refactor: replace components context in app

Signed-off-by: Camila Belo <camilaibs@gmail.com>

packages/frontend-app-api/src/apis/implementations/ComponentsApi/ComponentsApi.ts

@@ -28,7 +28,11 @@ export class DefaultComponentsApi implements ComponentsApi {
     this.#components = components;
   }
 
-  getComponent<T>(ref: ComponentRef<T>): T | undefined {
-    return this.#components.get(ref);
+  getComponent<T>(ref: ComponentRef<T>): T {
+    const impl = this.#components.get(ref);
+    if (!impl) {
+      throw new Error(`No implementation found for component ref ${ref}`);
+    }
+    return impl;
   }
 }

packages/frontend-app-api/src/extensions/Core.tsx

@@ -18,9 +18,7 @@ import {
   coreExtensionData,
   createExtension,
   createExtensionInput,
-  ComponentsProvider,
 } from '@backstage/frontend-plugin-api';
-import React from 'react';
 
 export const Core = createExtension({
   id: 'core',
@@ -46,20 +44,8 @@ export const Core = createExtension({
     root: coreExtensionData.reactElement,
   },
   factory({ inputs }) {
-    const components = inputs.components.reduce(
-      (rest, { component }) => ({
-        ...rest,
-        [component.ref.id]: component.impl,
-      }),
-      {},
-    );
-
     return {
-      root: (
-        <ComponentsProvider value={components}>
-          {inputs.root.element}
-        </ComponentsProvider>
-      ),
+      root: inputs.root.element,
     };
   },
 });

packages/frontend-app-api/src/extensions/CoreRoutes.tsx

@@ -20,7 +20,8 @@ import {
   coreExtensionData,
   createExtensionInput,
   coreNotFoundErrorPageComponentRef,
-  useComponent,
+  useApi,
+  componentsApiRef,
 } from '@backstage/frontend-plugin-api';
 import { useRoutes } from 'react-router-dom';
 
@@ -39,7 +40,10 @@ export const CoreRoutes = createExtension({
   },
   factory({ inputs }) {
     const Routes = () => {
-      const NotFoundErrorPage = useComponent(coreNotFoundErrorPageComponentRef);
+      const componentsApi = useApi(componentsApiRef);
+      const NotFoundErrorPage = componentsApi.getComponent(
+        coreNotFoundErrorPageComponentRef,
+      );
 
       const element = useRoutes([
         ...inputs.routes.map(route => ({

packages/frontend-app-api/src/wiring/createApp.tsx

@@ -21,11 +21,8 @@ import {
   appTreeApiRef,
   BackstagePlugin,
   ComponentRef,
-  coreBootErrorPageComponentRef,
-  coreErrorBoundaryFallbackComponentRef,
+  componentsApiRef,
   coreExtensionData,
-  coreNotFoundErrorPageComponentRef,
-  coreProgressComponentRef,
   ExtensionDataRef,
   ExtensionOverrides,
   RouteRef,
@@ -108,6 +105,7 @@ import { CoreRouter } from '../extensions/CoreRouter';
 import { toInternalBackstagePlugin } from '../../../frontend-plugin-api/src/wiring/createPlugin';
 // eslint-disable-next-line @backstage/no-relative-monorepo-imports
 import { toInternalExtensionOverrides } from '../../../frontend-plugin-api/src/wiring/createExtensionOverrides';
+import { DefaultComponentsApi } from '../apis/implementations/ComponentsApi';
 
 export const builtinExtensions = [
   Core,
@@ -319,7 +317,6 @@ export function createSpecializedApp(options?: {
     features.filter(
       (f): f is BackstagePlugin => f.$$type === '@backstage/BackstagePlugin',
     ),
-    tree.root,
   );
 
   const appIdentityProxy = new AppIdentityProxy();
@@ -375,49 +372,7 @@ export function createSpecializedApp(options?: {
   };
 }
 
-function createLegacyAppContext(
-  plugins: BackstagePlugin[],
-  core: AppNode,
-): AppContext {
-  const components = core.edges.attachments
-    .get('components')
-    ?.map(e => e.instance?.getData(coreExtensionData.component));
-
-  function getComponent<TRef extends ComponentRef<unknown>>(
-    ref: TRef,
-  ): TRef['T'] | undefined {
-    return components?.find(component => component?.ref.id === ref.id)?.impl;
-  }
-
-  const {
-    Progress: DefaultProgress,
-    BootErrorPage: DefaultBootErrorPage,
-    NotFoundErrorPage: DefaultNotFoundErrorPage,
-    ErrorBoundaryFallback: DefaultErrorBoundaryFallback,
-    ...rest
-  } = defaultComponents;
-
-  const CustomProgress = getComponent(coreProgressComponentRef);
-
-  const CustomBootErrorPage = getComponent(coreBootErrorPageComponentRef);
-
-  const CustomNotFoundErrorPage = getComponent(
-    coreNotFoundErrorPageComponentRef,
-  );
-
-  const CustomErrorBoundaryFallback = getComponent(
-    coreErrorBoundaryFallbackComponentRef,
-  );
-
-  const overriddenComponents = {
-    ...rest,
-    Progress: CustomProgress ?? DefaultProgress,
-    BootErrorPage: CustomBootErrorPage ?? DefaultBootErrorPage,
-    NotFoundErrorPage: CustomNotFoundErrorPage ?? DefaultNotFoundErrorPage,
-    ErrorBoundaryFallback:
-      CustomErrorBoundaryFallback ?? DefaultErrorBoundaryFallback,
-  };
-
+function createLegacyAppContext(plugins: BackstagePlugin[]): AppContext {
   return {
     getPlugins(): LegacyBackstagePlugin[] {
       return plugins.map(toLegacyPlugin);
@@ -434,7 +389,7 @@ function createLegacyAppContext(
     },
 
     getComponents(): AppComponents {
-      return overriddenComponents;
+      return defaultComponents;
     },
   };
 }
@@ -483,6 +438,24 @@ function createApiHolder(
     }),
   });
 
+  const componentsExtensions =
+    tree.root.edges.attachments
+      .get('components')
+      ?.map(e => e.instance?.getData(coreExtensionData.component))
+      .filter(x => !!x) ?? [];
+
+  const componentsMap = componentsExtensions.reduce(
+    (components, component) =>
+      component ? components.set(component.ref, component?.impl) : components,
+    new Map<ComponentRef<any>, any>(),
+  );
+
+  factoryRegistry.register('static', {
+    api: componentsApiRef,
+    deps: {},
+    factory: () => new DefaultComponentsApi(componentsMap),
+  });
+
   factoryRegistry.register('static', {
     api: appThemeApiRef,
     deps: {},

packages/frontend-plugin-api/api-report.md

@@ -13,6 +13,7 @@ import { AnyApiRef } from '@backstage/core-plugin-api';
 import { ApiFactory } from '@backstage/core-plugin-api';
 import { ApiHolder } from '@backstage/core-plugin-api';
 import { ApiRef } from '@backstage/core-plugin-api';
+import { ApiRef as ApiRef_2 } from '@backstage/core-plugin-api/src/apis/system/types';
 import { ApiRefConfig } from '@backstage/core-plugin-api';
 import { AppTheme } from '@backstage/core-plugin-api';
 import { AppThemeApi } from '@backstage/core-plugin-api';
@@ -26,7 +27,6 @@ import { BackstagePlugin as BackstagePlugin_2 } from '@backstage/core-plugin-api
 import { BackstageUserIdentity } from '@backstage/core-plugin-api';
 import { bitbucketAuthApiRef } from '@backstage/core-plugin-api';
 import { bitbucketServerAuthApiRef } from '@backstage/core-plugin-api';
-import { ComponentRef as ComponentRef_2 } from '@backstage/frontend-plugin-api';
 import { ComponentType } from 'react';
 import { ConfigApi } from '@backstage/core-plugin-api';
 import { configApiRef } from '@backstage/core-plugin-api';
@@ -293,15 +293,14 @@ export type ComponentRef<T> = {
   T: T;
 };
 
-// @public (undocumented)
-export type ComponentsContextValue = Record<string, ComponentType<any>>;
+// @public
+export interface ComponentsApi {
+  // (undocumented)
+  getComponent<T>(ref: ComponentRef<T>): T;
+}
 
-// @public (undocumented)
-export function ComponentsProvider(
-  props: PropsWithChildren<{
-    value: ComponentsContextValue;
-  }>,
-): React_2.JSX.Element;
+// @public
+export const componentsApiRef: ApiRef_2<ComponentsApi>;
 
 export { ConfigApi };
 
@@ -910,12 +909,6 @@ export { useApi };
 
 export { useApiHolder };
 
-// @public (undocumented)
-export function useComponent<
-  P extends {},
-  T extends ComponentRef_2<ComponentType<P>>,
->(ref: T): T['T'];
-
 // @public
 export function useRouteRef<
   TOptional extends boolean,

packages/frontend-plugin-api/src/apis/definitions/ComponentsApi.ts

@@ -24,7 +24,7 @@ import { createApiRef } from '../system';
  */
 export interface ComponentsApi {
   // TODO: Should component refs also provide the default implementation so that we're guaranteed to get a component?
-  getComponent<T>(ref: ComponentRef<T>): T | undefined;
+  getComponent<T>(ref: ComponentRef<T>): T;
 }
 
 /**

packages/frontend-plugin-api/src/components/ComponentsContext.tsx

@@ -1,58 +0,0 @@
-/*
- * Copyright 2023 The Backstage Authors
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-import { ComponentRef } from '@backstage/frontend-plugin-api';
-import {
-  createVersionedContext,
-  createVersionedValueMap,
-  useVersionedContext,
-} from '@backstage/version-bridge';
-import React from 'react';
-import { ComponentType, PropsWithChildren } from 'react';
-
-/** @public */
-export type ComponentsContextValue = Record<string, ComponentType<any>>;
-
-const ComponentsContext = createVersionedContext<{ 1: ComponentsContextValue }>(
-  'components-context',
-);
-
-/** @public */
-export function ComponentsProvider(
-  props: PropsWithChildren<{ value: ComponentsContextValue }>,
-) {
-  const { value, children } = props;
-  return (
-    <ComponentsContext.Provider value={createVersionedValueMap({ 1: value })}>
-      {children}
-    </ComponentsContext.Provider>
-  );
-}
-
-/** @public */
-export function useComponent<
-  P extends {},
-  T extends ComponentRef<ComponentType<P>>,
->(ref: T): T['T'] {
-  const components = useVersionedContext<{ 1: ComponentsContextValue }>(
-    'components-context',
-  );
-  const component = components?.atVersion(1)?.[ref.id];
-  if (!component) {
-    throw new Error(`No implementation available for ${ref.id}`);
-  }
-  return component;
-}

packages/frontend-plugin-api/src/components/index.ts

@@ -14,12 +14,6 @@
  * limitations under the License.
  */
 
-export {
-  ComponentsProvider,
-  useComponent,
-  type ComponentsContextValue,
-} from './ComponentsContext';
-
 export {
   coreProgressComponentRef,
   coreBootErrorPageComponentRef,