R2 设计模式

# R2 模式与最佳实践 ## 流式传输大文件 typescript const object = await env.MY_BUCKET.get(key); if (!object) return new Response('Not found', { status: 404 }); const headers = new Headers(); object.writeHttpMetadata(headers); headers.set('etag', object.httpEtag); return new Response(object.body, { headers }); ## 条件 GET (304 Not Modified) typescript const ifNoneMatch = request.headers.get('if-none-match'); const object = await env.MY_BUCKET.get(key, { onlyIf: { etagDoesNotMatch: ifNoneMatch?.replace(/"/g, '') || '' } }); if (!object) return new Response('Not found', { status: 404 }); if (!object.body) return new Response(null, { status: 304, headers: { 'etag': object.httpEtag } }); return new Response(object.body, { headers: { 'etag': object.httpEtag } }); ## 带验证的上传 typescript const key = url.pathname.slice(1); if (!key || key.includes('..')) return new Response('Invalid key', { status: 400 }); const object = await env.MY_BUCKET.put(key, request.body, { httpMetadata: { contentType: request.headers.get('content-type') || 'application/octet-stream' }, customMetadata: { uploadedAt: new Date().toISOString(), ip: request.headers.get('cf-connecting-ip') || 'unknown' } }); return Response.json({ key: object.key, size: object.size, etag: object.httpEtag }); ## 带进度的分片上传 typescript const PART_SIZE = 5 * 1024 * 1024; // 5MB const partCount = Math.ceil(file.size / PART_SIZE); const multipart = await env.MY_BUCKET.createMultipartUpload(key, { httpMetadata: { contentType: file.type } }); const uploadedParts: R2UploadedPart[] = []; try { for (let i = 0; i 0) { await env.MY_BUCKET.delete(listed.objects.map(o => o.key)); } truncated = listed.truncated; cursor = listed.cursor; } } ## 校验和验证与存储转换 t