chore: update public repo

utils/oauth.ts

@@ -0,0 +1,78 @@
+import type { MaybePromise } from '@fuman/utils'
+import * as fsp from 'node:fs/promises'
+import { z } from 'zod'
+
+export interface OauthStorage {
+  write: (value: string) => MaybePromise<void>
+  read: () => MaybePromise<string | null>
+}
+
+export class LocalOauthStorage implements OauthStorage {
+  constructor(private filename: string) {}
+
+  async write(value: string) {
+    await fsp.writeFile(this.filename, value)
+  }
+
+  async read() {
+    try {
+      return await fsp.readFile(this.filename, 'utf8')
+    } catch (e) {
+      return null
+    }
+  }
+}
+
+const OauthState = z.object({
+  accessToken: z.string(),
+  refreshToken: z.string().optional(),
+  expiresAt: z.number(),
+})
+type OauthState = z.infer<typeof OauthState>
+
+export class OauthHandler {
+  constructor(private params: {
+    storage: OauthStorage
+    refreshToken: (refreshToken: string) => MaybePromise<{
+      accessToken: string
+      refreshToken: string
+      expiresIn: number
+    }>
+    /** number of milliseconds to subtract from token expiration time */
+    jitter?: number
+  }) {
+    this.params.jitter = this.params.jitter ?? 5000
+  }
+
+  #cache: OauthState | null = null
+  async readOauthState() {
+    if (this.#cache) return this.#cache
+    const value = await this.params.storage.read()
+    if (!value) return null
+
+    return OauthState.parse(JSON.parse(value))
+  }
+
+  async writeOauthState(value: OauthState) {
+    this.#cache = value
+    await this.params.storage.write(JSON.stringify(value))
+  }
+
+  async getAccessToken() {
+    const state = await this.readOauthState()
+    if (!state) return null
+
+    if (state.expiresAt < Date.now() + this.params.jitter!) {
+      if (!state.refreshToken) return null
+      const { accessToken, refreshToken, expiresIn } = await this.params.refreshToken(state.refreshToken)
+      await this.writeOauthState({
+        accessToken,
+        refreshToken,
+        expiresAt: Date.now() + expiresIn * 1000,
+      })
+      return accessToken
+    }
+
+    return state.accessToken
+  }
+}