Managing State & HTTP Requests In Ionic.

Managing State & HTTP
requests in Ionic
Devansh Kapoor & Anuj Tomar

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1. What is State?
2. State management using Rxjs subject
3. How ionic app connects to server
4. HTTP requests & reponses in Ionic
5. Demo

What is State?
 Unlike backend applications, which use databases for state management, frontend applications
need some sort of mechanism for handling data. This data can range from server responses
gotten from HTTP request, to form input data and user routes.
 It’s a good practice to compose all your application state in a central store for easy
management and data communication. So, basically, our state is a representation of our
application that actually lives in the store.

What is State?
State
UI State Local State Persistent State
List of all events
List of loaded
events
We are loading
something
Managed inside of
the components
Managed inside of
services
Managed on backend
server/database

State management using Rxjs Subject
 RxJS Subject facilitates a reactive approach to state management by acting as a centralized
event bus. It allows multiple components to subscribe to state changes, ensuring real-time
updates across the application.
 Implementing state management with RxJS Subject involves creating a dedicated service
where a Subject instance is initialized. This Subject serves as a conduit for emitting and
subscribing to state changes.
 Ionic components can consume this state management service by injecting it via Angular's
dependency injection mechanism. Components subscribe to the data$ Observable in their
ngOnInit() lifecycle hook to receive and react to state updates.

Implementing State Management with RxJS
 Creating the state store Start by defining a central store using RxJS’s BehaviorSubject
or Subject.
 Defining actions Actions represent the events or user interactions that trigger state changes
 Handling state updates Use RxJS operators like map, scan, take and merge to handle state
updates.
 Subscribing to state changes
 Optimizing performance

Advantages of using RxJS Subject
 Centralized State Management: RxJS Subject promotes centralized state management,
reducing redundancy and ensuring consistency across components.
 Reactive Updates: Components react in real-time to changes in state, enhancing
responsiveness and user interaction.
 Simplified Data Flow: The use of Observables and reactive programming principles simplifies
data flow and enhances the predictability of state changes.

Best Practices of using RxJS Subject
 Error Handling: Implement robust error handling within Observables to gracefully manage
failures and enhance user experience.
 Performance Optimization: Use RxJS operators like debounceTime and distinctUntilChanged to
optimize state updates and prevent unnecessary renders.
 Testing: Write unit tests to validate the behavior of state management services and
components, ensuring reliability and stability.

How ionic app connect to server ?
Can be custom backend or
service like firebase
Server [REST API] Database ( SQL/ NoSQL )
Ionic App
Directly accessing the
database will be highly
insecure
Send request
& receive
response
Store & fetch data

HTTP requests & responses
Importance of HTTP Requests
 Data Fetching: Essential for retrieving data from external APIs or backend servers.
 Data Submission: Used for sending data, such as form submissions, to a server for processing.
 Asynchronous Operations: Handles operations asynchronously, ensuring the UI remains
responsive.

Angular HttpClient
 Setup and Configuration: Angular's HttpClient module needs to be imported and configured in
the app module. It provides a simplified API for making HTTP requests.
 Making Requests: Supports various HTTP methods such as GET, POST, PUT, DELETE. The
HttpClient returns Observables, making it easy to handle asynchronous data streams.
 Error Handling: Use RxJS operators like catchError to manage errors gracefully and provide user
feedback.

Ionic Native HTTP
 Native Capabilities: The Ionic Native HTTP plugin offers enhanced performance and handles
CORS issues for mobile applications. It is particularly useful for native builds (iOS and Android).
 Setup and Usage: The plugin needs to be installed and configured. It provides methods like get,
post, put, and delete similar to HttpClient but with native capabilities.
 Security and Performance: Utilizes native capabilities for secure data transmission and better
performance in handling requests.

Best Practices
 Error Handling: Implement comprehensive error handling to manage network errors, server
failures, and invalid responses.
 Loading Indicators: Display loading indicators while waiting for HTTP responses to enhance
user experience.
 Data Caching: Use caching strategies to store frequently accessed data locally, reducing the
need for repeated network requests.
 Security Considerations: Always use HTTPS to ensure data security during transmission.
Validate and sanitize inputs and outputs to prevent security vulnerabilities.

Managing State & HTTP Requests In Ionic.

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