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Introduction to Web Services
Today, companies rely on thousands of different software applications each with
their own role to play in running a business. These different software applications run
on a wide range of different platforms and operating systems, and they are
implemented in different programming languages. As a result, it is very difficult for
different applications to communicate with one another and share their resources in a
coordinated way.
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What are Web Services?
• Web services are application components
• Web services communicate using open protocols
• Web services are self-contained and self-describing
• Web services can be used by other applications
• XML is the basis for Web services
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Why Web Services?Interoperability has highest priority.
• When all major platforms could access the Web using Web browsers, different platforms could interact. For
these platforms to work together, Web applications were developed.
• Web applications are simple applications run on the web. These are built around the Web browser standards
and can mostly be used by any browser on any platform.
Web services take Web applications to the next level.
• Using Web services your application can publish its function or message to the rest of the world.
• Web services uses XML to code and decode your data and SOAP to transport it using open protocols.
Web services have two types of uses.
• Reusable application components. Ideally, there will only be one type of each application component, and
anyone can use it in their application.
Connect existing software
• Web services help solve the interoperability problem by giving different applications a way to link their data.
• Using Web services you can exchange data between different applications and different platforms.
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The base of WS
– The basic Web services platform is XML + HTTP.
– The HTTP protocol is the most used Internet protocol.
– XML provides a language which can be used between different platforms and programming
languages and still express complex messages and functions.
Web services platform elements
• SOAP (Simple Object Access Protocol)
• WSDL (Web Services Description Language)
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What is SOAP?
The basic Web services platform is XML plus
HTTP.
• SOAP stands for Simple Object Access Protocol
• SOAP is a communication protocol
• SOAP is for communication between applications
• SOAP is a format for sending messages
• SOAP is designed to communicate via Internet
• SOAP is platform independent
• SOAP is language independent
• SOAP is based on XML
• SOAP is simple and extensible
• SOAP allows you to get around firewalls
• SOAP will be developed as a W3C standard
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What is WSDL?
WSDL is an XML-based language for describing Web services and
how to access them.
• WSDL stands for Web Services Description Language
• WSDL is written in XML
• WSDL is an XML document
• WSDL is used to describe Web services
• WSDL is also used to locate Web services
• WSDL is not yet a W3C standard
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How to test a web service?
• As a web service is something that has no user interface, we can’t interact with it
without a special tool. That tool should allow composing XML requests via its
own user interface. Commonly such user interfaces are text editors where you
write your XML requests and controls for posting requests to the server.
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How to test a web service?
• Project structure. As in every well-established testing activity, I’ve started with test
specification. The main part of a test specification is test cases divided into test areas.
Visual Studio allows structuring your test project into test suites (the same as test
areas in my test specification) that contain test cases, which can contain test steps, you
can add, modify, delete and change order of every item in the structure.
• Test cases. Visual Sdudio provides enough convenient tools to manage and run your
test cases, and view result in test requests.
• Load Testing. You can perform Load Testing.
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How to test a web service?
• Automation. But what if your web service contains too many methods with too many
input and output parameters? It may take several days for each complete test of your
web service if your tool does not provide functionality to automate your testing. You
can automate validation of your web service’s response against you input. You can
automate the output of validation results into a file (which could be just a text file of
HTML depending on your choice).
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Example: ESRB Rating System
Search Widget. Project Description
• ESRB requires functionality to query their database to generate search results for a
third party web widget.
• Netsoft shall be responsible for the developing a web service to generate result sets in
response to queries from the Clear Spring widget. The widget shall make requests for
rated games by specifying a keyword. The work performed by Netsoft USA shall
encompass the following items:
• Define the interface for the calls to be made by the widget
• Define the result set format (XML) to be provided in response to widget calls
• Provide a mechanism by which the number of results returned can be attenuated (limit the number of
rows)
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Scope
• URL (subject to change) http://esrb.org/SearchWidget/services/Search?wsdl (no https
requested)
• Parameters
– searchKeyword
• Text to search
– maxResultCount
• Maximum number of records to return (e.g. 50 records)
– user (subject to change)
• “ESRB_test”
– pass (subject to change)
• “ESRB_test”
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Scope
• Return fields
– Certificate
• Game certificate number (5 digits)
– Title
• Game title (like ‘%[search text]%’ search condition against the game title and
sorted by Rating Release Date)
– Rating
• Game rating (short text format), e.g. “E,” “E10+,” “T,” etc.
– Platforms
• Comma delimited list of platforms, e.g. “Xbox, Xbox 360, Playstation 3”
– Descriptors
• Comma delimited list of content descriptors, e.g. “Blood and Gore, Strong
Language, Violence”
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Altova XML, Data Management, and
Web service toolsThe Altova MissionKit is an integrated suite of XML, database tools designed to meet
the diverse development and data management needs of today’s software architects
and XML developers.
XMLSpy® 2009 is the industry's best selling XML development environment. It offers
the top XML editor, schema designer, code generator, file converters, debuggers,
profilers, support for XSLT, XQuery, Office 2007/OOXML, XBRL, WSDL, SOAP, Visual
Studio, Eclipse, & more.
Link of a Flash demo of the SOAP client and SOAP debugger.
http://www.altova.com/videos.asp?type=1&video=soap
