auto-detect CSV delimiter

packages/api/src/controllers/jsldata.js

@@ -18,11 +18,14 @@ function readFirstLine(file) {
       }
       if (reader.hasNextLine()) {
         reader.nextLine((err, line) => {
-          if (err) reject(err);
-          resolve(line);
+          if (err) {
+            reader.close(() => reject(err)); // Ensure reader is closed on error
+            return;
+          }
+          reader.close(() => resolve(line)); // Ensure reader is closed after reading
         });
       } else {
-        resolve(null);
+        reader.close(() => resolve(null)); // Properly close if no lines are present
       }
     });
   });

plugins/dbgate-plugin-csv/package.json

@@ -34,8 +34,9 @@
   "devDependencies": {
     "csv": "^6.3.10",
     "dbgate-plugin-tools": "^1.0.7",
+    "line-reader": "^0.4.0",
     "lodash": "^4.17.21",
     "webpack": "^5.91.0",
     "webpack-cli": "^5.1.4"
   }
-}
+}

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

@@ -2,8 +2,32 @@ const zipObject = require('lodash/zipObject');
 const csv = require('csv');
 const fs = require('fs');
 const stream = require('stream');
+const lineReader = require('line-reader');
 
 let dbgateApi;
+
+function readFirstLine(file) {
+  return new Promise((resolve, reject) => {
+    lineReader.open(file, (err, reader) => {
+      if (err) {
+        reject(err);
+        return;
+      }
+      if (reader.hasNextLine()) {
+        reader.nextLine((err, line) => {
+          if (err) {
+            reader.close(() => reject(err)); // Ensure reader is closed on error
+            return;
+          }
+          reader.close(() => resolve(line)); // Ensure reader is closed after reading
+        });
+      } else {
+        reader.close(() => resolve(null)); // Properly close if no lines are present
+      }
+    });
+  });
+}
+
 class CsvPrepareStream extends stream.Transform {
   constructor({ header }) {
     super({ objectMode: true });
@@ -46,6 +70,22 @@ class CsvPrepareStream extends stream.Transform {
 
 async function reader({ fileName, encoding = 'utf-8', header = true, delimiter, limitRows = undefined }) {
   console.log(`Reading file ${fileName}`);
+  const downloadedFile = await dbgateApi.download(fileName);
+
+  if (!delimiter) {
+    // auto detect delimiter
+    // read first line from downloadedFile
+    const firstLine = await readFirstLine(downloadedFile);
+    if (firstLine) {
+      const delimiterCounts = {
+        ',': firstLine.replace(/[^,]/g, '').length,
+        ';': firstLine.replace(/[^;]/g, '').length,
+        '|': firstLine.replace(/[^|]/g, '').length,
+      };
+
+      delimiter = Object.keys(delimiterCounts).reduce((a, b) => (delimiterCounts[a] > delimiterCounts[b] ? a : b), ',');
+    }
+  }
   const csvStream = csv.parse({
     // @ts-ignore
     delimiter,
@@ -53,7 +93,6 @@ async function reader({ fileName, encoding = 'utf-8', header = true, delimiter,
     to_line: limitRows ? limitRows + 1 : undefined,
     ltrim: true,
   });
-  const downloadedFile = await dbgateApi.download(fileName);
   const fileStream = fs.createReadStream(downloadedFile, encoding);
   const csvPrepare = new CsvPrepareStream({ header });
   fileStream.pipe(csvStream);

plugins/dbgate-plugin-csv/src/frontend/index.js

@@ -17,6 +17,7 @@ const fileFormat = {
       name: 'delimiter',
       label: 'Delimiter',
       options: [
+        { name: 'Auto-detect', value: '' },
         { name: 'Comma (,)', value: ',' },
         { name: 'Semicolon (;)', value: ';' },
         { name: 'Tab', value: '\t' },