Dates : Feb 2019 - May 2019

ECTS : 2

Lecturer : Jean-Yves Tigli

Number of Students : 39

Agenda

• During some sessions, MCQ will be submitted to student.

• Any grade mustn't be more than 50 % the final grade
• The final evaluation must consist in 2 grades at least

• During this course, students groups have to developp step by step a complete project using a web service architecture.
• The groups production will be deposited in the groups GitHubs
• Projects Documentation will be detailed in the GitHub Wiki
• A group is no more than two students.
• Students of a same group will be assessed separatly.

• Because this course follows the SI3 socket programming course, you can still use Python programming language.

• For client Only some services clients can run on your PC in native mode. Nevertheless most of the time, Web clients are more adapted for portability thanks to web browsers. Indeed Web browsers can run on a mobile phone, PC, interactive terminal and so on…
• Servers must run on systems that are always available. Generaly they are installed in virtualized computer to be deployed easily (continuous delivery) from a computer to another, in a datacenter (in the Fog) or in a IAAS (in the cloud).

Historically (until 2017), Introduction to the Web was licence / SI3 course.

Because of the required background on the Web to study Web Service Technologies (at least to also understand the Web popularity), in 2019, this introduction is coming back in this course.

Web Introduction

• Where Web Services are coming from ? Introduction to Web Services in SI3 : WS-REST and WS-SOAP/WSDL

• Software Tool to Design Client Applications for Web Services (Visual Studio IDE)

• Software Tool to Deploy WS SOAP/WSDL Client Application on Docker with Visual Studio

• Orchestrate services with Node RED

• Web Service REST and tutorial with VS
• First definition of Representational State Transfer (REST)Architectural Styles and the Design of Network-based Software Architectures - Ph.D. DISSERTATION of Roy Thomas Fielding, 2000

Comment CRUD and REST REST vs CRUD: What’s The Difference?

• Web Service SOAP and tutorial with VS

• Introduction to ABC Model of Microsoft

• Tutorial on Address

• Tutorial on types of Contract

• Tutorial on Bindings

All service contracts in WCF, no matter the parameters types and return values, use WCF attributes to specify a particular message exchange pattern between client and service. WCF automatically routes inbound and outbound messages to the appropriate service operation or running client code.

The client possesses only the service contract, which specifies the message exchange pattern for a particular operation. Clients can offer the developer any programming model they choose, so long as the underlying message exchange pattern is observed. So, too, can services implement operations in any manner, so long as the specified message pattern is observed.

The independence of the service contract from either the service or client implementation enables the following forms of asynchronous execution in WCF applications:

• Clients can invoke request/response operations asynchronously using a synchronous message exchange.

• Services can implement a request/response operation asynchronously using a synchronous message exchange.

• Message exchanges can be one-way, regardless of the implementation of the client or service.

Find here details on the different types of Asynchronous Operations in WCF services

App.config is an XML file to set a list of parameters required to instanciate some classes of the System.ServiceModel Namespace.

Find the System.ServiceModel Namespace description here and some complete source code instead of App.config configurations

ABC Model is not only dedicated to Web Service but can use non over http binding like direct TCP/IP protocol. One of the standard Binding for that is netTcpBinding.

Step by step tutorial to create a netTcpBinding Service

Here you can see that the App.config file is only an other way to defined different parameters required by the Service/Client Constructor.

WCF service cannot exist on its own; it has to be hosted in windows process called as host process. Single host process can host multiple servers and same service type can be hosted in multiple host process. There are mainly four different way of hosting the WCF service.

• IIS hosting
• Self hosting
• Windows Activation Service
• Windows Service

For more details and examples

Lot of parameters are generaly predefined and precomputed on WCF projects. Anyway everything can be tuned to a new required configuration.

Here find most of the possible extensions : WCF Extensibility

Windows Communication Foundation (WCF) provides a rich infrastructure for exporting, publishing, retrieving, and importing service metadata. WCF services use metadata to describe how to interact with the service's endpoints so that tools, such as Svcutil.exe, can automatically generate client code for accessing the service.

WSDL, Web Service Description Language for WS-SOAP

Sample with one Mex endpoint for multiple endpoints with different contracts in a service

The event-driven messaging is a design pattern, applied within the service-orientation design paradigm to enable the service consumers, which are interested in events that occur within the periphery of a service provider, to get notifications about these events as and when they occur without resorting to the traditional inefficient polling based mechanism .

Events allow the client or clients to be notified about something that has occurred on the service side.

W3C consortium propose a Web Services Eventing (WS-Eventing) - W3C Recommendation

Tutorial

Event based Communication and Event driven Architecture with web services

• Web Service and Event driven architecture Lab 2

gSOAP

Raspberry Pi is a series of small single-board computers developed in the United Kingdom by the Raspberry Pi Foundation to promote the teaching of basic computer science in schools and in developing countries. The original model became far more popular than anticipated,selling outside its target market for uses such as robotics.

Raspbian is a free operating system based on Debian optimized for the Raspberry Pi hardware. An operating system is the set of basic programs and utilities that make your Raspberry Pi run. However, Raspbian provides more than a pure OS: it comes with over 35,000 packages, pre-compiled software bundled in a nice format for easy installation on your Raspberry Pi.

Install a Raspbian OS in docker container and test the previous calc WS-SOAP.

Please look at different comments in this page hindsight issues about Web Services, and provide your best analysis with your own explanations and/or illustrations.

Docker can also be a way to easily deploy some solutions on RaspberryPi. Of course, first thing to do is to install Docker on Raspberry Pi … but that works (Example).

Microsoft C# Modèle Cache-Aside

DevOps Workflow for Docker Applications and Microsoft Tools

Google Elevation Map Web Service and Velib WS

Cloud References, Containerized Docker Application Lifecycle with Microsoft Platform and Tools

Set of most used Web services

• Applications Réparties : du Web, Web Services au Services (SI4)

• Frequently Ask Questions