Delphi – find indy 10 demos for each and every component

The main problem with Telnet is that it DOES NOT utilize a command/response model like most other Internet protocols do. Either party can send data at any time, and each direction of data is independant from the other direction. This is reflected in TIdTelnet by the fact that it runs an internal reading thread to receive data. Because of this, you cannot simply connect, send a command, and wait for a response in a single block of code like you can with other Indy components. You have to write the command, then wait for the OnDataAvailable event to fire, and then parse the data to determine what it actually is (and be prepared to handle situations where partial data may be received, since that is just how TCP/IP works).

If you are connecting to a server that actually implements a command/response model, then you are better off using TIdTCPClient directly instead of TIdTelnet (and then implement any Telnet sequence decoding manually if the server really is using Telnet, which is rare nowadays but not impossible). For Indy 11, we might refactor TIdTelnet's logic to support a non-threaded version, but that is undecided yet.

I have posted the complete set of demos for SOAP on CodeCentral as item 28789.

These contain every single one of the Delphi 2007 era SOAP demos from the WebServices folder, now updated for Delphi XE and XE2, including converting the old WAD servers into new INDY VCL servers. You'd think that was impressive, except it's not. It's really easy. Just use the wizard to create a new project, and then add the web service interface and implementation units, and any other units that belong in the old demo, to the project. Once they're added to the project, they just work. Basic demo SOAP Servers are really easy to build in Delphi, once you have a working demo, you'll find it's pretty easy to modify and extend it.

The demo that best answers the question I asked above is in the SOAPDataModule sub-folder.

The basic problems with the demo from the 2007 era are two:

1. The WAD (web app debugger) is gone. you have to make a new server using the Indy server, for optimal demo purposes, saving you from using WAD (which is gone) or setting up ISAPI environment, under IIS, which is hardly ideal for demo purposes. The new demo project I made is called SoapDMServerINDY, and it consists of a data module (datamod_u.pas), a VCL form User Interface unit (IndyServerVCLFormUnit.pas) and an Indy Server web module, called IndyServerWebModule.pas.

2. The Delphi 2007 demo broke thanks to the new practice of having a Debug/Win32 subfolder that the demo executable is now in, you need to go up further. I fixed the demo server so that it warns you with an error message if the data files cannot be located, saving you from the mysterious "XML parsing error". I also added some error checking in a few of the demos so that it tells you that you need to install interbase for this demo to work, since some of the demos require Interbase installed and running, and one requires an alias called IBLOCAL to exist, and preferably a table called EMPLOYEE to exist.

The elements of this demo are a server (SoapDMServerINDY, based on the code from SOAPDMServerWAD), and the client SOAPDMClient which connects to the demo and has two pages, one page will show basic data access via a DBGrid + dataset remoting, and the second page shows how to invoke a custom SOAP method.

To use the demo: You have to start the server, click the start button, then start the client and click Connect.