Using RemObjects Hydra to consume a .NET WCF service from Delphi

Using RemObjects Hydra is probably the easiest way to consume a WCF service from Delphi in case you need to support .NET-specific bindings which might require a lot of work to implement on your side but are already available for .NET.

This series of videos shows how you can write a managed Hydra plugin module to consume a WCF service and expose it to a Delphi Hydra host application as a custom interface, delegating the method calls to the WCF service.

01. WCF Service Library

• Create a new WCF Service Library project:
• File\New\Project...
• Templates\Visual C#\WCF\WCF Service Library
• Add a new method to the service contract (interface)
• Implement the new method
• Test the service with the WCF test client

02. WCF Service Client Library

• Create a new class library project:
• Right-click solution, Add\New Project...
• Installed\Visual C#\Class Library
• Add service reference (to the service created in the previous step)
• Delete the default empty class module

03. WCF Service Client Console Application

• Create a new console project:
• Right-click solution, Add\New Project...
• Installed\Visual C#\Console Application
• Add System.ServiceModel reference
• Add service client library reference
• Add code to call the service methods
• Run the console application

04. Hydra C# Plugin Module

• Create a new Hydra Plugin Library project:
• Right-click solution, Add\New\Project...
• Installed\Visual C#\Hydra\Plugin Module
• Create a new Hydra Plugin:
• Right-click project, Add\New Item...
• Installed\Visual C# Items\Non-Visual Plugin
• Add System.ServiceModel reference
• Add service client library reference
• Create a COM-compatible interface
• Right-click project, Add\New Item...
• Installed\Visual C# Items\Code\Interface
• Declare interface IService1Client (public)
• Inherit from IHYCrossPlatformInterface (RemObjects.Hydra.CrossPlatform)
• Add IID
• Add methods
• Add CompositeType struct
• Add StructLayout attribute
• Add MarshalAs attributes
• Declare data contract parameter ref on the C# side, const on Delphi side
• Make the plugin implement the interface by delegating to the WCF service client library

05. Delphi Hydra Host Console Application

• Create a console application
• Add Vcl to unit scope names
• Change the output directory to be the same as the plugin output directory
• Write code to load the plugin and call its interface
• Copy and patch uHYCLRWrappers.pas unit to load configuration from a .config file
• Create the configuration file

You can find the source code here:
https://github.com/tondrej/hydra-wcf-delphi