Awesome
NgxHttpRetryService
An Angular service that provides HTTP methods (GET
, POST
, PUT
, DELETE
) with built-in retry logic using RxJS's retry
operator.
Table of Contents
- Installation
- Usage
- Retry Strategy
- Error Handling
- Extending the Service
- FAQs
- Contributing
- License
- Author
- Changelog
Installation
Install the package via npm:
npm install ngx-http-retry
Usage
Importing the Service
Import NgxHttpRetryService
into your Angular component or service:
import { NgxHttpRetryService } from 'ngx-http-retry';
@Component({
// ...
})
export class YourComponent {
constructor(private httpRetryService: NgxHttpRetryService) {}
}
Available Methods
The service provides the following methods, which mirror Angular's HttpClient
methods but include retry logic:
get<T>(url: string, options?: any, retries?: number, delayMs?: number): Observable<T>
post<T>(url: string, body: any, options?: any, retries?: number, delayMs?: number): Observable<T>
put<T>(url: string, body: any, options?: any, retries?: number, delayMs?: number): Observable<T>
delete<T>(url: string, options?: any, retries?: number, delayMs?: number): Observable<T>
get
Performs a GET request with retry logic.
Parameters:
url: string
- The endpoint URL.options?: any
- Optional HTTP options.retries?: number
- Number of retry attempts (default:3
).delayMs?: number
- Delay between retries in milliseconds (default:1000
).
Returns:
Observable<T>
- An observable of the response.
Example:
this.httpRetryService.get<User[]>('https://api.example.com/users')
.subscribe(
users => console.log(users),
error => console.error('Request failed', error)
);
post
Performs a POST request with retry logic.
Parameters:
url: string
- The endpoint URL.body: any
- The payload to send.options?: any
- Optional HTTP options.retries?: number
- Number of retry attempts (default:3
).delayMs?: number
- Delay between retries in milliseconds (default:1000
).
Returns:
Observable<T>
- An observable of the response.
Example:
const payload = { name: 'John Doe', email: 'john@example.com' };
this.httpRetryService.post<User>('https://api.example.com/users', payload)
.subscribe(
user => console.log('User created:', user),
error => console.error('Request failed', error)
);
put
Performs a PUT request with retry logic.
Parameters:
url: string
- The endpoint URL.body: any
- The payload to update.options?: any
- Optional HTTP options.retries?: number
- Number of retry attempts (default:3
).delayMs?: number
- Delay between retries in milliseconds (default:1000
).
Returns:
Observable<T>
- An observable of the response.
Example:
const updatedData = { name: 'Jane Doe' };
this.httpRetryService.put<User>('https://api.example.com/users/1', updatedData)
.subscribe(
user => console.log('User updated:', user),
error => console.error('Request failed', error)
);
delete
Performs a DELETE request with retry logic.
Parameters:
url: string
- The endpoint URL.options?: any
- Optional HTTP options.retries?: number
- Number of retry attempts (default:3
).delayMs?: number
- Delay between retries in milliseconds (default:1000
).
Returns:
Observable<T>
- An observable of the response.
Example:
this.httpRetryService.delete<void>('https://api.example.com/users/1')
.subscribe(
() => console.log('User deleted'),
error => console.error('Request failed', error)
);
Customizing Retries
Customize the number of retries and delay between retries:
this.httpRetryService.get<User[]>('https://api.example.com/users', {}, 5, 2000)
.subscribe(
users => console.log(users),
error => console.error('Request failed after retries', error)
);
- Retries:
5
- Delay:
2000
milliseconds
Retry Strategy
The retry logic uses RxJS's retry
operator with a custom strategy.
private retryStrategy<T>(retries: number, delayMs: number) {
return retry<T>({
count: retries,
delay: (error: HttpErrorResponse, retryCount: number) => {
if (this.isNonRetryableError(error)) {
throw error;
} else {
console.warn(`Retry attempt #${retryCount}`);
return timer(delayMs);
}
},
});
}
Non-Retryable Errors
By default, the following HTTP errors are not retried:
- Client-side errors (
4xx
), except for408 Request Timeout
.
private isNonRetryableError(error: HttpErrorResponse): boolean {
return error.status >= 400 && error.status < 500 && error.status !== 408;
}
Exponential Backoff
To implement exponential backoff, modify the retryStrategy
:
private retryStrategy<T>(retries: number, delayMs: number) {
return retry<T>({
count: retries,
delay: (error: HttpErrorResponse, retryCount: number) => {
if (this.isNonRetryableError(error)) {
throw error;
} else {
const backoffDelay = delayMs * Math.pow(2, retryCount - 1);
console.warn(`Retry attempt #${retryCount} after ${backoffDelay}ms`);
return timer(backoffDelay);
}
},
});
}
Custom Retry Conditions
Customize retry conditions based on specific error codes or responses:
private retryStrategy<T>(retries: number, delayMs: number) {
return retry<T>({
count: retries,
delay: (error: HttpErrorResponse, retryCount: number) => {
if (this.isNonRetryableError(error) || retryCount > retries) {
throw error;
} else if (error.status === 500) {
// Immediate retry for server errors
return timer(0);
} else {
return timer(delayMs);
}
},
});
}
Error Handling
Handle errors where you consume the service:
this.httpRetryService.get<User[]>('https://api.example.com/users')
.subscribe(
users => {
// Successful response
},
error => {
// Error after all retries
console.error('Request failed', error);
}
);
Extending the Service
For extensive customization, extend NgxHttpRetryService
:
@Injectable({
providedIn: 'root',
})
export class CustomHttpRetryService extends NgxHttpRetryService {
protected isNonRetryableError(error: HttpErrorResponse): boolean {
// Custom logic (e.g., don't retry on 404)
return error.status === 404;
}
}
Use CustomHttpRetryService
in your components:
constructor(private httpRetryService: CustomHttpRetryService) {}
FAQs
Does this service support Angular Universal (Server-Side Rendering)?
Yes, it is compatible with Angular Universal.
How is this different from using HttpClient
directly?
NgxHttpRetryService
wraps HttpClient
methods and adds configurable retry logic.
Can I use this service for file uploads or downloads?
Yes, any HTTP request supported by HttpClient
can be used.
Does it support HTTP interceptors?
Yes, any interceptors configured with HttpClient
are applied.
Contributing
Contributions are welcome! Please submit issues or pull requests on GitHub.
License
This project is licensed under the MIT License. See the LICENSE file for details.
Author
Changelog
v1.0.0
- Initial release with GET, POST, PUT, DELETE methods and retry logic.