Delphi REST Client API

A Delphi REST client API to consume REST services written in any programming language.

The API was tested in Delphi 7, XE, XE2, XE3 and XE4. It is also compatible with Mac OSX and iOS.

Connection Layer

There are a IHttpConnection interface to abstract the real Http conection. This interface currently have two implementations, using Indy 10, WinHTTP and WinInet.

Indy 9 does not handles HTTP response codes correctly, then if you are using Delphi 7, you must update your indy library to version 10 or use WinHttp (recommended). To disable indy support comment the compiler directive {.$DEFINE USE_INDY} in DelphiRest.inc file.

Serialization/Desserialization

The objects are streamed as JSON format, and SuperObject was chosen for deal with json transformation. SuperObject it's lighter and less intrusive than DBX framework. He too have a good support to serialization through TSuperObjectHelper class helper.

The framework SuperObject is not compatible with OSX and iOS, for such is used DBXJson framework, which has no compatibility issues. By default SuperObject still used, enabling DBXJson only on MacOS environment. You can configure DBXJson as default framework disabling compiler directive USE_SUPER_OBJECT in the file DelphiRest.inc.

Serialization is not available (yet) for Delphi 7.

For serialization work fine, the object must be declared as follows, with public fields. How public fields are a bad smell(IMHO), the serialization process will be improved to read properties too, and give some configuration options.

TPerson = class(TObject)
public 
  (* Reflect the server side object field names, for Java must be case-sensitive *)
  id: Integer;
  name: String;
  email: String;

  (* Static constructor *)
  class function NewFrom(Id: Integer; Name, EMail: String): TPerson;
end;

Samples

• GET

   var
     vList : TList<TPerson>;
   begin
     vList := RestClient.Resource('http://localhost:8080/java-rest-server/rest/persons')
                        .Accept(RestUtils.MediaType_Json)
                        .Get<TList<TPerson>>();
  

• GET ONE

   var
     vPerson : TPerson;
   begin
     vPerson := RestClient.Resource('http://localhost:8080/java-rest-server/rest/person/1')
                        .Accept(RestUtils.MediaType_Json)
                        .Get<TPerson>();
  

• POST

   var
     vPerson : TPerson;
   begin
     vPerson := TPerson.NewFrom(123, 'Fabricio', '[email protected]');          
     RestClient.Resource('http://localhost:8080/java-rest-server/rest/person')
               .Accept(RestUtils.MediaType_Json)
               .ContentType(RestUtils.MediaType_Json)
               .Post<TPerson>(vPerson);
  

• PUT

   var
     vPerson : TPerson;
   begin
     vPerson := //Load person
     vPerson.Email := '[email protected]';
     RestClient.Resource('http://localhost:8080/java-rest-server/rest/person')
               .Accept(RestUtils.MediaType_Json)
               .ContentType(RestUtils.MediaType_Json)
               .Put<TPerson>(vPerson);
  

• DELETE

   var
     vPerson : TPerson;
   begin
     vPerson := //Load person
     RestClient.Resource('http://localhost:8080/java-rest-server/rest/person')
               .Accept(RestUtils.MediaType_Json)
               .ContentType(RestUtils.MediaType_Json)
               .Delete(vPerson);
  

• GET AS DATASET

The fields need be predefined.

    var
      vDataSet: TClientDataSet;
    begin
      vDataSet := TClientDataSet.Create(nil);
      try
        TDataSetUtils.CreateField(vDataSet, ftInteger, 'id');
        TDataSetUtils.CreateField(vDataSet, ftString, 'name', 100);
        TDataSetUtils.CreateField(vDataSet, ftString, 'email', 100);
        vDataSet.CreateDataSet;

       RestClient.Resource(CONTEXT_PATH + 'persons')
                  .Accept(RestUtils.MediaType_Json)
                  .GetAsDataSet(vDataSet);
      finally
        vDataSet.Free;
      end;

• GET AS DYNAMIC DATASET

The fields are created dynamically according to the returned content.

    var
      vDataSet: TDataSet;
    begin
      vDataSet := RestClient.Resource(CONTEXT_PATH + 'persons')
                            .Accept(RestUtils.MediaType_Json)
                            .GetAsDataSet();        
      try
        //Do something
      finally
        vDataSet.Free;
      end;

Java Rest Server

The java project is only for test purpose and has built using Maven and Jersey, so it's needed have installed the JRE 6+ (Java Runtime Environment) and Maven 2 to build and run the application. The Maven bin directory must be included in Windows Path environment variable.

After install Java and Maven just run 'start-java-server.bat' to start the application and 'stop-java-server.bat' to shut down them.

When 'start-java-server.bat' is first run maven dependencies will be downloaded, and it may take a while.