v0.2.1: update readme & manifests

.github/workflows/build-publish-npm.yaml

@@ -27,8 +27,10 @@ jobs:
 
       - run: make patch-upstream lib-build
 
+      - run: cp -v README.md docs ./socket.io-serverless/
+
       - uses: JS-DevTools/npm-publish@v3
         with:
           token: ${{ secrets.NPM_TOKEN }}
           dry-run: ${{ !(github.event_name == 'push' && startsWith(github.ref, 'refs/tags/')) }}
-          package: ./socket.io-serverless/package.json
+          package: ./socket.io-serverless/package.json

.gitignore

@@ -28,3 +28,4 @@ dist-ssr
 .yarn
 *.tgz
 /socket.io-serverless/README.md
+/socket.io-serverless/docs

README.md

@@ -2,7 +2,7 @@
 
 A custom [socket.io](https://socket.io/) build for serverless environments. Currently [Cloudflare Worker + Durable Objects](https://developers.cloudflare.com/durable-objects/).
 
-Demo client app: [sio-serverless-demo-client](https://sio-serverless-demo-client.ihate.work) running `demo-client/` `demo-server/` code in this repo.
+Demo client app: [sio-serverless-demo-client](https://sio-serverless-demo-client.ihate.work) running `demo-client/` `demo-server/` code in [source code repo](https://github.com/jokester/socket.io-serverless)
 
 ## Getting started
 

docs/development.md

@@ -0,0 +1,10 @@
+### how the code is developed and built
+
+Because socket.io does not publish original TS code in NPM, I included the `socket.io` repo ([now a monorepo too](https://github.com/socketio/socket.io/issues/3533)) as a git submodule. My monorepo therefore contains packages like `socket.io-serverless` `socket.io/packages/socket.io` ``socket.io/packages/engine.io` `
+
+Some socket.io code need to be patched, including export map in `package.json`. The patches are contained in the monorepo and applied by Makefile.
+
+`esbuild` bundle `socket.io-serverless` code , along with Socket.io and other deps, into a non minified bundle.
+
+A `esbuild` [build script](https://github.com/jokester/socket.io-serverless/blob/main/socket.io-serverless/build.mjs) is used to customize the deps resolution process. Some npm packages are replaced with CF-compatible implementation (like `debug`), or simple stubbed (like `node:http` ).
+

docs/how-it-works.md

@@ -0,0 +1,50 @@
+### how socket.io works
+
+Socket.io (the top level library) have 2 main components: npm packages `socket.io` and `engine.io`.
+
+The `socket.io` packages deals with the high level concepts: namespace / room / clustering / etc. It depends on `engine.io` which holds a `http.Server` instance and deals with the transport-aware logic.
+
+In Node.js the 2 components just run in the same process, communicate with a event emitter API.
+
+### develop for CF worker / DO
+
+In CF DO / worker, JS runs in a non-Node.js special serverless environment. I think [workerd](https://github.com/cloudflare/workerd/tree/main/src/workerd) .
+
+The biggest difference compared to Node.js / web for a JS developer is perhaps the volatile state.
+
+In a traditional environment like Node.js process or a browser tab, the code just run till server down or tab close. But in CF the serverless environment they will stop running and destroy the in-memory state of your JS code when it is inactive. Having a JS `setTimeout` or `setInterval` timer counts as active. A pending HTTP request counts. An active WebSocket connection may or may not count (depending on the API used to accept the connection).
+
+Specificlly, for DO the destruction of in-memory state is actually called [hibernation](). Developers can manually persist/revive state using provided KV store-like API.
+
+<!--
+For DO there is some guarantee like "no 2 instance of the same actor (identified by id) will exist at the same time". For worker I guess almost nothing is guaranteed. S
+-->
+Also the available standard libraries is different too.
+
+The code using only JS language APIs should just work. Code requiring Node.js API can have Node.js polyfills behind Node.js compatibility flags.
+
+Since sometime in 2024 the Node.js stdlib polyfill is based on [unenv]() , behind `nodejs_compat_v2` flag. This article has a quite complete explanation [Cloudflare Workersのnodejs\_compat\_v2で何が変わったのか](https://zenn.dev/laiso/articles/8280d026a08de0)
+
+Prior to this, based on my non-authoritative investigation the `nodejs_compat` flag is eventually based on `ionic-team/rollup-plugin-node-polyfills` used by `@esbuild-plugins/node-modules-polyfill`, used by `esbuild`, used by `wrangler` CLI.
+
+### how socket.io-serverless works
+
+I used 2 DO to run heavily rewired `socket.io` `engine.io` code.
+
+`class EngineActor extends DurableObject {...}` is the DO running `engine.io` code. It just accepts WebSocket connection, forwards bidirectional WS messages between `SocketActor` and real WS connection.
+
+`class SocketActor extends DurableObject {...}` is the DO running `socket.io` code. It responds to RPC calls from `EngineActor`, emit messages into objects like `Namespace`. If application code above send message to a engine.io Socket (an abstraction of different transports), the message got forwarded to `EngineActor`, and flow to the other end of WS connection.
+
+Therefore application logic code based on  on `sio.Namespace` `sio.Client` `sio.Room` should work as with the original Socket.io, but with [limitations](https://github.com/jokester/socket.io-serverless?tab=readme-ov-file#limitations).
+
+Besides the 2 DOs , there will need to be a worker entrypoint, a simple HTTP handler to forward request to `EngineActor`
+
+While it is not impossible to prevent aforementioned hibernation (I did this in a first simpler version), I decided that a serverless version should instead exploit hibernation to save energy and protect our earth.
+
+The states inside `EngineActor` `SocketActor`, including connection IDs, possibly dynamically created namespaces and conn IDs within, are now persisted/revived across different life cycles.
+
+Most of `engine.io` `socket.io` code is already driven by message events. But there was a ping timer to drive [heartbeat check](https://socket.io/docs/v4/engine-io-protocol/#heartbeat). I had to stub the original code to use [alarm]() instead.
+
+Currently socket.io-serverless only creates 1 instance for each DO class. In the future if performance becomes a problem it should be able to split the load with more DOs (similar to the adapter/cluster structure used by Socket.io)
+
+

socket.io-serverless/package.json

@@ -1,8 +1,16 @@
 {
   "name": "socket.io-serverless",
   "description": "A custom socket.io build to run in Cloudflare workers.",
-  "version": "0.2.0",
+  "version": "0.2.1",
   "type": "module",
+  "homepage": "https://github.com/jokester/socket.io-serverless",
+  "repository": {
+    "type": "git",
+    "url": "git+https://github.com/jokester/socket.io-serverless.git"
+  },
+  "bugs": {
+    "url": "https://github.com/jokester/socket.io-serverless/issues"
+  },
   "dependencies": {},
   "files": [
     "dist",
@@ -13,7 +21,6 @@
     "tsconfig.json"
   ],
   "scripts": {
-    "prepack": "node build.mjs && cp -v ../README.md .",
     "build": "node build.mjs",
     "build:watch": "node build.mjs --watch",
     "lint": "eslint src",