@akala/core
Version:
146 lines • 5.71 kB
JavaScript
import { each as eachAsync } from '../eachAsync.js';
import { NotHandled, convertToErrorMiddleware, convertToMiddleware, isErrorMiddleware, isStandardMiddleware } from './shared.js';
/**
* A class representing a composite middleware that handles asynchronous operations.
*/
export class MiddlewareCompositeAsync {
name;
/**
* Creates an instance of MiddlewareCompositeAsync.
* @param {string} [name] - The name of the middleware composite.
*/
constructor(name) {
this.name = name;
}
/**
* Creates a new MiddlewareCompositeAsync instance with the provided middlewares.
* @param {...AnyAsyncMiddleware<T>[]} middlewares - The middlewares to be used.
* @returns {MiddlewareCompositeAsync<T>} A new MiddlewareCompositeAsync instance.
*/
static new(...middlewares) {
return new MiddlewareCompositeAsync().useMiddleware(...middlewares);
}
stack = [];
/**
* Adds middlewares to the stack.
* @param {...AnyAsyncMiddleware<T, TSpecialNextParam>[]} middlewares - The middlewares to be added.
* @returns {this} The current instance of MiddlewareCompositeAsync.
*/
useMiddleware(...middlewares) {
this.stack.push(...middlewares);
return this;
}
/**
* Adds standard middlewares to the stack.
* @param {...((...args: T) => Promise<unknown>)[]} middlewares - The standard middlewares to be added.
* @returns {this} The current instance of MiddlewareCompositeAsync.
*/
use(...middlewares) {
return this.useMiddleware(...middlewares.map(m => convertToMiddleware(m)));
}
/**
* Adds error middlewares to the stack.
* @param {...((error: Error | OptionsResponse, ...args: T) => Promise<unknown>)[]} middlewares - The error middlewares to be added.
* @returns {this} The current instance of MiddlewareCompositeAsync.
*/
useError(...middlewares) {
return this.useMiddleware(...middlewares.map(m => convertToErrorMiddleware(m)));
}
/**
* Processes the request and returns a promise.
* @param {...T} req - The request parameters.
* @returns {Promise<X>} A promise that resolves or rejects based on the middleware processing.
*/
process(...req) {
return this.handle(...req).then(x => Promise.reject(x), x => Promise.resolve(x));
}
/**
* Handles errors in the middleware stack.
* @param {MiddlewareResult} error - The error to be handled.
* @param {...T} req - The request parameters.
* @returns {MiddlewarePromise} A promise that resolves or rejects based on the error handling.
*/
async handleError(error, ...req) {
let failed = !!error;
try {
if (this.stack.length === 0)
return error;
await eachAsync(this.stack, async (middleware) => {
try {
if (failed && isErrorMiddleware(middleware)) {
const err = await middleware.handleError(error, ...req);
if (err === 'break')
throw err;
if (typeof err != 'string' && typeof err != 'undefined')
error = err;
failed = true;
}
}
catch (x) {
throw { success: x };
}
}, true);
return error;
}
catch (err) {
switch (typeof err) {
case 'string':
return;
case 'undefined':
return error;
default:
throw err.success;
}
}
}
/**
* Handles the middleware stack.
* @param {...T} req - The request parameters.
* @returns {MiddlewarePromise<TSpecialNextParam>} A promise that resolves or rejects based on the middleware processing.
*/
async handle(...req) {
let error = undefined;
let failed = undefined;
try {
if (this.stack.length === 0)
return error;
await eachAsync(this.stack, (middleware) => {
if (failed && isErrorMiddleware(middleware)) {
return middleware.handleError(error, ...req).then(err => {
if (err === 'break')
throw err;
if (typeof err != 'string' && typeof err != 'undefined')
error = err;
failed = true;
});
}
else if (!failed && isStandardMiddleware(middleware)) {
return middleware.handle(...req).then(err => {
if (err === 'break')
throw err;
if (typeof err != 'string' && typeof err != 'undefined') {
if (err['allow'])
error['allow'].push(...err['allow']);
else
error = err;
}
failed = err instanceof Error;
}).catch(e => Promise.reject({ success: e }));
}
return NotHandled;
}, true);
return error;
}
catch (err) {
switch (typeof err) {
case 'string':
return;
case 'undefined':
return error;
default:
throw err.success;
}
}
}
}
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