fix(common): warn if using supported CDN but not built-in loader

goldens/public-api/common/errors.md

@@ -15,6 +15,8 @@ export const enum RuntimeErrorCode {
     // (undocumented)
     LCP_IMG_MISSING_PRIORITY = 2955,
     // (undocumented)
+    MISSING_BUILTIN_LOADER = 2962,
+    // (undocumented)
     NG_FOR_MISSING_DIFFER = -2200,
     // (undocumented)
     OVERSIZED_IMAGE = 2960,

packages/common/src/directives/ng_optimized_image/image_loaders/cloudinary_loader.ts

@@ -6,7 +6,23 @@
  * found in the LICENSE file at https://angular.io/license
  */
 
-import {createImageLoader, ImageLoaderConfig} from './image_loader';
+import {createImageLoader, ImageLoaderConfig, ImageLoaderInfo} from './image_loader';
+
+/**
+ * Name and URL tester for Cloudinary.
+ */
+export const cloudinaryLoaderInfo: ImageLoaderInfo = {
+  name: 'Cloudinary',
+  testUrl: isCloudinaryUrl
+};
+
+const CLOUDINARY_LOADER_REGEX = /https?\:\/\/[^\/]+\.cloudinary\.com\/.+/;
+/**
+ * Tests whether a URL is from Cloudinary CDN.
+ */
+function isCloudinaryUrl(url: string): boolean {
+  return CLOUDINARY_LOADER_REGEX.test(url);
+}
 
 /**
  * Function that generates an ImageLoader for Cloudinary and turns it into an Angular provider.

packages/common/src/directives/ng_optimized_image/image_loaders/image_loader.ts

@@ -46,7 +46,15 @@ export type ImageLoader = (config: ImageLoaderConfig) => string;
  * @see `ImageLoader`
  * @see `NgOptimizedImage`
  */
-const noopImageLoader = (config: ImageLoaderConfig) => config.src;
+export const noopImageLoader = (config: ImageLoaderConfig) => config.src;
+
+/**
+ * Metadata about the image loader.
+ */
+export type ImageLoaderInfo = {
+  name: string,
+  testUrl: (url: string) => boolean
+};
 
 /**
  * Injection token that configures the image loader function.

packages/common/src/directives/ng_optimized_image/image_loaders/imagekit_loader.ts

@@ -6,7 +6,23 @@
  * found in the LICENSE file at https://angular.io/license
  */
 
-import {createImageLoader, ImageLoaderConfig} from './image_loader';
+import {createImageLoader, ImageLoaderConfig, ImageLoaderInfo} from './image_loader';
+
+/**
+ * Name and URL tester for ImageKit.
+ */
+export const imageKitLoaderInfo: ImageLoaderInfo = {
+  name: 'ImageKit',
+  testUrl: isImageKitUrl
+};
+
+const IMAGE_KIT_LOADER_REGEX = /https?\:\/\/[^\/]+\.imagekit\.io\/.+/;
+/**
+ * Tests whether a URL is from ImageKit CDN.
+ */
+function isImageKitUrl(url: string): boolean {
+  return IMAGE_KIT_LOADER_REGEX.test(url);
+}
 
 /**
  * Function that generates an ImageLoader for ImageKit and turns it into an Angular provider.

packages/common/src/directives/ng_optimized_image/image_loaders/imgix_loader.ts

@@ -6,7 +6,23 @@
  * found in the LICENSE file at https://angular.io/license
  */
 
-import {createImageLoader, ImageLoaderConfig} from './image_loader';
+import {createImageLoader, ImageLoaderConfig, ImageLoaderInfo} from './image_loader';
+
+/**
+ * Name and URL tester for Imgix.
+ */
+export const imgixLoaderInfo: ImageLoaderInfo = {
+  name: 'Imgix',
+  testUrl: isImgixUrl
+};
+
+const IMGIX_LOADER_REGEX = /https?\:\/\/[^\/]+\.imgix\.net\/.+/;
+/**
+ * Tests whether a URL is from Imgix CDN.
+ */
+function isImgixUrl(url: string): boolean {
+  return IMGIX_LOADER_REGEX.test(url);
+}
 
 /**
  * Function that generates an ImageLoader for Imgix and turns it into an Angular provider.

packages/common/src/directives/ng_optimized_image/ng_optimized_image.ts

@@ -12,7 +12,10 @@ import {RuntimeErrorCode} from '../../errors';
 import {isPlatformServer} from '../../platform_id';
 
 import {imgDirectiveDetails} from './error_helper';
-import {IMAGE_LOADER} from './image_loaders/image_loader';
+import {cloudinaryLoaderInfo} from './image_loaders/cloudinary_loader';
+import {IMAGE_LOADER, ImageLoader, noopImageLoader} from './image_loaders/image_loader';
+import {imageKitLoaderInfo} from './image_loaders/imagekit_loader';
+import {imgixLoaderInfo} from './image_loaders/imgix_loader';
 import {LCPImageObserver} from './lcp_image_observer';
 import {PreconnectLinkChecker} from './preconnect_link_checker';
 import {PreloadLinkCreator} from './preload-link-creator';
@@ -72,6 +75,9 @@ const ASPECT_RATIO_TOLERANCE = .1;
  */
 const OVERSIZED_IMAGE_TOLERANCE = 1000;
 
+/** Info about built-in loaders we can test for. */
+export const BUILT_IN_LOADERS = [imgixLoaderInfo, imageKitLoaderInfo, cloudinaryLoaderInfo];
+
 /**
  * A configuration object for the NgOptimizedImage directive. Contains:
  * - breakpoints: An array of integer breakpoints used to generate
@@ -385,6 +391,7 @@ export class NgOptimizedImage implements OnInit, OnChanges, OnDestroy {
       if (!this.ngSrcset) {
         assertNoComplexSizes(this);
       }
+      assertNotMissingBuiltInLoader(this.ngSrc, this.imageLoader);
       if (this.priority) {
         const checker = this.injector.get(PreconnectLinkChecker);
         checker.assertPreconnect(this.getRewrittenSrc(), this.ngSrc);
@@ -873,3 +880,35 @@ function assertValidLoadingInput(dir: NgOptimizedImage) {
             `To fix this, provide a valid value ("lazy", "eager", or "auto").`);
   }
 }
+
+/**
+ * Warns if NOT using a loader (falling back to the generic loader) and
+ * the image appears to be hosted on one of the image CDNs for which
+ * we do have a built-in image loader. Suggests switching to the
+ * built-in loader.
+ *
+ * @param ngSrc Value of the ngSrc attribute
+ * @param imageLoader ImageLoader provided
+ */
+function assertNotMissingBuiltInLoader(ngSrc: string, imageLoader: ImageLoader) {
+  if (imageLoader === noopImageLoader) {
+    let builtInLoaderName = '';
+    for (const loader of BUILT_IN_LOADERS) {
+      if (loader.testUrl(ngSrc)) {
+        builtInLoaderName = loader.name;
+        break;
+      }
+    }
+    if (builtInLoaderName) {
+      console.warn(formatRuntimeError(
+          RuntimeErrorCode.MISSING_BUILTIN_LOADER,
+          `NgOptimizedImage: It looks like your images may be hosted on the ` +
+              `${builtInLoaderName} CDN, but your app is not using Angular's ` +
+              `built-in loader for that CDN. We recommend switching to use ` +
+              `the built-in by calling \`provide${builtInLoaderName}Loader()\` ` +
+              `in your \`providers\` and passing it your instance's base URL. ` +
+              `If you don't want to use the built-in loader, define a custom ` +
+              `loader function using IMAGE_LOADER to silence this warning.`));
+    }
+  }
+}

packages/common/src/errors.ts

@@ -32,4 +32,5 @@ export const enum RuntimeErrorCode {
   INVALID_LOADER_ARGUMENTS = 2959,
   OVERSIZED_IMAGE = 2960,
   TOO_MANY_PRELOADED_IMAGES = 2961,
+  MISSING_BUILTIN_LOADER = 2962,
 }

packages/common/test/directives/ng_optimized_image_spec.ts

@@ -1097,6 +1097,56 @@ describe('Image directive', () => {
       expect(img.src).toBe(`${IMG_BASE_URL}/img.png`);
     });
 
+    it('should warn if there is no image loader but using Imgix URL', () => {
+      setUpModuleNoLoader();
+
+      const template = `<img ngSrc="https://some.imgix.net/img.png" width="100" height="50">`;
+      const fixture = createTestComponent(template);
+      const consoleWarnSpy = spyOn(console, 'warn');
+      fixture.detectChanges();
+
+      expect(consoleWarnSpy.calls.count()).toBe(1);
+      expect(consoleWarnSpy.calls.argsFor(0)[0])
+          .toMatch(/your images may be hosted on the Imgix CDN/);
+    });
+
+    it('should warn if there is no image loader but using ImageKit URL', () => {
+      setUpModuleNoLoader();
+
+      const template = `<img ngSrc="https://some.imagekit.io/img.png" width="100" height="50">`;
+      const fixture = createTestComponent(template);
+      const consoleWarnSpy = spyOn(console, 'warn');
+      fixture.detectChanges();
+
+      expect(consoleWarnSpy.calls.count()).toBe(1);
+      expect(consoleWarnSpy.calls.argsFor(0)[0])
+          .toMatch(/your images may be hosted on the ImageKit CDN/);
+    });
+
+    it('should warn if there is no image loader but using Cloudinary URL', () => {
+      setUpModuleNoLoader();
+
+      const template = `<img ngSrc="https://some.cloudinary.com/img.png" width="100" height="50">`;
+      const fixture = createTestComponent(template);
+      const consoleWarnSpy = spyOn(console, 'warn');
+      fixture.detectChanges();
+
+      expect(consoleWarnSpy.calls.count()).toBe(1);
+      expect(consoleWarnSpy.calls.argsFor(0)[0])
+          .toMatch(/your images may be hosted on the Cloudinary CDN/);
+    });
+
+    it('should NOT warn if there is a custom loader but using CDN URL', () => {
+      setupTestingModule();
+
+      const template = `<img ngSrc="https://some.cloudinary.com/img.png" width="100" height="50">`;
+      const fixture = createTestComponent(template);
+      const consoleWarnSpy = spyOn(console, 'warn');
+      fixture.detectChanges();
+
+      expect(consoleWarnSpy.calls.count()).toBe(0);
+    });
+
     it('should set `src` using the image loader provided via the `IMAGE_LOADER` token to compose src URL',
        () => {
          const imageLoader = (config: ImageLoaderConfig) => `${IMG_BASE_URL}/${config.src}`;
@@ -1526,6 +1576,16 @@ function setupTestingModule(config?: {
   });
 }
 
+// Same as above but explicitly doesn't provide a custom loader,
+// so the noopImageLoader should be used.
+function setUpModuleNoLoader() {
+  TestBed.configureTestingModule({
+    declarations: [TestComponent],
+    imports: [CommonModule, NgOptimizedImage],
+    providers: [{provide: DOCUMENT, useValue: window.document}]
+  });
+}
+
 function createTestComponent(template: string): ComponentFixture<TestComponent> {
   return TestBed.overrideComponent(TestComponent, {set: {template: template}})
       .createComponent(TestComponent);