CSV for MS Excel export

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

@@ -6,6 +6,54 @@ const { getLogger } = global.DBGATE_PACKAGES['dbgate-tools'];
 
 const logger = getLogger('csvWriter');
 
+class RecodeTransform extends stream.Transform {
+  constructor(toEncoding = 'utf8') {
+    super({ readableObjectMode: false, writableObjectMode: false });
+    this.to = String(toEncoding).toLowerCase();
+    this.decoder = new (global.TextDecoder || require('util').TextDecoder)('utf-8', { fatal: false });
+  }
+
+  _encodeString(str) {
+    if (this.to === 'utf8' || this.to === 'utf-8') {
+      return Buffer.from(str, 'utf8');
+    }
+    if (this.to === 'utf16le' || this.to === 'ucs2' || this.to === 'utf-16le') {
+      return Buffer.from(str, 'utf16le');
+    }
+    if (this.to === 'utf16be' || this.to === 'utf-16be') {
+      const le = Buffer.from(str, 'utf16le');
+      for (let i = 0; i + 1 < le.length; i += 2) {
+        const a = le[i];
+        le[i] = le[i + 1];
+        le[i + 1] = a;
+      }
+      return le;
+    }
+    throw new Error(`Unsupported target encoding: ${this.to}`);
+  }
+
+  _transform(chunk, enc, cb) {
+    try {
+      if (!Buffer.isBuffer(chunk)) chunk = Buffer.from(chunk, enc);
+      const part = this.decoder.decode(chunk, { stream: true });
+      if (part.length) this.push(this._encodeString(part));
+      cb();
+    } catch (e) {
+      cb(e);
+    }
+  }
+
+  _flush(cb) {
+    try {
+      const rest = this.decoder.decode();
+      if (rest.length) this.push(this._encodeString(rest));
+      cb();
+    } catch (e) {
+      cb(e);
+    }
+  }
+}
+
 class CsvPrepareStream extends stream.Transform {
   constructor({ header }) {
     super({ objectMode: true });
@@ -26,18 +74,59 @@ class CsvPrepareStream extends stream.Transform {
   }
 }
 
-async function writer({ fileName, encoding = 'utf-8', header = true, delimiter, quoted }) {
+async function writer({
+  fileName,
+  encoding = 'utf-8',
+  header = true,
+  delimiter,
+  quoted,
+  writeBom,
+  writeSepHeader,
+  recordDelimiter,
+}) {
   logger.info(`DBGM-00133 Writing file ${fileName}`);
   const csvPrepare = new CsvPrepareStream({ header });
-  const csvStream = csv.stringify({ delimiter, quoted });
+  const csvStream = csv.stringify({ delimiter, quoted, record_delimiter: recordDelimiter });
   const fileStream = fs.createWriteStream(fileName, encoding);
-  // csvPrepare.pipe(csvStream);
-  // csvStream.pipe(fileStream);
-  // csvPrepare['finisher'] = fileStream;
+  if (writeBom) {
+    switch (encoding.toLowerCase()) {
+      case 'utf-8':
+      case 'utf8':
+        fileStream.write(Buffer.from([0xef, 0xbb, 0xbf]));
+        break;
+      case 'utf-16':
+      case 'utf16':
+        fileStream.write(Buffer.from([0xff, 0xfe]));
+        break;
+      case 'utf-16le':
+      case 'utf16le':
+        fileStream.write(Buffer.from([0xff, 0xfe]));
+        break;
+      case 'utf-16be':
+      case 'utf16be':
+        fileStream.write(Buffer.from([0xfe, 0xff]));
+        break;
+      case 'utf-32le':
+      case 'utf32le':
+        fileStream.write(Buffer.from([0xff, 0xfe, 0x00, 0x00]));
+        break;
+      case 'utf-32be':
+      case 'utf32be':
+        fileStream.write(Buffer.from([0x00, 0x00, 0xfe, 0xff]));
+        break;
+      default:
+        break;
+    }
+  }
+  if (writeSepHeader) {
+    fileStream.write(`sep=${delimiter}${recordDelimiter || '\n'}`);
+  }
+
   csvPrepare.requireFixedStructure = true;
 
-  return [csvPrepare, csvStream, fileStream];
-  // return csvPrepare;
+  return encoding.toLowerCase() === 'utf8' || encoding.toLowerCase() === 'utf-8'
+    ? [csvPrepare, csvStream, fileStream]
+    : [csvPrepare, csvStream, new RecodeTransform(encoding), fileStream];
 }
 
 module.exports = writer;