Merge pull request #4133 from Vito0912/feat/downloadMultiple

Adds the option to download selected books

server/utils/zipHelpers.js

@@ -1,3 +1,5 @@
+const Path = require('path')
+const { Response } = require('express')
 const Logger = require('../Logger')
 const archiver = require('../libs/archiver')
 
@@ -50,3 +52,86 @@ module.exports.zipDirectoryPipe = (path, filename, res) => {
     archive.finalize()
   })
 }
+
+/**
+ * Creates a zip archive containing multiple directories and streams it to the response.
+ *
+ * @param {{ path: string, isFile: boolean }[]} pathObjects
+ * @param {string} filename - Name of the zip file to be sent as attachment.
+ * @param {Response} res - Response object to pipe the archive data to.
+ * @returns {Promise<void>} - Promise that resolves when the zip operation completes.
+ */
+module.exports.zipDirectoriesPipe = (pathObjects, filename, res) => {
+  return new Promise((resolve, reject) => {
+    // create a file to stream archive data to
+    res.attachment(filename)
+
+    const archive = archiver('zip', {
+      zlib: { level: 0 } // Sets the compression level.
+    })
+
+    // listen for all archive data to be written
+    // 'close' event is fired only when a file descriptor is involved
+    res.on('close', () => {
+      Logger.info(archive.pointer() + ' total bytes')
+      Logger.debug('archiver has been finalized and the output file descriptor has closed.')
+      resolve()
+    })
+
+    // This event is fired when the data source is drained no matter what was the data source.
+    // It is not part of this library but rather from the NodeJS Stream API.
+    // @see: https://nodejs.org/api/stream.html#stream_event_end
+    res.on('end', () => {
+      Logger.debug('Data has been drained')
+    })
+
+    // good practice to catch warnings (ie stat failures and other non-blocking errors)
+    archive.on('warning', function (err) {
+      if (err.code === 'ENOENT') {
+        // log warning
+        Logger.warn(`[DownloadManager] Archiver warning: ${err.message}`)
+      } else {
+        // throw error
+        Logger.error(`[DownloadManager] Archiver error: ${err.message}`)
+        // throw err
+        reject(err)
+      }
+    })
+    archive.on('error', function (err) {
+      Logger.error(`[DownloadManager] Archiver error: ${err.message}`)
+      reject(err)
+    })
+
+    // pipe archive data to the file
+    archive.pipe(res)
+
+    // Add each path as a directory in the zip
+    pathObjects.forEach((pathObject) => {
+      if (!pathObject.isFile) {
+        // Add the directory to the archive with its name as the root folder
+        archive.directory(pathObject.path, Path.basename(pathObject.path))
+      } else {
+        archive.file(pathObject.path, { name: Path.basename(pathObject.path) })
+      }
+    })
+
+    archive.finalize()
+  })
+}
+
+/**
+ * Handles errors that occur during the download process.
+ *
+ * @param {*} error
+ * @param {Response} res
+ * @returns {*}
+ */
+module.exports.handleDownloadError = (error, res) => {
+  if (!res.headersSent) {
+    if (error.code === 'ENOENT') {
+      return res.status(404).send('File not found')
+    } else {
+      return res.status(500).send('Download failed')
+    }
+  }
+}