1 / 32

Web Services

Web Services. Definisi. Menurut W3C [6] Web service adalah suatu sistem perangkat lunak yang didisain untuk mendukung interaksi mesin ke mesin pada suatu jaringan.

alan-parsons
Download Presentation

Web Services

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Web Services

  2. Definisi • Menurut W3C [6] Web service adalah suatu sistem perangkat lunak yang didisain untuk mendukung interaksi mesin ke mesin pada suatu jaringan. • menurut Michael C. Daconta, Web Service adalah aplikasi perangkat lunak yang dapat ditemukan, diuraikan, dan diakses berdasarkan pada XML dan protokol standard Web pada intranet, extranet, dan Internet.

  3. CreditResponse InventoryResponse CreditCheck Purchase Order ReserveInventory Invoice What Is Web Services Example: Web based purchase Credit Service Consolidate Results PO Service Web services are self contained, self describing, modular applications that can be published, located, and invoked across the web. Web services perform functions, which can be anything from simple requests to complicated business processes". ---- According to IBM Figure Taken from Oracle Session id: 40024

  4. Features Of Web Services Search / Use Directory Service Service Integration Service Description Publish Virtual Travel Agency B2B Migration Of Existing web Application Standards are the Base Communicate using messages Robust , Effective, Flexible Security Services Description Web Service Discovery Service Description Service Description B2B B2B Figure Taken from Intelligent agent course 2003/2004 by Dr. Omar Belakhdar

  5. Why to use more than one computer? • Distributed resources • access to shared data • access to shared programs • access to CPU (e.g. many desktop PCs together), to memory, to special devices (e.g. printer) • Complete independence on the internal implementation

  6. Distributed architecture • gives • access to distributed resources • development encapsulation • maintainability, re-usability, legacy-awareness • implementation independence • requires • adding a communication layer between parts • synchronization of efforts • including such nasty things as distributed garbage collection

  7. Distributed architecture Waiting for requests (known location, known port) Sending requests, getting results Communication protocol, Data format • Basic questions are: • What kind of protocol to use, and what data to transmit • What to do with requests on the server side

  8. Traditional CGI-based approach Waiting for requests (known location, known port) Sending requests, getting results Data as name/value pairs • cgi-bin scripts: • Data transmitted as name-value pairs (HTML forms) • Transport over (state-less) HTTP protocol • no standards for keeping user sessions (state-fullness) • server side: a script is called

  9. CORBA-based approach Waiting for requests (known location, known port) Sending requests, getting results Data in binary format • CORBA: • Data transmitted as objects (at least it looks like that) • Transport (usually) over well standardised IIOP protocol • user sessions (state-fullness) very inter-operable • server side: an RPC call is made

  10. SOAP-based communication Waiting for requests (known location, known port) Sending requests, getting results Data in XML format • SOAP: • Data in a well-defined XML format • Transport over various protocols • HTTP, SMTP are the most used, perhaps because they are firewall-friendly • server side: either an RPC call or a message delivered

  11. Web services • A collection of XML-based technologies developed by the e-business community to address issues of: • service discovery • interoperable data exchange and/or application invocation • service compositions (workflow, business processes) • Major developers include: • Apache, IBM, HP, SUN & Microsoft (.NET) • http://www.webservices.org/

  12. W3C (working group) definition • "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 artefacts. A Web service supports direct interactions with other software agents using XML based messages exchanged via internet-based protocols." • http://www.w3c.org/TR/2002/WD-wsa-reqs-20020819

  13. Characteristics of Web services • Providing services to other computer programs (not to Web browsers) • Interoperability between software applications running on different computers • Loosely coupled • Machine-processable • Use of standards: XML, HTTP, SOAP, WSDL

  14. Basic idea of Web services • Exchange of messages • Messages are encoded using XML •  SOAP • – Using standard protocols to transport messages • HTTP, SMTP, . . . • • Message can be sent: • – One-way: Call the service, but don’t expect an answer • ! asynchronous messaging • – Request / response: Call the service and wait for the response • ¤ most common style • ¤ synchronous messagging

  15. SOAP (Simple Object Access Protocol) • Extensible Markup Language (XML) • Hypertext Transport Protocol (HTTP) • Web Services Description Language (WSDL) • Universal Discovery Description Integration (UDDI)

  16. . Langkah 1, aplikasi klien menemukan informasi tentang Web Service A dalam suatu UDDI registry. Langkah 2, aplikasi klien mendapatkan WSDL untuk Web Service A dari UDDI registry untuk menentukan API milik Web Service A. Akhirnya, pada langkah 3 dan 4, aplikasi klien berkomunikasi dengan Web Service melalui SOAP, menggunakan API yang ditemukan dalam langkah 2.

  17. State of the Art • UDDI provides a mechanism for clients to find web services. • WSDL defines services as collections of network endpoints or ports. A port is defined by associating a network address with a binding; a collection of ports define a service. • SOAP is a message layout specification that defines a uniform way of passing XML-encoded data. It also defines a way to bind to HTTP as the underlying communication protocol. SOAP is basically a technology to allow for “RPC over the web”.

  18. State of the Art UDDI WSDL SOAP URI HTML HTTP

  19. Web Services Stack

  20. SOAP (Simple Object Access Protocol) • Extensible Markup Language (XML) • Hypertext Transport Protocol (HTTP) • Web Services Description Language (WSDL) • Universal Discovery Description Integration (UDDI)

  21. SOAP adalah spesifikasi yang mendefinisikan tata tata bahasa XML untuk mengirim (request) dan menanggapi (respond) pesan yang diterima dari pihak lain. • Standar SOAP memiliki dua bagian : • Header yang membawa proses instruksi • Body yang berisi payload (berisi informasi yang dikirim) • Pesan SOAP ada 3 tipe : • Dokumen (XML) • RPC (Remote Procedure Calls)

  22. XML Messaging Using SOAP

  23. WSDL adalah sebuah spesifikasi yang berbasis XML yang digunakan untuk mendeskripsikan apa yang akan dilakukan oleh Web Service dan bagaimana untuk mengoperasikannya • WSDL memiliki bagian-bagian yang berisi detail bagaimana membuat koneksi ke service disimpan

  24. WSDL • Web Services Definition Language • http://www.w3.org/TR/wsdl/ • An XML-based language for describing Web Services • what the service does (description) • how to use it (method signatures) • where to find the service • It does not depend on the underlying protocol • But: It is not much human-readable

  25. UDDI adalah sebuah spesifikasi XML yang menggambarkan bagaimana calon pelanggandari layanan Web bisa belajar tentang kemampuannya dan memperoleh informasi dasaryang dibutuhkan untuk membuat kontak awal dengan situs • Registry UDDI bisa public, private, atau semiprivate

  26. UDDI (and alternatives) • Universal Description, Discovery and Integration • http://www.uddi.org • UDDI creates a platform-independent, open framework & registry for: • Describing services • Discovering businesses • Integrating business services • The UDDI may be less used than predicted, especially on the Internet level • BioMoby - an alternative for Life Sciences domain?

  27. Mengintegrasikan sistem-sistem legacy • Menurunkan biaya operasional • Menurunkan biaya pengembangan software • pengembangan sistem dilakukan lebih cepat • Antarmuka yang lebih baik untuk pelanggan • Integrasi yang lebih baik dengan partner bisnis • Peluang pendapatan baru • Merupakan model bisnis baru

  28. Kesulitan tersembunyi dari Layanan Web : • Masalah ketersediaan • Matching Requirements • Immutable Interfaces • Guaranteed Execution • Memiliki masalah pada performance nya • Standarisasi Web service belum lengkap atau belum final

More Related