initial koa-api implementation

Author: ivandotv

lib/koa-api/src/koa-api.ts

@@ -0,0 +1,76 @@
+import Router, { RouterOptions } from '@koa/router'
+import { default as Koa } from 'koa'
+import type { NextApiRequest, NextApiResponse } from 'next'
+
+declare module 'koa' {
+  type IncomingMessage = NextApiRequest
+  type ServerResponse = NextApiResponse
+  interface Request extends Koa.BaseRequest {
+    body?: any
+  }
+}
+
+type KoaOptions = {
+  env?: string
+  keys?: string[]
+  proxy?: boolean
+  subdomainOffset?: number
+  proxyIpHeader?: string
+  maxIpsCount?: number
+}
+
+type KoaApiOptions = {
+  koa?: KoaOptions
+  attachBody?: boolean
+  router?: Router.RouterOptions
+  routerAllowedMethods?: Router.RouterAllowedMethodsOptions
+}
+
+export class KoaApi extends Koa {
+  router: Router
+
+  protected firstRun = true
+
+  protected options: KoaApiOptions
+
+  constructor(options: KoaApiOptions = {}) {
+    super(options.koa)
+
+    const { router: routerOpts = {} } = options || {}
+    this.options = {
+      ...options,
+      attachBody: options?.attachBody ?? true,
+      router: {
+        ...routerOpts,
+        prefix: routerOpts.prefix ?? '/api'
+      }
+    }
+
+    this.router = new Router(this.options.router)
+    if (this.options.attachBody) {
+      this.use((ctx, next) => {
+        ctx.request.body = ctx.req.body
+        next()
+      })
+    }
+  }
+
+  run(req: NextApiRequest, res: NextApiResponse) {
+    if (this.firstRun) {
+      this.firstRun = false
+      this.use(this.router.routes()).use(
+        this.router.allowedMethods(this.options.routerAllowedMethods)
+      )
+    }
+
+    return this.callback()(req, res)
+  }
+
+  getNewRouter(opts?: RouterOptions) {
+    return new Router(opts)
+  }
+}
+
+export function withKoaApi(koa: KoaApi) {
+  return (req: NextApiRequest, res: NextApiResponse) => koa.run(req, res)
+}