builder do
     result.body.should eq %(300.4)
   end
 
+  it "String bodies should work with text/plain mime" do
+    result = client.post("/filtering/string_entry", headers: HTTP::Headers{
+      "Content-Type" => "text/plain",
+    }, body: "some text")
+    result.body.should eq %("some text")
+
+    expect_raises(JSON::ParseException) do
+      client.post("/filtering/string_entry", body: "some text")
+    end
+  end
+
   it "should work with other charsets" do
     body_text = "34.8".encode("UTF-16")
     body_text.bytesize.should eq 10

spec/spec_helper.cr

@@ -165,6 +165,11 @@ class Filtering < FilterOrdering
     float
   end
 
+  @[AC::Route::POST("/string_entry/", status_code: HTTP::Status::ACCEPTED, body: :string)]
+  def create_string_entry(string : String) : String
+    string
+  end
+
   @[AC::Route::POST("/some_other_entry/", status_code: HTTP::Status::ACCEPTED)]
   def create_form_encoded_entry(float : Float64) : Float64
     float

src/action-controller/router/builder.cr

@@ -366,10 +366,24 @@ module ActionController::Route::Builder
               {% end %}
             {% else %}
               # check we can parse the body if a content type is provided
+              {% string_body_possible = false %}
               {% if body_argument != "%" %}
                 body_type = request_content_type || {{ DEFAULT_PARSER[0] }}
                 unless {{@type.name.id}}.can_parse?(body_type)
-                  raise AC::Route::UnsupportedMediaType.new("no parser available for #{body_type}", {{@type.name.id}}.parsable)
+                  # special case for mime type text/plain and String body types
+                  {% for arg, arg_index in method.args %}
+                    {% if body_argument == arg.name.id.stringify %}
+                      {% union_types = arg.restriction.resolve.union_types.reject(&.nilable?) %}
+                      {% if union_types.includes?(String) %}
+                        {% string_body_possible = true %}
+                        if body_type != "text/plain"
+                          raise AC::Route::UnsupportedMediaType.new("no parser available for #{body_type}", {{@type.name.id}}.parsable)
+                        end
+                      {% else %}
+                        raise AC::Route::UnsupportedMediaType.new("no parser available for #{body_type}", {{@type.name.id}}.parsable)
+                      {% end %}
+                    {% end %}
+                  {% end %}
                 end
               {% end %}
 
@@ -466,6 +480,10 @@ module ActionController::Route::Builder
                             when {{type}}
                               {{@type.name.id}}.parse_{{type.gsub(/\W/, "_").id}}({{ arg.restriction }}, body_io, request: @__context__.request)
                           {% end %}
+                          {% if string_body_possible == true %}
+                            when "text/plain"
+                              body_io.gets_to_end
+                          {% end %}
                           end
                         {% if arg.default_value.stringify != "" %}
                         else