Implement middleware

Author: owjs3901

examples/next/app/page.tsx

@@ -19,6 +19,9 @@ export default function Home() {
     api
       .get('getUserById', {
         params: { id: 1 },
+        query: {
+          name: 'John Doe',
+        },
       })
       .then((res) => {
         console.log(res)

examples/next/openapi.json

@@ -65,6 +65,14 @@
             "schema": {
               "type": "integer"
             }
+          },
+          {
+            "name": "name",
+            "in": "query",
+            "required": true,
+            "schema": {
+              "type": "string"
+            }
           }
         ],
         "responses": {

packages/core/src/additional.ts

@@ -1,3 +1,5 @@
+import type { Middleware } from './middleware'
+
 export type Additional<
   T extends string,
   Target extends object,
@@ -9,6 +11,8 @@ export type RequiredOptions<T extends object> = keyof T extends undefined
 export type DevupApiRequestInit = Omit<RequestInit, 'body'> & {
   body?: object | RequestInit['body']
   params?: Record<string, string | number | boolean | null | undefined>
+  query?: Record<string, string | number | boolean | null | undefined>
+  middleware?: Middleware[]
 }
 
 // biome-ignore lint/suspicious/noExplicitAny: any is used to allow for flexibility in the type

packages/core/src/index.ts

@@ -1,5 +1,6 @@
 export * from './additional'
 export * from './api-struct'
+export * from './middleware'
 export * from './options'
 export * from './url-map'
 export * from './utils'

packages/core/src/middleware.ts

@@ -0,0 +1,38 @@
+import type { DevupApiRequestInit } from './additional'
+import type { PromiseOr } from './utils'
+
+export interface MiddlewareCallbackParams {
+  request: Request
+  schemaPath: string
+  params?: Record<string, unknown>
+  query?: Record<string, unknown>
+  headers?: DevupApiRequestInit['headers']
+  body?: DevupApiRequestInit['body']
+}
+
+type MiddlewareOnRequest = (
+  params: MiddlewareCallbackParams,
+) => PromiseOr<undefined | Request | Response>
+type MiddlewareOnResponse = (
+  params: MiddlewareCallbackParams & { response: Response },
+) => PromiseOr<undefined | Error | Response>
+type MiddlewareOnError = (
+  params: MiddlewareCallbackParams & { error: unknown },
+) => PromiseOr<undefined | Error | Response>
+
+export type Middleware =
+  | {
+      onRequest: MiddlewareOnRequest
+      onResponse?: MiddlewareOnResponse
+      onError?: MiddlewareOnError
+    }
+  | {
+      onRequest?: MiddlewareOnRequest
+      onResponse: MiddlewareOnResponse
+      onError?: MiddlewareOnError
+    }
+  | {
+      onRequest?: MiddlewareOnRequest
+      onResponse?: MiddlewareOnResponse
+      onError: MiddlewareOnError
+    }

packages/core/src/utils.ts

@@ -4,3 +4,5 @@ export type ConditionalKeys<T, F = string> = keyof T extends undefined
 export type ConditionalScope<T, K extends string> = K extends keyof T
   ? T[K]
   : object
+
+export type PromiseOr<T> = Promise<T> | T

packages/fetch/src/__tests__/api.test.ts

@@ -1,3 +1,4 @@
+/** biome-ignore-all lint/suspicious/noExplicitAny: any is used to allow for flexibility in the type */
 import { afterEach, beforeEach, expect, mock, test } from 'bun:test'
 import { DevupApi } from '../api'
 
@@ -24,7 +25,7 @@ test.each([
   ['http://localhost:3000', 'http://localhost:3000'],
   ['http://localhost:3000/', 'http://localhost:3000'],
 ] as const)('constructor removes trailing slash: %s -> %s', (baseUrl, expected) => {
-  const api = new DevupApi(baseUrl)
+  const api = new DevupApi(baseUrl, undefined, 'openapi.json')
   expect(api.getBaseUrl()).toBe(expected)
 })
 
@@ -36,7 +37,11 @@ test.each([
     { headers: { Authorization: 'Bearer token' } },
   ],
 ] as const)('constructor accepts defaultOptions: %s -> %s', (defaultOptions, expected) => {
-  const api = new DevupApi('https://api.example.com', defaultOptions)
+  const api = new DevupApi(
+    'https://api.example.com',
+    defaultOptions,
+    'openapi.json',
+  )
   expect(api.getDefaultOptions()).toEqual(expected)
 })
 
@@ -47,7 +52,7 @@ test.each([
     { headers: { 'Content-Type': 'application/json' } },
   ],
 ] as const)('setDefaultOptions updates defaultOptions: %s -> %s', (options, expected) => {
-  const api = new DevupApi('https://api.example.com')
+  const api = new DevupApi('https://api.example.com', undefined, 'openapi.json')
   api.setDefaultOptions(options)
   expect(api.getDefaultOptions()).toEqual(expected)
 })
@@ -64,10 +69,10 @@ test.each([
   ['PATCH', 'patch'],
   ['PATCH', 'PATCH'],
 ] as const)('HTTP method %s calls request with correct method', async (expectedMethod, methodName) => {
-  const api = new DevupApi('https://api.example.com')
+  const api = new DevupApi('https://api.example.com', undefined, 'openapi.json')
   const mockFetch = globalThis.fetch as unknown as ReturnType<typeof mock>
 
-  await api[methodName]('/test' as never)
+  await (api as any)[methodName]('/test' as never)
 
   expect(mockFetch).toHaveBeenCalledTimes(1)
   const call = mockFetch.mock.calls[0]
@@ -79,7 +84,7 @@ test.each([
 })
 
 test('request serializes plain object body to JSON', async () => {
-  const api = new DevupApi('https://api.example.com')
+  const api = new DevupApi('https://api.example.com', undefined, 'openapi.json')
   const mockFetch = globalThis.fetch as unknown as ReturnType<typeof mock>
 
   await api.post(
@@ -100,7 +105,7 @@ test('request serializes plain object body to JSON', async () => {
 })
 
 test('request does not serialize non-plain object body', async () => {
-  const api = new DevupApi('https://api.example.com')
+  const api = new DevupApi('https://api.example.com', undefined, 'openapi.json')
   const mockFetch = globalThis.fetch as unknown as ReturnType<typeof mock>
   const formData = new FormData()
   formData.append('file', 'test')
@@ -127,9 +132,13 @@ test('request does not serialize non-plain object body', async () => {
 })
 
 test('request merges defaultOptions with request options', async () => {
-  const api = new DevupApi('https://api.example.com', {
-    headers: { 'X-Default': 'default-value' },
-  })
+  const api = new DevupApi(
+    'https://api.example.com',
+    {
+      headers: { 'X-Default': 'default-value' },
+    },
+    'openapi.json',
+  )
   const mockFetch = globalThis.fetch as unknown as ReturnType<typeof mock>
 
   await api.get(
@@ -151,7 +160,7 @@ test('request merges defaultOptions with request options', async () => {
 })
 
 test('request uses params to replace path parameters', async () => {
-  const api = new DevupApi('https://api.example.com')
+  const api = new DevupApi('https://api.example.com', undefined, 'openapi.json')
   const mockFetch = globalThis.fetch as unknown as ReturnType<typeof mock>
 
   await api.get(
@@ -180,7 +189,7 @@ test('request returns response with data on success', async () => {
     ),
   ) as unknown as typeof fetch
 
-  const api = new DevupApi('https://api.example.com')
+  const api = new DevupApi('https://api.example.com', undefined, 'openapi.json')
   const result = (await api.get('/test' as never)) as {
     data?: unknown
     error?: unknown
@@ -191,7 +200,7 @@ test('request returns response with data on success', async () => {
   if ('data' in result && result.data !== undefined) {
     expect(result.data).toEqual({ id: 1, name: 'test' })
   }
-  expect('error' in result).toBe(false)
+  expect(result.error).toBeUndefined()
   expect(result.response).toBeDefined()
   expect(result.response.ok).toBe(true)
 })
@@ -206,7 +215,7 @@ test('request returns response with error on failure', async () => {
     ),
   ) as unknown as typeof fetch
 
-  const api = new DevupApi('https://api.example.com')
+  const api = new DevupApi('https://api.example.com', undefined, 'openapi.json')
   const result = (await api.get('/test' as never)) as {
     data?: unknown
     error?: unknown
@@ -217,7 +226,7 @@ test('request returns response with error on failure', async () => {
   if ('error' in result && result.error !== undefined) {
     expect(result.error).toEqual({ message: 'Not found' })
   }
-  expect('data' in result).toBe(false)
+  expect(result.data).toBeUndefined()
   expect(result.response).toBeDefined()
   expect(result.response.ok).toBe(false)
 })
@@ -231,7 +240,7 @@ test('request handles 204 No Content response', async () => {
     ),
   ) as unknown as typeof fetch
 
-  const api = new DevupApi('https://api.example.com')
+  const api = new DevupApi('https://api.example.com', undefined, 'openapi.json')
   const result = await api.delete('/test' as never)
 
   if ('data' in result) {

packages/fetch/src/api.ts

@@ -17,6 +17,7 @@ import type {
   DevupPutApiStruct,
   DevupPutApiStructKey,
   ExtractValue,
+  Middleware,
   RequiredOptions,
 } from '@devup-api/core'
 import { convertResponse } from './response-converter'
@@ -40,6 +41,7 @@ export class DevupApi<S extends ConditionalKeys<DevupApiServers>> {
   private baseUrl: string
   private defaultOptions: DevupApiRequestInit
   private serverName: S
+  private middleware: Middleware[]
 
   constructor(
     baseUrl: string,
@@ -49,6 +51,7 @@ export class DevupApi<S extends ConditionalKeys<DevupApiServers>> {
     this.baseUrl = baseUrl.replace(/\/$/, '')
     this.defaultOptions = defaultOptions
     this.serverName = serverName as S
+    this.middleware = []
   }
 
   get<
@@ -221,7 +224,7 @@ export class DevupApi<S extends ConditionalKeys<DevupApiServers>> {
     } as DevupApiRequestInit & Omit<O, 'response' | 'error'>)
   }
 
-  request<
+  async request<
     T extends DevupApiStructKey<S>,
     O extends Additional<T, ConditionalScope<DevupApiStruct, S>>,
   >(
@@ -233,9 +236,10 @@ export class DevupApi<S extends ConditionalKeys<DevupApiServers>> {
     DevupApiResponse<ExtractValue<O, 'response'>, ExtractValue<O, 'error'>>
   > {
     const { method, url } = getApiEndpointInfo(path, this.serverName)
+    const { middleware = [], ...restOptions } = options[0] || {}
     const mergedOptions = {
       ...this.defaultOptions,
-      ...options[0],
+      ...restOptions,
     }
     const requestOptions = {
       ...mergedOptions,
@@ -244,7 +248,7 @@ export class DevupApi<S extends ConditionalKeys<DevupApiServers>> {
     if (requestOptions.body && isPlainObject(requestOptions.body)) {
       requestOptions.body = JSON.stringify(requestOptions.body)
     }
-    const request = new Request(
+    let request = new Request(
       getApiEndpoint(
         this.baseUrl,
         url,
@@ -259,11 +263,88 @@ export class DevupApi<S extends ConditionalKeys<DevupApiServers>> {
       ),
       requestOptions as RequestInit,
     )
-    return fetch(request).then((response) =>
-      convertResponse(request, response),
-    ) as Promise<
-      DevupApiResponse<ExtractValue<O, 'response'>, ExtractValue<O, 'error'>>
+
+    const finalMiddleware = [...this.middleware, ...middleware]
+
+    let tempResponse: Response | undefined
+
+    for (const middleware of finalMiddleware) {
+      if (middleware.onRequest) {
+        const result = await middleware.onRequest({
+          request,
+          schemaPath: path,
+          params: requestOptions.params,
+          query: requestOptions.query,
+          headers: requestOptions.headers,
+          body: requestOptions.body,
+        })
+        if (result) {
+          if (result instanceof Request) {
+            request = result
+          } else if (result instanceof Response) {
+            tempResponse = result
+            break
+          } else {
+            throw new Error(
+              'onRequest: must return new Request() or Response() when modifying the request',
+            )
+          }
+        }
+      }
+    }
+
+    const ret = (await (tempResponse
+      ? convertResponse(request, tempResponse)
+      : fetch(request).then((response) =>
+          convertResponse(request, response),
+        ))) as DevupApiResponse<
+      ExtractValue<O, 'response'>,
+      ExtractValue<O, 'error'>
     >
+
+    let response = ret.response
+    let error: unknown = ret.error
+
+    for (const middleware of finalMiddleware) {
+      if (response && middleware.onResponse) {
+        const result = await (response && middleware.onResponse
+          ? middleware.onResponse({
+              request,
+              schemaPath: path,
+              params: requestOptions.params,
+              query: requestOptions.query,
+              headers: requestOptions.headers,
+              body: requestOptions.body,
+              response: ret.response,
+            })
+          : error && middleware.onError
+            ? middleware.onError({
+                request,
+                schemaPath: path,
+                params: requestOptions.params,
+                query: requestOptions.query,
+                headers: requestOptions.headers,
+                body: requestOptions.body,
+                error: ret.error,
+              })
+            : undefined)
+        if (result) {
+          if (result instanceof Response) {
+            response = result
+            break
+          } else if (result instanceof Error) {
+            error = result
+            break
+          }
+        }
+      }
+    }
+
+    return {
+      data: ret.data,
+      error: error,
+      response,
+    } as DevupApiResponse<ExtractValue<O, 'response'>, ExtractValue<O, 'error'>>
   }
 
   setDefaultOptions(options: DevupApiRequestInit) {
@@ -277,4 +358,8 @@ export class DevupApi<S extends ConditionalKeys<DevupApiServers>> {
   getDefaultOptions() {
     return this.defaultOptions
   }
+
+  use(...middleware: Middleware[]) {
+    this.middleware.push(...middleware)
+  }
 }