1.  
2. // Global variables
3. const jwkKey = '???'
4. const keyID = '???'
5. const videoID = '???'
6. // expiresTimeInS is the expired time in second of the video
7. const expiresTimeInS = 3600
8.  
9. // Main function
10. async function streamSignedUrl () {
11.   const encoder = new TextEncoder()
12.   const expiresIn = Math.floor(Date.now() / 1000) + expiresTimeInS
13.   const headers = {
14.     "alg": "RS256",
15.     "kid": keyID
16.   }
17.   const data = {
18.     "sub": videoID,
19.     "kid": keyID,
20.     "exp": expiresIn,
21.     "accessRules": [
22.       {
23.         "type": "ip.geoip.country",
24.         "action": "allow",
25.         "country": [
26.           "US"
27.         ]
28.       },
29.       {
30.         "type": "any",
31.         "action": "block"
32.       }
33.     ]
34.   }
35.  
36.   const token = `${objectToBase64url(headers)}.${objectToBase64url(data)}`
37.  
38.   const jwk = JSON.parse(atob(jwkKey))
39.  
40.   const key = await crypto.subtle.importKey(
41.     "jwk", jwk,
42.     {
43.       name: 'RSASSA-PKCS1-v1_5',
44.       hash: 'SHA-256',
45.     },
46.     false, [ "sign" ]
47.   )
48.  
49.   const signature = await crypto.subtle.sign(
50.     { name: 'RSASSA-PKCS1-v1_5' }, key,
51.     encoder.encode(token)
52.   )
53.  
54.   const signedToken = `${token}.${arrayBufferToBase64Url(signature)}`
55.  
56.   return signedToken
57. }
58.  
59. // Utilities functions
60. function arrayBufferToBase64Url(buffer) {
61.   return btoa(String.fromCharCode(...new Uint8Array(buffer)))
62.     .replace(/=/g, '')
63.     .replace(/\+/g, '-')
64.     .replace(/\//g, '_')
65. }
66.  
67. function objectToBase64url(payload) {
68.   return arrayBufferToBase64Url(
69.     new TextEncoder().encode(JSON.stringify(payload)),
70.   )
71. }
72.  
73. addEventListener('fetch', event => {
74.   event.respondWith(handleRequest(event.request))
75. })
76.  
77. /**
78.  * Respond to the request
79.  * @param {Request} request
80.  */
81. async function handleRequest(request) {
82.   const signedURL = await streamSignedUrl()
83.   return new Response(signedURL, {status: 200})
84. }
85.  
86.