yarn add dx-server jchainCheck below sample with comment for more details.
Simple server
import {Server} from 'node:http'
import chain from 'jchain'
import dxServer, {getReq, getRes, router, setHtml, setText,} from 'dx-server'
new Server().on('request', (req, res) => chain(
dxServer(req, res),
async next => {
try {
getRes().setHeader('Cache-Control', 'no-cache')
console.log(getReq().method, getReq().url)
await next()
} catch (e) {
console.error(e)
setHtml('internal server error', {status: 500})
}
},
router.get({
'/'() {setHtml('hello world')},
'/health'() {setText('ok')}
}),
() => setHtml('not found', {status: 404}),
)()
).listen(3000, () => console.log('server is listening at 3000'))File server:
import {Server} from 'node:http'
import chain from 'jchain'
import dxServer, {chainStatic, setHtml} from 'dx-server'
import {resolve, dirname} from 'node:path'
import {fileURLToPath} from 'node:url'
new Server().on('request', (req, res) => chain(
dxServer(req, res),
chainStatic('/*', {root: resolve(dirname(fileURLToPath(import.meta.url)), 'public')}),
() => setHtml('not found', {status: 404}),
)()
).listen(3000, () => console.log('server is listening at 3000'))More complex server with express.
This sample additionally requires: yarn install express morgan
import {Server} from 'node:http'
import {promisify} from 'node:util'
import chain from 'jchain'
import dxServer, {
getReq, getRes,
getBuffer, getJson, getRaw, getText, getUrlEncoded, getQuery,
setHtml, setJson, setText, setEmpty, setBuffer, setRedirect, setNodeStream, setWebStream, setFile,
router, connectMiddlewares, chainStatic, makeDxContext
} from 'dx-server'
import {expressApp} from 'dx-server/express'
import express from 'express'
import morgan from 'morgan'
// it is best practice to create custom error class for non-system error
class ServerError extends Error {
name = 'ServerError'
constructor(message, status = 400, code = 'unknown') {
super(message)
this.status = status
this.code = code
}
}
const authContext = makeDxContext(async () => {
if (getReq().headers.authorization) return {id: 1, name: 'joe (private)'}
})
const requireAuth = () => {
if (!authContext.value) throw new ServerError('unauthorized', 401, 'unauthorized')
}
const serverChain = chain(
next => {
// this is the difference between express and dx-server
// req, res can be accessed from anywhere via context which uses NodeJS's AsyncLocalStorage under the hood
getRes().setHeader('Cache-Control', 'no-cache')
return next() // must return or await
},
async next => {// global error catching for all following middlewares
try {
await next()
} catch (e) {// only app error message should be shown to user
if (e instanceof ServerError) setHtml(`${e.message} (code: ${e.code})`, {status: e.status})
else {// report system error
console.error(e)
setHtml('internal server error (code: internal)', {status: 500})
}
}
},
connectMiddlewares(
morgan('common'),
// cors(),
),
await expressApp(app => {// any express feature can be used. This requires express installed, with for e.g., `yarn add express`
app.set('trust proxy', true)
if (process.env.NODE_ENV !== 'production') app.set('json spaces', 2)
app.use('/public', express.static('public'))
}),
authContext.chain(), // chain context will set the context value to authContext.value in every request
router.post('/api/*', async ({next}) => {// example of catching error for all /api/* routes
try {
await next()
} catch (e) {
if (e instanceof ServerError) setJson({// only app error message should be shown to user
error: e.message,
code: e.code,
}, {status: e.status})
else {// report system error
console.error(e)
setJson({
message: 'internal server error',
code: 'internal'
}, {status: 500})
}
}
}),
router.post({
'/api/sample-public-api'() { // sample POST router
setJson({name: 'joe'})
},
'/api/me'() { // sample private router
requireAuth()
setJson({name: authContext.value.name})
},
}),
router.get('/', () => setHtml('ok')), // router.method() accepts 2 formats
router.get('/health', () => setText('ok')),
() => { // not found router
throw new ServerError('not found', 404, 'not_found')
},
)
const tcpServer = new Server()
.on('request', async (req, res) => {
try {
await chain(
dxServer(req, res, {jsonBeautify: process.env.NODE_ENV !== 'production'}), // basic dx-server context
serverChain,
)()
} catch (e) {
console.error(e)
res.end()
}
})
await promisify(tcpServer.listen.bind(tcpServer))(3000)
console.log('server is listening at 3000')getBuffer, getJson, getRaw, getText, getUrlEncoded, getQuery are all asynchronous functions.
The associated results are calculated in the first time they are called and cached for subsequent calls.
If you want to get these values synchronously, chain it, like follows:
import {getJson} from 'dx-server'
chain(
getJson.chain(/*option*/), // json body is parsed and stored in context in every request
next => {
console.log(getJson.value) // json body can be accessed synchronously
return next()
}
)Context can be created using makeDxContext function:
import {makeDxContext} from 'dx-server'
const authContext = makeDxContext(() => {
if (getReq().headers.authorization) return {id: 1, name: 'joe (authorized)'}
})
const requireAuth = () => {
if (!authContext.value) throw new Error('unauthorized')
}
chain(
authContext.chain(),
next => {
requireAuth()
return next()
}
)
// or await authContext() to lazy load the context and don't require chaining authContext.chain()
chain(
async next => {
console.log(await authContext())
return next()
}
)All exported APIs:
import dxServer, {
getReq, getRes, getBuffer, getJson, getRaw, getText, getUrlEncoded, getQuery,
setHtml, setJson, setText, setEmpty, setBuffer, setRedirect, setNodeStream, setWebStream, setFile,
router, connectMiddlewares, chainStatic, makeDxContext
} from 'dx-server'
import {expressApp, expressRouter} from 'dx-server/express' // requires express installed
import {
setBufferBodyDefaultOptions,
bufferFromReq, jsonFromReq, rawFromReq, textFromReq, urlEncodedFromReq, queryFromReq,
} from 'dx-server/helpers'import dxServer, {
getReq, getRes, getBuffer, getJson, getRaw, getText, getUrlEncoded, getQuery,
setHtml, setJson, setText, setEmpty, setBuffer, setRedirect, setNodeStream, setWebStream, setFile,
makeDxContext
} from 'dx-server'-
getReq(),getRes(): get request and response objects from anywhere. -
getBuffer(),getJson(),getRaw(),getText(),getUrlEncoded(),getQuery(): get parsed request body, raw body, text body, url encoded body, query string from anywhere. These are DX context object, can be used as follows:const json = await getJson(): lazily load the context, once loaded, it is cached for subsequent calls. No chaining is required.- Chain it to get the value synchronously:
chain(getJson.chain(), next => console.log(getJson.value)). Note that the value is calculated in every request.
-
ctx = makeDxContext(fn): create a DX context object.fnis called once per request to calculate the value. The value is cached for subsequent calls. -
Context value can be accessed by:
const value = await ctx(): lazily load the context, once loaded, it is cached for subsequent calls.const value = ctx.value: get the value synchronously. Note that the value must be fetched at least once before viaawait ctx()or by chainingchain(ctx.chain()).const value = ctx.get(req): similar condition asctx.value.
-
Context value can be set or overridden by:
ctx.value = value.ctx.set(req, value).
-
setHtml,setJson,setText,setEmpty,setBuffer,setRedirect,setNodeStream,setWebStream,setFile: set response body. -
connectMiddlewares(...middlewares): connect middlewares. For example:
import {connectMiddlewares} from 'dx-server'
import morgan from 'morgan'
import cors from 'cors'
connectMiddlewares(
morgan('common'),
cors(),
)chainStatic(path, options): serve static files. For example:
import {chainStatic} from 'dx-server'
import {resolve, dirname} from 'node:path'
import {fileURLToPath} from 'node:url'
chain(
chainStatic('/assets/*', {
root: resolve(dirname(fileURLToPath(import.meta.url)), 'public'),
getPathname(matched) {
return new URL(getReq().url, 'http://localhost').pathname.slice('/assets'.length)
},
}),
)import {router} from 'dx-server'-
router.get,router.post,router.put,router.delete,router.patch,router.head,router.options,router.connect,router.trace: create router. These functions accept 2 formats:router.get(routes: {[pattern: string]: Route}, options: RouterOptions): create multiple routes.router.get(pattern: string, handler: Route, options: RouterOptions): create route for GET method.
-
router.all(...): same asrouter.get()but for any method. -
router.method(): create router with custom method. Similar torouter.get(), this function accepts 2 formats.router.method(method: string, routes: {[pattern: string]: Route}, options: RouterOptions): create multiple routes.router.method(method: string, pattern: string, handler: Route, options: RouterOptions): create route formethodmethod.
RouterOptions is defined as follows:
interface RouterOptions {
prefix?: string
}Patterns are matched using URLPattern.
This does not always match the same as ExpressJS.
For example, to match any path prefixed with /api/, use /api/*.
Note the following:
''matches nothing.'/'matches both https://example.com and https://example.com/.'/foo'matches https://example.com/foo but not https://example.com/foo/.'/foo/'matches https://example.com/foo/ but not https://example.com/foo.
Route is defined as follows:
interface RouteContext {
matched: URLPatternResult // result returned from URLPattern.exec(). To get params: matched.pathname.groups
next(): any
}
type Route = (context: RouteContext) => anyimport {
setBufferBodyDefaultOptions,
bufferFromReq, jsonFromReq, rawFromReq, textFromReq, urlEncodedFromReq, queryFromReq,
} from 'dx-server/helpers'Helpers are all pure functions, and do not rely on any context. These functions are independent of the context and can be used anywhere, even outside of this package. They require request and response objects to be passed.
import {expressApp, expressRouter} from 'dx-server/express' // requires express installed
chain(
await expressApp(app => {// any express feature can be used. This requires express installed, with for e.g., `yarn add express`
app.set('trust proxy', true)
if (process.env.NODE_ENV !== 'production') app.set('json spaces', 2)
app.use('/public', express.static('public'))
}),
expressRouter(router => {
router.use(cors())
}),
)- Download file: set the Content-Disposition header.
- Upload file: recommend busboy package.
- Cookie: recommend cookie package.