6.8 KiB
6.8 KiB
Cloudflare Workers Runtime APIs
Key runtime APIs for Workers development.
Fetch API
// Subrequest
const response = await fetch('https://api.example.com/data', {
method: 'POST',
headers: { 'Content-Type': 'application/json' },
body: JSON.stringify({ key: 'value' }),
cf: {
cacheTtl: 3600,
cacheEverything: true
}
});
const data = await response.json();
Headers API
// Read headers
const userAgent = request.headers.get('User-Agent');
// Cloudflare-specific
const country = request.cf?.country;
const colo = request.cf?.colo;
const clientIP = request.headers.get('CF-Connecting-IP');
// Set headers
const headers = new Headers();
headers.set('Content-Type', 'application/json');
headers.append('X-Custom-Header', 'value');
HTMLRewriter
export default {
async fetch(request: Request): Promise<Response> {
const response = await fetch(request);
return new HTMLRewriter()
.on('title', {
element(element) {
element.setInnerContent('New Title');
}
})
.on('a[href]', {
element(element) {
const href = element.getAttribute('href');
element.setAttribute('href', href.replace('http://', 'https://'));
}
})
.transform(response);
}
};
WebSockets
export default {
async fetch(request: Request): Promise<Response> {
const upgradeHeader = request.headers.get('Upgrade');
if (upgradeHeader !== 'websocket') {
return new Response('Expected WebSocket', { status: 426 });
}
const pair = new WebSocketPair();
const [client, server] = Object.values(pair);
server.accept();
server.addEventListener('message', (event) => {
server.send(`Echo: ${event.data}`);
});
return new Response(null, {
status: 101,
webSocket: client
});
}
};
Streams API
const { readable, writable } = new TransformStream();
const writer = writable.getWriter();
writer.write(new TextEncoder().encode('chunk 1'));
writer.write(new TextEncoder().encode('chunk 2'));
writer.close();
return new Response(readable, {
headers: { 'Content-Type': 'text/plain' }
});
Web Crypto API
// Generate hash
const data = new TextEncoder().encode('message');
const hashBuffer = await crypto.subtle.digest('SHA-256', data);
const hashArray = Array.from(new Uint8Array(hashBuffer));
const hashHex = hashArray.map(b => b.toString(16).padStart(2, '0')).join('');
// HMAC signature
const key = await crypto.subtle.importKey(
'raw',
new TextEncoder().encode('secret'),
{ name: 'HMAC', hash: 'SHA-256' },
false,
['sign', 'verify']
);
const signature = await crypto.subtle.sign('HMAC', key, data);
const valid = await crypto.subtle.verify('HMAC', key, signature, data);
// Random values
const randomBytes = crypto.getRandomValues(new Uint8Array(32));
const uuid = crypto.randomUUID();
Encoding APIs
// TextEncoder
const encoder = new TextEncoder();
const bytes = encoder.encode('Hello');
// TextDecoder
const decoder = new TextDecoder();
const text = decoder.decode(bytes);
// Base64
const base64 = btoa('Hello');
const decoded = atob(base64);
URL API
const url = new URL(request.url);
const hostname = url.hostname;
const pathname = url.pathname;
const search = url.search;
// Query parameters
const name = url.searchParams.get('name');
url.searchParams.set('page', '2');
url.searchParams.delete('old');
FormData API
// Parse form data
const formData = await request.formData();
const name = formData.get('name');
const file = formData.get('file');
// Create form data
const form = new FormData();
form.append('name', 'value');
form.append('file', blob, 'filename.txt');
Response Types
// Text
return new Response('Hello');
// JSON
return Response.json({ message: 'Hello' });
// Stream
return new Response(readable);
// Redirect
return Response.redirect('https://example.com', 302);
// Error
return new Response('Not Found', { status: 404 });
Request Cloning
// Clone for multiple reads
const clone = request.clone();
const body1 = await request.json();
const body2 = await clone.json();
AbortController
const controller = new AbortController();
const { signal } = controller;
setTimeout(() => controller.abort(), 5000);
try {
const response = await fetch('https://slow-api.com', { signal });
} catch (error) {
if (error.name === 'AbortError') {
console.log('Request timed out');
}
}
Scheduling APIs
// setTimeout
const timeoutId = setTimeout(() => {
console.log('Delayed');
}, 1000);
// setInterval
const intervalId = setInterval(() => {
console.log('Repeated');
}, 1000);
// Clear
clearTimeout(timeoutId);
clearInterval(intervalId);
Console API
console.log('Info message');
console.error('Error message');
console.warn('Warning message');
console.debug('Debug message');
// Structured logging
console.log(JSON.stringify({
level: 'info',
message: 'Request processed',
url: request.url,
timestamp: new Date().toISOString()
}));
Performance API
const start = performance.now();
await processRequest();
const duration = performance.now() - start;
console.log(`Processed in ${duration}ms`);
Bindings Reference
KV Operations
await env.KV.put(key, value, { expirationTtl: 3600, metadata: { userId: '123' } });
const value = await env.KV.get(key, 'json');
const { value, metadata } = await env.KV.getWithMetadata(key);
await env.KV.delete(key);
const list = await env.KV.list({ prefix: 'user:' });
D1 Operations
const result = await env.DB.prepare('SELECT * FROM users WHERE id = ?').bind(userId).first();
const { results } = await env.DB.prepare('SELECT * FROM users').all();
await env.DB.prepare('INSERT INTO users (name) VALUES (?)').bind(name).run();
await env.DB.batch([stmt1, stmt2, stmt3]);
R2 Operations
await env.R2.put(key, value, { httpMetadata: { contentType: 'image/jpeg' } });
const object = await env.R2.get(key);
await env.R2.delete(key);
const list = await env.R2.list({ prefix: 'uploads/' });
const multipart = await env.R2.createMultipartUpload(key);
Queue Operations
await env.QUEUE.send({ type: 'email', to: 'user@example.com' });
await env.QUEUE.sendBatch([{ body: msg1 }, { body: msg2 }]);
Workers AI
const response = await env.AI.run('@cf/meta/llama-3-8b-instruct', {
messages: [{ role: 'user', content: 'What is edge computing?' }]
});