Web services Flashcards
web service = (by W3C)
a software application. identified by a URL, whose interfaces and binding are capable of being defined, described and discovered by XML artifacts and supports direct interactions with other software applications using XML based messages.
characteristics of Web services:
- XML based everywhere
- Message-based
- Programming language independent
- Could be dynamically located
- Could be dynamically assembled or aggregated
- Accessed over the internet
- Loosely coupled
- Based on industry standards
4 aspects that covers the SOAP specification:
- Message enveloppe
- Encoding rules
- RPC (Remote Procedure Call) mechanism
- RPC representation
SOAP =
(Simple Object Access Protocol) It is a protocol used in software engineering for exchanging structured information in the implementation of web services. SOAP relies on XML (Extensible Markup Language) for its message format, and it typically operates over HTTP or SMTP protocols.
encoding =
a set of rules of how to express application-defined data types on the wire in XML form.
SOAP encoding, supports:
- simple values
- compound values
simple values =
the values of built-in types from XML schema part 2 or enumeration or byte array
compound values =
constructed as a composite of several parts, each with a type and can be of struct or arrays or complex type
WSDL =
industry-agreed-upon XML language that can be used to describe web services.
web service = (description)
A set of communication endpoints (= ports) that are capable of exchanging messages.
Endpoint is made of 2 parts:
o Abstract definitions of operations and messages
o Concrete binding to networking protocol (and corresponding endpoint address) and message format
Why WSDL?:
- Enables automation of communication details between communicating partners -> (machines can read WSDL, machines can invoke a service defined in WSDL)
- Discoverable through registry
- Arbitration -> (3rd party can verify if communication conforms to WSDL)
Universal Description, Discovery and Integration (UDDI) standard = -> R.I.P.
Provides a mechanism for businesses to ‘describe’ themselves and the types of services they provide and then register and publish themselves in a UDDI registry. -> defines a way to publish and find information about web services
Different types of information stored in the UDDI registry:
- White pages: information about the business or organization that publishes a web service.
- Yellow pages: information about the services themselves
- Green pages: provide technical details about the web services listed in the Yellow Pages.
Kinds of web services:
- SOAP-based web services
- RESTful Web Services
- GraphQL APIs
API keys =
a key to limit access. the API key is required to send with each request.
Integrating the Healthcare Enterprise (IHE) = (-> ! een test voor de interoperability)
International platform for healthcare and software providers, IT professionals, and governments to promote interoperability
IHE solves ambiguities by
- specifying integration profiles
- organizing connectathons
IHE connectathons =
events organized by the IHE initiative to test the interoperability and integration of healthcare IT systems based on IHE profiles and standards.
(soort evenement waarin iedereen hun systemen testen in een test omgeving. zodat ze goed werken in echte zorg. )
Screen scraping =
the process of extracting data from the display output of another program or system. Like for example testing the GUI.
disadvantage of Screen scraping:
- slow, takes a lot of time. Therefore the last resort solution, but sometimes the only solution.
