ATI 5 – Web Services (SOAP) Antonius Rachmat C, S.Kom, M.Cs
Today’s Web • Web designed for application to human interactions • It’s purpose: – Information sharing: a distributed content library. – Enabled B2C e-commerce. – Non-automated interactions between applicaiton
• Standard – Built on very few standards: http + html
• The Web is everywhere. – E-marketplaces. – Business process integration on the Web.
• Current approach is ad-hoc on top of existing standards. – e.g., application-to-application interactions with HTML forms.
• How to: enabling systematic application-to-application interaction on the Web.
Application Solution Provider, Software as a Service, and Web Service
Web Service can… • Web Services can convert your applications into Web-application service. – By using Web services, your application can publish its function or message to the rest of the world.
• Web Services can be used by other applications. – Ex: with Web services your accounting department's Win 2k servers can connect with your IT supplier's UNIX server. – Can be used as Web API – Interacting among application
Pengertian-pengertian WS • Generic: any application accessible to other applications over the Web – Very open definition, almost any URL becomes a “Web service” under this definition
• UDDI consortium: web services are self-contained, modular business applications that have open, Internet-oriented, standards-based interfaces – Better, but still not specific enough
• W3C: A Web service is a software application identified by a URI, whose interfaces and bindings are capable of being defined, described, and discovered as XML. – A Web service supports direct interactions with other software agents using XML-based messages exchanged via Internet-based protocols – Slightly better
Pengertian-pengertian WS • Wikipedia: according to the W3C, a Web service is a software system designed to support interoperable machine-tomachine interaction over a network. • It has an interface that is described in a machine-process-able format such as WSDL. • Software applications written in various programming languages and running on various platforms can use web services to exchange data over computer networks like the Internet in a manner similar to inter-process communication on a single computer. – Much more specific
Designing Web Services I • Goals – Enable universal interoperability. – Widespread adoption, ubiquity, fast! – Enable (Internet scale) dynamic binding. • Support a service oriented architecture (SOA).
– Efficiently support both open (Web) and more constrained environments.
Designing Web Services II • Requirements – Based on standards – Minimal amount of required infrastructure is assumed. • Only a minimal set of standards must be implemented.
– Very low level of application integration is expected. – Focuses on messages and documents
WS Example • http://www.google.com/apis/ • http://terraserver.microsoft.net/TerraService. asmx • http://www.xmethods.net • http://soap.amazon.com/schemas2/Amazon WebServices.wsdl • http://api.google.com/GoogleSearch.wsdl
Example: A Google Client • Create a local proxy class, instantiate, and invoke • The proxy class MyService generated from a WSDL file, an XMLencoded service description Dim MyLicenseKey As String ' Variable to Store the License Key ' Declare variable for the Google search service Dim MyService As com.google.api.GoogleSearchService = New _ com.google.api.GoogleSearchService ' Declare variable for the Google Search Result Dim MyResult As com.google.api.GoogleSearchResult ' Please Type your license key here MyLicenseKey = "tGCTJkYos3YItLYzI9Hg5quBRY8bGqiM" ' Execute Google search on the text enter and license key MyResult = MyService.doGoogleSearch(MyLicenseKey, _ TextBox1.Text, 0, 1, False, "", False, "", "", "") ' output the total Results found Label2.Text = "Total Found : " & _ CStr(MyResult.estimatedTotalResultsCount)
Outline Architecture My Desktop Windows
The Internet TCP/IP
MyService s = new
[WebMethod] … doGoogleSearch(myKey, q) …
com.google.api.GoogleSearchService();
Implementation via proxy class and HTTP transport
Vendor-neutral XML-encoding over HTTP
Google.com/apis Unix/Linux?
SOAP Request
SOAP Response
Implementation via WebService classes in Web Server Google database
Google WSDL
Contoh penggunaan web service
Web Service • Mempertukarkan data dalam format XML. • Tersedia dan dikomunikasikan melalui Internet atau intranet. • Bersifat operating system/programming language independent. • Berupa web application yang tidak memiliki web interface. • Web service mempertukarkan data antara service requestor) dan service provider menggunakan service registry, dengan salah satu teknologi: – XML-RPC – SOAP – REST
Web Service • Web service mempertukarkan data dalam format message yang berarti tidak bersifat binary • Web service dapat dipanggil/digunakan melalui web, aplikasi desktop, ataupun aplikasi mobile • Kelebihan: – Interoperability (platform dan aplikasi) – Dapat mempublikasikan service dan method sehingga mudah digunakan – Mendukung reusable-components
Bentuk Web Services
Website vs Web service • • • • •
Memiliki web interface Dibuat untuk berinteraksi langsung dengan user Dibuat untuk bekerja pada web browser Bersifat front-end Bersifat human-centric: manusia menjadi aktor utama
Website vs Web Service • • • • •
Tidak memiliki interface yang baik Dibuat untuk berinteraksi langsung dengan applikasi yang lain, baik berbeda OS sekalipun, bukan dengan user. Dibuat untuk bekerja pada semua tipe client applikasi / perangkat device Bersifat behind the scene. Bersifat application-centric: komunikasi terjadi antar aplikasi
Web Service properties • Web service harus ”self-describing”: jika kita membuat web service, kita harus juga mempublikasikan public interface yang dapat dimengerti dan dipakai. – Minimalnya, service harus memiliki human-readable documentation sehingga developer lain dapat mengintegrasikan aplikasinya dengan web service yang kita buat.
• Web service harus ”discoverable”: jika kita membuat web service, harus ada mekanisme sederhana agar service dan public method yang kita buat dapat dikenal dan ditemukan oleh aplikasi lain.
WS Layer • Service transport – Bagian ini bertanggung jawab untuk mengirim message antar aplikasi. – Internet Protokol yang ada di bagian ini: Hyper Text Transfer Protocol (HTTP)
• XML messaging dan encoding/decoding – Bagian ini bertanggung jawab untuk mengencode/mendecode message dalam format XML sehingga message dapat dimengerti dan dipertukarkan. – Protokol/Service Interaction yang ada di bagian ini: XML-RPC dan SOAP.
WS Layer • Service description – Bagian ini bertanggung jawab untuk mendeskripsikan public interface sesuai dengan web service yang spesifik. – Bagian ini dihandle melalui Service Description: Web Service Description Language (WSDL) dan XML Schema
• Service discovery – Bagian ini bertanggung jawab untuk mengumpulkan services ke dalam common registry dan menyediakan kemudahan untuk mempublikasikan interface dan kemudahan dalam pencarian method. – Bagian ini dihandle oleh Service Directory: Universal Description, Discovery, and Integration (UDDI).
Pondasi Teknologi Web Service
Web service architecture (1) Browser GUI Client Web Server
WSDL SOAP
SOAP
WSDL
WSDL Web Server Service JDBC DB
WS Architecture (2)
Pengembangan sisi Client
Pengembangan sisi Server
Service Broker / Service Registry • The service brokers allow service providers to publish their services (register, save, and categorize). • They provide also mechanisms to locate services and their providers • Diimplementasikan pada UDDI (Universal Description Discovery and Integration)
SOAP (Simple Object Access Protocol) • SOAP merupakan protokol komunikasi berbasis XML yang memperbolehkan aplikasi saling bertukar informasi melalui HTTP • SOAP merupakan salah satu protokol yang menangani web service • SOAP merupakan format untuk mengirimkan message melalui Internet, bersifat platform independent, language independent, dan merupakan standar W3C • SOAP membungkus request & response XML
SOAP call anatomy
SOAP Skeleton
Elemen SOAP • Elemen Envelope yang mengidentifikasi XML dokumen sebagai SOAP message (wajib)
– Top element of the XML document representing the message • Elemen Header yang berisi informasi header (opsional)
– Determines how a recipient of a SOAP message should process the message – Adds features to the SOAP message such as authentication, message routes, additional information, etc… • Elemen Body yang berisi informasi call dan response (wajib) • Elemen Fault yang berisi informasi error yang terjadi (opsional)
Plus-Minus SOAP Plus • Uses HTTP which is widely used and scalable • Flexible for growth because of XML properties • Data in String message Minus • Parsing of SOAP packet and mapping to objects reduces performance • If XML data are too long • Doesn’t implement security because it is a wire protocol—relies on HTTP
Request Message <SOAP-ENV:Envelope
xmlns:SOAP-ENV="http://schemas.xmlsoap.org/soap/envelope/" xmlns:ns1="urn:testns“ xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:SOAP-ENC="http://schemas.xmlsoap.org/soap/encoding/" SOAP-ENV:encodingStyle="http://schemas.xmlsoap.org/soap/encoding/">
<SOAP<SOAP-ENV:Body> <ns1:getProf <ns1:getProfessor getProfessor> essor>
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Response Message <SOAP-ENV:Envelope
xmlns:SOAP-ENV="http://schemas.xmlsoap.org/soap/envelope/" xmlns:ns1="urn:testns" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:SOAP-ENC="http://schemas.xmlsoap.org/soap/encoding/" SOAP-ENV:encodingStyle="http://schemas.xmlsoap.org/soap/encoding/">
<SOAP<SOAP-ENV:Body> <ns1:getProf getProfessorResponse essorResponse> Response> <ns1:getProfessor
Ant Antonie Antonie onie
SOAP dengan NuSOAP 0.95
Web Services Description Language • Provides functional description of network services: – Method description – Protocol details
• A short history: – WSDL v1.0, 9/2000 – WSDL v1.1 submitted to W3C 3/2001. – A de facto industry standard.
The Main Structure of WSDL <definition namespace = “http/… “> Bagian Abstract
xschema types <message> … <port> a set of operations Bagian Konkret
communication protocols <service> a list of binding and ports <definition>
UDDI Overview • UDDI defines the operation and data structures of a service registry: – Data structures for registering • Businesses • Technical specifications • Service and service endpoints
– SOAP Access API – Rules for the operation of a global registry
How UDDI Works 1.
SW companies, standards bodies, and programmers populate the registry with descriptions of different types of services
2. UDDI Business Registry
Businesses populate the registry with descriptions of the services they support
Business Registrations
3.
Segrvice Type Reistrations
Programmer assigns a programmatically unique identifier to each service and business registration
4.
Marketplaces, search engines, and business apps query the registry to discover services at other companies
5.
Business uses this data to facilitate easier integration with each other over the Web
WSDL and UDDI relationship
Web Services Example
WSDL generated by inspecting the Java Implementation of WS
Demo • MathWebService SOAP in VB.NET
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