bai 2 mo hinh lap trinh wcf

Bi 2

M HNH LP TRNH VI

WINDOWS COMMUNICATION FOUNDATION

Mc lc

1 M hnh lp trnh WCF ..................................................................................................................................... 2 1.1 S dng phng php hng i tng hay hng dch v? .......................................................2 1.2 Service Model (M hnh dch v) .................................................................................................4 1.3 Cc phng php lp trnh vi WCF ............................................................................................6

1.3.1 Declarative programming (Phng php khai bo) ..............................................................6

1.3.2 Explicit programming (Phng php lp trnh trc tip) .....................................................7

1.3.3 Phng php s dng tp tin cu hnh ..................................................................................7

2 Xy dng mt dch v WCF .............................................................................................................................. 9 2.1 Ci t WCF .................................................................................................................................9

2.1.1 .NET Framework 3.5 SP1 .....................................................................................................9

2.1.2 Visual Studio 2008 SP1 ........................................................................................................9

2.2 To dch v WCF u tin ca bn...............................................................................................9 2.2.1 To ng dng pha server .....................................................................................................9

2.2.2 Pht hnh thng tin v dch v ...........................................................................................18

2.2.3 To ng dng pha client ....................................................................................................23

2.3 Cch khc to tham chiu client .........................................................................................25

3 Cu hi n tp .................................................................................................................................................. 27

4 Ti liu tham kho ........................................................................................................................................... 28

Microsoft Vietnam DPE Team | Bi 2: M hnh lp trnh vi WCF 2

Nhn lt qua th thy rng WCF c v ri rm phc tp. Tuy nhin nu bn hiu v WSDL (Web

Service Description Language) v v Web services (cc dch v web), th vic nm c cc khi nim

trong WCF rt n gin. Nhng nu khng quen v cc khi nim trn, hiu c khi nim trong

WCF thng qua bi trc qu l mt vic hi qu sc, do WCF c qu nhiu lp v thnh phn.

Tuy vy, WCF hay ch l n em n mt m hnh lp trnh v dch v rt n gin. Mc d nn

tng bn di cho WCF tng i ln, WCF c xy dng trn c s .NET Framework do bn c

th s dng ngn ng lp trnh v nn tng quen thuc lm vic vi n. Thm na, khi pht trin cc

dch v vi WCF bn ch cn bit cch s dng mt phn ca cc lp m thi. Cch tt nht hc

cch pht trin cc dch v vi WCF l lm vic trc tip vi n. Bi ny gii thiu vi cc bn m hnh

lp trnh vi WCF, ng thi hng dn cc bn xy dng mt dch v WCF u tin.

1 M hnh lp trnh WCF

1.1 S dng phng php hng i tng hay hng dch v?

Nu cc bn hc qua mn hc v cc phng php lp trnh hn s thy c 2 phng php chnh

l hng th tc v hng i tng. V phng php hng i tng trong thi gian gn y c

pht trin rt mnh v c h tr ngay trong cc ngn ng lp trnh nh C# hay VB.NET. Khi lm vic

vi cc dch v web bn lm quen vi mt phng php na l lp trnh hng dch v (Service-

oriented programming). Microsoft cung cp nhiu cng c trn .NET Framework h tr phng

php lp trnh ny thng qua cc lp trong khng gian tn: System.Web.Services.

Nh vy khi lm vic vi WCF bn c hai la chn l hng i tng v hng dch v. Vy ta

nn s dng phng php no? Cu tr li l dng c hai. Ni mt cch n gin l phng php hng

i tng c s dng pht trin cc ng dng trn desktop, cn phng php hng dch v c

s dng kt ni cc ng dng vi nhau. iu quan trng y l lm sao hiu c s khc

nhau gia hai phng php v hiu c khi no chng c s dng v s dng nh th no ng thi

cng phi hiu v cc li ch chng cung cp.

V hng i tng c th hiu nh sau. Cc ng dng hng i tng l hai hay nhiu lp ph

thuc ln nhau v chia s chung cc kiu d liu. Nhng lp ny lin lc vi nhau thng qua cc li gi

cc hm m lp i tng cung cp.

Cc ng dng hng dch v l cc chng trnh khng bit g v nhau. Mi ng dng lin lc vi

ng dng khc thng qua cc bn tin. im c bit l cc bn tin ny c gi t mt ng dng sang

ng dng khc m khng quan tm ti nn tng m dch v ang chy.

Khi pht trin cc dch v WCF, iu quan trng l cn hiu s lin kt gia hng i tng v

hng dch v. Khi lm vic vi .NET Framework bn chc chn rt quen thuc vi thut ng lp (class)


v giao din (interface). Cc thut ng ny vn c s dng khi pht trin dch v WCF. Cc lp v

giao din l phn hng i tng trong WCF, cn phn hng dch v trong WCF s c thy khi bn

a vo cc thuc tnh WCF nh ngha cc thc th.

V d, lp sau y nh ngha mt giao din hng i tng

public interface DichVuBanHang

{

decimal TinhGiaVanChuyen(string diachi, decimal trongluong)

{

// thc hin tnh ton

}

decimal TinhTienThue(decimal tongGiaTien)

{

// thc hin tnh ton

}

}

Ta s c phn hng dch v cho dch v WCF khi thm vo cc thuc tnh cho giao din trn

[ServiceContract]

public interface DichVuBanHang

{

[OperationContract]

decimal TinhGiaVanChuyen(string diachi, decimal trongluong)

{

// thc hin tnh ton

}

[OperationContract]

decimal TinhTienThue(decimal tongGiaTien)

{

// thc hin tnh ton

}

}

Nh vy l qua v d trn cc bn c th thy mi lin kt gia phng php hng i tng v

hng dch v trong WCF. Cc bn cha cn quan tm ti cc thuc tnh [ServiceContract] v

[OperationContract] vi, bi v nhng thuc tnh ny, v cn nhiu th khc na s c gii thiu mt

cch chi tit khi thch hp.


1.2 Service Model (M hnh dch v)

Nu bn tng lm vic vi dch v web, bn s thy m hnh ny quen thuc vi bn theo mt

cch no . Khi bn to mt dch v web, bn thc s to ra mt dch v (service). Dch v web cha

mt ti liu XML m t tt c mi th cn bit v dch v . Ti liu ny c m t bng ngn ng

Web Service Description Language (ngn ng m t dch v web). N cha ba phn:

Service (dch v): Cha thng tin v v tr ca dch v

Binding: Cha thng tin v cch lin lc vi dch v, nh dch v s dng giao thc g,

vv.

PortType (kiu cng): Gii thch v dch v s lm g

M hnh dch v trn WCF cng tng t nh vi m hnh dch v web. im khc bit l cch

t tn. Trong WCF cc phn khng c gi l service, binding, v portType m c gi tng ng l

address (a ch), binding, v contract.

M hnh dch v WCF c cung cp trong khng gian tn System.ServiceModel. Khng gian tn

ny cha rt nhiu lp, nhng bn hon ton khng cn bit ton b chng. s dng m hnh v xy

dng dch v, ta thng s dng mt s lp sau:

Lp M t

BasicHTTPBinding L binding m cc im cui dch v c th s dng lin lc

vi cc ng dng khch v dch v web (ASMX)

NetMsmqBinding L binding m cc im cui dch v c th s dng lin lc

vi cc MSMQ khch v cc dch v khc

NetNamedPipeBinding L binding m cc im cui dch v c th s dng lin lc

vi cc ng dng khch/dch v trn cng mt my

NetTCPBinding L binding m cc im cui dch v c th s dng lin lc

vi cc ng dng khch/dch v cc my khc nhau

WSHTTPBinding L binding m cc im cui dch v c th s dng lin lc

vi cc ng dng khch/dch v s dng cc giao dch phn tn v

cc phin lm vic bo mt v tin cy c.

EndpointAddress Lp biu din a ch duy nht c cung cp v truy xut c


cho my khch lin lc vi im cui dch v

EndpointAddressBuilding L phng php to mi cc a ch u cui vi cc gi tr

tham s xc nh

ChannelFactory L phng php trong cc kiu knh khc nhau c to ra

v qun l, v a ti cho cc ng dng khch gi bn tin ti cc

im cui

Identity Cch m mt nh danh c xc nh, cho php xc thc gia

cc im cui khi trao i bn tin

MessageHeader Biu din ni dung ca mt u bn tin SOAP

ServiceHost Phng php cung cp vt cha cho cc dch v

ReliableSession Cung cp truy xut ti cc thuc tnh ca thnh phn binding

trong phin lm vic tin cy.

nh ngha vic lin lc ca dch v, ta thng hay s dng cc lp sau

Lp M t

AddressHeader Phn u cha thng tin a ch c s dng xc nh v

lin lc vi mt im cui

AddressHeaderCollection Mt tp hp cc u a ch

Binding Tp hp cc thnh phn binding, mi binding nh ngha cch

m mt im cui lin lc vi th gii bn ngoi

BindingContext Cung cp a ch v thng tin binding cn thit cho vic xy

dng knh

BindingElement Biu din mt thnh phn binding, c s dng xy dng

cc binding

CustomBinding S dng nh ngha v xy dng mt tu bin binding t mt

tp cc thnh phn binding

Message Mt n v ca lin lc gia cc im cui


MessageHeader Ni dung ca u bn tin SOAP

MessageHeaders Tp hp cc u bn tin

1.3 Cc phng php lp trnh vi WCF

C mt s phng php lp trnh vi WCF, mi phng php c u im v khuyt im ring ca

n. iu c bit v WCF l lun c hn mt cch gii quyt mt vn trong WCF, v bn khng

nht thit phi chn duy nht mt phng php no. Trong thc t, cch lm tt nht l t hp cc

phng php c c s linh hot v mm do cho dch v ca bn.

C ba phng php hay c s dng khi pht trin dch v WCF nh sau:

Phng php khai bo

Phng php lp trnh trc tip

Phng php s dng tp tin cu hnh

1.3.1 Declarative programming (Phng php khai bo)

Lp trnh khai bo t c thng qua cc thuc tnh. Nhng thuc tnh ny c s dng nh

ngha cc contract v xc nh hnh x ca dch v. Chng c s dng xc nh thm cc tham s

thay i cc chi tit ca contract v hnh x dch v.

Thuc tnh ServiceContract dng quy nh l giao din ny nh ngha cc chc nng ca

mt dch v. Thuc tnh OperationContract c s dng cc hm quy nh rng hm ny

c khai bo l mt phn ca dch v. l tt c nhng g cn to ra mt dch v WCF.

Thm na, bn khng nht thit phi s dng cc giao din (interface) khi ci t mt dch v, iu

ny cng ging nh vic bn khng cn phi s dng giao din nh ngha mt lp. Tuy vy bn nht

thit phi quy nh phn no thuc v dch v. Bn c th nh ngha nhng phn khc cn cho giao din,

nhng ch nhng hm (phng thc) c gn thuc tnh [OperationContract].

V d ta c mt dch v thc hin php tnh cng gia 2 s nguyn AddInt v 2 s thc

AddDouble. Ta khai bo dch v nh sau:

[ServiceContract]

public interface ICalcService

{

[OperationContract]

int AddInt(int x, int y);


[OperationContract]

double AddDouble(double x, double y);

}

Nh vy dch v ca chng ta sau khi khai bo s c 2 phng thc (khai bo vi thuc tnh

OperationContract) l AddInt v AddDouble. Tuy nhin khi khai bo trong C#, vic t tn

AddInt v AddDouble, v c th c mt s hm add cho cc kiu d liu khc, c th rt gn li

thnh mt tn hm Add m thi. Nhng cc dch v li khng cho php t trng tn hm nh th.

Chng ta c th khai bo thm vi thuc tnh OperationContract thc hin, cch lm nh sau:

[ServiceContract]

public interface ICalcService

{

[OperationContract(Name="AddInt")]

int Add(int x, int y);

[OperationContract(Name="AddDouble")]

double Add(double x, double y);

}

Cc bn c th thy l chng ta s dng c php np chng tn trong C# v s dng thm tham s

Name quy nh thm tn hm dch v. Ngoi u im trong vic gii quyt np chng tn hm, ta

cn thy mt li ch khc na l, vic quy nh tham s Name trong thuc tnh OperationContract

cn cho ta thm linh hot trong vic i tn cc hm trong giao din m khng lm thay i nh ngha

dch v, ngha l cc ng dng khc s dng dch v ny khng cn phi bin dch li.

1.3.2 Explicit programming (Phng php lp trnh trc tip)

L phng php lp trnh hng i tng, bn lm vic trc tip vi cc lp v giao din cung cp

bi m hnh i tng ca WCF. Lm vic trc tip vi m hnh i tng cho php nh pht trin tnh

linh hot cao hn v kh nng iu khin tt hn thng qua m ngun ca h. Thm na n cho php

iu khin su hn rt nhiu so vi phng php khai bo v phng php s dng tp tin cu hnh.

1.3.3 Phng php s dng tp tin cu hnh

Cng ging nh phng php khai bo, c rt nhiu th m bn c th quy nh lin quan n hnh

x ca mt dch v thng qua tp tin cu hnh ca dch v. iu hay trong cch tip cn ny l nhng

thay i tp tin cu hnh hon ton khng cn phi bin dch li dch v mi s dng c.

Sau y l v d s dng tp tin cu hnh nh ngha dch v tnh ton trong v d ca phn

phng php khai bo.


2 Xy dng mt dch v WCF

2.1 Ci t WCF

2.1.1 .NET Framework 3.5 SP1

xy dng mt dch v WCF, u tin bn cn phi ci t .NET Framework 3.5 SP1. Thc ra ch

cn .NET Framework 3.0 l , tuy nhin .NET Framework 3.5 SP1 cn cung cp thm cho bn nhiu

tnh nng na, nn bn nn ci .NET Framework 3.5 SP1. Bn ci t ca framework c Microsoft

cung cp trang web http://www.microsoft.com/downloads/details.aspx?familyid=ab99342f-5d1a-413d-

8319-81da479ab0d7&displaylang=en hoc ti http://download.microsoft.com/download/2/0/e/20e90413-

712f-438c-988e-fdaa79a8ac3d/dotnetfx35.exe

2.1.2 Visual Studio 2008 SP1

Sau khi ci t .NET Framework 3.5 SP1, bn thc hin ci t Visual Studio 2008 bn Express

hoc bn Professional tu theo bn c bn no. Nu kinh ph hn hp, bn c th ti v bn Visual Studio

2008 Express Edition min ph trn trang web ca Microsoft, link y:

http://go.microsoft.com/?linkid=9350817

Gi y bn sn sng to ra dch v u tin trn WCF

2.2 To dch v WCF u tin ca bn

Bn c th hnh dung ng dng chng ta s xy dng nh sau. Cng ty Contoso cn xy dng mt

h thng qun l cc nhn vin ca cng ty. Ban u, chng ta cn phi xy dng mt ng dng server

Cung cp danh sch cc nhn vin, v

Cho php hi v ngy sinh ca mt nhn vin no .

Sau cn mt ng dng pha client lm nhng vic sau

Hin th danh sch cc nhn vin

Chn mt nhn vin v hin th ngy sinh ca nhn vin .

2.2.1 To ng dng pha server

Bc 1. To ng dng

1. M Visual Studio 2008, chn to mi C# Console Project t tn l StaffService, xem

Figure 1


Figure 1 To mi project

2. Thm tham chiu ti System.ServiceModel.dll.


Figure 2 Tham chiu ti ServiceModel

Bc 2. To contract dch v

1. nh ngha giao din s c s dng nh l contract cho ng dng ca chng ta, thm

vo thuc tnh ServiceContract cho giao din

2. nh ngha 2 hm nh on m ngun sau, cc hm ny ng vai tr l cc contract

operations miu t chc nng ca dch v

[ServiceContract]

public interface IStaff

{

[OperationContract]

string DisplayStaff();

[OperationContract]

DateTime GetBirthday(int staffId);

}

Bc 3. Ci t dch v

1. nh ngha lp Staff ci t giao din IStaff

2. Thc hin ci t cho 2 hm c nh ngha trong giao din IStaff

using System;


namespace StaffService

{

public class Staff : IStaff

{

#region IStaff Members

public string DisplayStaff()

{

return "1. L Anh\n2. Trn Vn Bnh\n3. Nguyn Vn

Cng\n4.inh Vn Dng";

}

public DateTime GetBirthday(int staffId)

{

switch (staffId)

{

case 1:

return new DateTime(1979, 1, 20);

case 2:


case 3:


case 4:


default:

return DateTime.Now;

}

}

#endregion

}

}

Bc 4. To vt cha dch v

1. Thm on m ngun sau vo hm main

ServiceHost sh = new ServiceHost(typeof(Staff));

try

{

sh.Open();

Console.WriteLine("Staff Service opened successfully");

Console.WriteLine("Press Enter to terminate Staff Service");


Console.ReadLine();

}

finally

{

sh.Close();

}

Bc 5. To cc cu hnh dch v

1. Compile project ca bn, m bo rng khng c li xy ra trong qu trnh bin dch

2. M trnh son tho dch v, Service Configuration Editor v np tp ng dng, bng

cch trong Visual Studio 2008, chn menu Tools, chn la chn WCF Service Configuration

Editor

3. Chn New Config, t tn l Staff.Service

Figure 3 To config cho service

4. t contract dch v l StaffService.IStaff


Figure 4 t tn cho contract dch v

5. Chn cch lin lc l HTTP


Figure 5 Chn cch lin lc

6. Tip theo chn phng php lm vic l Advanced Web Services interoperability, v t

kiu lin kt l Simplex Communication


Figure 6 Chn Simplex communication

7. t mc nh (trng) cho trng a ch, v bm Finish, bn s thy kt qu sau


Figure 7 Kt qa cu hnh dch v

8. Gi bn bm vo biu tng Host pha bn tri, sau chn thm mi a ch c s cho

dch v ca bn, t a ch l http://localhost:8000/StaffService


Figure 8 Thm a ch c s

9. M rng nt EndPoints, chn im cui, ri t tn l ep1

Figure 9 t tn cho im cui

10. Kt thc qu trnh ny bn s c tp cu hnh nh sau:

2.2.2 Pht hnh thng tin v dch v

pht hnh thng tin v dch v cho cc ng dng khc khai thc, ta cn theo cc bc sau:

1. M rng nt Advanced (bn tri), sau chn nt Service Behaviors v bm vo New

Service Behavior Configuration bn phi


Figure 10 To mi cu hnh cho hnh x dch v

2. t tn l MetaDataBehavior, bm Add thm thnh phn hnh x, chn

ServiceMetaData

Figure 11 Thm hnh s siu d liu

3. Chn nt serviceMetadata bn tri v nhp vo gi tr HttpGetEnabled thnh true l

HttpGetUrl l http://localhost:8000/StaffService


Figure 12 t cu hnh cho serviceMetadata

4. Gi bn chn nt StaffService.Staff v t Behavior Configuration vi gi tr l

MetaDataBehavior

Figure 13 t BehaviorConfiguration cho dch v

5. Cui cng l to im cui cc ng dng c th kt ni ti dch v ly cc thng

tin v dch v. Bm chut phi vo Endpoints vo chn New Service Endpoint sau t cu

hnh nh sau:

Name: ep2

Address: mex


Binding: mexHttpBinding

Contract: ImetaDataExchange

Figure 14 Cu hnh cho im cui

6. Bm menu Save bn s c tp cu hnh nh sau:


7. Gi bn c th chy dch v. S khng c li g xy ra v bn s c mn hnh nh sau:

Figure 15 Thc hin dch v

8. Nu s dng Internet Explorer truy xut ti a ch

http://localhost:8000/StaffService bn s thy mn hnh sau:


Figure 16 S dng IE xem dch v

2.2.3 To ng dng pha client

Phn ny hng dn cc bn to ng dng pha client truy xut cc hm do dch v trn cung cp.

im hay trong WCF l bn ch cn s dng mt dng m ngun gi n dch v StaffService, ch

mt dng m thi, nhng th khc c to ra t ng s dng cng c svcutil.exe.

1. M console dng lnh v chuyn ti th mc bn mun to cc tp, g vo lnh sau v

bm Enter:

Svcutil.exe http://localhost:8000/StaffService?wsdl

Bn s thy kt qu sau:


Figure 17 Kt qu to ra khai bo dch v

2. To ra mt console project mi t tn l StaffClient v thm tham chiu ti

System.ServiceModel. Thm vo tp va to ra l Staff.cs, ng thi i tn tp cu hnh thnh

app.config v thm vo project. Kt qu nh sau:

Figure 18 To client

3. Sau khi bin dch v chy chng trnh bn c kt qu sau:


Figure 19 Kt qu chy chng trnh

2.3 Cch khc to tham chiu client

Ngoi cch thc hin bng dng lnh nh trn, ta hon ton c th s dng s gip ca cng c

Visual Studio to ra tham chiu dch v pha client. Cch ny thc hin rt nhanh v rt tin li. Cch

lm nh sau:

Bc 1. Chn chut phi vo project cn thm tham chiu, y l StaffClient, sau chn menu

l Add Service Reference nh hnh sau:


Figure 20 Thm tham chiu dch v

Bc 2. G vo a ch ca dch v cn thm, sau bm nt Go, pha di t tn cho tham chiu

dch v l StaffService nh hnh di.


Figure 21 Cu hnh cc tham s cho tham chiu dch v

Sau bc ny bn hon ton c th s dng lp StaffClient ci t ng dng pha client.

3 Cu hi n tp

1. Lit k cc m hnh lp trnh vi WCF

C 2 m hnh lp trnh ch yu vi WCF l phng php hng i tng v phng php

hng dch v. Phng php hng i tng thng thng c s dng khi pht trin ng

dng desktop, cn phng php hng dch v c s dng pht trin cc dch v pha

server. Mi lin kt gia hai phng php ny thng qua cc lp v giao din (hng i tng)

v cc thuc tnh WCF trn cc lp hay giao din (hng dch v)

2. Cc phng php lp trnh vi WCF

C 3 phng php lp trnh vi WCF l phng php khai bo, phng php hin hin, v

phng php s dng tp tin cu hnh. Thng thng khi lm vic vi WCF, ta khng s dng


ring bit mt phng php no m s dng kt hp c ba phng php t c kt qu tt

nht.

4 Ti liu tham kho

1. Programming your first WCF service (URL:

http://www.myitblog.com/sundararajan/programming-your-first-wcf-service.html)

2. Your first WCF Service (URL: http://eng.ahmedelmalt.googlepages.com/wcf02.htm)

bai 2 mo hinh lap trinh wcf

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