L8 - Technology Perspective of Service-oriented System Integration Flashcards
What are the goals of the lecture?
Explain Web service technology and its use in SoSI.
Explain RESTful service technology and its use in SoSI.
What is the SOA principle of Contracts?
Services must have a common way to describe their interface, documents, and constraints.
What is the SOA principle of Discoverability?
There must be means to find out which services are available.
What is the SOA principle of Loose Coupling?
Dependencies between services, contracts, implementations, and consumers should be minimized.
What is the SOA principle of Statelessness?
Services should not hold intermediate states in running instances to support scalability and reuse.
What is the SOA principle of Composability?
Services should be designed to be repeatedly combined with other services.
What are the standardized steps of Web Services?
Publish, Find, Bind.
What are the standardized sub-technologies of Web Services?
XML, SOAP, WSDL, UDDI.
What is XML in Web Services?
A data representation language used for exchanging information.
What is WSDL in Web Services?
A contract description language that describes the service interface.
What is SOAP in Web Services?
A text-based application protocol for sending and receiving messages.
What is UDDI in Web Services?
An architecture for service discovery that catalogs and publishes WSDL descriptions.
Why is XML used in Web Services?
It is a standard format for data exchange, middleware-independent, and forms the basis of WSDL, SOAP, and UDDI.
What is WSDL?
An XML-based language that describes the interface of web services, including network addresses and operations.
What are the three parts of a WSDL document?
Root – Service name and included standards.
Abstract interface – Service operations and messages.
Implementation interface – Binding of abstract part to message format, protocol, and address.
What are the key elements of the abstract interface part in WSDL?
PortType: Specifies operations and messages.
Operation: Defines a function.
Message: Defines data exchanged, including input and output.
What are the key elements of the implementation interface part in WSDL?
Binding: Binds operations to a transport protocol.
Service and Port: Define the service name and network address.
What is SOAP?
A text-based protocol for exchanging messages in Web Services.
What are the elements of a SOAP message?
Envelope: Identifies the XML document as a SOAP message.
Header (optional): Contains metadata like security and priority.
Body: Contains the actual message data.
What transport protocols does SOAP support?
Originally designed for HTTP but can also use HTTPS and other protocols.
What is UDDI?
A registry that allows service providers to publish services and consumers to discover them.
What is the UDDI Invocation Model?
- Provider registers the service.
- Consumer searches for a service.
- Consumer binds to the service.
- Consumer invokes the service.
What is a RESTful service?
A service that transfers resource representations over HTTP using a URI.
What is a resource in RESTful services?
An object (e.g., product, customer, order) accessed at a unique URI.
What are the four basic HTTP methods in REST?
GET
POST
PUT
DELETE
What does the GET method do?
Retrieves a resource.
Example: GET /api/customers/2.
What does the POST method do?
Creates a new resource.
Example: POST /api/customers.
What does the PUT method do?
Updates an existing resource.
Example: PUT /api/customers/2.
What does the DELETE method do?
Deletes a resource.
Example: DELETE /api/customers/3.
What is the role of media types in RESTful services?
Defines the format of data exchange between client and server.
What are common media types in RESTful APIs?
application/JSON
application/XML
text/plain
text/html
How does RESTful services support the SOA principle of Contracts?
By applying defined HTTP methods and media types over a URI.
How does RESTful services support the SOA principle of Discoverability?
Through resource URIs managed by IANA.
How does RESTful services support the SOA principle of Loose Coupling?
The client-server architecture ensures separation of concerns.
How does RESTful services support the SOA principle of Statelessness?
RESTful services do not maintain session states between requests.
How does RESTful services support the SOA principle of Composability?
Limited composability as there is no explicit structuring.
What are the key differences in architecture between Web Services and RESTful services?
Web Services: Rigid architecture with WSDL, heavyweight.
RESTful: Simpler architecture based on REST principles, lightweight.
What are the key differences in flexibility between Web Services and RESTful services?
Web Services: Supports multiple protocols, security, and reliability.
RESTful: Supports different data formats (JSON, XML) with fewer constraints.
What are the key differences in complexity between Web Services and RESTful services?
Web Services: Complex due to formal WSDL and SOAP definitions.
RESTful: Simpler, relying on HTTP methods and resources.
What are the key differences in communication style between Web Services and RESTful services?
Web Services: Message-oriented, using SOAP envelopes.
RESTful: Resource-oriented, using HTTP methods.
What are the key differences in adoption and use cases between Web Services and RESTful services?
Web Services: Used in enterprise applications requiring security and transactions.
RESTful: Used in modern web and mobile applications for simplicity and performance.
