Added TokenProvider class

.semaphore/semaphore.yml

@@ -13,7 +13,8 @@ blocks:
         - name: prepare
           commands:
             - checkout
-            - nvm use $(cat .nvmrc) # semaphore does not use node version from .nvmrc for some reason
+            - nvm install $(cat .nvmrc)
+            - nvm use
             - cache restore node-modules-$SEMAPHORE_GIT_BRANCH-$(checksum package-lock.json),node-modules-$SEMAPHORE_GIT_BRANCH,node-modules-master
             - npm ci
             - cache store node-modules-$SEMAPHORE_GIT_BRANCH-$(checksum package-lock.json) node_modules
@@ -23,14 +24,16 @@ blocks:
         - name: lint
           commands:
             - checkout
-            - nvm use $(cat .nvmrc) # semaphore does not use node version from .nvmrc for some reason
+            - nvm install $(cat .nvmrc)
+            - nvm use
             - cache restore node-modules-$SEMAPHORE_GIT_BRANCH-$(checksum package-lock.json)
             - npm ci
             - npm run lint
         - name: test
           commands:
             - checkout
-            - nvm use $(cat .nvmrc) # semaphore does not use node version from .nvmrc for some reason
+            - nvm install $(cat .nvmrc)
+            - nvm use
             - cache restore node-modules-$SEMAPHORE_GIT_BRANCH-$(checksum package-lock.json)
             - npm ci
             - npm test

package.json

@@ -1,6 +1,6 @@
 {
   "name": "@ulms/api-clients",
-  "version": "5.13.1",
+  "version": "5.14.0",
   "description": "JavaScript API clients for ULMS platform",
   "keywords": [],
   "homepage": "https://github.com/foxford/ulms-api-clients-js#readme",

src/error.js

@@ -57,3 +57,26 @@ export class PresenceError extends Error {
     return new PresenceError(errorType)
   }
 }
+
+export class TokenProviderError extends Error {
+  constructor(...args) {
+    super(...args)
+
+    this.name = 'TokenProviderError'
+  }
+
+  static get types() {
+    return {
+      UNAUTHENTICATED: 'UNAUTHENTICATED',
+      NETWORK_ERROR: 'NETWORK_ERROR',
+      UNKNOWN_ERROR: 'UNKNOWN_ERROR',
+    }
+  }
+
+  static fromType(type) {
+    const errorType =
+      TokenProviderError.types[type] || TokenProviderError.types.UNKNOWN_ERROR
+
+    return new TokenProviderError(errorType)
+  }
+}

src/index.js

@@ -10,4 +10,5 @@ export { default as Presence } from './presence'
 export { default as PresenceWS } from './presence-ws'
 export { default as Telemetry } from './telemetry'
 export { default as Tenant } from './tenant'
+export { default as TokenProvider } from './token-provider'
 export { default as Portal } from './portal'

src/token-provider.js

@@ -0,0 +1,108 @@
+/* eslint-disable camelcase, promise/always-return */
+import { makeDeferred } from './common'
+import { TokenProviderError } from './error'
+
+class TokenProvider {
+  constructor(baseUrl, httpClient) {
+    this.baseUrl = baseUrl
+    this.context = undefined
+    this.httpClient = httpClient
+    this.tokenData = undefined
+    this.tokenP = undefined
+  }
+
+  setContext(context) {
+    this.context = context
+  }
+
+  getToken() {
+    if (this.tokenP) {
+      return this.tokenP.promise
+    }
+
+    const isTokenDataEmpty = !this.tokenData
+    const isAccessTokenExpired = isTokenDataEmpty
+      ? false
+      : Date.now() > this.tokenData.expires_ts
+
+    if (isTokenDataEmpty || isAccessTokenExpired) {
+      this.tokenP = makeDeferred()
+
+      this.fetchTokenData()
+        .then((response) => {
+          this.updateTokenData(response)
+          this.resolveAndReset()
+        })
+        .catch((error) => {
+          this.rejectAndReset(error)
+        })
+
+      return this.tokenP.promise
+    }
+
+    return Promise.resolve(this.tokenData.access_token)
+  }
+
+  fetchTokenData() {
+    const qs = this.context ? `?context=${this.context}` : ''
+    const url = `${this.baseUrl}/api/user/ulms_token${qs}`
+
+    return this.httpClient.post(url, undefined, { credentials: 'include' })
+  }
+
+  rejectAndReset(error) {
+    /*
+     * Errors
+     *
+     * - unrecoverable (нет смысла повторять запрос)
+     *   401 {"error":"Авторизуйтесь"} (когда разлогинился в админке или на портале)
+     *   401 {"error":"Войдите, пожалуйста, чтобы приступить к занятиям."} (когда указан неверный контекст для запроса)
+     *
+     * - network error
+     *   error instanceof TypeError && error.message.startsWith('Failed to fetch')
+     *     - отсутствует соединение с сетью
+     *     - ошибка CORS (внезапно ответ 200, но ошибка по заголовкам)
+     * */
+    let transformedError
+
+    if (
+      error instanceof TypeError &&
+      error.message.startsWith('Failed to fetch')
+    ) {
+      transformedError = TokenProviderError.fromType(
+        TokenProviderError.types.NETWORK_ERROR
+      )
+    } else if (error.error) {
+      transformedError = TokenProviderError.fromType(
+        TokenProviderError.types.UNAUTHENTICATED
+      )
+    } else {
+      transformedError = TokenProviderError.fromType(
+        TokenProviderError.types.UNKNOWN_ERROR
+      )
+    }
+
+    this.tokenP.reject(transformedError)
+
+    this.tokenP = undefined
+  }
+
+  resolveAndReset() {
+    this.tokenP.resolve(this.tokenData.access_token)
+
+    this.tokenP = undefined
+  }
+
+  updateTokenData(updates) {
+    const { expires_in } = updates
+    const expires_ts = Date.now() + expires_in * 1e3 - 3e3
+
+    this.tokenData = {
+      ...this.tokenData,
+      ...updates,
+      expires_ts,
+    }
+  }
+}
+
+export default TokenProvider