ADDED an action which uses a custom serializer in sample "renders.dproj"

NEW the JsonDataObjects based serializer is the default serializer
FIX Rendering a nil value, will result in a "null" json (with the json serializers)

samples/renders/CustomTypesSerializersU.pas

@@ -0,0 +1,92 @@
+// ***************************************************************************
+//
+// Delphi MVC Framework
+//
+// Copyright (c) 2010-2017 Daniele Teti and the DMVCFramework Team
+//
+// https://github.com/danieleteti/delphimvcframework
+//
+// Collaborators with this file: Ezequiel Juliano Müller (ezequieljuliano@gmail.com)
+//
+// ***************************************************************************
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//
+// ***************************************************************************
+
+unit CustomTypesSerializersU;
+
+interface
+
+uses
+  MVCFramework.Serializer.Intf,
+  System.Rtti;
+
+type
+  // Custom serializer for TUserRoles type
+  TUserRolesSerializer = class(TInterfacedObject, IMVCTypeSerializer)
+  public
+    procedure Serialize(
+      const AElementValue: TValue;
+      var ASerializerObject: TObject;
+      const AAttributes: TArray<TCustomAttribute>
+      );
+    procedure Deserialize(
+      const ASerializedObject: TObject;
+      var AElementValue: TValue;
+      const AAttributes: TArray<TCustomAttribute>
+      );
+  end;
+
+implementation
+
+uses
+  JsonDataObjects, CustomTypesU;
+
+{ TUserPasswordSerializer }
+
+procedure TUserRolesSerializer.Deserialize(const ASerializedObject: TObject;
+  var AElementValue: TValue; const AAttributes: TArray<TCustomAttribute>);
+begin
+  // todo: if you need, implement the deserilize method
+end;
+
+procedure TUserRolesSerializer.Serialize(const AElementValue: TValue;
+  var ASerializerObject: TObject; const AAttributes: TArray<TCustomAttribute>);
+var
+  lJSONArr: TJDOJsonArray;
+  lRole: string;
+  I: Integer;
+begin
+  { Here I want to serialize the userroles array as json array }
+
+  // I know that the selected serializer uses JsonDataObject as serialization engine.
+  // You have to check the serializer documentation to find out what are the
+  // correct objects to create here!
+  lJSONArr := TJDOJsonArray.Create;
+
+  // Assign to the var parameter the correct object
+  ASerializerObject := lJSONArr;
+
+  // Then fill the returned object with the correct values
+  // reading from the AElementValue
+  lJSONArr.Add('--begin--'); { just to prove that the custom serializaion happends }
+  for I := 0 to AElementValue.GetArrayLength - 1 do
+  begin
+    lRole := AElementValue.GetArrayElement(i).AsString;
+    lJSONArr.Add(lRole);
+  end;
+  lJSONArr.Add('--end--'); { just to prove that the custom serializaion happends }
+end;
+
+end.

samples/renders/CustomTypesU.pas

@@ -0,0 +1,74 @@
+// ***************************************************************************
+//
+// Delphi MVC Framework
+//
+// Copyright (c) 2010-2017 Daniele Teti and the DMVCFramework Team
+//
+// https://github.com/danieleteti/delphimvcframework
+//
+// Collaborators with this file: Ezequiel Juliano Müller (ezequieljuliano@gmail.com)
+//
+// ***************************************************************************
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//
+// ***************************************************************************
+
+unit CustomTypesU;
+
+interface
+
+type
+  // custom serialization is by-type so we define a type alias
+  // useful to identify all the fields that must be serialized
+  // using the custom serializer defined for this type
+  TUserRoles = TArray<string>;
+
+  // This is the main object which uses the
+  // custom serialized type as property Roles
+  TSysUser = class
+  private
+    FUserName: string;
+    FRoles: TUserRoles;
+    procedure SetUserName(const Value: string);
+    function GetUserRoles: TUserRoles;
+  public
+    constructor Create(aUserName: string; aRoles: TUserRoles);
+    property UserName: string read FUserName write SetUserName;
+    // Here we are using the custom-serialized type TUserRoles
+    property Roles: TUserRoles read GetUserRoles;
+  end;
+
+implementation
+
+
+{ TSysUser }
+
+constructor TSysUser.Create(aUserName: string; aRoles: TUserRoles);
+begin
+  inherited Create;
+  FUserName := aUserName;
+  FRoles := aRoles;
+end;
+
+function TSysUser.GetUserRoles: TUserRoles;
+begin
+  Result := FRoles;
+end;
+
+procedure TSysUser.SetUserName(const Value: string);
+begin
+  FUserName := Value;
+end;
+
+end.

samples/renders/MyDataModuleU.pas

@@ -1,3 +1,29 @@
+// ***************************************************************************
+//
+// Delphi MVC Framework
+//
+// Copyright (c) 2010-2017 Daniele Teti and the DMVCFramework Team
+//
+// https://github.com/danieleteti/delphimvcframework
+//
+// Collaborators with this file: Ezequiel Juliano Müller (ezequieljuliano@gmail.com)
+//
+// ***************************************************************************
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//
+// ***************************************************************************
+
 unit MyDataModuleU;
 
 interface

samples/renders/RenderSampleControllerU.pas

@@ -1,11 +1,38 @@
-unit RenderSampleControllerU;
+// ***************************************************************************
+//
+// Delphi MVC Framework
+//
+// Copyright (c) 2010-2017 Daniele Teti and the DMVCFramework Team
+//
+// https://github.com/danieleteti/delphimvcframework
+//
+// Collaborators with this file: Ezequiel Juliano Müller (ezequieljuliano@gmail.com)
+//
+// ***************************************************************************
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//
+// ***************************************************************************
+
+unit RenderSampleControllerU;
 
 interface
 
 uses
   MVCFramework,
   MVCFramework.Commons,
-  System.JSON;
+  MVCFramework.Serializer.Intf,
+  System.Rtti;
 
 type
 
@@ -78,20 +105,25 @@ type
     [MVCPath('/exception')]
     procedure RaiseException;
 
+    [MVCHTTPMethod([httpGET])]
+    [MVCPath('/customserializationtype')]
+    procedure GetCustomSerializationType;
+
   end;
 
 implementation
 
 uses
   BusinessObjectsU,
-  Data.DBXJSON,
   Generics.Collections,
   MVCFramework.DataSet.Utils,
   MVCFramework.Serializer.Commons,
   MyDataModuleU,
   System.Classes,
   System.SysUtils,
-  WebModuleU;
+  WebModuleU,
+  JsonDataObjects,
+  MVCFramework.TypesAliases, CustomTypesU;
 
 { TRoutingSampleController }
 
@@ -177,6 +209,12 @@ begin
   end;
 end;
 
+procedure TRenderSampleController.GetCustomSerializationType;
+begin
+  // TSysUser contains a type with a custom serializer
+  Render(TSysUser.Create('daniele', ['poweruser', 'role1', 'role2']), True);
+end;
+
 procedure TRenderSampleController.GetPerson_AsHTML(CTX: TWebContext);
 begin
   ResponseStream

samples/renders/WebModuleU.pas

@@ -1,3 +1,29 @@
+// ***************************************************************************
+//
+// Delphi MVC Framework
+//
+// Copyright (c) 2010-2017 Daniele Teti and the DMVCFramework Team
+//
+// https://github.com/danieleteti/delphimvcframework
+//
+// Collaborators with this file: Ezequiel Juliano Müller (ezequieljuliano@gmail.com)
+//
+// ***************************************************************************
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//
+// ***************************************************************************
+
 unit WebModuleU;
 
 interface
@@ -25,16 +51,36 @@ implementation
 
 {$R *.dfm}
 
-uses RenderSampleControllerU, MVCFramework.Commons;
+uses
+  MVCFramework.Commons, RenderSampleControllerU, CustomTypesU,
+  CustomTypesSerializersU,
+  MVCFramework.Serializer.JSON,
+  MVCFramework.Serializer.Intf,
+  System.Generics.Collections;
 
 procedure TWebModule1.WebModuleCreate(Sender: TObject);
 begin
   DMVC := TMVCEngine.Create(self,
     procedure(Config: TMVCConfig)
+    var
+      lX: TDictionary<string, IMVCSerializer>;
     begin
       Config[TMVCConfigKey.ViewPath] := 'templates';
     end);
+
+  // Now the default json serializer is set, but how to set a different
+  // serializer? Check the lines below!
+  // ------------------------------------
+  // DMVC
+  // .Serializers
+  // .AddOrSetValue(TMVCMediaType.APPLICATION_JSON, TMVCJSONSerializer.Create);
+  // ------------------------------------
+
   DMVC.AddController(TRenderSampleController);
+  DMVC
+    .Serializers
+    .Items[TMVCMediaType.APPLICATION_JSON]
+    .RegisterTypeSerializer(TypeInfo(TUserRoles), TUserRolesSerializer.Create);
 end;
 
 end.

samples/renders/renders.dpr

@@ -1,3 +1,29 @@
+// ***************************************************************************
+//
+// Delphi MVC Framework
+//
+// Copyright (c) 2010-2017 Daniele Teti and the DMVCFramework Team
+//
+// https://github.com/danieleteti/delphimvcframework
+//
+// Collaborators with this file: Ezequiel Juliano Müller (ezequieljuliano@gmail.com)
+//
+// ***************************************************************************
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//
+// ***************************************************************************
+
 program renders;
 
 {$APPTYPE CONSOLE}
@@ -11,7 +37,9 @@ uses
   WebModuleU in 'WebModuleU.pas' {WebModule1: TWebModule},
   RenderSampleControllerU in 'RenderSampleControllerU.pas',
   BusinessObjectsU in '..\commons\BusinessObjectsU.pas',
-  MyDataModuleU in 'MyDataModuleU.pas' {MyDataModule: TDataModule};
+  MyDataModuleU in 'MyDataModuleU.pas' {MyDataModule: TDataModule},
+  CustomTypesU in 'CustomTypesU.pas',
+  CustomTypesSerializersU in 'CustomTypesSerializersU.pas';
 
 {$R *.res}
 

samples/renders/renders.dproj

@@ -206,6 +206,8 @@
             <Form>MyDataModule</Form>
             <DesignClass>TDataModule</DesignClass>
         </DCCReference>
+        <DCCReference Include="CustomTypesU.pas"/>
+        <DCCReference Include="CustomTypesSerializersU.pas"/>
         <None Include="ModelSupport_renders\default.txaPackage"/>
         <None Include="ModelSupport_renders\default.txvpck"/>
         <None Include="ModelSupport_renders\WebModuleU\default.txaPackage"/>

sources/MVCFramework.Serializer.JSON.pas

@@ -665,17 +665,17 @@ begin
   begin
     for Field in ADataSet.Fields do
     begin
-      Name := GetNameAs(ADataSet.Owner, Field.Name, Field.FieldName);
+      name := GetNameAs(ADataSet.Owner, Field.Name, Field.FieldName);
 
-      if (IsIgnoredAttribute(AIgnoredFields, Name)) or (IsIgnoredComponent(ADataSet.Owner, Field.Name)) then
+      if (IsIgnoredAttribute(AIgnoredFields, name)) or (IsIgnoredComponent(ADataSet.Owner, Field.Name)) then
         Continue;
 
       case GetNameCase(ADataSet, ANameCase) of
-        ncLowerCase: Name := LowerCase(Field.FieldName);
-        ncUpperCase: Name := UpperCase(Field.FieldName);
+        ncLowerCase: name := LowerCase(Field.FieldName);
+        ncUpperCase: name := UpperCase(Field.FieldName);
       end;
 
-      Jv := AJSONObject.Get(Name).JsonValue;
+      Jv := AJSONObject.Get(name).JsonValue;
       if not Assigned(Jv) then
         Continue;
 
@@ -928,8 +928,8 @@ var
 begin
   Result := EmptyStr;
 
-  if not Assigned(AObject) then
-    Exit;
+  if AObject = nil then
+    Exit('null');
 
   if AObject is TJSONValue then
     Exit(TJSONValue(AObject).ToJSON);

sources/MVCFramework.Serializer.JsonDataObjects.pas

@@ -44,7 +44,8 @@ uses
   MVCFramework.Serializer.Abstract,
   MVCFramework.Serializer.Commons,
   MVCFramework.DuckTyping,
-  JsonDataObjects;
+  MVCFramework.TypesAliases,
+  JsonDataObjects {JsonDataObjects must be after MVCFramework.TypesAliases};
 
 type
 
@@ -56,7 +57,6 @@ type
   public
     constructor Create; overload;
     constructor Create(const AValue: string); overload;
-
     property Value: string read FValue write FValue;
   end;
 
@@ -642,14 +642,9 @@ begin
         else
         begin
           // dt: if a key is null, jsondataobjects assign it the type jdtObject
-          if AJsonObject[AName].ObjectValue = nil then
-          begin
-            ChildObject := nil; // dt
-          end
-          else
+          if AJsonObject[AName].ObjectValue <> nil then
           begin
             ChildObject := AValue.AsObject;
-            if Assigned(ChildObject) then
             JsonObjectToObject(AJsonObject.O[AName], ChildObject, GetSerializationType(ChildObject, AType), AIgnored);
           end;
         end;
@@ -941,10 +936,13 @@ begin
   Result := EmptyStr;
 
   if not Assigned(AObject) then
-    Exit;
+    Exit('null');
 
   if AObject is TJsonBaseObject then
-    Exit(TJsonBaseObject(AObject).ToJSON(False));
+    Exit(TJsonBaseObject(AObject).ToJSON(True));
+
+  if AObject is MVCFramework.TypesAliases.TJSONValue then
+    Exit(MVCFramework.TypesAliases.TJSONValue(AObject).ToJSON);
 
   ObjType := GetRttiContext.GetType(AObject.ClassType);
   if GetTypeSerializers.ContainsKey(ObjType.Handle) then

sources/MVCFramework.pas

@@ -184,7 +184,7 @@ type
     function GetParamAsInt64(const AParamName: string): Int64;
     function GetFiles: TAbstractWebRequestFiles;
     function GetParamNames: TArray<string>;
-    function GetParamsMulti(const AParamName: string): TArray<String>;
+    function GetParamsMulti(const AParamName: string): TArray<string>;
   protected
     { protected declarations }
   public
@@ -221,7 +221,7 @@ type
     property ParamsTable: TMVCRequestParamsTable read FParamsTable write FParamsTable;
     property ParamNames: TArray<string> read GetParamNames;
     property Params[const AParamName: string]: string read GetParams;
-    property ParamsMulti[const AParamName: string]: TArray<String> read GetParamsMulti;
+    property ParamsMulti[const AParamName: string]: TArray<string> read GetParamsMulti;
     property ParamsAsInteger[const AParamName: string]: Integer read GetParamAsInteger;
     property ParamsAsInt64[const AParamName: string]: Int64 read GetParamAsInt64;
     property IsAjax: Boolean read GetIsAjax;
@@ -564,7 +564,7 @@ type
     FApplicationSession: TWebApplicationSession;
     FSavedOnBeforeDispatch: THTTPMethodEvent;
     function IsStaticFileRequest(const ARequest: TWebRequest; out AFileName: string): Boolean;
-    function SendStaticFileIfPresent(const AContext: TWebContext; const AFileName: String): Boolean;
+    function SendStaticFileIfPresent(const AContext: TWebContext; const AFileName: string): Boolean;
     procedure FillActualParamsForAction(
       const AContext: TWebContext;
       const AActionFormalParams: TArray<TRttiParameter>;
@@ -667,7 +667,7 @@ type
     { protected declarations }
   public
     constructor Create; overload;
-    constructor Create(AStatusCode: Integer; AReasonString: String; AMessage: String); overload;
+    constructor Create(AStatusCode: Integer; AReasonString: string; AMessage: string); overload;
     destructor Destroy; override;
 
     property StatusCode: Integer read FStatusCode write FStatusCode;
@@ -690,7 +690,7 @@ type
   protected
     function GetRealFileName(const AViewName: string): string; virtual;
     function IsCompiledVersionUpToDate(const AFileName, ACompiledFileName: string): Boolean; virtual; abstract;
-    procedure SetOutput(const AOutput: String);
+    procedure SetOutput(const AOutput: string);
   public
     constructor Create(
       const AViewName: string;
@@ -718,7 +718,8 @@ implementation
 
 uses
   MVCFramework.Router,
-  MVCFramework.SysControllers;
+  MVCFramework.SysControllers,
+  MVCFramework.Serializer.JsonDataObjects;
 
 var
   _IsShuttingDown: Int64 = 0;
@@ -747,7 +748,7 @@ var
 begin
   Result := '';
 
-  for I := Low(TMVCHTTPMethodType) to High(TMVCHTTPMethodType) do
+  for I := low(TMVCHTTPMethodType) to high(TMVCHTTPMethodType) do
     if I in FMVCHTTPMethods then
       Result := Result + ',' + GetEnumName(TypeInfo(TMVCHTTPMethodType), Ord(I));
 
@@ -1087,10 +1088,10 @@ begin
 end;
 
 function TMVCWebRequest.GetParamsMulti(
-  const AParamName: string): TArray<String>;
+  const AParamName: string): TArray<string>;
 var
-  lList: TList<String>;
-  procedure AddParamsToList(const AStrings: TStrings; const AList: TList<String>);
+  lList: TList<string>;
+  procedure AddParamsToList(const AStrings: TStrings; const AList: TList<string>);
   var
     I: Integer;
   begin
@@ -1100,7 +1101,7 @@ var
   end;
 
 begin
-  lList := TList<String>.Create;
+  lList := TList<string>.Create;
   try
     AddParamsToList(FWebRequest.ContentFields, lList);
     AddParamsToList(FWebRequest.QueryFields, lList);
@@ -2056,7 +2057,11 @@ end;
 
 procedure TMVCEngine.RegisterDefaultsSerializers;
 begin
-  FSerializers.Add(TMVCMediaType.APPLICATION_JSON, TMVCJSONSerializer.Create);
+  if not FSerializers.ContainsKey(TMVCMediaType.APPLICATION_JSON) then
+  begin
+    FSerializers.Add(TMVCMediaType.APPLICATION_JSON, TMVCJSONDataObjectsSerializer.Create);
+    // FSerializers.Add(TMVCMediaType.APPLICATION_JSON, TMVCJSONSerializer.Create);
+  end;
 end;
 
 procedure TMVCEngine.ResponseErrorPage(const AException: Exception; const ARequest: TWebRequest; const AResponse: TWebResponse);
@@ -2098,7 +2103,7 @@ begin
   Result := ASessionId;
 end;
 
-function TMVCEngine.SendStaticFileIfPresent(const AContext: TWebContext; const AFileName: String): Boolean;
+function TMVCEngine.SendStaticFileIfPresent(const AContext: TWebContext; const AFileName: string): Boolean;
 var
   LContentType: string;
 begin
@@ -2485,8 +2490,6 @@ begin
 end;
 
 procedure TMVCController.Render(const AObject: TObject; const AOwns: Boolean; const AType: TMVCSerializationType);
-begin
-  if Assigned(AObject) then
 begin
   try
     Render(Serializer(ContentType).SerializeObject(AObject, AType));
@@ -2494,9 +2497,6 @@ begin
     if AOwns then
       AObject.Free;
   end;
-  end
-  else
-    raise EMVCException.Create('Can not render an empty object.');
 end;
 
 procedure TMVCController.Render(const AStream: TStream; const AOwns: Boolean);
@@ -2770,7 +2770,7 @@ begin
 end;
 
 constructor TMVCErrorResponse.Create(AStatusCode: Integer; AReasonString,
-  AMessage: String);
+  AMessage: string);
 begin
   Create;
   StatusCode := AStatusCode;
@@ -2839,7 +2839,7 @@ begin
     Result := EmptyStr;
 end;
 
-procedure TMVCBaseViewEngine.SetOutput(const AOutput: String);
+procedure TMVCBaseViewEngine.SetOutput(const AOutput: string);
 begin
   FOutput := AOutput;
 end;

unittests/serializer/jsondataobjects/MVCFramework.Tests.Serializer.JsonDataObjects.pas

@@ -54,6 +54,7 @@ type
   published
     { serialize declarations }
     procedure TestSerializeEntity;
+    procedure TestSerializeNil;
     procedure TestSerializeEntityUpperCaseNames;
     procedure TestSerializeEntityLowerCaseNames;
     procedure TestSerializeEntityNameAs;
@@ -1032,6 +1033,11 @@ begin
   end;
 end;
 
+procedure TMVCTestSerializerJsonDataObjects.TestSerializeNil;
+begin
+  CheckEquals('null', FSerializer.SerializeObject(nil));
+end;
+
 { TMVCEntityCustomSerializerJsonDataObjects }
 
 procedure TMVCEntityCustomSerializerJsonDataObjects.Deserialize(

unittests/serializer/systemjson/MVCFramework.Tests.Serializer.JSON.pas

@@ -54,6 +54,7 @@ type
   published
     { serialize declarations }
     procedure TestSerializeEntity;
+    procedure TestSerializeNill;
     procedure TestSerializeEntityUpperCaseNames;
     procedure TestSerializeEntityLowerCaseNames;
     procedure TestSerializeEntityNameAs;
@@ -1028,6 +1029,11 @@ begin
   end;
 end;
 
+procedure TMVCTestSerializerJSON.TestSerializeNill;
+begin
+  CheckEquals('null', FSerializer.SerializeObject(nil));
+end;
+
 { TMVCEntityCustomSerializerJSON }
 
 procedure TMVCEntityCustomSerializerJSON.Deserialize(