[TD-6078]<fix>: fix binary/nchar null error in node.js [ci skip] (#7366)

src/connector/nodejs/nodetaos/cinterface.js

@@ -109,6 +109,24 @@ function convertDouble(data, num_of_rows, nbytes = 0, offset = 0, precision = 0)
   return res;
 }
 
+function convertBinary(data, num_of_rows, nbytes = 0, offset = 0, precision = 0) {
+  data = ref.reinterpret(data.deref(), nbytes * num_of_rows, offset);
+  let res = [];
+
+  let currOffset = 0;
+  while (currOffset < data.length) {
+    let len = data.readIntLE(currOffset, 2);
+    let dataEntry = data.slice(currOffset + 2, currOffset + len + 2); //one entry in a row under a column;
+    if (dataEntry[0] == 255) {
+      res.push(null)
+    } else {
+      res.push(dataEntry.toString("utf-8"));
+    }
+    currOffset += nbytes;
+  }
+  return res;
+}
+
 function convertNchar(data, num_of_rows, nbytes = 0, offset = 0, precision = 0) {
   data = ref.reinterpret(data.deref(), nbytes * num_of_rows, offset);
   let res = [];
@@ -117,7 +135,11 @@ function convertNchar(data, num_of_rows, nbytes = 0, offset = 0, precision = 0)
   while (currOffset < data.length) {
     let len = data.readIntLE(currOffset, 2);
     let dataEntry = data.slice(currOffset + 2, currOffset + len + 2); //one entry in a row under a column;
-    res.push(dataEntry.toString("utf-8"));
+    if (dataEntry[0] == 255 && dataEntry[1] == 255) {
+      res.push(null)
+    } else {
+      res.push(dataEntry.toString("utf-8"));
+    }
     currOffset += nbytes;
   }
   return res;
@@ -132,7 +154,7 @@ let convertFunctions = {
   [FieldTypes.C_BIGINT]: convertBigint,
   [FieldTypes.C_FLOAT]: convertFloat,
   [FieldTypes.C_DOUBLE]: convertDouble,
-  [FieldTypes.C_BINARY]: convertNchar,
+  [FieldTypes.C_BINARY]: convertBinary,
   [FieldTypes.C_TIMESTAMP]: convertTimestamp,
   [FieldTypes.C_NCHAR]: convertNchar
 }

src/connector/nodejs/test/testnchar.js

+const taos = require('../tdengine');
+var conn = taos.connect({ host: "localhost" });
+var c1 = conn.cursor();
+
+
+function checkData(data, row, col, expect) {
+	let checkdata = data[row][col];
+	if (checkdata == expect) {
+		// console.log('check pass')
+	}
+	else {
+		console.log('check failed, expect ' + expect + ', but is ' + checkdata)
+	}
+}
+
+c1.execute('drop database if exists testnodejsnchar')
+c1.execute('create database testnodejsnchar')
+c1.execute('use testnodejsnchar');
+c1.execute('create table tb (ts timestamp, value float, text binary(200))')
+c1.execute("insert into tb values('2021-06-10 00:00:00', 24.7, '中文10000000000000000000000');") -
+c1.execute('insert into tb values(1623254400150, 24.7, NULL);')
+c1.execute('import into tb values(1623254400300, 24.7, "中文3中文10000000000000000000000中文10000000000000000000000中文10000000000000000000000中文10000000000000000000000");')
+sql = 'select * from tb;'
+
+console.log('*******************************************')
+
+c1.execute(sql);
+data = c1.fetchall();
+console.log(data)
+//check data about insert data
+checkData(data, 0, 2, '中文10000000000000000000000')
+checkData(data, 1, 2, null)
+checkData(data, 2, 2, '中文3中文10000000000000000000000中文10000000000000000000000中文10000000000000000000000中文10000000000000000000000')
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