From 24fd4d4fc0ab57661b7cd49306d3d4395eb6acea Mon Sep 17 00:00:00 2001
From: Vitaly <vital2580@icloud.com>
Date: Mon, 19 Aug 2024 14:01:13 +0300
Subject: [PATCH] feat: implement fast world loading with file descriptor &
 http backend! (#182)

---
 README.MD                  | 26 +++++++++++++++++++++++++-
 server.js                  |  1 +
 src/browserfs.ts           | 38 ++++++++++++++++++++++++++++++++++++++
 src/downloadAndOpenFile.ts | 13 ++++++++++++-
 4 files changed, 76 insertions(+), 2 deletions(-)

diff --git a/README.MD b/README.MD
index dcfe3fd4..b21e8c8a 100644
--- a/README.MD
+++ b/README.MD
@@ -141,7 +141,31 @@ Single player specific:
 - `?singleplayer=1` - Create empty world on load. Nothing will be saved
 - `?version=<version>` - Set the version for the singleplayer world (when used with `?singleplayer=1`)
 - `?noSave=true` - Disable auto save on unload / disconnect / export whenever a world is loaded. Only manual save with `/save` command will work.
-- `?map=<map_url>` - Load the map from ZIP. You can use any url, but it must be CORS enabled.
+- `?map=<map_url>` - Load the map from ZIP. You can use any url, but it must be **CORS enabled**.
+- `?mapDir=<index_file_url>` - Load the map from a file descriptor. It's recommended and the fastest way to load world but requires additional setup. The file must be in the following format:
+
+```json
+{
+    "baseUrl": "<url>",
+    "index": {
+        "level.dat": null,
+        "region": {
+            "r.-1.-1.mca": null,
+            "r.-1.0.mca": null,
+            "r.0.-1.mca": null,
+            "r.0.0.mca": null,
+        }
+    }
+}
+```
+
+Note that `mapDir` also accepts base64 encoded JSON like so:
+`?mapDir=data:application/json;base64,...` where `...` is the base64 encoded JSON of the index file.
+In this case you must use `?mapDirBaseUrl` to specify the base URL to fetch the files from index.
+
+- `?mapDirBaseUrl` - See above.
+
+<!-- - `?mapDirGuess=<base_url>` - Load the map from the provided URL and paths will be guessed with a few additional fetch requests. -->
 
 General:
 
diff --git a/server.js b/server.js
index 7adae4bb..dd1ccaa1 100644
--- a/server.js
+++ b/server.js
@@ -17,6 +17,7 @@ const app = express()
 
 const isProd = process.argv.includes('--prod')
 app.use(compression())
+// app.use(cors())
 app.use(netApi({ allowOrigin: '*' }))
 if (!isProd) {
   app.use('/sounds', express.static(path.join(__dirname, './generated/sounds/')))
diff --git a/src/browserfs.ts b/src/browserfs.ts
index 16691986..0c4c7664 100644
--- a/src/browserfs.ts
+++ b/src/browserfs.ts
@@ -433,6 +433,44 @@ export const copyFilesAsync = async (pathSrc: string, pathDest: string, fileCopi
   }))
 }
 
+export const openWorldFromHttpDir = async (fileDescriptorUrl: string/*  | undefined */, baseUrl = fileDescriptorUrl.split('/').slice(0, -1).join('/')) => {
+  // todo try go guess mode
+  let index
+  const file = await fetch(fileDescriptorUrl).then(async a => a.json())
+  if (file.baseUrl) {
+    baseUrl = new URL(file.baseUrl, baseUrl).toString()
+    index = file.index
+  } else {
+    index = file
+  }
+  if (!index) throw new Error(`The provided mapDir file is not valid descriptor file! ${fileDescriptorUrl}`)
+  await new Promise<void>(async resolve => {
+    browserfs.configure({
+      fs: 'MountableFileSystem',
+      options: {
+        ...defaultMountablePoints,
+        '/world': {
+          fs: 'HTTPRequest',
+          options: {
+            index,
+            baseUrl
+          }
+        }
+      },
+    }, (e) => {
+      if (e) throw e
+      resolve()
+    })
+  })
+
+  fsState.saveLoaded = false
+  fsState.isReadonly = true
+  fsState.syncFs = false
+  fsState.inMemorySave = false
+
+  await loadSave()
+}
+
 // todo rename method
 const openWorldZipInner = async (file: File | ArrayBuffer, name = file['name']) => {
   await new Promise<void>(async resolve => {
diff --git a/src/downloadAndOpenFile.ts b/src/downloadAndOpenFile.ts
index 7ae8547f..49fc5c35 100644
--- a/src/downloadAndOpenFile.ts
+++ b/src/downloadAndOpenFile.ts
@@ -1,5 +1,5 @@
 import prettyBytes from 'pretty-bytes'
-import { openWorldZip } from './browserfs'
+import { openWorldFromHttpDir, openWorldZip } from './browserfs'
 import { getResourcePackNames, installTexturePack, resourcePackState, updateTexturePackInstalledState } from './resourcePack'
 import { setLoadingScreenStatus } from './utils'
 
@@ -9,6 +9,17 @@ export const getFixedFilesize = (bytes: number) => {
 
 const inner = async () => {
   const qs = new URLSearchParams(window.location.search)
+  const mapUrlDir = qs.get('mapDir')
+  const mapUrlDirGuess = qs.get('mapDirGuess')
+  const mapUrlDirBaseUrl = qs.get('mapDirBaseUrl')
+  if (mapUrlDir) {
+    await openWorldFromHttpDir(mapUrlDir, mapUrlDirBaseUrl ?? undefined)
+    return true
+  }
+  if (mapUrlDirGuess) {
+    // await openWorldFromHttpDir(undefined, mapUrlDirGuess)
+    return true
+  }
   let mapUrl = qs.get('map')
   const texturepack = qs.get('texturepack')
   // fixme