REST library

This is the small library for creating REST applications with express-like middleware.

Installation

Library can be install via package manager like npm or yarn

yarn add rest-library

or

npm install rest-library

Example

You can see full example in example.mjs file

All available methods of RestLibrary you can see here https://pungy.github.io/rest-library/classes/rest.RestLib.html

Here's another one. Checking is there are a file on the server. You can pass server options in the parameters to constructor.

import Rest from 'rest-library'
import { access } from 'node:fs/promises'

// Creating new instance of rest library
const app = new Rest(
    // { server: { cert: fs.readFileSync('cert'), key: fs.readFileSync('key') } }
) // You can put options for server. If in server cert and key are persist, server will be started as https

// Assigning middleware which would be called at every request
app.use((ctx, next) => { 
    console.log(`${ctx.request.method}: ${ctx.request.url}`)
    next()
})

// Assigning on method GET with url '/' listener, which is responds with hello world message
app.get('/', (ctx) => {
    ctx.response.send('Hello world')
})

/**
 * Assigning on method GET with url /file with parameter :file two listeners
 * First one is async and checks is there are a file on the server. Then writes it in the context
 * Second one is sending to the client a message is file exists or not, depends on parameter from the context
 */
app.get(
    '/file/:file', 
    async (ctx, next) => {
        ctx.fileExists = await (access(ctx.request.params.file).then(() => true).catch(() => false))
        next()
    },
    (ctx) => {
        ctx.response.send(`File ${ctx.request.params.file} is ${ctx.fileExists ? 'exists' : 'not exists'} on the server`)
    }
)

app.listen(3000, () => console.log('Server started on port 3000'))

API

You can see full documentation on this page: https://pungy.github.io/rest-library/

Utils

This library also contain utils module, from where you currently can pick the body parser middleware. For now it's only works with such Content-Types as application/json and plain/text.

Here are the full list of functions and types https://pungy.github.io/rest-library/modules/utils.html

import Rest from 'rest-library'
import { parseBodyMiddleware } from 'rest-library/utils.js'
const app = new Rest()

app.use(parseBodyMiddleware)

app.post('/post', (ctx) => {
    ctx.response.send(ctx.request.body)
})

app.listen(3000)

Creating a listener

For creating a listener, you should use library instance, add call appropriate method for the desired HTTP method, or all (in this case listeners would be assigned on all methods). The first parameter is the path, and other parameters is the list of listeners.

Example:

app.all('/')
app.get('/some/path', listener1, listener2)
app.post('/another/path', listener1, listener2)

Path

The path could have a parameters and patterns. For example, if path of listener is /post/:id and the request url is /post/10, the context.request,params would be an object { id: '10' }.

You may also use asterisk in the path for eager evaluation. Here's an example what would be matched in this case.

/**
 * /file/1 - matched
 * /file/1/2 - matched
 * /file/1/2/3 - matched
 */
app.get('/file/*')

/**
 * When the last path entry is not the asterisk - it's working the same as with parameters, but skipping writing into request.params
 * /file/1/min - matched
 * /file/1/2/min - not matched
 * /file/1 - not matched
 * /file/1/min/max - not matched
 */
app.get('/file/*/min')

/**
 * /file/1/2/min - matched
 * /file/1/min - not matched
 * /file/1/2/3/min - not matched
 */
app.get('/file/*/*/min')

/**
 * You also can combine these parameters
 * /file/directory/1/2/min - matched (params: { file1: '1', file2: '2' })
 */
app.get('/file/*/:file1/:file2/min')

Context

The context argument in the listener by default contains two parameters:

• request - is the base IncomingMessage with few additional parameter
  • query - query(what is after ? in the url) parameters string. By default is empty string
  • queryParams - parsed query parameters object. By default is empty object
  • params - parameters object from the url. By default is empty object
• response - is the base ServerResponse with one additional parameter
  • send - function, where first parameter is the response body, and the second is optional response state (by default is 200)

Next

Next is the second parameter in the listener. If it was called, the next middleware in the queue would be called.

Middleware order

Listeners would be called in the order as they was assigned, and the last one would be the middleware, which is not called the next function (or was just the last one)

Special handlers

You also can set custom error and 404 handler via app.error and app.notFound

• app.error - sets error handler which is called when during the execution of listeners an unhandled error was occurred.
• app.notFound - sets 404 handler which is called when the request url path was not matched with any of registered listeners