Web Service Toolkit

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"Web Service Toolkit” is a web services package for FPC, Lazarus and Delphi; “Web Service Toolkit” is meant to ease web services consumption and creation by FPC, Lazarus and Delphi users.

Contents

Client Side ( service consumption )

SVN version available for download at: http://groups.google.com/group/wst-list

Subversion checkout: svn co https://lazarus-ccr.svn.sourceforge.net/svnroot/lazarus-ccr/wst/trunk

(The author's site[1] displays versions up until 0.5. But that version doesn't compile with any recent Lazarus version).

Overview

“Web Service Toolkit” is made of two parts :

  • a set of programs : “typ_lib_edtr” a WSDL based type library editor, a command line tool “ws_helper” and a Lazarus integration package which contains some wizards,
  • a collection of runtime units.

Given an interface definition file(a WSDL file or a pascal file describing a web service), “ws_helper” (or within Lazarus, the WSDL file importer wizard) will create a object pascal unit containing a proxy implementing that interface. At runtime when a call targeting the web service is issued, the proxy's role is to :

  • marshall the call paramaters,
  • make the call to the target web service,
  • receive the call return and unmarshall output parameters to the caller.

Behind the scene, the proxy will take care of the SOAP plumbing details.

Example

We will use the “Amazon E-Commerce Service”, freely available (you will need to create a account, it's free) for personal use at this address [2].In order to use this service, we have to download its exposed WSDL (Web Services Description Language) interface and translate it to Pascal language. To that end, within Lazarus we can use the import wizard; we can also use ws_helper as a standalone program.

The “WSDL importer” wizard

This wizard is contained in the wst_design.lpk package located in the \ide\lazarus directory of the toolkit. Once the package installed, it adds a menu section “Web Services Toolkit” with two (2) sub-menus items to the Lazarus “Project” menu :

  • Import WSDL file ...
  • Type Library Editor ...

Web Services Toolkit Lazarus wizards menu.


Click on the first menu item (Import WSDL file ...), it will bring up the dialog below. We specify the WSDL file and the directory where to store the generated files and click on OK button to finish.

Web Services Toolkit Lazarus WSDL importer wizard.


It will produce two (2) pascal source files :

  • AWSECommerceService.pas, the service definition file (Pascal equivalent of the WSDL file)
  • AWSECommerceService_proxy.pas, this file contains a proxy which implements the service interface defined in the first file.

Import by ws_helper.

The ws_helper program is a command line version of the import wizard. In order to present its capabilities, below are printed the command line arguments it supports.

  ws_helper [-uMODE] [-p] [-b] [-i] [-oPATH] inputFilename
    -u MODE Generate the pascal translation of the WSDL input file
       MODE value may be U for used types or A for all types
    -p  Generate service proxy
    -b  Generate service binder
    -i  Generate service minimal implementation
    -o  PATH  Relative output directory
    -a  PATH  Absolute output directory

To translate the WDSL file downloaded from the “Amazon E-Commerce Service” web site execute the following command at the prompt:

  ..\..\ws_helper\ws_helper.exe -uA -p -o. AWSECommerceService.wsdl
  ws_helper, Web Service Toolkit 0.4 Copyright (c) 2006, 2007 by Inoussa OUEDRAOGO

  Parsing the file : AWSECommerceService.wsdl
  (...)
  Interface file generation...
  Proxy file generation...
  Metadata file generation...
  File "AWSECommerceService.wsdl" parsed succesfully.


below is printed an extract of both files :

unit AWSECommerceService;
{$IFDEF FPC} {$mode objfpc}{$H+} {$ENDIF}
interface
 
uses SysUtils, Classes, TypInfo, base_service_intf, service_intf;
 
const
  sNAME_SPACE = 'http://webservices.amazon.com/AWSECommerceService/2007-04-04';
  sUNIT_NAME = 'AWSECommerceService';
 
type
 
  HelpRequest = class;
  Help_RequestArray = class;
 
(...)
 
  AWSECommerceServicePortType = interface(IInvokable)
    ['{305A7E48-DD92-4C20-B699-4F2B47C93342}']
    function Help(
      Const HelpParam : Help_Type
    ):HelpResponse_Type;
    function ItemSearch(
      Const ItemSearchParam : ItemSearch_Type
    ):ItemSearchResponse_Type;
    function ItemLookup(
      Const ItemLookupParam : ItemLookup_Type
    ):ItemLookupResponse_Type;
    (...)
  end;
 
  procedure Register_AWSECommerceService_ServiceMetadata();
Unit AWSECommerceService_proxy;
{$IFDEF FPC} {$mode objfpc}{$H+} {$ENDIF}
Interface
 
Uses SysUtils, Classes, TypInfo, base_service_intf, service_intf, AWSECommerceService;
 
Type
 
  TAWSECommerceServicePortType_Proxy=class(TBaseProxy,AWSECommerceServicePortType)
  Protected
    class function GetServiceType() : PTypeInfo;override;
    function Help(
      Const HelpParam : Help_Type
    ):HelpResponse_Type;
    function ItemSearch(
      Const ItemSearchParam : ItemSearch_Type
    ):ItemSearchResponse_Type;
    function ItemLookup(
      Const ItemLookupParam : ItemLookup_Type
    ):ItemLookupResponse_Type;   
    (...)
  End;
 
  Function wst_CreateInstance_AWSECommerceServicePortType(
    const AFormat : string = 'SOAP:'; 
    const ATransport : string = 'HTTP:'
  ):AWSECommerceServicePortType;
 
Implementation
uses wst_resources_imp, metadata_repository;
 
 
Function wst_CreateInstance_AWSECommerceServicePortType(
  const AFormat : string; 
  const ATransport : string
):AWSECommerceServicePortType;
Begin
  Result := TAWSECommerceServicePortType_Proxy.Create(
    'AWSECommerceServicePortType',
     AFormat + 
       GetServiceDefaultFormatProperties(TypeInfo(AWSECommerceServicePortType)),
     ATransport + 'address=' + GetServiceDefaultAddress(TypeInfo(AWSECommerceServicePortType))
  );
End;
 
function TAWSECommerceServicePortType_Proxy.ItemSearch(
  Const ItemSearchParam : ItemSearch_Type
):ItemSearchResponse_Type;
Var
  locSerializer : IFormatterClient;
  strPrmName : string;
Begin
  locSerializer := GetSerializer();
  Try
    locSerializer.BeginCall('ItemSearch', GetTarget(),(Self as ICallContext));
      locSerializer.Put('ItemSearch', TypeInfo(ItemSearch_Type), ItemSearchParam);
    locSerializer.EndCall();
 
    MakeCall();
 
    locSerializer.BeginCallRead((Self as ICallContext));
      TObject(Result) := Nil;
      strPrmName := 'ItemSearchResponse';
      locSerializer.Get(TypeInfo(ItemSearchResponse_Type), strPrmName, Result);
 
  Finally
    locSerializer.Clear();
  End;
End;
(...)

We are now able to build a simple program for the service. The Synapse Library is required to compile the program as it is used for the HTTP communication. This library can be downloaded free of charge at this location[3]. The Indy[4] Library or ICS[5] library can also be used.

program amazon_sample;
{$mode objfpc}{$H+}
uses
  Classes, SysUtils, soap_formatter, synapse_http_protocol,
  metadata_repository, AWSECommerceService, AWSECommerceService_proxy;
 
const sACCES_ID = <Your AccesID here>;
 
function ReadEntry(const APromp : string):string ;
begin
  Result := '';
  Write(APromp);
  while True do begin
    ReadLn(Result);
    Result := Trim(Result);
    if ( Length(Result) > 0 ) then
      Break;
  end;
end;
 
var
  locService : AWSECommerceServicePortType;
  rqst : ItemSearch_Type;
  rsps : ItemSearchResponse_Type;
  rspsItem : Items_Type;
  i, j, k : Integer;
  itm : Item_Type;
begin
  SYNAPSE_RegisterHTTP_Transport();
  WriteLn('Web Services Toolkit Amazon sample');
  WriteLn('This sample demonstrates the "ItemSearch" method of the Amazon web service');
  WriteLn();
  rqst := ItemSearch_Type.Create();
  try
    locService := wst_CreateInstance_AWSECommerceServicePortType();
    rqst.AWSAccessKeyId := sACCES_ID;
    while True do begin
      rqst.Request.SetLength(1);
      rqst.Request[0].SearchIndex := ReadEntry('Enter the Search Index : ');
      rqst.Request[0].Availability := Available;
      rqst.Request[0].Count := 10;
      rqst.Request[0].MerchantId := 'Amazon';
      rqst.Request[0].ItemPage := 1;
      rqst.Request[0].Keywords := ReadEntry('Enter the Keywords : ');
      rsps := locService.ItemSearch(rqst);
      if ( rsps.OperationRequest.Errors.Length > 0 ) then begin
        WriteLn(Format('Errors ( %d ) : ',[rsps.OperationRequest.Errors.Length]));
        for i := 0 to Pred(rsps.OperationRequest.Errors.Length) do begin
          WriteLn(Format('  Error[%d] :',[i]));
          WriteLn('    ' + rsps.OperationRequest.Errors[i].Code);
          WriteLn('    ' + rsps.OperationRequest.Errors[i].Message);
        end;
      end else begin
        WriteLn(Format('Response ( %d ) : ',[rsps.Items.Length]));
        if Assigned(rsps) then begin
          for i := 0 to Pred(rsps.Items.Length) do begin
            rspsItem := rsps.Items[i];
            WriteLn('    TotalPages :' + IntToStr(rspsItem.TotalPages));
            WriteLn('    TotalResults :' + IntToStr(rspsItem.TotalResults));
            WriteLn('    Items :' + IntToStr(rspsItem._Item.Length));
            WriteLn('');
            for j := 0 to Pred(rspsItem._Item.Length) do begin
              itm := rspsItem._Item[j];;
              WriteLn('        ASIN :' + itm.ASIN);
              WriteLn('        DetailPageURL :' + itm.DetailPageURL);
              if Assigned(itm.ItemAttributes) then begin
                WriteLn('               Title :' + itm.ItemAttributes.Title);
                for k := 0 to Pred(itm.ItemAttributes.Author.Length) do begin
                  WriteLn('               Author[ ' + IntToStr(k) + ' ] ' + itm.ItemAttributes.Author.Item[k]);
                end;
                WriteLn('               Manufacturer :' + itm.ItemAttributes.Manufacturer);
                WriteLn('               ProductGroup :' + itm.ItemAttributes.ProductGroup);
              end;
              WriteLn('');
            end;
          end;
        end else begin
          WriteLn('Unexpected service response : Invalid response');
        end;
      end;
      WriteLn();
      WriteLn();
      if ( UpperCase(ReadEntry('Continue ( Y/N ) :'))[1] <> 'Y' ) then
        Break;
    end;
  finally
    FreeAndNil(rqst);
    FreeAndNil(rsps);
  end;
  ReadLn;
end.

The units base_service_intf, service_intf, soap_formatter, synapse_http_protocol, wst_resources_imp and metadata_repository are provided with the toolkit; Below is the result of a execution session searching for “Freepascal” in the “All” search index ( the service is case-sensitive!) .

Web Services Toolkit Amazon sample
This sample demonstrates the "ItemSearch" method of the Amazon web service

Enter the Search Index : All
Enter the Keywords : Freepascal
Response ( 1 ) :
    TotalPages :1
    TotalResults :9
    Items :9

        ASIN :0470088702
        DetailPageURL : http://www.amazon.com/gp/redirect.html%3FASIN=0470088702%26tag=ws%26lcode=sp1%26cID=2025%26ccmID=165953%26location=/o/ASIN/0470088702%253FSubscriptionId=0W3H25JMMGBNBXSTQN82
               Title :Beginning Programming For Dummies (Beginning Programming f
or Dummies)
               Author[ 0 ] Wallace Wang
               Manufacturer :For Dummies
               ProductGroup :Book

        ASIN :0471375233
        DetailPageURL : http://www.amazon.com/gp/redirect.html%3FASIN=0471375233%26tag=ws%26lcode=sp1%26cID=2025%26ccmID=165953%26location=/o/ASIN/0471375233%253FSubscriptionId=0W3H25JMMGBNBXSTQN82
               Title :Assembly Language Step-by-step: Programming with DOS and Linux (with CD-ROM)
               Author[ 0 ] Jeff Duntemann
               Manufacturer :Wiley
               ProductGroup :Book
(...)

It finds one (1) page containing nine (9) items! The wst_CreateInstance_AWSECommerceServicePortType() function, located in the AWSECommerceService.pas file create a proxy instance based on the service's informations contained in the WSDL file.

Function wst_CreateInstance_AWSECommerceServicePortType(
  const AFormat    : string; 
  const ATransport : string
):AWSECommerceServicePortType;
Begin
  Result := TAWSECommerceServicePortType_Proxy.Create(
              'AWSECommerceServicePortType',
              Aformat + GetServiceDefaultFormatProperties(TypeInfo(AWSECommerceServicePortType)),
              ATransport + 'address=' + GetServiceDefaultAddress(TypeInfo(AWSECommerceServicePortType))
            );
End;

The complete source code of the amazon example is located in the \samples\amazon folder for fpc; The Delphi sample is located in the \samples\delphi\amazon folder.

Connection Parameters

The general format is:

  protocol:paramName=paramValue(;paramName=paramValue)*

HTTP Proxy Parameters

For HTTP the supported parameters are:

  • Address ( required for a service supporting a unique address )
  • ProxyServer
  • ProxyPort
  • ProxyUsername
  • ProxyPassword

HTTP Connection through proxy are supported. Below is an example address string.

  const
    sADDRESS = 'http:address=http://webservices.amazon.com/AWSECommerceService/2007-04-04'+
                 ';ProxyServer=197.150.10.10;ProxyPort=9881'+
                 ';ProxyUsername=inoussa;ProxyPassword=wst';

The toolkit has two TCP implementations based on Synapse ( synapse_tcp_protocol.pas ) and ICS ( ics_tcp_protocol.pas ).

TCP connection Parameters

TCP supported parameters are:

  • address ( required for a service supporting a unique address )
  • Port
  • target( the target service )

Below is an example address string.

  Const
    sADDRESS = 'TCP:Address=10.0.0.3;Port=1234;target=UserService';

The toolkit has two TCP implementations based on Synapse ( synapse_tcp_protocol.pas ) and ICS ( ics_tcp_protocol.pas ).

LIBRARY ( LIB ) connection Parameters

The idea behind this protocol is to be able to host services in dynamic libraries ( DLL/DSO ). It can be viewed as a plug-in framework where plug-ins ( services ) are provided by dynamic libraries. LIB supported parameters are:

  • FileName ( the DLL/SO filename )
  • target( the target service )

Below is an example address string.

  Const
    sADDRESS = 'LIB:FileName=..\library_server\lib_server.dll;target=UserService';

The toolkit has one LIB implementation ( library_protocol.pas ).

The samples folder contains 4 projects user_client_console, tcp_server, http_server and library_server which demonstrate the TCP, HTTP and LIBRARY protocols.

Multi-Address service ( Address per operation )

Certain services ( like the eBay SOAP services ) use a address per operation. The toolkit uses extended meta data ( see the services meta data chapter below ) to set operation's addresses. The “ebay” SOAP sample located under the tests\ebay folder demonstrates the operation's address setting.

Troubleshooting

'Invalid parameter : "AProtocolData"' error message

This happens when it is not clear wich protocol to use. Make sure that a valid formatter is selected (for example: 'SOAP:') and that the corresponding formatter is registered. This is done by adding the appropiate xxx_formatter unit to your uses-clausule. (for example: soap_formatter)

Server Side ( service creation )

Overview

Web Service Toolkit contains a server side framework and a WSDL based type library editor for service creation. Key features are:

  • Service definition ( interface ) is separated from implementation,
  • Interface and implementations are not bound to message protocol,
  • WSDL generation
  • Support for SOAP 1.1 serialization
  • Support for XMLRPC serialization
  • Support for custom binary serialization
  • The framework is not bound to a transport protocol
  • Easy to add support for application servers.

Example

In order to create a service, we have to :

  • define its interface,
  • provide an implementation and register that one for the service,
  • provide a binder that will route calls targeting the service to the implementation and register that one,
  • host the service into an application server( TCP server, HTTP Server, LIBRARY server, ... ).

Defining the service Interface

Starting from the 0.5 version, the WST provides a WSDL based Type library Editor to define types and services used by an implementation. The figure (3) below presents the general interface of this tool. The Type library Editor is provided as

  • a Lazarus wizard as a menu item “Project/Web Services Toolkit/Type Library Editor..”
  • a standalone program typ_lib_edtr.exe.

Web Services Toolkit Type Library editor


Type Library Editor features:

  • Graphical user interface
  • WSDL source view
  • Pascal source view of the library
  • Pascal Proxy source view
  • Pascal implementation skeleton source view
  • Pascal Proxy binder view
  • enumeration creation interface
  • class creation interface
  • array creation interface
  • type alias creation interface
  • service interface creation interface.

Below some sample images are shown. We will use the user_service_intf.wsdl file located in the \samples directory for our sample.

Web Services Toolkit Type library editor, class editor.

Web Services Toolkit Type library editor, service interface editor

Export the pascal files.

The Type Library Editor has option to generate the pascal version of the WSDL file. To do so, click on the “Files\Save generated files ...” ( it can also be done through the contextual menu ); It will bring up the dialog box shown in the following image. Web Services Toolkit Type library editor, exporting to pascal files.

Click OK the button to complete. The program ws_helper has the same capabilities and the files can be generated with the following command :

ws_helper\ws_helper.exe -i -b -o. user_service_intf.wsdl
ws_helper, Web Service Toolkit 0.5 Copyright (c) 2006, 2007 by Inoussa OUEDRAOGO
Parsing the file : user_service_intf.wsdl
Information : Parsing "tns:TUserArray" ...
Information : Parsing "tns:TUser" ...
Information : Parsing "tns:TUser" ...
Information : Parsing "xsd:string" ...
Information : Parsing "tns:TUser" ...
Information : Parsing "xsd:string" ...
Information : Parsing "xsd:boolean" ...
Information : Parsing "TUserArray" ...
Information : Parsing "TUser" ...
Information : Parsing "TUserCategory" ...
Information : Parsing "TNote" ...
Interface file generation...
Proxy file generation...
Metadata file generation...
File "user_service_intf.wsdl" parsed succesfully.

The complete projects of the example is located in the folder “samples”. Below is printed a extract of the generated interface file.

unit user_service_intf;
{$IFDEF FPC} {$mode objfpc}{$H+} {$ENDIF}
interface
 
uses SysUtils, Classes, TypInfo, base_service_intf, service_intf;
 
const
  sNAME_SPACE = 'urn:UserService';
  sUNIT_NAME = 'user_service_intf';
 
type
 
  TUser = class;
  TUserArray = class;
 
  TUserCategory = ( 
    Normal
    ,Admin
  );
 
  TUser = class(TBaseComplexRemotable)
  published
    property Category : TUserCategory read FCategory write FCategory;
    property UserName : string read FUserName write FUserName;
    property eMail : string read FeMail write FeMail;
    property Preferences : string read FPreferences write FPreferences;
    property Note : TNote read FNote write FNote;
  end;
 
  TUserArray = class(TBaseObjectArrayRemotable)
  private
    function GetItem(AIndex: Integer): TUser;
  public
    class function GetItemClass():TBaseRemotableClass;override;
    property Item[AIndex:Integer] : TUser Read GetItem;Default;
  end;
 
  UserService = interface(IInvokable)
    ['{CA6F6192-C3DE-4D9C-B3DF-E616376A0DC9}']
    function GetList():TUserArray;
    procedure Add(
      Const AUser : TUser
    );
    procedure Update(
      Const AUser : TUser
    );
    function Find(
      Const AName : string
    ):TUser;
    function Delete(
      Const AName : string
    ):boolean;
  end;
(...)

Providing an implementation for the service

The user_service_intf_imp.pas unit generated above contains a skeleton implementation class for the interface. It defines a procedure named RegisterUserServiceImplementationFactory. The procedure registers the class as the service implementation provider in the implementation registry.

Unit user_service_intf_imp;
{$IFDEF FPC} {$mode objfpc}{$H+} {$ENDIF}
Interface
Uses SysUtils, Classes, 
     base_service_intf, server_service_intf, server_service_imputils,
     user_service_intf, cursor_intf;
 
Type
  { TUserService_ServiceImp }
 
  TUserService_ServiceImp=class(TBaseServiceImplementation,UserService)
  Protected
    function GetList():TUserArray;
    procedure Add(
      Const AUser : TUser
    );
    procedure Update(
      Const AUser : TUser
    );
    function Find(
      Const AName : string
    ):TUser;
    function Delete(
      Const AName : string
    ):boolean;
  End;
 
  procedure RegisterUserServiceImplementationFactory();
 
Implementation
(...)
 
procedure TUserService_ServiceImp.Add(Const AUser : TUser);
var
  locObj : TUser;
Begin
  locObj := Find(AUser.UserName);
  if ( locObj <> nil ) then
    raise Exception.CreateFmt('Duplicated user : "%s"',[AUser.UserName]);
  locObj := TUser.Create();
  locObj.Assign(AUser);
  FUserList.Add(locObj);
End; 
 
procedure RegisterUserServiceImplementationFactory();
Begin
  GetServiceImplementationRegistry().Register(
    'UserService',
TImplementationFactory.Create(TUserService_ServiceImp) as IServiceImplementationFactory);
End;
 
(...)

“ws_helper” has options to generate proxy file, basic implementation skeleton file and a binder file ( see the following listing).

ws_helper, Web Service Toolkit 0.4 Copyright (c) 2006, 2007 by Inoussa OUEDRAOGO
ws_helper [-uMODE] [-p] [-b] [-i] [-oPATH] inputFilename
  -u MODE Generate the pascal translation of the WSDL input file
       MODE value may be U for used types or A for all types
  -p  Generate service proxy
  -b  Generate service binder
  -i  Generate service minimal implementation
  -o  PATH  Relative output directory
  -a  PATH  Absolute output directory

The starting implementation file could also be create using ws_helper with the -i and -b options as above;

ws_helper\ws_helper.exe -i -b -o. user_service_intf.wsdl
ws_helper, Web Service Toolkit 0.4 Copyright (c) 2006, 2007 by Inoussa OUEDRAOGO
Parsing the file : user_service_intf.wsdl
Proxy file generation...
Binder file generation...
Implementation file generation...
Metadata file generation...
File "user_service_intf.wsdl" parsed succesfully..

Providing a binder for the service.

The binder's role is to:

  • unpack the incoming message,
  • set up the call stack,
  • make the call against the registered implementation,
  • serialize the execution stack to create the return message.

The user_service_intf_binder.pas unit generated above, contains :

  • TUserService_ServiceBinder : the actual binder class,
  • TUserService_ServiceBinderFactory a factory class for the binder and
  • Server_service_RegisterUserServiceService : the binder factory registration procedure.

The following code extract shows the unit interface part and a method handler of the binder.

unit user_service_intf_binder;
{$IFDEF FPC} {$mode objfpc}{$H+} {$ENDIF}
interface
uses SysUtils, Classes, base_service_intf, server_service_intf, user_service_intf;
 
type
  TUserService_ServiceBinder=class(TBaseServiceBinder)
  Protected
    procedure GetListHandler(AFormatter:IFormatterResponse);
    procedure AddHandler(AFormatter:IFormatterResponse);
    procedure UpdateHandler(AFormatter:IFormatterResponse);
    procedure FindHandler(AFormatter:IFormatterResponse);
    procedure DeleteHandler(AFormatter:IFormatterResponse);
  Public
    constructor Create();
  End;
 
  TUserService_ServiceBinderFactory = class(TInterfacedObject,IItemFactory)
  protected
    function CreateInstance():IInterface;
  End;
 
  procedure Server_service_RegisterUserServiceService();
 
(...)
 
procedure TUserService_ServiceBinder.AddHandler(AFormatter:IFormatterResponse);
Var
  cllCntrl : ICallControl;
  tmpObj : UserService;
  callCtx : ICallContext;
  strPrmName : string;
  procName,trgName : string;
  AUser : TUser;
Begin
  callCtx := GetCallContext();
  TObject(AUser) := Nil;
 
  strPrmName := 'AUser';  AFormatter.Get(TypeInfo(TUser),strPrmName,AUser);
  If Assigned(Pointer(AUser)) Then
    callCtx.AddObjectToFree(TObject(AUser));
 
  tmpObj := Self.GetFactory().CreateInstance() as UserService;
  if Supports(tmpObj,ICallControl,cllCntrl) then
    cllCntrl.SetCallContext(GetCallContext());
 
  tmpObj.Add(AUser);
 
  procName := AFormatter.GetCallProcedureName();
  trgName := AFormatter.GetCallTarget();
  AFormatter.Clear();
  AFormatter.BeginCallResponse(procName,trgName);
  AFormatter.EndCallResponse();
 
  callCtx := Nil;
End;

Host the service into an application server.

The application server's role is to route incoming service requests to the Web Service Toolkit runtime. For the runtime to process service requests :

  • The services and their implementations have to be registered ,
  • The message protocol (SOAP, binary,...) have to be registered.

The runtime interface is defined in the server_service_intf unit. This unit contains :

  • GetServerServiceRegistry, which returns the service registry,
  • GetServiceImplementationRegistry which returns the service implementation registry,
  • GetFormatterRegistry which returns the message format registry and
  • HandleServiceRequest which is the unique entry point for request processing.

Starting from the version 0.5, the toolkit provides a simplified model to develop applications server . This is achieved using the listener classes. A listener implements a transport between the server and its clients. The toolkit provides three (3) listeners implementations:

  • TwstIndyHttpListener ( indy_http_server.pas ),
  • TwstIndyTcpListener ( indy_tcp_server.pas ) and
  • TwstSynapseTcpListener ( synapse_tcp_server.pas ).

All listeners derive from TwstListener defined in the server_listener.pas file.

Below is printed a Indy based HTTP server sample. The code is divided into three (3) parts :

  • messaging format registration :
  Server_service_RegisterSoapFormat(); 
  Server_service_RegisterXmlRpcFormat();
  Server_service_RegisterBinaryFormat() ;
  • service implementation and binder registration :
  RegisterUserServiceImplementationFactory();
  Server_service_RegisterUserServiceService();
  • the listner creation and starting : the listener is created and started by the lines
  AppObject  := TwstIndyHttpListener.Create();
  AppObject.Start();


Complete listing :

program http_server;
{$mode objfpc}{$H+}
uses
  {$IFDEF UNIX}{$IFDEF UseCThreads}
  cthreads,
  {$ENDIF}{$ENDIF}
  Classes, SysUtils,
  indy_http_server, metadata_service, logger_extension, server_listener,
  server_service_soap, server_binary_formatter, server_service_xmlrpc, config_objects,
  user_service_intf, user_service_intf_binder, user_service_intf_imp;
var
  AppObject : TwstListener;
begin
  Server_service_RegisterBinaryFormat();
  Server_service_RegisterSoapFormat();
  Server_service_RegisterXmlRpcFormat();
 
  RegisterUserServiceImplementationFactory();
  Server_service_RegisterUserServiceService();
  AppObject := TwstIndyHttpListener.Create();
  try
    WriteLn('"Web Service Toolkit" HTTP Server sample listening at:');
    WriteLn('');
    WriteLn('http://127.0.0.1:8000/');
    WriteLn('');
    WriteLn('Press enter to quit.');
    AppObject.Start();
    ReadLn();
  finally
    FreeAndNil(AppObject);
  end;
end.

Server_service_RegisterUserServiceService located in the user_service_intf_binder unit ( generated by ws_helper ) registers the UserService service by calling in turn GetServerServiceRegistry:

procedure Server_service_RegisterUserServiceService();
Begin
  GetServerServiceRegistry().Register(
    'UserService',TUserService_ServiceBinderFactory.Create() as IitemFactory
  );
End;

Server_service_RegisterSoapFormat located in the server_service_soap unit ( provided by the toolkit ) registers the SOAP implementation by calling in turn GetFormatterRegistry:

  procedure Server_service_RegisterSoapFormat();
  begin
    GetFormatterRegistry().Register(
      sPROTOCOL_NAME,
      sSOAP_CONTENT_TYPE,
      TSimpleItemFactory.Create(TSOAPFormatter) as IitemFactory
    );
    RegisterStdTypes();
  end;

Server_service_RegisterBinaryFormat located in the server_binary_formatter unit ( provided by the toolkit ) registers the Binary message implementation by calling in turn GetFormatterRegistry:

  procedure Server_service_RegisterBinaryFormat();
  begin
    GetFormatterRegistry().Register(
      sPROTOCOL_NAME,
      sBINARY_CONTENT_TYPE,
      TBinaryFormatterFactory.Create() as IitemFactory
    );
  end;

Server_service_RegisterXmlRpcFormat located in the server_service_xmlrpc unit ( provided by the toolkit ) registers the XMLRPC message implementation by calling in turn GetFormatterRegistry:

  procedure Server_service_RegisterXmlRpcFormat();
  begin
    GetFormatterRegistry().Register(
      sPROTOCOL_NAME,
      sXMLRPC_CONTENT_TYPE,
      TSimpleItemFactory.Create(TXmlRpcFormatter) as IItemFactory
    );
  end;

In order to give it a try one have to :

  1. compile the server ( \samples\tcp_server\tcp_server.lpi it is a console program),
  2. compile the client application ( \samples\user_client_console\user_client_console.lpi ),
  3. execute the server and start listening,
  4. execute the client.

WSDL generation

Services in the toolkit are organized into meta data repositories. Conceptually a repository corresponds :

  • at compile time to the pascal unit containing the service definition
  • at runtime to a name space.

The repository is the toolkit WSDL generation unit.


The Metadata Service

The toolkit is provided with an easy to use metadata service implementation which in turn uses the raw interface defined in the metadata_repository unit (see above). A Lazarus GUI client application is located in the tests\metadata_browser folder.

WSDL generation API

The metadata_wsdl pascal unit contains the GenerateWSDL function for WSDL generation from a repository (see the signature below).

  PServiceRepository = ^TServiceRepository;
  TServiceRepository = record
    NameSpace        : ShortString;
    Name             : ShortString;
    RootAddress      : ShortString;
    ServicesCount    : Byte;
    Services         : PService;
  end;
 
  procedure GenerateWSDL(AMdtdRep : PServiceRepository; ADoc : TDOMDocument);
WSDL Customization

The WSDL generation is based on the IWsdlTypeHandler and the IWsdlTypeHandlerRegistry interfaces located in the metadata_wsdl unit. In order to customize the generated WSDL, one has to provide a class implementing the IWsdlTypeHandler interface. Then that class has to be registered in the registry. The metadata_wsdl unit contains implementations for pascal enumerations, TBaseComplexRemotable descendants, and TBaseArrayRemotable descendants.

Sample

A functional sample project is located under \samples\http_server . It is an Indy base http server.

Services Extensions

Services extensions provide a mean to hook into all the services request processing stages. Services extensions may be used, for example, to implement authentication, request logging, data compression, etc. The IServiceExtension below is the interface used by the toolkit runtime to call services extensions.

  TMessageStage = (
    msAfterDeserialize, msAfterSerialize, msBeforeDeserialize, msBeforeSerialize
  );
 
  IServiceExtension = interface
    ['{E192E6B3-7932-4D44-A8AC-135D7A0B8C93}']
    procedure ProcessMessage(
      const AMessageStage     : TMessageStage;
               ACallContext   : ICallContext;
               AMsgData       : IInterface
    );
  end;

The AMsgData parameter actual type depends on the message processing state and corresponds to :

  • IRequestBuffer on "msBeforeDeserialize" and "msAfterSerialize"
  • IFormatterResponse on "msAfterDeserialize" and "msBeforeSerialize"

These types are located in the server_service_intf unit. Extensions have to be registered in the extensions registry ( located in the server_service_intf unit ) printed below

  IServiceExtensionRegistry = Interface
    ['{68DC78F1-E6CF-4D6B-8473-75288794769C}']
    function Find(const AName : string):IServiceExtension;
    procedure Register(
      const AName    : string;
            AFactory : IItemFactory
    );
  end;

In order for an service implementation to use a service extension, it has to register himself to that extension. To that end, the IServiceImplementationFactory interface provides the RegisterExtension method. A complete sample is included in the \samples\http_server sample ( implemented in \samples\logger_extension.pas ).

Services meta data

Services in the toolkit are organized into meta data repositories( see the “services's meta data” below ). Conceptually a repository corresponds :

  • at compile time to the pascal unit containing the service definition
  • at runtime to a name space.

The ws_helper tool, when parsing the interface definition file, records the meta data of the services contained in the file to a Lazarus resource file. The resource file is then embedded into the generated binder's unit file( see the unit “initialization” part ). At runtime the service's recorded meta data are accessible through the interface IModuleMetadataMngr defined in the metadata_repository unit ( see below ). The GetModuleMetadataMngr function defined in the same unit returns an instance of an object supporting that interface.

  IModuleMetadataMngr = interface
    ['{B10ACF6A-A599-45A3-B083-BEEFB810C889}']
    function IndexOfName(const ARepName : shortstring):Integer;
    function GetCount():Integer;
    function GetRepositoryName(const AIndex : Integer):shortstring;
    procedure SetRepositoryNameSpace(const ARepName,ANameSpace : shortstring);
    function LoadRepositoryName(
      const ARepName,ARootAddress  : shortstring;
      out   ARepository  : PServiceRepository
    ):Integer;
    procedure ClearRepository(var ARepository : PServiceRepository);
    procedure SetServiceCustomData(
      const ARepName       : shortstring;
      const AServiceName   : shortstring;
      const ADataName,
            AData          : string
    );
    procedure SetOperationCustomData(
      const ARepName       : shortstring;
      const AServiceName   : shortstring;
      const AOperationName : shortstring;
      const ADataName,
            AData          : string
    );
    function GetServiceMetadata(const ARepName,AServiceName : shortstring) : PService;
    procedure ClearServiceMetadata(var AService : PService);
  end;

Extended Meta data

The meta data interface provides a way to add custom data to recorded ones. Services's metadata can be set through SetServiceCustomData, operation's metadata be set through the SetOperationCustomData method. A repository's extended meta data has to be registered after the service meta data recorded in the resource file have been registered. So for client application the generated proxy unit contains a conditional code fragment to call a registration procedure like shown below for the eBay sample located in the tests\ebay folder. The procedure name is obtained from the interface unit name ( the repository's name )  : Register_%UNIT_NAME%_ServiceMetadata .

  initialization
    {$i ebay.lrs}
 
    {$IF DECLARED(Register_ebay_ServiceMetadata)}
    Register_ebay_ServiceMetadata();
    {$ENDIF}
  End.

Headers support

The THeaderBlock class

  THeaderBlock = class(TBaseComplexRemotable)
  public
    property Direction : THeaderDirection read FDirection write FDirection;
    property Understood : Boolean read FUnderstood write FUnderstood;
  published
    property mustUnderstand : Integer read FmustUnderstand write SetmustUnderstand 
      stored HasmustUnderstand;
  end;

The THeaderBlock shown above ( the private part has been omitted for brevity), located in the base_service_intf unit, is the root class all header classes are derived from.. The Direction property indicate whether it is an incoming header or an outgoing one. The mustUnderstand property define whether the header is a mandatory one.

Defining header class

Soap headers are derived from the THeaderBlock base class located in the base_service_intf unit. They have to be registered in the type registry. Below is reproduced an header example extracted from the “calculator” sample project.

  TCalcHeader = class(THeaderBlock)
  published
    property Login : string read FLogin write FLogin;
    property Password : string read FPassword write FPassword;
    property WantedPrecision : Integer read FWantedPrecision write FWantedPrecision;
  end;

The ICallContext interface

  ICallContext = Interface
    ['{855EB8E2-0700-45B1-B852-2101023200E0}']
    procedure AddObjectToFree(const AObject : TObject);
    procedure Clear();
    function AddHeader(
      const AHeader        : THeaderBlock;
      const AKeepOwnership : Boolean
    ):Integer;
    function GetHeaderCount(const ADirections : THeaderDirections):Integer;
    function GetHeader(const AIndex : Integer) : THeaderBlock;
    procedure ClearHeaders(const ADirection : THeaderDirection);
  End;

The ICallContext interface defined in the base_service_intf unit represents the service call context. The AddHeader method allows headers sending while the GetHeader method retrieves header in the call context.

Client side headers

An ICallContext reference may be obtained from the current service proxy instance simply by querying it for that interface as shown in the code fragment below extracted from the “calculator” client example project.

  var
    ch : TCalcHeader;
    hdrs : ICallContext;
  begin
    FObj := TCalculator_Proxy.Create('Calculator', edtFormat.Text, edtAddress.Text);
 
    ch := TCalcHeader.Create();
    ch.mustUnderstand := 1;
    ch.Login := 'azerty';
    ch.Password := 'qwerty';
    ch.WantedPrecision := 1210;
    hdrs := FObj as ICallContext;
    hdrs.AddHeader(ch,true);

A header may be made mandatory by setting its mustUnderstand property to 1 as in the code above.

Server side headers

The ICallControl interface

  ICallControl = interface
    ['{7B4B7192-EE96-4B52-92C7-AE855FBC31E7}']
    procedure SetCallContext(ACallContext : ICallContext);
    function GetCallContext():ICallContext;
  end;

The ICallControl interface, located in the server_service_intf unit, is used by the toolkit runtime to share the executing call environment with service implementation classes. When the runtime is about to issue a call against a implementation class instance, it queries that instance for ICallControl interface support; If the implementation has ICallControl interface support then the obtained reference is used to set the call context through the SetCallContext method. The implementation instance can then access the call context by calling the GetCallContex method. The toolkit provides the TBaseServiceImplementation class which has support for the ICallControl interface and can be used as a base implementation class. It is the base class used by the ws_helper generated skeleton implementation class when invoked with the -i command line option. The method printed below, extracted from the calculator sample service demonstrates the access to headers for read and write.

  function TCalculator_ServiceImp.AddInt(
    Const A : Integer;
    Const B : Integer
  ):TBinaryArgsResult;
  var
    hdr : TCalcResultHeader;
    h : TCalcHeader;
    cc : ICallContext;
  Begin
    hdr := TCalcResultHeader.Create();
    cc := GetCallContext();
    if Assigned(cc) and ( cc.GetHeaderCount([hdIn]) > 0 ) and ( cc.GetHeader(0).InheritsFrom(TCalcHeader) ) then begin
      h := cc.GetHeader(0) as TCalcHeader;
      h.Understood := True;
      hdr.Assign(h);
    end;
    hdr.TimeStamp := DateTimeToStr(Now());
    hdr.SessionID := 'testSession';
    cc.AddHeader(hdr,True);
    hdr := nil;
    Result := TBinaryArgsResult.Create();
    Try
      Result.Arg_OP := '+';
      Result.Arg_OpEnum := coAdd;
      Result.Arg_A := A;
      Result.Arg_B := B;
      Result.Arg_R := A + B;
      Result.Comment := 'Doing an + operation';
    Except
      FreeAndNil(Result);
      Raise;
    End;
  End;

SOAP Specific

Binding style

The binding style is used to indicate whether the service is RPC oriented or Document oriented.

Client side

The binding style may be specified in the SOAP protocol string on the creation of a service proxy. The default value for the binding style is RPC. Below is printed a sample code that demonstrates the use of Document style.

  locService := TSampleService_Proxy.Create(
                  'SampleService',
                  'SOAP:Style=Document;EncodingStyle=Litteral',
                  'http:Address=http://127.0.0.1/services/SampleService'
                );

Server side

Currently services created with the toolkit use the RPC binding style.

Encoding style

The encoding style indicates the rules used to encode types in XML. Supported values are Encoded and Litteral.

Client side

The encoding style may be specified in the SOAP protocol string on the creation of a service proxy. The default value for the encoding style is Encoded. The above sample demonstrates the use of Litteral style.

Server side

Currently services created with the toolkit use the Encoded encoding style.

Provided examples

The samples are located under the “tests” folder.

Client side examples ( tested on Windows XP, Ubuntu and MacOS on PowerPC)

  • UserService, samples\http_server, samples\tcp_server, samples\user_client_console, sample\library_server : the client console uses the three client and server protocols (HTTP, TCP, LIBRARY)
  • Google sample : It demonstrates use of class and array data types .
  • Metadata Browser : This sample demonstrates use of class and array data types and mainly the toolkit metadata service.
  • eBay sample, this sample uses OpenSLL which can be found at http://www.openssl.org and SYNAPSE ( http://www.ararat.cz/synapse/ ).
  • \samples\delphi\ : This folder contains Delphi ( compile with Delphi 7) client and server samples. Used protocol : the TCP, HTTP, LIBRARY; Used format : SOAP, XMLRPC and BINARY.

Server side examples

  • samples\tcp_server : This is a sample TCP server based on the Synapse components. It uses the UserService.
  • samples\http_server : This is a sample HTTP server based on the Indy10 components. It uses the UserService and the toolkit metadata service. It demonstrates the WSDL generation.
  • samples\apache_module : Apache module sample, this sample demonstrates the hosting of the toolkit into the Apache HTTP web server. It is based on Sekelsenmat's Apache headers translation. It uses the UserService service and the toolkit metadata service. It demonstrates the WSDL generation.

Status

The toolkit is usable for simple types and for class types. The serialization is designed to allow customization of basic types and class types by implementing classes derived from “TBaseRemotable”. This classes have to be registered in the type registry.

Serialization

The serialization is based on the IFormatterBase interface located in the base_service_intf unit.

The toolkit has three serializers implementations : the SOAP serializer, the XMLRPC serializer and a binary serializer. This serializers has been tested on fpc 2.x and Delphi 7.

SOAP serializer

The SOAP serializer implements SOAP 1.1. It has support for the following pascal types:

  • Available integers :
    • Byte mapped to unsignedByte
    • ShortInt mapped to byte
    • SmallInt mapped to short
    • Word mapped to unsignedShort
    • LongInt mapped to int
    • LongWord mapped to unsignedInt
    • Int64 mapped to long
    • QWord mapped to int
  • String mapped to string
  • Boolean mapped to boolean
  • Enumerations mapped to their string representation
  • Float types :
    • Single mapped to float
    • Double mapped to double
    • Extended mapped to double
    • Currency mapped to float
  • Object (class instances, not TP ones ) : The toolkit has support for instances of classes derived from TBaseRemotable. TBaseRemotable is the base class used by the formatter interface to allow customization of the serialization. The toolkit provides the TBaseComplexRemotable class which implements serialization for its ( or its descendants ) published properties.

Binary serializer

The Binary serializer is more efficient in time and space compared to the SOAP serializer . It uses big endian to stream data. It has support for the following pascal types:

  • Available integers :
    • Byte
    • ShortInt
    • SmallInt
    • Word
    • LongInt
    • LongWord
    • Int64
    • QWord
  • String
  • Boolean
  • Enumerations
  • Float types :
    • Single
    • Double
    • Extended
    • Currency
  • Object (class instances, not TP ones ) :The toolkit has support for instances of classes derived from TBaseRemotable. TBaseRemotable is the base class used by the formatter interface to allow customization of the serialization. The toolkit provides the TBaseComplexRemotable class which implements serialization for its ( or its descendants ) published properties.

Class type serialization

The toolkit has support for instances of classes derived from TBaseRemotable. TBaseRemotable is the abstract base class used by the formatter interface to allow customization of the serialization. The toolkit provides the TBaseComplexRemotable class which implements serialization for its descendants classes published properties. It also provides TBaseObjectArrayRemotable class for serialization of array of TBaseRemotable descendant classes.

The root “TBaseRemotable” class
  TBaseRemotable = class(TPersistent)
  Public
    constructor Create();virtual;
    class procedure Save(
            AObject   : TBaseRemotable;
            AStore    : IFormatterBase;
      Const AName     : String;
      Const ATypeInfo : PTypeInfo
    );virtual;abstract;
    class procedure Load(
      Var   AObject   : TObject;
            AStore    : IFormatterBase;
      var   AName     : String;
      const ATypeInfo : PTypeInfo
    );virtual;abstract;
  End;

TBaseRemotable is the abstract base class used by the formatter interface to allow customization of the serialization. This class defines a virtual constructor and mainly two(2) virtual abstract class methods :

  • Save : this method is called when the toolkit needs to serialize the AObject parameter.
  • Load: this method is called when the toolkit needs to un-serialize to the AObject parameter.
The “TBaseComplexRemotable” serialization
  TBaseComplexRemotable = class(TAbstractComplexRemotable)
  public
    class procedure Save(
            AObject   : TBaseRemotable;
            AStore    : IFormatterBase;
      const AName     : string;
      const ATypeInfo : PTypeInfo
    );override;
    class procedure Load(
      var   AObject   : TObject;
            AStore    : IFormatterBase;
      var   AName     : string;
      const ATypeInfo : PTypeInfo
    );override;
    class procedure RegisterAttributeProperty(const AProperty : shortstring);virtual;
    class procedure RegisterAttributeProperties(const APropertList : array of shortstring);virtual;
    class function IsAttributeProperty(const AProperty : shortstring):Boolean;
    procedure Assign(Source: TPersistent); override;
  end;

TBaseComplexRemotable implements serialization for its descendants classes published properties. The serialization is based on runtime type information (RTTI) and can be customized to:

  • ignore always some published properties.
  • ignore conditionally some published properties.

The following class shows a the serialization's customization sample.

  TSampleClass = class(TBaseComplexRemotable)
  private
    FProp_Always: Integer;
    FProp_Never: Integer;
    FProp_Optional: Integer;
    function GetStoredProp_Optional: boolean;
  published
    //This property will always be serialized
    property Prop_Always : Integer read FProp_Always write FProp_Always;
    //This property will never be serialized
    property Prop_Never : Integer read FProp_Never write FProp_Never stored False;
    //This property will be serialized if "Self.GetStoredProp_Optional() = True"
    property Prop_Optional : Integer read FProp_Optional write FProp_Optional stored GetStoredProp_Optional;
  End;
  • Attribute properties

TBaseComplexRemotable allows properties serialization as attributes. Theses properties have to be registered as such with the RegisterAttributeProperty class method or RegisterAttributeProperties one.


TBaseComplexRemotable

TBaseComplexSimpleContentRemotable provides implementation for the “XML Schema” complex types which extend simple types with attributes. The following example illustrates this :

  <xs:complexType name="DecimalWithUnits">
    <xs:simpleContent>
      <xs:extension base="xs:decimal">
        <xs:attribute name="Units" type="xs:string"
                      use="required"/>
      </xs:extension>
    </xs:simpleContent>
  </xs:complexType>

This type will be translate by ws_helper to Pascal as

  DecimalWithUnits = class(TComplexFloatExtendedContentRemotable)
  private
    FUnits : string;
  published
    property Units : string read FUnits write FUnits;
  end;

using the predefined types ( in base_service_intf.pas )

  TBaseComplexSimpleContentRemotable =
     class(TAbstractComplexRemotable)
  protected
    class procedure SaveValue(
      AObject : TBaseRemotable; 
      AStore : IformatterBase
    );virtual;abstract;
    class procedure LoadValue(
      var AObject : TObject; 
      AStore : IformatterBase
    );virtual;abstract;
  public
    class procedure Save(
            AObject   : TBaseRemotable;
            AStore    : IFormatterBase;
      const AName     : string;
      const ATypeInfo : PTypeInfo
    );override;
    class procedure Load(
      var   AObject   : TObject;
            AStore    : IFormatterBase;
      var   AName     : string;
      const ATypeInfo : PTypeInfo
    );override;
  end;
 
  TComplexFloatExtendedContentRemotable =
     class(TBaseComplexSimpleContentRemotable)
  private
    FValue: Extended;
  protected
    class procedure SaveValue(
      AObject : TBaseRemotable; 
      AStore : IformatterBase
    );override;
    class procedure LoadValue(
       var AObject : TObject; 
       AStore : IformatterBase
    );override;
  public
    property Value : Extended read FValue write FValue;
  end;

An instance of this type looks like the one below. Every attribute must be registered using the RegisterAttributeProperty() method. The toolkit provides class for Pascal basic types( TComplexInt8UContentRemotable, TComplexInt8SContentRemotable, TComplexInt16SContentRemotable, ...).

  <example Units = "meter">
    12.10
  </example>
Provided array implementations

The toolkit provides array implementation for basic types ( in the base_service_intf unit ) listed below. The implementations are based on the serialization's customization.

  • Available integers :
    • Byte TArrayOfInt8URemotable
    • ShortInt TArrayOfInt8SRemotable
    • SmallInt TArrayOfInt16SRemotable
    • Word TArrayOfInt16URemotable
    • LongInt TArrayOfInt32SRemotable
    • LongWord TArrayOfInt32URemotable
    • Int64 TArrayOfInt64SRemotable
    • Qword TArrayOfInt64URemotable
  • String TarrayOfStringRemotable( AnsiString )
  • Boolean TArrayOfBooleanRemotable
  • Float types :
    • Single TArrayOfFloatSingleRemotable
    • Double TArrayOfFloatDoubleRemotable
    • Extended TArrayOfFloatExtendedRemotable
    • Currency TArrayOfFloatCurrencyRemotable

The toolkit array's implementation support “embedded” array serialization. This type of array occurs typically with types like the following one ( the "ResponseGroup" may be repeated ):

  <xs:complexType name="CustomerContentSearchRequest">
    <xs:sequence>
      <xs:element name="CustomerPage" type="xs:positiveInteger"
         minOccurs="0"/>
      <xs:element name="Email" type="xs:string" minOccurs="0"/>
      <xs:element name="Name" type="xs:string" minOccurs="0"/>
      <xs:element name="ResponseGroup" type="xs:string"
           minOccurs="0" maxOccurs="unbounded"/>
    </xs:sequence>
  </xs:complexType>

which could be instantiated as

  <search>
    <CustomerPage> 1 </CustomerPage>
    <Name>Sample name</Name>
    <ResponseGroup>Group 1</ResponseGroup>
    <ResponseGroup>Group 2</ResponseGroup>
    <ResponseGroup>Group 3</ResponseGroup>
  </search>

This type will be translate to Pascal by ws_helper as (the private and protected parts are omitted to be short)

(...)
  CustomerContentSearchRequest_ResponseGroupArray =
    class(TBaseSimpleTypeArrayRemotable)
  public
    class function GetItemTypeInfo():PTypeInfo;override;
    procedure SetLength(const ANewSize : Integer);override;
    property Item[AIndex:Integer] : string 
      read GetItem write SetItem; default;
  end;
 
  CustomerContentSearchRequest = class(TBaseComplexRemotable)
  published
    property CustomerPage : positiveInteger 
       read FCustomerPage 
       write FCustomerPage stored HasCustomerPage;
    property Email : string 
       read FEmail 
       write FEmail 
       stored HasEmail;
    property Name : string read FName write FName stored HasName;
    property ResponseGroup :
       CustomerContentSearchRequest_ResponseGroupArray
       read FResponseGroup 
       write FResponseGroup;
  end;
 
implementation
(...)
  GetTypeRegistry().ItemByTypeInfo[
    TypeInfo(CustomerContentSearchRequest_ResponseGroupArray)]
    .RegisterExternalPropertyName(sARRAY_STYLE,sEmbedded);
(...)

The last instruction set the array style to “Embedded” and so the SOAP formatter will serialize the array accordingly.

Test cases

  • The toolkit uses FPCUnit for test cases. The test project is located in the \tests\test_suite folder.
  • The Delphi tests suite is based on Dunit and is located in the \tests\test_suite\delphi folder.

TODO

TODO Common

  • Simple type support in headers
  • Header support for the binary format
  • True Attribute serialization support for the binary format

TODO Client-Side

  • Basic array support for SOAP
  • Basic array support for Binary format
  • XML-RPC formatter
  • More documentation and samples !
    • eBay basic client : demonstrates the GetPopularKeywords operation call
    • "Amazon E-Commerce Service" sample
  • WSDL to pascal compiler
  • Enhance the pascal parser : the toolkit now uses the fcl-passrc
  • Client side services extensions
  • import functions from XMLRPC server via introspect http://scripts.incutio.com/xmlrpc/introspection.html

TODO Server-Side

Extend the toolkit to Server side for :

  • SOAP
  • Binary serialization
  • Bytes ordering in binary serialization : alaways use big-endian
  • XML-RPC
  • TCP transport ( first implementation).
  • WSDL generation
  • More documentation and samples !
  • Apache support : services as Apache modules using Sekelsenmat 's Apache headers translation
    • See the apache_module sample located in the tests\apache_module folder
  • Classes inheritance generation in WSDL

Licence

  • The support units are provided under modified LGPL
  • ws_helper sources are provided under GPL 2 ( or later version )

Download & NewsGroup

FAQ

The Web Service Toolkit:FAQ.

Changes Log

Version 0.5

  • Lazarus IDE WSDL importer wizard
  • WSDL GUI editor ( Type library editor )
  • Listener design : easy server development
    • Indy HTTP server listener
    • Indy TCP server listener
    • Synapse TCP server listener
  • XMLRPC support : client and server
  • Switch from the custom pascal parser to fcl-passrc
  • Server side : implementation objects pooling
  • Better Delphi support
    • SOAP XMLRPC and binary format support
    • DUnit test suite
  • WST has been tested on
    • Windows
    • Linux
    • Mac OS X PowerPC
  • Better WSDL parsing
  • Services configuration in external file
  • TStringBufferRemotable ( reading a node's raw buffer )
  • Bugs fixes

Version 0.4

  • WSDL to Pascal translation support in "ws_helper"
  • new TCP transport implementation ( using synapse library ) in synapse_tcp_protocol.pas
  • new library protocol implementation in library_protocol.pas
  • TCP server implementation ( using synapse library ) in synapse_tcp_server.pas
  • Delphi : first binary format support
  • Embedded array support
  • Object Pascal reserved words can now be used as service methods's name, enumeration, ... ( see TTypeRegistryItem.RegisterExternalPropertyName() )
  • The toolkit can now be used with FPC without Lazarus
  • "Amazon E-Commerce Service" sample
  • Bugs Fixes.

Version 0.3.1 ( 21 August 2006 )

  • Apache Web Server support : services hosting as Apache's module.
    • See the apache_module sample located in the tests\apache_module folder.
  • Important : In the connection string the address token was mis-spelled as adress (one letter "d" instead of two), it has been corrected to address.
  • Bugs Fixes.

Version 0.3 ( 5 August 2006 )

  • Header support ( client and server side )
  • Server side service extensions
  • Attribute serialization
  • New transport implementation : Synapse HTTP client support
  • Address per operation support ( client side )
  • Extended meta data
  • Bug Fixes

Version 0.2.3.2 ( 5 July 2006 )

  • ICS and Indy HTTP Proxy "user" and "password" support.

Version 0.2.3 ( 4 July 2006 )

  • WSDL generation
  • Metadata service
  • Metadata Browser sample
  • HTTP server sample
  • Pascal basic types array implementation
  • The ws_helper's parser now supports:
    • {} comment style in the input file
    • service interfaces may have GUID
  • more test cases
  • bug fix

Version 0.2.2 ( 7 June 2006 )

  • All pascal basic types are supported by the SOAP serializer and the Binary serializer ( Available integers, available floats, string, boolean, Enumerations, class intances )
  • Array support for Binary serializer
  • FPCUnit test cases
    • SOAP serializer ( basic types and classes instances )
    • Binary serializer ( basic types and classes instances )
  • All interfaces now have GUID

Author

Inoussa OUEDRAOGO, http://inoussa12.googlepages.com/

See also

  • fcl-web FPC/Lazarus web server components
  • [6] Article on WST. Though written a while ago, it may still be useful

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