Edge Developer Platform

Edge Functions
- Overview
- Getting Started
- Operation Guide
  - Function Management
  - Web Debugging
  - Function Trigger
  - Environment Variable
- Runtime APIs
  - addEventListener
  - Cache
  - Cookies
  - Encoding
  - Fetch
  - FetchEvent
  - Headers
  - Request
  - Response
  - Streams
    - ReadableStream
    - ReadableStreamBYOBReader
    - ReadableStreamDefaultReader
    - TransformStream
    - WritableStream
    - WritableStreamDefaultWriter
  - Web Crypto
  - Web standards
  - Images
    - ImageProperties
- Sample Functions
  - Example Overview
  - 301 Redirect
  - Obtaining Client URL Information
  - Customization Based on Client Geo Location
  - Obtaining Client Geo Location Information
  - Batch Redirect
  - Returning an HTML Page
  - Returning a JSON Object
  - Fetch Remote Resources
  - Authenticating a Request Header
  - Modifying a Response Header
  - Performing an A/B Test
  - Setting Cookies
  - Performing Redirect Based on the Request Location
  - Using the Cache API
  - Caching POST Requests
  - Responding in Streaming Mode
  - Merging Resources and Responding in Streaming Mode
  - Protecting Data from Tampering
  - Rewriting a m3u8 File and Configuring Authentication
  - Adaptive Image Resize
  - Image Adaptive WebP
  - Customize Referer restriction rules
  - Remote Authentication
  - HMAC Digital Signature
  - Naming a Downloaded File
  - Obtaining Client IP Address
- Best Practices
  - Adaptive Image Format Conversion via Edge Functions

Authenticating a Request Header

This example demonstrates how to use an edge function to perform simple permission control by verifying the value of the x-custom-token request header. If the value is token-123456, access is allowed. Otherwise, access is denied.
Sample Code
async function handleRequest(request) {
  const token = request.headers.get('x-custom-token');
﻿
  if (token === 'token-123456') {
    return new Response('hello world');
  }
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  // Incorrect key supplied. Reject the request.
  return new Response('Sorry, you have supplied an invalid token.', {
    status: 403,
  });
}
﻿
addEventListener('fetch', event => {
  event.respondWith(handleRequest(event.request));
});
Sample Preview
In the address bar of the browser, enter a URL that matches a trigger rule of the edge function to preview the effect of the sample code.
If authentication fails, access is denied.
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If authentication is successful, access is allowed.
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References
Runtime APIs: Headers
Runtime APIs: Response