Twitch Extensions 101
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The document provides an overview of Twitch Extensions presented at TwitchCon 2018, detailing their architecture, backend services, and communication methods. It addresses practical considerations for developers, including issues related to scaling, authorization using JSON Web Tokens (JWT), and common pitfalls. Additionally, it offers resources for getting started with Twitch Extensions and highlights the importance of best practices in development.
![createNewPoll(request) {
incomingToken = getJWT(request)
if not verifySignature(incomingToken, sharedSecret) {
return 401
}
if incomingToken["role"] != "broadcaster" {
return 403
}
questions = getPollQuestions(request)
poll = setupPoll(request)
outgoingToken = createAndSignJWT(
incomingToken["user_id"],
incomingToken["channel_id"],
sharedSecret)
sendPollOverPubsub(poll, outgoingToken)
}
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New Poll Backend
Example
// Extract JWT
// Check for proper signature
// Now that we trust the
// JWT, verify that the
// broadcaster requested this
// Construct a new JWT
// using our shared signature
// and use that JWT to
// authorize a broadcast
// over Twitch PubSub](https://image.slidesharecdn.com/n75ykjx9trbs59ju1bw1-signature-c2a497493ea34dd1d6f3789f4a804e2faf97e334ef8696f459ab553f94cb8413-poli-181113031751/85/Twitch-Extensions-101-15-320.jpg)
![Signed
{
"exp": 1484242525,
"user_id": "14900522",
"role": "external"
}
Signed with PubSub Broadcast to Channel
{
"exp": 1484242525,
"user_id": "14900522",
"role": "external",
"channel_id": “14900522",
"pubsub_perms": {
send: ["broadcast"]
}
}
Signed with PubSub Global
{
"exp": 1484242525,
"user_id": "14900522",
"role": "external",
"channel_id": "all",
"pubsub_perms": {
send: ["global"]
}
}
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Twitch Extensions 101
- 1. TwitchCon 2018 San Jose, California Greg Humphreys Extensions Tech Lead @deflatormouse7 Andy Morrell Dev Speedrunner @LuckyNoS7evin
- 3. TwitchCon 2018 San Jose, California What are Extensions?
- 6. TwitchCon 2018 San Jose, California Extension Architecture
- 7. TwitchCon 2018 San Jose, California Extension Architecture Extension Backend Service (EBS) /broadcast Twitch API Browser Extension Helper Iframe Twitch PubSub Twitch CDN Front-end Javascript / HTML
- 8. TwitchCon 2018 San Jose, California Viewer HTML
- 9. TwitchCon 2018 San Jose, California Viewer HTML
- 10. TwitchCon 2018 San Jose, California Configuration HTML
- 11. TwitchCon 2018 San Jose, California Live Dashboard HTML
- 12. TwitchCon 2018 San Jose, California Extension Communication Extension Viewer App EBS (hosted somewhere) Twitch PubSub Extension Viewer App Extension Viewer App Extension Viewer App State Updates (Broadcast, Websocket) User Actions (HTTP AJAX) State Updates (Twitch API)
- 13. TwitchCon 2018 San Jose, California Extension Authorization
- 14. TwitchCon 2018 San Jose, California JSON Web Tokens (JWT) Opaque User ID Channel ID Role Twitch User ID 1 2 3 4 Authorization & Per-User Data
- 15. createNewPoll(request) { incomingToken = getJWT(request) if not verifySignature(incomingToken, sharedSecret) { return 401 } if incomingToken["role"] != "broadcaster" { return 403 } questions = getPollQuestions(request) poll = setupPoll(request) outgoingToken = createAndSignJWT( incomingToken["user_id"], incomingToken["channel_id"], sharedSecret) sendPollOverPubsub(poll, outgoingToken) } 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 New Poll Backend Example // Extract JWT // Check for proper signature // Now that we trust the // JWT, verify that the // broadcaster requested this // Construct a new JWT // using our shared signature // and use that JWT to // authorize a broadcast // over Twitch PubSub
- 16. TwitchCon 2018 San Jose, California Practical Considerations and Common Mistakes Andy Morrell @LuckyNoS7evin
- 17. Pitfalls & Issues PRACTICAL CONSIDERATIONS & COMMON MISTAKES Scaling Include the Extension Helper Library - <script src="https://extension- files.twitch.tv/helper/v1/twitch- ext.min.js"></script> PubSub Rate Limits - 1 message per second, per channel - 1 message per second to “global” Secret Rotation - Please keep your EBS safe; rotate your secret every 12 hours - Previous secret still available for up to an hour Zip Assets - Wrong directory
- 18. TwitchCon 2018 San Jose, California iOS Support Join the Apple Developer Program, this is required for you Extension tp be on mobile iOS devices JSON Web Tokens (JWT) 4 Types of JWT, 6 variations User not Authenticated User Authenticated: - User Authenticated & Not Sharing User ID - User Authenticated & Sharing User ID Shared Pitfalls & Issues PRACTICAL CONSIDERATIONS & COMMON MISTAKES Broadcaster EBS - Signed - Signed with PubSub Broadcast to Channel - Signed with PubSub Global
- 19. Signed { "exp": 1484242525, "user_id": "14900522", "role": "external" } Signed with PubSub Broadcast to Channel { "exp": 1484242525, "user_id": "14900522", "role": "external", "channel_id": “14900522", "pubsub_perms": { send: ["broadcast"] } } Signed with PubSub Global { "exp": 1484242525, "user_id": "14900522", "role": "external", "channel_id": "all", "pubsub_perms": { send: ["global"] } } 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24
- 20. TwitchCon 2018 San Jose, California What is it for - Get your Extension up and running quickly, with faster iteration - A lot better than when there was no rig Developer Rig PRACTICAL CONSIDERATIONS & COMMON MISTAKES Where to get it - https://dev.twitch.tv/dashboard/extensions - https://github.com/twitchdev/developer-rig Prerequisites - Node - Yarn - Python 2 - Git
- 21. TwitchCon 2018 San Jose, California Scaling Bursty Traffic - Single or Multiple Channel; build to your needs - Multiple Channel ‣ Possible two million unique broadcasters a month ‣ Hundreds of thousands of requests in bursts Twitch AWS Program - https://dev.twitch.tv/extensions/aws My Architecture and Mistakes - Single server - Single application - Microservices PRACTICAL CONSIDERATIONS & COMMON MISTAKES
- 22. Other Talks To Attend - Get Your Extension Discovered - Rapid Prototyping Twitch Extensions - Monetize your Extension One Bit at a Time - Extension Design Patterns for Twitch Scale
- 23. Questions?