feat(storage): add shared R2 media proxy and orphan cleanup tooling for R2/Bunny

lib/r2-media-proxy.ts

@@ -0,0 +1,178 @@
+import { GetObjectCommand, type GetObjectCommandInput, type GetObjectCommandOutput } from '@aws-sdk/client-s3';
+import { Readable } from 'node:stream';
+import { NextResponse } from 'next/server';
+import { apiErrors } from '@/lib/api-response';
+import { r2Client, R2_BUCKET_NAME } from '@/lib/r2';
+
+type ProxyR2MediaOptions = {
+  request: Request;
+  key: string;
+  fallbackContentType: string;
+  cacheControl: string;
+  extraHeaders?: Record<string, string>;
+  notFoundLabel?: string;
+  internalErrorMessage: string;
+};
+
+type R2LikeError = {
+  name?: string;
+  Code?: string;
+  $metadata?: { httpStatusCode?: number };
+};
+
+function isStrongEtag(value: string): boolean {
+  return /^"[^"]+"$/.test(value);
+}
+
+function parseHttpDate(value: string): Date | null {
+  const parsed = new Date(value);
+  return Number.isNaN(parsed.getTime()) ? null : parsed;
+}
+
+function getErrorStatus(error: unknown): number | null {
+  const status = (error as R2LikeError | null | undefined)?.$metadata?.httpStatusCode;
+  return typeof status === 'number' ? status : null;
+}
+
+function isNotFoundError(error: unknown): boolean {
+  const err = error as R2LikeError | null | undefined;
+  return err?.name === 'NoSuchKey' || err?.Code === 'NoSuchKey' || getErrorStatus(error) === 404;
+}
+
+function isInvalidRangeError(error: unknown): boolean {
+  const err = error as R2LikeError | null | undefined;
+  return err?.name === 'InvalidRange' || err?.Code === 'InvalidRange' || getErrorStatus(error) === 416;
+}
+
+function isPreconditionFailed(error: unknown): boolean {
+  return getErrorStatus(error) === 412;
+}
+
+function toWebStream(body: unknown): ReadableStream<Uint8Array> | null {
+  if (!body) return null;
+
+  const withTransform = body as { transformToWebStream?: () => ReadableStream<Uint8Array> };
+  if (typeof withTransform.transformToWebStream === 'function') {
+    return withTransform.transformToWebStream();
+  }
+
+  if (body instanceof Readable) {
+    return Readable.toWeb(body) as ReadableStream<Uint8Array>;
+  }
+
+  if (body instanceof ReadableStream) {
+    return body;
+  }
+
+  return null;
+}
+
+function setIfPresent(headers: Headers, key: string, value: string | number | null | undefined): void {
+  if (value === undefined || value === null) return;
+  headers.set(key, String(value));
+}
+
+export async function proxyR2MediaObject({
+  request,
+  key,
+  fallbackContentType,
+  cacheControl,
+  extraHeaders,
+  notFoundLabel = 'File',
+  internalErrorMessage,
+}: ProxyR2MediaOptions): Promise<NextResponse> {
+  const range = request.headers.get('range');
+  const ifRange = request.headers.get('if-range');
+  const commandInput: GetObjectCommandInput = {
+    Bucket: R2_BUCKET_NAME,
+    Key: key,
+  };
+
+  let usedConditionalIfRange = false;
+  if (range) {
+    commandInput.Range = range;
+
+    if (ifRange) {
+      const token = ifRange.trim();
+      if (isStrongEtag(token)) {
+        commandInput.IfMatch = token;
+        usedConditionalIfRange = true;
+      } else {
+        const asDate = parseHttpDate(token);
+        if (asDate) {
+          commandInput.IfUnmodifiedSince = asDate;
+          usedConditionalIfRange = true;
+        }
+      }
+    }
+  }
+
+  let objectResponse: GetObjectCommandOutput;
+  try {
+    objectResponse = await r2Client.send(new GetObjectCommand(commandInput));
+  } catch (error) {
+    if (usedConditionalIfRange && range && isPreconditionFailed(error)) {
+      try {
+        objectResponse = await r2Client.send(
+          new GetObjectCommand({
+            Bucket: R2_BUCKET_NAME,
+            Key: key,
+          })
+        );
+      } catch (retryError) {
+        if (isNotFoundError(retryError)) {
+          return apiErrors.notFound(notFoundLabel);
+        }
+        if (isInvalidRangeError(retryError)) {
+          return new NextResponse(null, {
+            status: 416,
+            headers: {
+              'Cache-Control': cacheControl,
+              'Accept-Ranges': 'bytes',
+            },
+          });
+        }
+        console.error('Error proxying R2 object:', retryError);
+        return apiErrors.internalError(internalErrorMessage);
+      }
+    } else if (isNotFoundError(error)) {
+      return apiErrors.notFound(notFoundLabel);
+    } else if (isInvalidRangeError(error)) {
+      return new NextResponse(null, {
+        status: 416,
+        headers: {
+          'Cache-Control': cacheControl,
+          'Accept-Ranges': 'bytes',
+        },
+      });
+    } else {
+      console.error('Error proxying R2 object:', error);
+      return apiErrors.internalError(internalErrorMessage);
+    }
+  }
+
+  const stream = toWebStream(objectResponse.Body);
+  if (!stream) {
+    return apiErrors.internalError('Empty file');
+  }
+
+  const headers = new Headers();
+  setIfPresent(headers, 'Content-Type', objectResponse.ContentType || fallbackContentType);
+  setIfPresent(headers, 'Content-Length', objectResponse.ContentLength);
+  setIfPresent(headers, 'Content-Range', objectResponse.ContentRange);
+  setIfPresent(headers, 'ETag', objectResponse.ETag);
+  setIfPresent(headers, 'Last-Modified', objectResponse.LastModified?.toUTCString());
+  setIfPresent(headers, 'Accept-Ranges', objectResponse.AcceptRanges || 'bytes');
+  headers.set('Cache-Control', cacheControl);
+
+  if (extraHeaders) {
+    for (const [name, value] of Object.entries(extraHeaders)) {
+      headers.set(name, value);
+    }
+  }
+
+  return new NextResponse(stream, {
+    status: objectResponse.ContentRange ? 206 : 200,
+    headers,
+  });
+}