feat(provide-origin-from-env): introduce origin provider function for ssr

Author: mumenthalers

libs/core/src/lib/origin/provide-origin-from-env.function.spec.ts

@@ -0,0 +1,54 @@
+import { PLATFORM_ID } from '@angular/core'
+import { provideOriginFromEnv } from './provide-origin-from-env.function'
+import { ORIGIN } from './origin.token'
+import { TestBed } from '@angular/core/testing'
+
+describe('provideOriginFromEnv', () => {
+  const ENV_KEY = 'TEST_ORIGIN'
+
+  let originalEnv: NodeJS.ProcessEnv
+
+  beforeEach(() => {
+    originalEnv = { ...process.env }
+  })
+
+  afterEach(() => {
+    process.env = originalEnv
+  })
+
+  function setup(platformId: 'browser' | 'server') {
+    TestBed.configureTestingModule({
+      providers: [{ provide: PLATFORM_ID, useValue: platformId }, provideOriginFromEnv(ENV_KEY)],
+    })
+  }
+
+  it('should provide the ORIGIN token with a valid origin from env', () => {
+    setup('server')
+
+    const validOrigin = 'https://example.valid.com'
+
+    process.env[ENV_KEY] = validOrigin
+
+    expect(TestBed.inject(ORIGIN)).toBe(validOrigin)
+  })
+
+  it('should throw if not running on the server', () => {
+    setup('browser')
+
+    process.env[ENV_KEY] = 'https://example.valid.com'
+
+    expect(() => TestBed.inject(ORIGIN)).toThrowError(`provideOriginFromEnv can only be used on the server`)
+  })
+
+  it('should throw if env var is not defined', () => {
+    setup('server')
+    delete process.env[ENV_KEY]
+    expect(() => TestBed.inject(ORIGIN)).toThrowError(`Env var ${ENV_KEY} needs to be defined`)
+  })
+
+  it('should throw if env var is not a valid origin', () => {
+    setup('server')
+    process.env[ENV_KEY] = 'invalid-origin'
+    expect(() => TestBed.inject(ORIGIN)).toThrowError(`Env var ${ENV_KEY} is not a valid origin: invalid-origin`)
+  })
+})

libs/core/src/lib/origin/provide-origin-from-env.function.ts

@@ -0,0 +1,32 @@
+import { inject, PLATFORM_ID, Provider } from '@angular/core'
+import { ORIGIN } from './origin.token'
+import { isPlatformServer } from '@angular/common'
+
+declare const process: { env: Record<string, undefined | string> }
+
+/**
+ * Provides the {@link ORIGIN} token from the environment variable.
+ */
+export function provideOriginFromEnv(key: string): Provider[] {
+  return [
+    {
+      provide: ORIGIN,
+      useFactory: () => {
+        if (!isPlatformServer(inject(PLATFORM_ID))) {
+          throw new Error(`${provideOriginFromEnv.name} can only be used on the server`)
+        }
+
+        const value = process.env[key]?.trim()
+        if (!value) {
+          throw new Error(`Env var ${key} needs to be defined`)
+        }
+        try {
+          new URL(value)
+          return value
+        } catch (error) {
+          throw new Error(`Env var ${key} is not a valid origin: ${value}`, { cause: error })
+        }
+      },
+    },
+  ]
+}

libs/core/src/public-api.ts

@@ -48,6 +48,7 @@ export * from './lib/logger/remote/with-remote-transport.function'
 // origin
 export * from './lib/origin/origin.token'
 export * from './lib/origin/ensure-origin.interceptor'
+export * from './lib/origin/provide-origin-from-env.function'
 
 // resize
 export * from './lib/resize/resize.service'