declaratively disable external routes

Signed-off-by: Fredrik Adelöw <freben@gmail.com>

.changeset/famous-dodos-crash.md

@@ -0,0 +1,15 @@
+---
+'@backstage/core-app-api': minor
+'@backstage/frontend-app-api': patch
+---
+
+Allow for the disabling of external routes through config, which was rendered impossible after the introduction of default targets.
+
+```yaml
+app:
+  routes:
+    bindings:
+      # This has the effect of removing the button for registering new
+      # catalog entities in the scaffolder template list view
+      scaffolder.registerComponent: false
+```

packages/core-app-api/src/app/resolveRouteBindings.test.ts

@@ -194,4 +194,35 @@ describe('collectRouteIds', () => {
       'test.extRef': extRef,
     });
   });
+
+  it('can disable external routes that have defaults', () => {
+    const source = createExternalRouteRef({
+      id: 'test',
+      defaultTarget: 'test.target1',
+    });
+    const target1 = createRouteRef({ id: 'test' });
+    const plugin = createPlugin({
+      id: 'test',
+      routes: { target1 },
+      externalRoutes: { source },
+    });
+
+    // resolves normally with no config
+    let result = resolveRouteBindings(() => {}, new MockConfigApi({}), [
+      plugin,
+    ]);
+
+    expect(result.get(source)).toBe(target1);
+
+    // can be disabled
+    result = resolveRouteBindings(
+      () => {},
+      new MockConfigApi({
+        app: { routes: { bindings: { 'test.source': false } } },
+      }),
+      [plugin],
+    );
+
+    expect(result.get(source)).toBe(undefined);
+  });
 });

packages/core-app-api/src/app/resolveRouteBindings.ts

@@ -102,11 +102,12 @@ export function resolveRouteBindings(
   const bindings = config
     .getOptionalConfig('app.routes.bindings')
     ?.get<JsonObject>();
+  const disabledExternalRefs = new Set<ExternalRouteRef>();
   if (bindings) {
     for (const [externalRefId, targetRefId] of Object.entries(bindings)) {
-      if (typeof targetRefId !== 'string' || targetRefId === '') {
+      if (!isValidTargetRefId(targetRefId)) {
         throw new Error(
-          `Invalid config at app.routes.bindings['${externalRefId}'], value must be a non-empty string`,
+          `Invalid config at app.routes.bindings['${externalRefId}'], value must be a non-empty string or false`,
         );
       }
 
@@ -116,23 +117,27 @@ export function resolveRouteBindings(
           `Invalid config at app.routes.bindings, '${externalRefId}' is not a valid external route`,
         );
       }
-      if (result.has(externalRef)) {
-        continue;
-      }
-      const targetRef = routesById.routes.get(targetRefId);
-      if (!targetRef) {
-        throw new Error(
-          `Invalid config at app.routes.bindings['${externalRefId}'], '${targetRefId}' is not a valid route`,
-        );
-      }
 
-      result.set(externalRef, targetRef);
+      if (targetRefId === false) {
+        disabledExternalRefs.add(externalRef);
+
+        result.delete(externalRef);
+      } else if (!result.has(externalRef)) {
+        const targetRef = routesById.routes.get(targetRefId);
+        if (!targetRef) {
+          throw new Error(
+            `Invalid config at app.routes.bindings['${externalRefId}'], '${targetRefId}' is not a valid route`,
+          );
+        }
+
+        result.set(externalRef, targetRef);
+      }
     }
   }
 
   // Finally fall back to attempting to map defaults, at lowest priority
   for (const externalRef of routesById.externalRoutes.values()) {
-    if (!result.has(externalRef)) {
+    if (!result.has(externalRef) && !disabledExternalRefs.has(externalRef)) {
       const defaultRefId =
         'getDefaultTarget' in externalRef
           ? (externalRef.getDefaultTarget as () => string | undefined)()
@@ -148,3 +153,15 @@ export function resolveRouteBindings(
 
   return result;
 }
+
+function isValidTargetRefId(value: unknown): value is string | false {
+  if (value === false) {
+    return true;
+  }
+
+  if (typeof value === 'string' && value) {
+    return true;
+  }
+
+  return false;
+}

packages/frontend-app-api/src/routing/resolveRouteBindings.test.ts

@@ -161,4 +161,31 @@ describe('resolveRouteBindings', () => {
 
     expect(result.get(source)).toBe(target2);
   });
+
+  it('can disable external routes that have defaults', () => {
+    const source = createExternalRouteRef({ defaultTarget: 'target1' });
+    const target1 = createRouteRef();
+    const routesById = {
+      routes: new Map([['target1', target1]]),
+      externalRoutes: new Map([['source', source]]),
+    };
+
+    // resolves normally with no config
+    let result = resolveRouteBindings(
+      () => {},
+      new ConfigReader({}),
+      routesById,
+    );
+
+    expect(result.get(source)).toBe(target1);
+
+    // can be disabled
+    result = resolveRouteBindings(
+      () => {},
+      new ConfigReader({ app: { routes: { bindings: { source: false } } } }),
+      routesById,
+    );
+
+    expect(result.get(source)).toBe(undefined);
+  });
 });

packages/frontend-app-api/src/routing/resolveRouteBindings.ts

@@ -112,11 +112,12 @@ export function resolveRouteBindings(
   const bindings = config
     .getOptionalConfig('app.routes.bindings')
     ?.get<JsonObject>();
+  const disabledExternalRefs = new Set<ExternalRouteRef>();
   if (bindings) {
     for (const [externalRefId, targetRefId] of Object.entries(bindings)) {
-      if (typeof targetRefId !== 'string' || targetRefId === '') {
+      if (!isValidTargetRefId(targetRefId)) {
         throw new Error(
-          `Invalid config at app.routes.bindings['${externalRefId}'], value must be a non-empty string`,
+          `Invalid config at app.routes.bindings['${externalRefId}'], value must be a non-empty string or false`,
         );
       }
 
@@ -126,23 +127,27 @@ export function resolveRouteBindings(
           `Invalid config at app.routes.bindings, '${externalRefId}' is not a valid external route`,
         );
       }
-      if (result.has(externalRef)) {
-        continue;
-      }
-      const targetRef = routesById.routes.get(targetRefId);
-      if (!targetRef) {
-        throw new Error(
-          `Invalid config at app.routes.bindings['${externalRefId}'], '${targetRefId}' is not a valid route`,
-        );
-      }
 
-      result.set(externalRef, targetRef);
+      if (targetRefId === false) {
+        disabledExternalRefs.add(externalRef);
+
+        result.delete(externalRef);
+      } else if (!result.has(externalRef)) {
+        const targetRef = routesById.routes.get(targetRefId);
+        if (!targetRef) {
+          throw new Error(
+            `Invalid config at app.routes.bindings['${externalRefId}'], '${targetRefId}' is not a valid route`,
+          );
+        }
+
+        result.set(externalRef, targetRef);
+      }
     }
   }
 
   // Finally fall back to attempting to map defaults, at lowest priority
   for (const externalRef of routesById.externalRoutes.values()) {
-    if (!result.has(externalRef)) {
+    if (!result.has(externalRef) && !disabledExternalRefs.has(externalRef)) {
       const defaultRefId =
         toInternalExternalRouteRef(externalRef).getDefaultTarget();
       if (defaultRefId) {
@@ -156,3 +161,15 @@ export function resolveRouteBindings(
 
   return result;
 }
+
+function isValidTargetRefId(value: unknown): value is string | false {
+  if (value === false) {
+    return true;
+  }
+
+  if (typeof value === 'string' && value) {
+    return true;
+  }
+
+  return false;
+}