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Web Service Toolkit/fr

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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.

Côté Client ( consommation de service )

Vue d'ensemble

“Web Service Toolkit” est composé de deux parties :

Etant donné un fichier de définition d'interface ( un fichier WSDL ou un fichier pascal décrivant un service web), “ws_helper” ( ou depuis Lazarus, l'assistant d'importation de fichier WSDL ) va créer une unité pascal object contenant un proxy implémentant cette interface. A l'exécution quand un un appel ciblant le service web sera émis, le rôle du proxy est de :

En coulisses, le proxy va prendre soin des détails de la "plomberie" de SOAP.

Exemple

Nous allons utiliser le “Amazon E-Commerce Service”, disponible librement ( vous aurez à créer un compte, c'est gratuit ) pour un usage personnel à cette adresse1. Afin d'utiliser ce service, nous avons à télécharger ses interfaces WSDL exposées (Web Services Description Language) et les traduire en langage Pascal. Pour cela, depuis Lazarus nous pouvons utiliser l'assistant d'import; nous pouvons aussi utiliser ws_helper comme programme indépendant.

L'assistant “WSDL importer”

Cet assistant est contenu dans le paquet wst_design.lpk situé dans le dossier \ide\lazarus du toolkit. Une fois ce paquet installé, il ajoute une section de menu “Web Services Toolkit” avec deux (2) sous-menus au menu Lazarus “Project” :

Cliquez sur le premier élément de menu (Importer Fichier WSDL ...), cela fera apparaître le dialogue ci-dessous. Nous spécifions le fichier WSDL et le dossier où stocker les fichiers générés et cliquez sur le bouton OK pour finir.

Cela va produire deux (2) fichiers source pascal :

Import par ws_helper.

Le programme ws_helper est une version en ligne de commande de l'assistant d'import. Afin de présenter ses capacités, les arguments de ligne de commande qu'il supporte sont sont affichées ci-dessous.

pascal
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

Pour traduire le fichier WDSL téléchargé depuis le site web "Amazon E-Commerce Service” exécutez la commande suivante à l'invite:

pascal
..\..\ws_helper\ws_helper.exe -uA -p -o. AWSECommerceService.wsdl
ws_helper, Web Service Toolkit 0.4 Copyright (c) 2006, 2007 by Inoussa OUEDRAOGO
pascal
Parsing the file : AWSECommerceService.wsdl
(...)
Interface file generation...
Proxy file generation...
Metadata file generation...
File "AWSECommerceService.wsdl" parsed succesfully.

ci-dessous est affiché un extrait des deux fichiers :

pascal
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();
pascal
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;
(...)

Noous avons maintenant la possibilité de construire un programme simple pour le service. La bibliothèque Synapse est requise pour compiler le programme pour qu'il soit utilisé pour les communications HTTP. Cette bibliothèque est téléchargeable gratuitement à cette adresse: 2. La bibliothèque Indy3 ou la bibliothèque ICS4 peuvent aussi être utilisées.

pascal
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.

Les unités base_service_intf, service_intf, soap_formatter, synapse_http_protocol, wst_resources_imp et metadata_repository sont fournies avec le toolkit; Ci-dessous le résultat d'une session d'exécution de recherche de “Freepascal” dans l'index de recherche “All” ( le service est sensible à la casse des caractères!) .

pascal
Web Services Toolkit Amazon sample
This sample demonstrates the "ItemSearch" method of the Amazon web service
pascal
Enter the Search Index : All
Enter the Keywords : Freepascal
Response ( 1 ) :
    TotalPages :1
    TotalResults :9
    Items :9
pascal
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
pascal
or Dummies)
               Author[ 0 ] Wallace Wang
               Manufacturer :For Dummies
               ProductGroup :Book
pascal
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
pascal
(...)

Cela trouve une (1) page contenant neuf (9) items! La fonction wst_CreateInstance_AWSECommerceServicePortType(), située dans le fichier AWSECommerceService.pas crée une instance de proxy basé sur les informations du service contenu dans le fichier WSDL.

pascal
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;

Le code source complet de l'exemple d'Amazon est situé dans le dossier \samples\amazon pour fpc; L'exemple Delphi est situé dans le dossier \samples\delphi\amazon.

Paramètres de Connection

Le format général est:

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

Paramètres de Proxy HTTP Proxy

Pour HTTP, les paramètres supportés sont les suivants:

Les connexions HTTP via un proxy sont supportées. Ci-dessous un exemple de chaîne d'adresse.

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

Le toolkit a deux implémentations TCP basées sur Synapse ( synapse_tcp_protocol.pas ) et ICS ( ics_tcp_protocol.pas ).

Paramètres de connexion TCP

Les paramètres TCP supportés sont:

Ci-dessous un exemple de chaîne d'adresse.

pascal
  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 ).

Paramètres de connexion LIBRARY ( LIB )

L'idée derrière ce protocole est d'être capable d'héberger des services dans des bibliothèques dynamiques ( DLL/DSO ). Cela peut -être vu comme un framework à plugins où les where plugins ( services ) sont fournis par des bibliothèques dynamiques. Les paramètres de LIB supportés sont:

Ci-dessous un exemple de chaîne d'adresse.

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

Le toolkit a une implémentation LIB ( library_protocol.pas ).

Le dossier d'exemples contient 4 projets user_client_console, tcp_server, http_server et library_server qui font la démonstration des protocoles TCP, HTTP et LIBRARY.

Service Multi-Adresses ( une adresse par opération )

Certains services ( comme les services SOAP eBay ) utilisent une adresse par opération. Le toolkit utilise des meta data étendues ( voir les meta data de services au chapitre précédent ) pour choisir les adresses des opération. L'exemple SOAP “ebay” situé dans le dossier tests\ebay fait la démonstration de la configuration de l'adresse par opération.

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:

Example

In order to create a service, we have to :

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

Type Library Editor features:

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

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 showed 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 :

pascal
ws_helper\ws_helper.exe -i -b -o. user_service_intf.pas
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.

pascal
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.

pascal
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).

pascal
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;

pascal
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:

The user_service_intf_binder.pas unit generated above, contains :

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

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

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:

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 :

pascal
  Server_service_RegisterSoapFormat(); 
  Server_service_RegisterXmlRpcFormat();
  Server_service_RegisterBinaryFormat() ;
pascal
  RegisterUserServiceImplementationFactory();
  Server_service_RegisterUserServiceService();
pascal
  AppObject  := TwstIndyHttpListener.Create();
  AppObject.Start();

Complete listing :

pascal
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:

pascal
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:

pascal
  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:

pascal
  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:

pascal
  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 :

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).

pascal
  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 bellow is the interface used by the toolkit runtime to call services extensions.

pascal
  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 :

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 bellow

pascal
  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 :

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.

pascal
  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 showed 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 .

pascal
  initialization
    {$i ebay.lrs}

    {$IF DECLARED(Register_ebay_ServiceMetadata)}
    Register_ebay_ServiceMetadata();
    {$ENDIF}
  End.

Headers support

The THeaderBlock class

pascal
  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 showed 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.

pascal
  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; 
</synraxhighlight>

=== The ICallContext interface ===
<syntaxhighlight lang=pascal>
  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 showed in the code fragment below extracted from the “calculator” client example project.

pascal
  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

pascal
  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 bellow, extracted from the calculator sample service demonstrates the access to headers for read and write.

pascal
  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.

pascal
  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)

Server side examples

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:

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:

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
pascal
  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 :

The “TBaseComplexRemotable” serialization
pascal
  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:

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

pascal
  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;

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 :

xml
  <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

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

using the predefined types ( in base_service_intf.pas )

pascal
  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, ...).

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

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

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 ):

xml
  <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

xml
  <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)

pascal
(...)
  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

TODO

TODO Common

TODO Client-Side

TODO Server-Side

Extend the toolkit to Server side for :

]]

Licence

Download & NewsGroup

The "Web Service Toolkit" now has a newsgroup hosted at news://news.dxmachine.com/public.wst

Changes Log

Version 0.5

Version 0.4

Version 0.3.1 ( 21 August 2006 )

Version 0.3 ( 5 August 2006 )

Version 0.2.3.2 ( 5 July 2006 )

Version 0.2.3 ( 4 July 2006 )

Version 0.2.2 ( 7 June 2006 )

Author

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

From the Free Pascal wiki, page "Web Service Toolkit/fr", as it stood on 2020-03-04 after a change by Trev, out of the wiki's dump of 2024-05-26. Copyright stays with the author who wrote it, according to the old wiki's Licensing page. If you have concerns about this material, message the admin.

Version 1, dernière modification par WikiArchive .