Modified Workers Binding Server to include R2 object tools and more options for R2 bucket tools.

Author: aninibread

apps/workers-bindings/src/bindings.app.ts

@@ -18,6 +18,7 @@ import { registerDocsTools } from '@repo/mcp-common/src/tools/docs-ai-search.too
 import { registerHyperdriveTools } from '@repo/mcp-common/src/tools/hyperdrive.tools'
 import { registerKVTools } from '@repo/mcp-common/src/tools/kv_namespace.tools'
 import { registerR2BucketTools } from '@repo/mcp-common/src/tools/r2_bucket.tools'
+import { registerR2ObjectTools } from '@repo/mcp-common/src/tools/r2_object.tools'
 import { registerWorkersTools } from '@repo/mcp-common/src/tools/worker.tools'
 import { MetricsTracker } from '@repo/mcp-observability'
 
@@ -79,6 +80,7 @@ export class WorkersBindingsMCP extends McpAgent<Env, WorkersBindingsMCPState, P
 		registerKVTools(this)
 		registerWorkersTools(this)
 		registerR2BucketTools(this)
+		registerR2ObjectTools(this)
 		registerD1Tools(this)
 		registerHyperdriveTools(this)
 

packages/mcp-common/package.json

@@ -19,6 +19,7 @@
 		"agents": "0.2.19",
 		"cloudflare": "4.2.0",
 		"hono": "4.7.6",
+		"mime": "4.0.6",
 		"toucan-js": "4.1.1",
 		"zod": "3.24.2"
 	},

packages/mcp-common/src/r2-api.ts

@@ -0,0 +1,327 @@
+/**
+ * R2 Object API helpers for interacting with R2 objects via the Cloudflare REST API.
+ * These functions handle raw object content (not JSON) which the Cloudflare SDK doesn't support.
+ */
+import { env } from 'cloudflare:workers'
+
+const CLOUDFLARE_API_BASE_URL = 'https://api.cloudflare.com/client/v4'
+
+/**
+ * Helper to get the API token, respecting dev mode
+ */
+function getApiToken(apiToken: string): string {
+	// @ts-expect-error We don't have actual env in this package
+	if (env.DEV_DISABLE_OAUTH) {
+		// @ts-expect-error We don't have actual env in this package
+		return env.DEV_CLOUDFLARE_API_TOKEN
+	}
+	return apiToken
+}
+
+/**
+ * R2 object metadata returned from get operations
+ */
+export interface R2ObjectMetadata {
+	key: string
+	size: number
+	etag: string
+	httpMetadata: {
+		contentType?: string
+		contentEncoding?: string
+		contentDisposition?: string
+		contentLanguage?: string
+		cacheControl?: string
+		expires?: string
+	}
+	customMetadata: Record<string, string>
+	uploaded: string
+	storageClass: string
+}
+
+/**
+ * Result of an R2 object GET operation
+ */
+export interface R2ObjectGetResult {
+	metadata: R2ObjectMetadata
+	content: string
+	isBase64: boolean
+}
+
+/**
+ * Fetches an R2 object content and metadata
+ */
+export async function fetchR2ObjectGet({
+	accountId,
+	bucketName,
+	objectKey,
+	apiToken,
+	jurisdiction,
+	maxSizeBytes,
+}: {
+	accountId: string
+	bucketName: string
+	objectKey: string
+	apiToken: string
+	jurisdiction?: string
+	maxSizeBytes?: number
+}): Promise<R2ObjectGetResult | null> {
+	const url = `${CLOUDFLARE_API_BASE_URL}/accounts/${accountId}/r2/buckets/${bucketName}/objects/${encodeURIComponent(objectKey)}`
+
+	const headers: Record<string, string> = {
+		Authorization: `Bearer ${getApiToken(apiToken)}`,
+	}
+
+	if (jurisdiction) {
+		headers['cf-r2-jurisdiction'] = jurisdiction
+	}
+
+	const response = await fetch(url, {
+		method: 'GET',
+		headers,
+	})
+
+	if (response.status === 404) {
+		return null
+	}
+
+	if (!response.ok) {
+		const error = await response.text()
+		throw new Error(`R2 GET request failed: ${error}`)
+	}
+
+	const metadata = parseR2ObjectMetadata(objectKey, response.headers)
+
+	// Check size limit
+	if (maxSizeBytes && metadata.size > maxSizeBytes) {
+		throw new Error(
+			`Object size (${metadata.size} bytes) exceeds maximum allowed size (${maxSizeBytes} bytes)`
+		)
+	}
+
+	// Get content and determine if it should be base64 encoded
+	const contentType = metadata.httpMetadata.contentType || 'application/octet-stream'
+	const isTextContent = isTextContentType(contentType)
+
+	let content: string
+	let isBase64: boolean
+
+	if (isTextContent) {
+		content = await response.text()
+		isBase64 = false
+	} else {
+		const arrayBuffer = await response.arrayBuffer()
+		content = arrayBufferToBase64(arrayBuffer)
+		isBase64 = true
+	}
+
+	return { metadata, content, isBase64 }
+}
+
+/**
+ * Uploads an R2 object
+ */
+export async function fetchR2ObjectPut({
+	accountId,
+	bucketName,
+	objectKey,
+	apiToken,
+	content,
+	jurisdiction,
+	storageClass,
+	contentType,
+	contentEncoding,
+	contentDisposition,
+	contentLanguage,
+	cacheControl,
+	expires,
+}: {
+	accountId: string
+	bucketName: string
+	objectKey: string
+	apiToken: string
+	content: BodyInit
+	jurisdiction?: string
+	storageClass?: string
+	contentType?: string
+	contentEncoding?: string
+	contentDisposition?: string
+	contentLanguage?: string
+	cacheControl?: string
+	expires?: string
+}): Promise<{ key: string; uploaded: string }> {
+	const url = `${CLOUDFLARE_API_BASE_URL}/accounts/${accountId}/r2/buckets/${bucketName}/objects/${encodeURIComponent(objectKey)}`
+
+	const headers: Record<string, string> = {
+		Authorization: `Bearer ${getApiToken(apiToken)}`,
+	}
+
+	if (jurisdiction) {
+		headers['cf-r2-jurisdiction'] = jurisdiction
+	}
+	if (storageClass) {
+		headers['cf-r2-storage-class'] = storageClass
+	}
+	if (contentType) {
+		headers['Content-Type'] = contentType
+	}
+	if (contentEncoding) {
+		headers['Content-Encoding'] = contentEncoding
+	}
+	if (contentDisposition) {
+		headers['Content-Disposition'] = contentDisposition
+	}
+	if (contentLanguage) {
+		headers['Content-Language'] = contentLanguage
+	}
+	if (cacheControl) {
+		headers['Cache-Control'] = cacheControl
+	}
+	if (expires) {
+		headers['Expires'] = expires
+	}
+
+	const response = await fetch(url, {
+		method: 'PUT',
+		headers,
+		body: content,
+	})
+
+	if (!response.ok) {
+		const error = await response.text()
+		throw new Error(`R2 PUT request failed: ${error}`)
+	}
+
+	return {
+		key: objectKey,
+		uploaded: new Date().toISOString(),
+	}
+}
+
+/**
+ * Deletes an R2 object
+ */
+export async function fetchR2ObjectDelete({
+	accountId,
+	bucketName,
+	objectKey,
+	apiToken,
+	jurisdiction,
+}: {
+	accountId: string
+	bucketName: string
+	objectKey: string
+	apiToken: string
+	jurisdiction?: string
+}): Promise<unknown> {
+	const url = `${CLOUDFLARE_API_BASE_URL}/accounts/${accountId}/r2/buckets/${bucketName}/objects/${encodeURIComponent(objectKey)}`
+
+	const headers: Record<string, string> = {
+		Authorization: `Bearer ${getApiToken(apiToken)}`,
+	}
+
+	if (jurisdiction) {
+		headers['cf-r2-jurisdiction'] = jurisdiction
+	}
+
+	const response = await fetch(url, {
+		method: 'DELETE',
+		headers,
+	})
+
+	if (!response.ok) {
+		const error = await response.text()
+		throw new Error(`R2 DELETE request failed: ${error}`)
+	}
+
+	const result = (await response.json()) as { success: boolean; errors?: Array<{ code: number; message: string }> }
+
+	if (!result.success) {
+		const errorMessage = result.errors?.[0]?.message ?? 'Unknown error'
+		throw new Error(errorMessage)
+	}
+
+	return result
+}
+
+/**
+ * Parse R2 object metadata from response headers
+ */
+function parseR2ObjectMetadata(objectKey: string, headers: Headers): R2ObjectMetadata {
+	const customMetadata: Record<string, string> = {}
+
+	// Extract custom metadata from x-amz-meta-* headers
+	headers.forEach((value, key) => {
+		if (key.toLowerCase().startsWith('x-amz-meta-')) {
+			const metaKey = key.slice('x-amz-meta-'.length)
+			customMetadata[metaKey] = value
+		}
+	})
+
+	return {
+		key: objectKey,
+		size: parseInt(headers.get('content-length') || '0', 10),
+		etag: headers.get('etag') || '',
+		httpMetadata: {
+			contentType: headers.get('content-type') || undefined,
+			contentEncoding: headers.get('content-encoding') || undefined,
+			contentDisposition: headers.get('content-disposition') || undefined,
+			contentLanguage: headers.get('content-language') || undefined,
+			cacheControl: headers.get('cache-control') || undefined,
+			expires: headers.get('expires') || undefined,
+		},
+		customMetadata,
+		uploaded: headers.get('last-modified') || new Date().toISOString(),
+		storageClass: headers.get('x-amz-storage-class') || 'Standard',
+	}
+}
+
+/**
+ * Check if a content type is text-based
+ */
+function isTextContentType(contentType: string): boolean {
+	const textTypes = [
+		'text/',
+		'application/json',
+		'application/xml',
+		'application/javascript',
+		'application/typescript',
+		'application/x-www-form-urlencoded',
+		'application/xhtml+xml',
+		'application/x-yaml',
+		'application/yaml',
+		'application/toml',
+		'application/graphql',
+		'application/ld+json',
+		'application/manifest+json',
+		'application/schema+json',
+		'application/sql',
+		'application/x-sh',
+	]
+
+	const lowerContentType = contentType.toLowerCase()
+	return textTypes.some((type) => lowerContentType.startsWith(type))
+}
+
+/**
+ * Convert ArrayBuffer to base64 string
+ */
+function arrayBufferToBase64(buffer: ArrayBuffer): string {
+	const bytes = new Uint8Array(buffer)
+	let binary = ''
+	for (let i = 0; i < bytes.length; i++) {
+		binary += String.fromCharCode(bytes[i])
+	}
+	return btoa(binary)
+}
+
+/**
+ * Convert base64 string to Uint8Array
+ */
+export function base64ToUint8Array(base64: string): Uint8Array {
+	const binary = atob(base64)
+	const bytes = new Uint8Array(binary.length)
+	for (let i = 0; i < binary.length; i++) {
+		bytes[i] = binary.charCodeAt(i)
+	}
+	return bytes
+}