xml plugin initial import

plugins/dbgate-plugin-xml/src/backend/writer.js

@@ -0,0 +1,23 @@
+const fs = require('fs');
+const stream = require('stream');
+
+class StringifyStream extends stream.Transform {
+  constructor() {
+    super({ objectMode: true });
+  }
+  _transform(chunk, encoding, done) {
+    this.push(JSON.stringify(chunk) + '\n');
+    done();
+  }
+}
+
+async function writer({ fileName, encoding = 'utf-8' }) {
+  console.log(`Writing file ${fileName}`);
+  const stringify = new StringifyStream();
+  const fileStream = fs.createWriteStream(fileName, encoding);
+  stringify.pipe(fileStream);
+  stringify['finisher'] = fileStream;
+  return stringify;
+}
+
+module.exports = writer;