The Wonderful World of Webhooks

This talk was presented at OSCON Europe 2016

Transcript

1. The Wonderful World of Webhooks Lorna Mitchell, IBM Analytics OSCON London, October 2016
2. Webhooks in the Wild Webhooks power: • slack notifications • continuous integration services • other integrations @lornajane
3. How APIs Work @lornajane
4. How APIs Work @lornajane
5. How APIs Work @lornajane
6. How Webhooks Work @lornajane
7. How Webhooks Work @lornajane
8. How Webhooks Work @lornajane
9. What About Time? @lornajane
10. APIs Over Time @lornajane
11. Webhooks Over Time @lornajane
12. Webhooks Require PreArrangement @lornajane
13. Designing Webhooks @lornajane
14. Webhooks in the Wild: GitHub "ref": "refs/heads/master", "before": "1ae6a404351cead52df24893621d82ba6ec84a1c", "after": "e8474d83985330fa36f8862b37ca84ada4313392", "created": false, "deleted": false, "forced": false, "compare": "https://github.com/lornajane/demo/compare/1ae6a404351c...e847 "commits": [ ... ], "repository": { ... }, "pusher": { ... }, "sender": { ... } @lornajane
15. Designing Webhooks Consider the use cases: • try to include all information for common outcomes • consider impact of payload size vs potentially many followup API calls @lornajane
16. Webhooks in your Applications @lornajane
17. Receiving Webhooks It's just a POST request! Advice: • DO: accept, store and acknowledge quickly • DON'T: validate or process before acknowledging @lornajane
18. Storing Data Simplest queue can go in your database! • an ID • the payload that came in (extract fields to search on) • a status field (new/processed/failed) A cron job to work through what needs doing and update the status field. @lornajane
19. Storing Data @lornajane
20. Storing Data @lornajane
21. Storing Data If you outgrow the database method, use a queue. • e.g. RabbitMQ, Beanstalkd, Gearman • easy way to link many workers with work to do @lornajane
22. Publishing Webhooks Offering webhook integrations is ideal if: • you have clients polling your API a lot • it's common for another system to react to changes in your system • you want to offer notifications for specific events • any of the above apply either internally or externally @lornajane
23. Example App: Retro Guestbook In the olden days, we had guestbooks on our websites. • Allow user to leave their name and a comment • Show the comments left so far • Include webhook management for notifications of new comments @lornajane
24. Example App: Retro Guestbook @lornajane
25. Saving Data: Basic Process @lornajane
26. Saving Data: Handling Webhooks @lornajane
27. Saving Data: Handling Webhooks @lornajane
28. Saving Data: Handling Webhooks @lornajane
29. Webhooks in Your Applications • Use them WHEN you want to notify other systems • Examples of HOW to use webhooks hopefully gave you some ideas • Webhooks are HTTP: we already understand this @lornajane
30. Webhooks ... are awesome :) @lornajane
31. Thanks! • Slides: http://lornajane.net/resources • Example app: https://github.com/ibm-cds-labs/guestbook • CouchDB: http://couchdb.apache.org/ • RabbitMQ: https://www.rabbitmq.com/ • Bluemix: http://www.ibm.com/bluemix • Requestbin: http://requestb.in • Website: http://lornajane.net @lornajane