fix: Include bucketRootPath in AWS publisher for Techdocs

Signed-off-by: aarontsharp <aaron.sharp@carta.com>

.changeset/big-spies-check.md

@@ -0,0 +1,5 @@
+---
+'@backstage/plugin-techdocs-node': patch
+---
+
+Fix Techdocs S3 publisher to include bucketRootPath in requests. Currently, requests made to S3 are omitting this path and fail with a 404

plugins/techdocs-node/src/stages/publish/awsS3.test.ts

@@ -537,13 +537,13 @@ describe('AwsS3Publish', () => {
       app = express().use(publisher.docsRouter());
 
       const pngResponse = await request(app).get(
-        `/${rootPath}/${entityTripletPath}/img/with%20spaces.png`,
+        `/${entityTripletPath}/img/with%20spaces.png`,
       );
       expect(Buffer.from(pngResponse.body).toString('utf8')).toEqual(
         'found it',
       );
       const jsResponse = await request(app).get(
-        `/${rootPath}/${entityTripletPath}/some%20folder/also%20with%20spaces.js`,
+        `/${entityTripletPath}/some%20folder/also%20with%20spaces.js`,
       );
       expect(jsResponse.text).toEqual('found it too');
     });
@@ -558,13 +558,13 @@ describe('AwsS3Publish', () => {
       app = express().use(publisher.docsRouter());
 
       const pngResponse = await request(app).get(
-        `/${rootPath}/${entityTripletPath}/img/with%20spaces.png`,
+        `/${entityTripletPath}/img/with%20spaces.png`,
       );
       expect(Buffer.from(pngResponse.body).toString('utf8')).toEqual(
         'found it',
       );
       const jsResponse = await request(app).get(
-        `/${rootPath}/${entityTripletPath}/some%20folder/also%20with%20spaces.js`,
+        `/${entityTripletPath}/some%20folder/also%20with%20spaces.js`,
       );
       expect(jsResponse.text).toEqual('found it too');
     });

plugins/techdocs-node/src/stages/publish/awsS3.ts

@@ -370,19 +370,14 @@ export class AwsS3Publish implements PublisherBase {
    */
   docsRouter(): express.Handler {
     return async (req, res) => {
-      // Decode and trim the leading forward slash
       const decodedUri = decodeURI(req.path.replace(/^\//, ''));
 
-      // Root path is removed from the Uri so that legacy casing can be applied
-      // to the entity triplet without manipulating the root path
-      const decodedUriNoRoot = path.relative(this.bucketRootPath, decodedUri);
-
       // filePath example - /default/component/documented-component/index.html
       const filePathNoRoot = this.legacyPathCasing
-        ? decodedUriNoRoot
-        : lowerCaseEntityTripletInStoragePath(decodedUriNoRoot);
+        ? decodedUri
+        : lowerCaseEntityTripletInStoragePath(decodedUri);
 
-      // Re-prepend the root path to the relative file path
+      // Prepend the root path to the relative file path
       const filePath = path.posix.join(this.bucketRootPath, filePathNoRoot);
 
       // Files with different extensions (CSS, HTML) need to be served with different headers