Near the end of the 2021-08-19 meeting we briefly discussed (but didn't capture) the idea of collecting background page use cases and design patterns that are not well served by service workers. My hope is that by collecting these use cases in a well known location, community members and browser vendors we will be able to more concretely discuss the challenges posed by this new background context and explore potential solutions.

Please use this issue to link to use use cases that are impossible to accomplish with or not well supported by service workers. If you'd like to report a new use case, please create a new issue and reference this one.

Use cases

Specific ways that background pages are used that cannot be accomplished with a service worker.

• HTML/XML parsing
  • Issue 1056354: Add support for parsing XML and HTML documents to Manifest V3
  • Issue 1051597: Extension Manifest V3 support for SingleFileZ and similar extensions
• Background page interaction
  • Issue 1128240: Background page loading & manipulation in service worker browser extensions
• Audio playback
  • Issue 1131236: Playing audio in service worker-based browser extensions
• Clipboard access
  • Issue 1160302: Cannot read clipboard from service worker in a MV3 chrome extension
• Blob URLs
  • Issue 1051597, comment #5+
• Requesting file:-scheme resources (aka file:// URLs)
  • Issue 1051597, comment #12+ – Discussion of file resource request limitations in Fetch
• WebRTC streams
  • Extension "Snowflake" Create RTCPeerConnections in workers webrtc-extensions#77 (comment)
  • Issue 1207214: RTCDataChannel for ManifestV3
• WebSockets
  • chromium-extensions: MV3 Service Workers Don't Support Websocket
  • Create RTCPeerConnections in workers webrtc-extensions#77
• Native messaging
  • Issue 1152255: ServiceWorker is shut down every 5 minutes for manifest V3 extension
• Wasm
  • Issue 1173354: wasm does not work in extensions manifest v3

Other discussions

• [Manifest V3] WebExtensionWorker instead of Service Worker #11
• clarification request: what happens when a MV3 SW is shut down before answering a message #16
• request: don't standardize around lowest common denominator platform (e.g., mobile) #25
• Proposal for Manifest V3: add permission allowing a background script to be persistent #44
• Requiring Service Workers for extensions fundamentally user hostile #51
• Considerations for WebAssembly runtime #39