Key Points

References

Key Concepts

Web Services framework overview

https://www.guru99.com/web-service-architecture.html

Web service summary

The client would invoke a series of web service calls via requests to a server which would host the actual web service.

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UDDI is a standard for describing, publishing, and discovering the web services that are provided by a particular service provider. It provides a specification which helps in hosting the information on web services.

Agent - Broker - Service architecture

1. Provider - The provider creates the web service and makes it available to client application who want to use it.
2. Requestor - A requestor is nothing but the client application that needs to contact a web service. The client application can be a .Net, Java, or any other language based application which looks for some sort of functionality via a web service.
3. Broker - The broker is nothing but the application which provides access to the UDDI. The UDDI, as discussed in the earlier topic enables the client application to locate the web service.

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1. Publish - A provider informs the broker (service registry) about the existence of the web service by using the broker's publish interface to make the service accessible to clients
2. Find - The requestor consults the broker to locate a published web service
3. Bind - With the information it gained from the broker(service registry) about the web service, the requestor is able to bind, or invoke, the web service.

Web services features

1. xml based
2. soap message has a header and a body
3. loosely coupled
4. synch or asynch
5. supports rpc
6. supports document exchange
7. wsdl defines how to bind to a service

Web Services Security with SOAP

https://www.guru99.com/security-web-services.html

Client Server Interaction over HTTPS

In a standard HTTPS communication between the client and the server, the following steps take place

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https://www.guru99.com/security-web-services.html

REST services

https://www.guru99.com/restful-web-services.html

REST is used to build Web services that are lightweight, maintainable, and scalable in nature. A service which is built on the REST architecture is called a RESTful service. The underlying protocol for REST is HTTP, which is the basic web protocol. REST stands for REpresentational State Transfer

REST elements

The key elements of a RESTful implementation are as follows:

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Response Status codes –
codes are returned with the response from the web server.

REST methods

• POST – This would be used to create a new employee using the RESTful web service
• GET - This would be used to get a list of all employee using the RESTful web service
• PUT - This would be used to update all employee using the RESTful web service
• DELETE - This would be used to delete all employee using the RESTful web service
• PATCH - Update a resource

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• Heterogeneous languages and environments – This is one of the fundamental reasons which is the same as we have seen for SOAP as well.
• It enables web applications that are built on various programming languages to communicate with each other
• With the help of Restful services, these web applications can reside on different environments, some could be on Windows, and others could be on Linux.

RESTful Architecture

1. State and functionality are divided into distributed resources – This means that every resource should be accessible via the normal HTTP commands of GET, POST, PUT, or DELETE. So if someone wanted to get a file from a server, they should be able to issue the GET request and get the file. If they want to put a file on the server, they should be able to either issue the POST or PUT request. And finally, if they wanted to delete a file from the server, they an issue the DELETE request.
2. The architecture is client/server, stateless, layered, and supports caching –
   1. Client-server is the typical architecture where the server can be the web server hosting the application, and the client can be as simple as the web browser.
      Stateless means that the state of the application is not maintained in REST.
   2. For example, if you delete a resource from a server using the DELETE command, you cannot expect that delete information to be passed to the next request.

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https://www.guru99.com/restful-web-services.html

Microservices Tutorial

https://www.guru99.com/microservices-tutorial.html

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Microservice Challenges

1. MicroServices rely on each other, and they will have to communicate with each other.
2. Compared to monolithic systems, there are more services to monitor which are developed using different programming languages.
3. As it is a distributed system, it is an inherently complex model.
4. Different services will have its separate mechanism, resulting in a large amount of memory for an unstructured data.
5. Effective management and teamwork required to prevent cascading issues
6. Reproducing a problem will be a difficult task when it's gone in one version, and comes back in the latest version.
7. Independent Deployment is complicated with Microservices.
8. Microservice architecture brings plenty of operations overhead.
9. It is difficult to manage application when new services are added to the system
10. A wide array of skilled professionals is required to support heterogeneously distributed microservices
11. Microservice is costly, as you need to maintain different server space for different business tasks.

SOA vs Microservices

Microservices Summary

1. Microservices is a service-oriented architecture pattern wherein applications are built as a collection of various smallest independent service units.
2. Microservice Architecture is an architectural development style that allows building an application as a collection of small autonomous services developed for a business domain.
3. Monolithic architecture is like a big container in which all the software components of an application are clubbed into a single package
4. In a Microservice, every unit of the entire application should be the smallest, and it should be able to deliver one specific business goal
5. In Monolithic architecture, large code base can slow down the entire development process. New releases can take months. Code maintenance is difficult
6. Two types of Microservices are 1) Stateless 2) Stateful
7. Microservices rely on each other, and they will have to communicate with each other. Helps you to give emphasizes on a specific feature and business needs
8. Service-oriented architecture shortly known as SOA is an evolution of distributed computing based on the request or reply design model for synchronous and asynchronous applications
9. In SOA, software components are exposed to the outer world for usage in the form of services whereas Micro Service is a part of SOA. It is an implementation of SOA
10. Wiremock, Docker, and Hystrix are some popular Microservices Tools

Service Virtualization

https://www.guru99.com/service-virtualization-tools.html

Service Virtualization is a method that helps you to emulate (virtual services) the behaviors of the component in a Service Oriented Architecture (Microservice). Practically the software development, testing, and operations teams do not work in synch, and each team has to wait for others to have components ready. This causes delays in workflows and may deliver an inferior product. With Service Virtualization, DevOps teams use virtual services instead of production services, so they can test the system even when key components are not ready. With Service Virtualization, integrating of applications takes place early in the development cycle thereby reducing time and cost to fix errors.

Mountebank for testing virtual services

Mountebank is an open source tool which can execute multi-protocol tests. The codebase is Node JS. It is easy to create stubs and mocks.

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1. Helps you to accelerate Application Delivery while mitigating business risks
2. It helps you to simulates the behavior of select components within an application to enable end-to-end testing of the application as a whole.
3. Allows the teams to work in parallel
4. Allows you to Test Early and often which expose defect when they are faster, easiest and least costly to resolve
5. Facilitates better test coverage
6. Virtual services offer rich tools for editing and managing which help you improve productivity, cut down on maintenance time and development costs.
7. It is useful for anyone involved in developing and delivering software applications.
8. Access to more systems and services
9. It supports test-driven development.
10. Gives you an isolated environment for testing

SOAPUI test tool tutorial

https://www.guru99.com/soapui-tutorial.html

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Messaging Concepts

#todo

API End Point Management Concepts

#todo

IBM API Connects creates and manages API's for IIB ( IBM Integration Bus )

DataPower API Gateway Appliance

https://www.ibm.com/products/datapower-gateway

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The new DataPower Gateway IDG X2 physical appliance delivers up to 2X the performance of IBM DataPower Gateway (IDG) with next generation hardware architecture. It also provides a flash drive with 2X higher capacity than IDG and 2X 10GbE network ports. IDG X2 accelerates application responsiveness and increases workload capacity, which is critical for higher performance and/or for running additional tenants with governance and a lower TCO.

Potential Value Opportunities

Potential Challenges

Candidate Solutions

Step-by-step guide for Example

sample code block

Recommended Next Steps

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