@idio/core
@idio/core
is a Koa2-based web server with some pre-installed middleware which facilitates quick creation of a web server with the essential functionality, such as serving static files, compression, body parsing, etc. It also provides full JSDoc documentation of all options for completion in IDEs. Other components such as @idio/database
, @idio/route
and @idio/jsx
allow to build more complex websites (to come).
yarn add -E @idio/core
Table Of Contents
- Table Of Contents
- API
-
async core(middlewareConfig?: MiddlewareConfig, config?: Config): IdioCore
- Middleware Configuration
- Custom Middleware
- Router Set-up
- Copyright
API
The package is available by importing its default function:
import idioCore from '@idio/core'
async core(
middlewareConfig?: MiddlewareConfig,
config?: Config,
): IdioCore
The @idio/core
accepts 2 arguments which are the middleware configuration object and server configuration object. It is possible to start the server without any configuration, however it will do nothing, therefore it is important to add some middleware configuration.
MiddlewareConfig
: Middleware configuration for the idio
core
server.
Name | Type | Description |
---|---|---|
session | SessionOptions |
session options. |
multer | MulterOptions |
multer options. |
csrf | CSRFOptions |
csrf options. |
bodyparser | BodyparserOptions |
bodyparser options. |
compress | CompressOptions |
compress options. |
checkauth | CheckauthOptions |
checkauth options. |
logger | LoggerOptions |
logger options. |
static | StaticOptions |
static options. |
cors | CorsOptions |
cors options. |
frontend | FrontendOptions |
frontend options. If the option is specified, the middleware always will be used, i.e., no need to pass use: true . |
Config
: Server configuration object.
Name | Type | Description | Default |
---|---|---|---|
port | number | The port on which to start the server. | 5000 |
host | string | The host on which to listen. | 0.0.0.0 |
The return type contains the URL, Application and Router instances, and the map of configured middleware, which could then be passed to the router.
import('@goa/koa').Application
_goa.Application
: An instance of the Koa application.
import('@goa/koa').Middleware
_goa.Middleware
: An async middleware function.
import('koa-router').Router
koa-router.Router
: An instance of the Koa router.
import('http').Server
http.Server
: An instance of the Node's Server class.
IdioCore
: An object containing the url and references to the app, router and middleware.
Name | Type | Description | Default |
---|---|---|---|
url | string | The url on which the server is accessible. | http://localhost:5000 |
app | _goa.Application | The Koa application. |
- |
router | Router | The koa-router instance. |
- |
server | http.Server | The http server instance. |
- |
middleware | Object<string, _goa.Middleware> | The map of configured middleware functions which could then be set up to be used on a certain route. | - |
To start the server, the async method needs to be called and passed the middleware and server configuration objects. For example, the following code will start a server which serves static files with enabled compression.
import idioCore from '@idio/core'
const Server = async () => {
const { url } = await idioCore({
logger: {
use: true,
},
static: {
use: true,
root: 'example/static',
mount: '/static',
},
compress: {
use: true,
config: {
threshold: 1024,
},
},
}, {
port: 8080,
})
console.log('File available at: %s/static/test.txt', url)
}
File available at: http://localhost:8080/static/test.txt
Middleware Configuration
The middleware can be configured according to the MiddlewareConfig
. @idio/core
comes with some installed middleware as dependencies to speed up the process of creating a web server. Moreover, any custom middleware which is not part of the bundle can also be specified here (see Custom Middleware).
Each middleware accepts the following properties:
Property | Description | Default |
---|---|---|
use |
Whether to use this middleware for every request. If not set to true , the configured middleware function will be included in the middleware property of the returned object, which can then be passed to a router configuration (not part of the @idio/core ). |
false |
config |
Configuration object expected by the middleware constructor. | {} |
...props |
Any additional specific properties (see individual middleware configuration). |
Session: handling sessions via cookies.
Name
Type
Description
Default
keys*
string[]
A set of keys to be installed in app.keys
.
-
use
boolean
Use this middleware for every request.
false
config
SessionConfig
koa-session
configuration.
-
app.keys
.false
koa-session
configuration.SessionConfig
: Configuration passed to koa-session
.
Name | Type | Description | Default |
---|---|---|---|
key | string | Cookie key. | koa:sess |
maxAge | (number | 'session') | maxAge in ms with default of 1 day. session will result in a cookie that expires when session/browser is closed. Warning: If a session cookie is stolen, this cookie will never expire. |
86400000 |
overwrite | boolean | Can overwrite or not. | true |
httpOnly | boolean | httpOnly or not. | true |
signed | boolean | Signed or not. | true |
rolling | boolean | Force a session identifier cookie to be set on every response. The expiration is reset to the original maxAge, resetting the expiration countdown. | false |
renew | boolean | Renew session when session is nearly expired, so we can always keep user logged in. | false |
File Uploads: receiving files on the server.
Name
Type
Description
Default
use
boolean
Use this middleware for every request.
false
config
MulterConfig
koa-multer
configuration.
-
false
koa-multer
configuration.import('http').IncomingMessage
http.IncomingMessage
import('koa-multer').StorageEngine
koa-multer.StorageEngine
import('koa-multer').File
koa-multer.File
Limits
: An object specifying the size limits.
Name | Type | Description | Default |
---|---|---|---|
fieldNameSize | number | Max field name size in bytes. | 100 |
fieldSize | number | Max field value size in bytes. | 1024 |
fields | number | Max number of non-file fields. | Infinity |
fileSize | number | For multipart forms, the max file size in bytes. | Infinity |
files | number | For multipart forms, the max number of file fields. | Infinity |
parts | number | For multipart forms, the max number of parts (fields + files). | Infinity |
headerPairs | number | For multipart forms, the max number of header key=> value pairs to parse. | 2000 |
Name | Type | Description | Default |
---|---|---|---|
dest | string | Where to store the files. | - |
storage | StorageEngine | Where to store the files. | - |
fileFilter | (req: IncomingMessage, file: File, callback: (error: (Error | null), acceptFile: boolean)) => void | Function to control which files are accepted. |
limits | Limits | Limits of the uploaded data. | - |
preservePath | boolean | Keep the full path of files instead of just the base name. | false |
Cross-Site Request Forgery: prevention against CSRF attacks.
Name
Type
Description
Default
use
boolean
Use this middleware for every request.
false
config
CSRFConfig
koa-csrf
configuration.
-
false
koa-csrf
configuration.Name | Type | Description |
---|---|---|
invalidSessionSecretMessage | string | |
invalidSessionSecretStatusCode | number | |
invalidTokenMessage | string | |
invalidTokenStatusCode | number | |
excludedMethods | string[] | |
disableQuery | boolean |
Parse Body: parsing of data sent with requests.
Name
Type
Description
Default
use
boolean
Use this middleware for every request.
false
config
BodyparserConfig
koa-bodyparser
configuration.
-
false
koa-bodyparser
configuration.import('koa').Context
koa.Context
Name | Type | Description | Default |
---|---|---|---|
enableTypes | string[] | Parser will only parse when request type hits enableTypes. | ['json', 'form'] |
encode | string | Requested encoding. | utf-8 |
formLimit | string | Limit of the urlencoded body. If the body ends up being larger than this limit a 413 error code is returned. | 56kb |
jsonLimit | string | Limit of the json body. | 1mb |
strict | boolean | When set to true, JSON parser will only accept arrays and objects. | true |
detectJSON | (ctx: Context) => boolean | Custom json request detect function. | null |
extendTypes | { json: string[], form: string[], text: string[] } | Support extend types. | - |
onerror | (err: Error, ctx: Context) => void | Support custom error handle. | - |
Checking Auth: a simple function which throws if ctx.session.user
is not set. Non-configurable.
Name
Type
Description
Default
use
boolean
Use this middleware for every request.
false
false
Logging: a logger of incoming requests / response times and sizes.
Name
Type
Description
Default
use
boolean
Use this middleware for every request.
false
config
LoggerConfig
koa-logger
configuration.
-
false
koa-logger
configuration.Name | Type | Description |
---|---|---|
transporter | (str: string, args: [string, string, string, string, string, string, string]) => void | Param str is output string with ANSI Color, and you can get pure text with other modules like strip-ansi . Param args is a array by [format, method, url, status, time, length] . |
Compression: enabling gzip and other compression.
Name
Type
Description
Default
use
boolean
Use this middleware for every request.
false
config
CompressConfig
koa-compress
configuration.
-
false
koa-compress
configuration.Name | Type | Description | Default |
---|---|---|---|
filter | (content_type: string) => boolean | An optional function that checks the response content type to decide whether to compress. By default, it uses compressible . |
- |
threshold | number | Minimum response size in bytes to compress. | 1024 |
flush | number | Default: zlib.constants.Z_NO_FLUSH . |
- |
finishFlush | number | Default: zlib.constants.Z_FINISH . |
- |
chunkSize | number | Default: 16*1024 . |
- |
windowBits | number | Support extend types. | - |
level | number | Compression only. | - |
memLevel | number | Compression only. | - |
strategy | number | Compression only. | - |
dictionary | * | Deflate/inflate only, empty dictionary by default. | - |
Static Files: serving files from filesystem.
Name
Type
Description
Default
root*
(string | string[])
Root or multiple roots from which to serve files.
-
use
boolean
Use this middleware for every request.
false
mount
string
Path from which to serve files.
/
maxage
number
How long to cache file for.
0
config
StaticConfig
koa-static
configuration.
-
false
/
0
koa-static
configuration.import('http').ServerResponse
http.ServerResponse
(res: ServerResponse, path: string, stats: Stats) => any
SetHeaders
Name | Type | Description | Default |
---|---|---|---|
maxage | number | Browser cache max-age in milliseconds. | 0 |
hidden | boolean | Allow transfer of hidden files. | false |
index | string | Default file name. | index.html |
defer | boolean | If true , serves after return next(), allowing any downstream middleware to respond first. |
false |
gzip | boolean | Try to serve the gzipped version of a file automatically when gzip is supported by a client and if the requested file with .gz extension exists. |
true |
br | boolean | Try to serve the brotli version of a file automatically when brotli is supported by a client and if the requested file with .br extension exists (note, that brotli is only accepted over https). |
true |
setHeaders | SetHeaders | Function to set custom headers on response. | - |
extensions | boolean | Try to match extensions from passed array to search for file when no extension is sufficed in URL. First found is served. | false |
For example, the below configuration will serve files from both the static
directory of the project, and the React.js dependency. When NODE_ENV
environment variable is set to production
, files will be cached for 10 days.
import { join, dirname } from 'path'
import idioCore from '@idio/core'
const STATIC = join(__dirname, 'static')
const REACT = join(dirname(require.resolve('react')), 'umd')
const DAY = 1000 * 60 * 60 * 24
const Static = async () => {
const { url } = await idioCore({
static: {
use: true,
root: [STATIC, REACT],
mount: '/scripts',
maxage: process.env.NODE_ENV == 'production' ? 10 * DAY : 0,
},
}, { port: 5004 })
return url
}
Static server started on http://localhost:5004
CORS: return Cross-Origin Resource Sharing headers.
import('koa').Context
koa.Context
Name
Type
Description
Default
origin
string
Array
((ctx: Context) => string)
use
boolean
Use this middleware for every request.
false
config
CorsConfig
@koa/cors
configuration.
-
import('koa').Context
koa.Context
false
@koa/cors
configuration.Name | Type | Description | Default |
---|---|---|---|
origin | string |
Access-Control-Allow-Origin header value. |
request Origin header |
allowMethods | (string | Array<string>) |
Access-Control-Allow-Methods header value. |
GET,HEAD,PUT,POST,DELETE,PATCH |
exposeHeaders | (string | Array<string>) |
Access-Control-Expose-Headers header value. |
- |
allowHeaders | (string | Array<string>) |
Access-Control-Allow-Headers header value. |
- |
maxAge | (string | number) |
Access-Control-Max-Age header value in seconds. |
- |
credentials | boolean |
Access-Control-Allow-Credentials header value. |
false |
keepHeadersOnError | boolean | Add set headers to err.header if an error is thrown. |
false |
Frontend: serve JS and CSS files as modules for modern browsers.
FrontendOptions
: Allows to serve front-end JS files and CSS as modules, including from node_modules folder.
Name
Type
Description
Default
directory
(string | Array<string>)
The directory or directories from which to serve files.
frontend
config
FrontendConfig
@idio/frontend
configuration.
-
FrontendOptions
: Allows to serve front-end JS files and CSS as modules, including from node_modules folder.frontend
@idio/frontend
configuration.Name | Type | Description | Default |
---|---|---|---|
pragma | string | The pragma function to import. This enables to skip writing h at the beginning of each file. JSX will be transpiled to have h pragma, therefore to use React it's possible to do import { createElement: h } from 'react' . |
import { h } from 'preact' |
Custom Middleware
When required to add any other middleware in the application not included in the @idio/core
bundle, it can be done in several ways.
- Passing the middleware function as part of the MiddlewareConfig. It will be automatically installed to be used by the Application. All middleware will be installed in order it is found in the MiddlewareConfig.
import idioCore from '@idio/core'
/** @typedef {import('koa').Middleware} Middleware */
const APIServer = async (port) => {
const { url } = await idioCore({
// 1. Add logging middleware.
/** @type {Middleware} */
async log(ctx, next) {
await next()
console.log(' --> API: %s %s %s', ctx.method, ctx.url, ctx.status)
},
// 2. Add always used error middleware.
/** @type {Middleware} */
async error(ctx, next) {
try {
await next()
} catch (err) {
ctx.status = 403
ctx.body = err.message
}
},
// 3. Add validation middleware.
/** @type {Middleware} */
async validateKey(ctx, next) {
if (ctx.query.key !== 'app-secret')
throw new Error('Wrong API key.')
ctx.body = 'ok'
await next()
},
}, { port })
return url
}
export default APIServer
Started API server at: http://localhost:5005
--> API: GET / 403
--> API: GET /?key=app-secret 200
- Passing a configuration object as part of the MiddlewareConfig that includes the
middlewareConstructor
property which will receive the reference to theapp
. Other properties such asconf
anduse
will be used in the same way as when setting up bundled middleware: settinguse
totrue
will result in the middleware being used for every request, and theconfig
will be passed to the constructor.
import rqt from 'rqt'
import idioCore from '@idio/core'
import APIServer from './api-server'
const ProxyServer = async (port) => {
// 1. Start the API server.
const API = await APIServer(5001)
console.log('API server started at %s', API)
// 2. Start a proxy server to the API.
const { url } = await idioCore({
/** @type {import('koa').Middleware} */
async log(ctx, next) {
await next()
console.log(' --> Proxy: %s %s %s', ctx.method, ctx.url, ctx.status)
},
api: {
use: true,
async middlewareConstructor(app, config) {
// e.g., read from a virtual network
app.context.SECRET = await Promise.resolve('app-secret')
/** @type {import('koa').Middleware} */
const fn = async(ctx, next) => {
const { path } = ctx
const res = await rqt(`${config.API}${path}?key=${ctx.SECRET}`)
ctx.body = res
await next()
}
return fn
},
config: {
API,
},
},
}, { port })
return url
}
API server started at http://localhost:5001
Proxy started at http://localhost:5002
--> API: GET /?key=app-secret 200
--> Proxy: GET / 200
Router Set-up
After the Application and Router instances are obtained after starting the server as the app
and router
properties of the returned object, the router can be configured to respond to custom paths. This can be done by assigning configured middleware from the map and standalone middleware, and calling the use
method on the Application instance.
import idioCore from '@idio/core'
async function pre(ctx, next) {
console.log(' <-- %s %s',
ctx.request.method,
ctx.request.path,
)
await next()
}
async function post(ctx, next) {
console.log(' --> %s %s %s',
ctx.request.method,
ctx.request.path,
ctx.response.status,
)
await next()
}
const Server = async () => {
const path = '/test'
const {
url, router, app, middleware: { bodyparser },
} = await idioCore({
// 1. Configure the bodyparser without using it for each request.
bodyparser: {
config: {
enableTypes: ['json'],
},
},
}, { port: 5003 })
// 2. Setup router with the bodyparser and path-specific middleware.
router.post(path,
pre,
bodyparser,
async (ctx, next) => {
ctx.body = {
ok: true,
request: ctx.request.body,
}
await next()
},
post,
)
app.use(router.routes())
return `${url}${path}`
}
Page available at: http://localhost:5003/test
<-- POST /test
--> POST /test 200
Copyright
Middleware icons and logo from Deco Dingbats NF font.
Middleware types descriptions by their respective authors.
© Art Deco for Idio 2019 | Tech Nation Visa Sucks |
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