SYNC: Merge pull request #3 from dbgate/feature/zip

packages/api/src/utility/extractSingleFileFromZip.js

@@ -0,0 +1,77 @@
+const yauzl = require('yauzl');
+const fs = require('fs');
+const { getLogger, extractErrorLogData } = require('dbgate-tools');
+const logger = getLogger('extractSingleFileFromZip');
+/**
+ * Extracts a single file from a ZIP using yauzl.
+ * Stops reading the rest of the archive once the file is found.
+ *
+ * @param {string} zipPath - Path to the ZIP file on disk.
+ * @param {string} fileInZip - The file path *inside* the ZIP to extract.
+ * @param {string} outputPath - Where to write the extracted file on disk.
+ * @returns {Promise<boolean>} - Resolves with a success message or a "not found" message.
+ */
+function extractSingleFileFromZip(zipPath, fileInZip, outputPath) {
+  return new Promise((resolve, reject) => {
+    yauzl.open(zipPath, { lazyEntries: true }, (err, zipFile) => {
+      if (err) return reject(err);
+
+      let fileFound = false;
+
+      // Start reading the first entry
+      zipFile.readEntry();
+
+      zipFile.on('entry', entry => {
+        // Compare the entry name to the file we want
+        if (entry.fileName === fileInZip) {
+          fileFound = true;
+
+          // Open a read stream for this entry
+          zipFile.openReadStream(entry, (err, readStream) => {
+            if (err) return reject(err);
+
+            // Create a write stream to outputPath
+            const writeStream = fs.createWriteStream(outputPath);
+            readStream.pipe(writeStream);
+
+            // When the read stream ends, we can close the zipFile
+            readStream.on('end', () => {
+              // We won't read further entries
+              zipFile.close();
+            });
+
+            // When the file is finished writing, resolve
+            writeStream.on('finish', () => {
+              logger.info(`File "${fileInZip}" extracted to "${outputPath}".`);
+              resolve(true);
+            });
+
+            // Handle write errors
+            writeStream.on('error', writeErr => {
+              logger.error(extractErrorLogData(writeErr), `Error extracting "${fileInZip}" from "${zipPath}".`);
+              reject(writeErr);
+            });
+          });
+        } else {
+          // Not the file we want; skip to the next entry
+          zipFile.readEntry();
+        }
+      });
+
+      // If we reach the end without finding the file
+      zipFile.on('end', () => {
+        if (!fileFound) {
+          resolve(false);
+        }
+      });
+
+      // Handle general errors
+      zipFile.on('error', err => {
+        logger.error(extractErrorLogData(err), `ZIP file error in ${zipPath}.`);
+        reject(err);
+      });
+    });
+  });
+}
+
+module.exports = extractSingleFileFromZip;