@nswhp/af-core-module
v0.1.3
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This module provides a base set of core tooling support for Azure Functions for the NodeJS runtime.
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Azure Function - Core Module
This module provides a base set of core tooling support for Azure Functions for the NodeJS runtime.
Bindings
Several Azure Function Binding definitions and Data Services
Models
Errors
The error model definition is build using RFC 7807. Several error class definitions are provided in this module to provide developers with a starting point
When using in conjunction with the azureFunctionWrapper
utility function, these error definitions
can be used to return HTTP error responses
The following error definitions are included in this module
- 400 Bad Request
- 401 Unauthorized
- 403 Forbidden
- 415 Unsupported Media Type
- 500 Internal Server Error
And a custom DownstreamApiError
class for handling and proxying errors returned from downstream api requests
An example usage:
const response = await azureFunctionWrapper(async () => {
// Validate the semantics of the inbound http request
if (!req.body || req.body === {}) {
throw new BadRequestError('Missing request body');
}
if (!req.headers || !req.headers['Content-Type'] || req.headers['Content-Type'] !== 'application/json') {
throw new UnsupportedMediaTypeError();
}
// ... Call service layer class to handle request business logic
return apiResponse;
});
return response;
$ curl -X POST http://localhost:7075/api/otp/_requestOtp -d'{}'
{
"status": 400,
"type": "https://httpstatuses.com/400",
"title": "BAD REQUEST",
"detail": "Missing request body"
}
Services
Loging Service
The LoggingService
provides an inversion layer between the Azure Functions runtime
context.log
object, and support for other logging implementations.
A ConsoleLogger
model is provided in this library for use with the LoggingService.
The Logging Service allows clients to provide a list of log aggregators (log aggregators must implement the Azure Function Logger interface)
An example usage:
const loggingService = new LoggingService(context.log, ConsoleLogger);
loggingService.verbose('Received HTTP Request Body', req.body);
loggingService.info('HTTP trigger function processed a request.');
loggingService.warn('Function Timer Trigger is running late');
loggingService.error('Fatal Error', err);
Axios HTTP Data Service
Axios is the chosen library for HTTP communications with downstream API services.
The AxiosHttpDataService
class implements the AbstractHttpDataService
(which
provides a base set of required functionality for developers to implement to make a compliant HTTP data Service.
See the AF App Insights HTTP Data Service for an App Insights enabled HTTP client
An example usage:
const http = new AxiosHttpDataService(Axios);
const response = await http.makeHttpGetCall('https://www.google.com');
Utilities
The azureFunctionWrapper
provides a simple to use wrapper for any HTTP based Azure Function trigger.
It safely returns a HTTP Response object model for a controller router and also safely handles exception
error handling.
An example usage:
export class VersionController {
constructor(
private readonly versionService: IVersionService
) { }
/**
* GET api for /version
* Returns the semantically tagged build number of the API
* @param req The inbound HTTP Request
*/
async getVersion(req: HttpRequest): Promise<IHttpResponse<IVersionMessage | IHttpErrorResponse>> {
const response = await azureFunctionWrapper(async () => {
// Code executed inside the azureFunctionWrapper can run safely
// with error handling in place to catch errors thrown and represent them
// as a HTTP Error Response
const version = await this.versionService.getVersion();
const apiResponse: IApiResponse<IVersionMessage> = {
body: version,
status: 200 // Success
};
return apiResponse;
});
return response;
}
}