Add:Cover image cache, resize & use webp image #223

server/CacheManager.js

@@ -0,0 +1,75 @@
+const Path = require('path')
+const fs = require('fs-extra')
+const stream = require('stream')
+const resize = require('./utils/resizeImage')
+const Logger = require('./Logger')
+
+class CacheManager {
+  constructor(MetadataPath) {
+    this.MetadataPath = MetadataPath
+    this.CachePath = Path.join(this.MetadataPath, 'cache')
+    this.CoverCachePath = Path.join(this.CachePath, 'covers')
+  }
+
+  async handleCoverCache(res, audiobook, options = {}) {
+    const format = options.format || 'webp'
+    const width = options.width || 400
+    const height = options.height || null
+
+    res.type(`image/${format}`)
+
+    var path = Path.join(this.CoverCachePath, audiobook.id) + '.' + format
+
+    // Cache exists
+    if (await fs.pathExists(path)) {
+      const r = fs.createReadStream(path)
+      const ps = new stream.PassThrough()
+      stream.pipeline(r, ps, (err) => {
+        if (err) {
+          console.log(err)
+          return res.sendStatus(400)
+        }
+      })
+      return ps.pipe(res)
+    }
+
+    // Write cache
+    await fs.ensureDir(this.CoverCachePath)
+    var readStream = resize(audiobook.book.coverFullPath, width, height, format)
+    var writeStream = fs.createWriteStream(path)
+    writeStream.on('error', (e) => {
+      Logger.error(`[CacheManager] Cache write error ${e.message}`)
+    })
+    readStream.pipe(writeStream)
+
+    readStream.pipe(res)
+  }
+
+  purgeCoverCache(audiobookId) {
+    var basepath = Path.join(this.CoverCachePath, audiobookId)
+    // Remove both webp and jpg caches if exist
+    var webpPath = basepath + '.webp'
+    var jpgPath = basepath + '.jpg'
+    return Promise.all([this.removeCache(webpPath), this.removeCache(jpgPath)])
+  }
+
+  removeCache(path) {
+    if (!path) return false
+    return fs.pathExists(path).then((exists) => {
+      if (!exists) return false
+      return fs.unlink(path).then(() => true).catch((err) => {
+        Logger.error(`[CacheManager] Failed to remove cache "${path}"`, err)
+        return false
+      })
+    })
+  }
+
+  async purgeAll() {
+    if (await fs.pathExists(this.CachePath)) {
+      await fs.remove(this.CachePath).catch((error) => {
+        Logger.error(`[CacheManager] Failed to remove cache dir "${this.CachePath}"`, error)
+      })
+    }
+  }
+}
+module.exports = CacheManager