try to properly interpret ncc.html encoding (seems to be a bit weird / incorrect sometimes)

package-lock.json

@@ -15,6 +15,7 @@
         "express-rate-limit": "^7.5.1",
         "express-session": "^1.17.3",
         "graceful-fs": "^4.2.10",
+        "html-encoding-sniffer": "^4.0.0",
         "htmlparser2": "^8.0.1",
         "lru-cache": "^10.0.3",
         "node-unrar-js": "^2.0.2",
@@ -28,6 +29,7 @@
         "socket.io": "^4.5.4",
         "sqlite3": "^5.1.7",
         "ssrf-req-filter": "^1.1.0",
+        "whatwg-encoding": "^3.1.1",
         "xml2js": "^0.5.0"
       },
       "bin": {
@@ -122,6 +124,7 @@
       "resolved": "https://registry.npmjs.org/@babel/core/-/core-7.23.3.tgz",
       "integrity": "sha512-Jg+msLuNuCJDyBvFv5+OKOUjWMZgd85bKjbICd3zWrKAo+bJ49HJufi7CQE0q0uR8NGyO6xkCACScNqyjHSZew==",
       "dev": true,
+      "peer": true,
       "dependencies": {
         "@ampproject/remapping": "^2.2.0",
         "@babel/code-frame": "^7.22.13",
@@ -1049,6 +1052,7 @@
           "url": "https://github.com/sponsors/ai"
         }
       ],
+      "peer": true,
       "dependencies": {
         "caniuse-lite": "^1.0.30001541",
         "electron-to-chromium": "^1.4.535",
@@ -1857,6 +1861,7 @@
       "version": "4.18.2",
       "resolved": "https://registry.npmjs.org/express/-/express-4.18.2.tgz",
       "integrity": "sha512-5/PsL6iGPdfQ/lKM1UuielYgv3BUoJfz1aUwU9vHZ+J7gyvwdQXFEBIEIaxeGf0GIcreATNyBExtalisDbuMqQ==",
+      "peer": true,
       "dependencies": {
         "accepts": "~1.3.8",
         "array-flatten": "1.1.1",
@@ -2113,6 +2118,21 @@
       "integrity": "sha512-OO0pH2lK6a0hZnAdau5ItzHPI6pUlvI7jMVnxUQRtw4owF2wk8lOSabtGDCTP4Ggrg2MbGnWO9X8K1t4+fGMDw==",
       "devOptional": true
     },
+    "node_modules/fsevents": {
+      "version": "2.3.3",
+      "resolved": "https://registry.npmjs.org/fsevents/-/fsevents-2.3.3.tgz",
+      "integrity": "sha512-5xoDfX+fL7faATnagmWPpbFtwh/R77WmMMqqHGS65C3vvB0YHrgF+B1YmZ3441tMj5n63k0212XNoJwzlhffQw==",
+      "dev": true,
+      "hasInstallScript": true,
+      "license": "MIT",
+      "optional": true,
+      "os": [
+        "darwin"
+      ],
+      "engines": {
+        "node": "^8.16.0 || ^10.6.0 || >=11.0.0"
+      }
+    },
     "node_modules/function-bind": {
       "version": "1.1.2",
       "resolved": "https://registry.npmjs.org/function-bind/-/function-bind-1.1.2.tgz",
@@ -2284,6 +2304,18 @@
         "he": "bin/he"
       }
     },
+    "node_modules/html-encoding-sniffer": {
+      "version": "4.0.0",
+      "resolved": "https://registry.npmjs.org/html-encoding-sniffer/-/html-encoding-sniffer-4.0.0.tgz",
+      "integrity": "sha512-Y22oTqIU4uuPgEemfz7NDJz6OeKf12Lsu+QC+s3BVpda64lTiMYCyGwg5ki4vFxkMwQdeZDl2adZoqUgdFuTgQ==",
+      "license": "MIT",
+      "dependencies": {
+        "whatwg-encoding": "^3.1.1"
+      },
+      "engines": {
+        "node": ">=18"
+      }
+    },
     "node_modules/html-escaper": {
       "version": "2.0.2",
       "resolved": "https://registry.npmjs.org/html-escaper/-/html-escaper-2.0.2.tgz",
@@ -5358,6 +5390,31 @@
         "node": ">= 0.8"
       }
     },
+    "node_modules/whatwg-encoding": {
+      "version": "3.1.1",
+      "resolved": "https://registry.npmjs.org/whatwg-encoding/-/whatwg-encoding-3.1.1.tgz",
+      "integrity": "sha512-6qN4hJdMwfYBtE3YBTTHhoeuUrDBPZmbQaxWAqSALV/MeEnR5z1xd8UKud2RAkFoPkmB+hli1TZSnyi84xz1vQ==",
+      "deprecated": "Use @exodus/bytes instead for a more spec-conformant and faster implementation",
+      "license": "MIT",
+      "dependencies": {
+        "iconv-lite": "0.6.3"
+      },
+      "engines": {
+        "node": ">=18"
+      }
+    },
+    "node_modules/whatwg-encoding/node_modules/iconv-lite": {
+      "version": "0.6.3",
+      "resolved": "https://registry.npmjs.org/iconv-lite/-/iconv-lite-0.6.3.tgz",
+      "integrity": "sha512-4fCk79wshMdzMp2rH06qWrJE4iolqLhCUH+OiuIgU++RB0+94NlDL81atO7GX55uUKueo0txHNtvEyI6D7WdMw==",
+      "license": "MIT",
+      "dependencies": {
+        "safer-buffer": ">= 2.1.2 < 3.0.0"
+      },
+      "engines": {
+        "node": ">=0.10.0"
+      }
+    },
     "node_modules/which": {
       "version": "2.0.2",
       "resolved": "https://registry.npmjs.org/which/-/which-2.0.2.tgz",

package.json

@@ -44,6 +44,7 @@
     "express-rate-limit": "^7.5.1",
     "express-session": "^1.17.3",
     "graceful-fs": "^4.2.10",
+    "html-encoding-sniffer": "^4.0.0",
     "htmlparser2": "^8.0.1",
     "lru-cache": "^10.0.3",
     "node-unrar-js": "^2.0.2",
@@ -57,6 +58,7 @@
     "socket.io": "^4.5.4",
     "sqlite3": "^5.1.7",
     "ssrf-req-filter": "^1.1.0",
+    "whatwg-encoding": "^3.1.1",
     "xml2js": "^0.5.0"
   },
   "devDependencies": {

server/scanner/DaisyFileScanner.js

@@ -12,7 +12,7 @@ class DaisyFileScanner {
    * @param {Object} bookMetadata
    */
   async scanBookDaisyFile(daisyLibraryFileObj, bookMetadata, audioFiles = []) {
-    const htmlText = await readTextFile(daisyLibraryFileObj.metadata.path)
+    const htmlText = await readTextFile(daisyLibraryFileObj.metadata.path, { detectEncoding: true, isHtml: true })
     const daisyMetadata = htmlText ? parseDaisyMetadata(htmlText) : null
     if (daisyMetadata) {
       for (const key in daisyMetadata) {

server/utils/fileUtils.js

@@ -6,6 +6,8 @@ const fs = require('../libs/fsExtra')
 const rra = require('../libs/recursiveReaddirAsync')
 const Logger = require('../Logger')
 const { AudioMimeType } = require('./constants')
+const sniffHTMLEncoding = require('html-encoding-sniffer')
+const whatwgEncoding = require('whatwg-encoding')
 
 /**
  * Make sure folder separator is POSIX for Windows file paths. e.g. "C:\Users\Abs" becomes "C:/Users/Abs"
@@ -116,14 +118,60 @@ function getIno(path) {
 module.exports.getIno = getIno
 
 /**
- * Read contents of file
- * @param {string} path
+ * @typedef ReadTextFileOptions
+ * @property {boolean} [detectEncoding] detect text encoding before decoding
+ * @property {boolean} [isHtml] use HTML charset hints when detectEncoding is enabled
+ */
+
+function detectTextEncoding(buffer, options = {}) {
+  const { isHtml = false } = options
+  if (!isHtml) {
+    return 'UTF-8'
+  }
+
+  try {
+    const sniffedEncoding = sniffHTMLEncoding(buffer, { defaultEncoding: 'windows-1252' }) || 'windows-1252'
+    return whatwgEncoding.labelToName(sniffedEncoding) || 'UTF-8'
+  } catch {
+    return 'UTF-8'
+  }
+}
+
+/**
+ * Decode raw text bytes with optional encoding detection.
+ *
+ * @param {Buffer} buffer
+ * @param {ReadTextFileOptions} [options]
  * @returns {string}
  */
-async function readTextFile(path) {
+function decodeTextBuffer(buffer, options = {}) {
+  if (!buffer) return ''
+  const { detectEncoding = false, isHtml = false } = options
+
+  if (!detectEncoding) {
+    return String(buffer)
+  }
+
+  const fallbackEncoding = detectTextEncoding(buffer, { isHtml })
+  try {
+    // WHATWG decode handles BOM override and legacy encoding tables.
+    return whatwgEncoding.decode(buffer, fallbackEncoding)
+  } catch {
+    return String(buffer)
+  }
+}
+module.exports.decodeTextBuffer = decodeTextBuffer
+
+/**
+ * Read contents of file
+ * @param {string} path
+ * @param {ReadTextFileOptions} [options]
+ * @returns {string}
+ */
+async function readTextFile(path, options = {}) {
   try {
     var data = await fs.readFile(path)
-    return String(data)
+    return decodeTextBuffer(data, options)
   } catch (error) {
     Logger.error(`[FileUtils] ReadTextFile error ${error}`)
     return ''

test/server/utils/fileUtils.test.js

@@ -6,6 +6,26 @@ const fs = require('fs')
 const Logger = require('../../../server/Logger')
 
 describe('fileUtils', () => {
+  describe('decodeTextBuffer', () => {
+    it('decodes html using charset declaration (windows-1252)', () => {
+      const htmlPrefix = Buffer.from('<html><head><meta charset="windows-1252"></head><body>M')
+      const htmlSuffix = Buffer.from('ller</body></html>')
+      const input = Buffer.concat([htmlPrefix, Buffer.from([0xfc]), htmlSuffix])
+
+      const decoded = fileUtils.decodeTextBuffer(input, { detectEncoding: true, isHtml: true })
+      expect(decoded).to.include('Müller')
+    })
+
+    it('falls back to windows-1252 for html without charset when utf-8 decoding is invalid', () => {
+      const htmlPrefix = Buffer.from('<html><body>Gr')
+      const htmlSuffix = Buffer.from('n</body></html>')
+      const input = Buffer.concat([htmlPrefix, Buffer.from([0xfc]), htmlSuffix])
+
+      const decoded = fileUtils.decodeTextBuffer(input, { detectEncoding: true, isHtml: true })
+      expect(decoded).to.include('Grün')
+    })
+  })
+
   it('shouldIgnoreFile', () => {
     global.isWin = process.platform === 'win32'