Advantages of Web Services

Introduction to Integrative Programming

• Course is about system integration, cross-platform development, and programming language compatibility.
• Objectives include explaining fundamental concepts, demonstrating basic program integration of two languages, and showing appreciation for the importance of diverse programming languages for software integration, and cross-platform development.

Overview of System Integration

• Combining different components and technologies to create cohesive software solutions.
• Critical in modern IT environments where diverse software systems need to interact.
• Includes databases, web services, and external APIs for smooth communication between disparate systems.
• Interoperability allows developers to select the best tools for each task.

Types of System Integration

• Enterprise Application Integration (EAI): Focuses on connecting various software applications within a single organization, targeting enterprise applications for different departments (like CRM, ERP, and inventory management).
• Point-to-Point Integration: Directly connects individual systems to share data or functionalities. Establishes a dedicated link between systems, enabling faster data exchange, less complexity in initial setup. Data exchange can be facilitated by custom code or APIs.

Types of System Integration (continued)

• Vertical Integration: Connects systems within a specific department. Aims to create streamlined workflow, unify data, and functionalities within a department area (HR, Finance, Manufacturing, and Supply-chain).
• Horizontal Integration: Integrates functionalities and data from different departments within an organization. Fosters a unified view of operations and breaks down departmental silos. Bridges the gap between different departments.

Benefits of System Integration

• Increased efficiency and productivity
• Enhanced collaboration
• Improved data visibility and accuracy
• Reduced costs
• Improved competitive advantage
• Scalability and flexibility
• Better customer experience
• Simplified IT management

Examples of System Integration

• Inventory Management & Point-of-Sale (POS) Integration
• Electronic Health Records (EHR) & Appointment Scheduling Systems Integration
• CAD & Manufacturing Execution Systems (MES) Integration
• Banking Systems & Accounting Software Integration
• CRM & Marketing Automation Integration

Role of APIs and Web Services

• Integral to system integration, providing standardized methods for interaction between systems regardless of programming language or platform.

Terminology Definition

• XML (eXtensible Markup Language): A markup language for encoding documents in a readable format for humans and machines.
• JSON (JavaScript Object Notation): Data interchange format, readable by both humans and machines.
• HTTP (HyperText Transfer Protocol): A set of rules for sending and receiving data over the web.
• SOAP (Simple Object Access Protocol): An XML-based protocol for accessing web services.
• REST (Representational State Transfer): A style of software architecture based on HTTP protocol for distributed web services. REST is based on principles like stateless communication, layered system, identification of resources.

What is a Web Service?

• A way for two machines to communicate across a network.
• Web server, running on one computer, listens for requests from another
• Upon receiving, web service returns the requested resources.
• Examples include JSON, XML, HTML files, images, and audio files

Advantages of Web Services

• Interoperability
• Reusability
• Usability
• Deployability
• Cost

Types of Web Service Testing

• SOAP: A protocol used for accessing web services (e.g. XML format).
• REST: A software architecture style that is used for building web services (e.g., JSON format).

What is an API?

• Application Programming Interface – a set of definitions and protocols allowing one application to communicate with another.

Is a REST API a Web Service?

• A REST API is a standardized architecture style for creating a Web Service API.
• Utilizing HTTP methods for network requests.
• REST API allows independent frontend from backend development.

A REST request from the client to the server

• Usually consists of components:
• URL path
• HTTP Methods
• Header (optional additional info.)
• Parameters (optional variable fields)
• Body (optional contains data sent to the sever)

What is Programming Language Interoperability?

• Programming languages' ability to interact within an application or system.
• Crucial for diverse development environments, needing to leverage diverse languages

Importance of Interoperability

• Code Reuse
• Efficiency
• Maintainability

Real World Examples

• Kayak (finding flight tickets from various airlines)
• Uber (using Facebook/Google login)

What is Cross-Platform Development?

• Process of creating software applications that run on multiple platforms (e.g. iOS, Android).
• Single codebase deployed on multiple platforms using frameworks/tools.

Native vs Cross-Platform Development

• Native Development uses separate codebases for each platform (e.g. iOS and Android, uses specific languages (Swift, Objective-C, Java, Kotlin).
• Cross-Platform Development uses a single codebase for multiple platforms. utilizes web technologies(HTML, CSS, JavaScript). Employ frameworks (React Native, Xamarin)
• Distinctive features include code reusability, efficiency of development, and speed.

Why Cross-Platform Development?

• Write code once, run anywhere
• Consistent user experience
• Cost-efficient and faster development time
• Access to wider range of developers

Examples of World-Class Apps using Cross-Platform Frameworks

• Google Ads
• UberEats
• Pinterest
• Instagram
• and more

Five Well-Known Cross-Platform Frameworks

• React Native
• Flutter
• Xamarin
• PhoneGap/Cordova
• Ionic

Objectives for Web Service and API Integration

• Describe differences between SOAP and REST web services. Explain how APIs enable system integration.
• Demonstrate the ability to create and consume SOAP and REST APIs.
• Show a positive attitude towards understanding and applying different techniques in real-world scenarios.

Introduction to Web Services (SOAP, REST)

• Web services provide platform-independent communication between applications.
• SOAP: XML-based protocol, defines rules for data exchange. Heavy weight protocol used in enterprise environments.
• REST: Using HTTP protocols, light weight alternative to SOAP, based on principles.

SOAP Web Services

• A standard protocol enabling communication over the internet,
• Utilizes XML format to exchange information and procedures between applications running different platforms.
• Widely standardized procedure for interacting with applications over various programming languages.

SOAP Message Structure

• Composed of Envelope (mandatory) with optional Header and mandatory Body that contains data to be transmitted.
• Data is structured for transmission between applications utilizing XML based format.

SOAP Architecture

• A common structure or style that facilitates interactions between applications running on different platforms.

How REST Works

• A stateless protocol facilitating communication between clients and servers through HTTP requests and responses (e.g. GET, POST, PUT, DELETE actions).
• Enables communication between different applications irrespective of platform or programming language.

RESTful Web Service Characteristics

• Stateless server
• JSON and XML support
• Simpler compared to SOAP.
• Good documentation

Constraints and Principles of REST

• Client-server model.
• Stateless server communication
• Uniform interface (using protocol).
• Cacheable resources.
• Layered system structure.
• Manipulation of resources through representations.
• Hypermedia as the engine of application state (HATEOAS)

RESTful Web Services – HTTP Methods

• GET: Read a resource
• POST: Create a resource
• PUT: Replace a resource
• PATCH: Partial update to a resource
• DELETE: Delete a resource

Advantages of REST

• Speed: Compared to SOAP, less bandwidth and resources required.
• Scalability and maintainability.
• Language and platform independence: Can be written in any language and run on any platform.
• Flexibility to use different data formats (e.g., JSON, XML).

Difference between SOAP and REST

• SOAP: XML-based messaging format, more verbose, better message security, heavier weight.
• REST: Uses JSON or XML format with HTTP. Simpler, greater bandwidth efficiency.

XML

• Evolved for structure data transmission.
• Uses tags to define data structure, allowing applications to handle data effectively.

JSON

• Modern lightweight interchange format.
• Primarily works with JavaScript but is language and platform independent.
• Used widely for data exchange.

Examples of APIs Usage

• Popular apps (Instagram, Uber) relying on APIs to fetch/update data.

What is an API, explained

• A set of protocols and definitions enabling applications to interact in a standard way.