Add support for request cancellation in msnodesqlv8 driver

CHANGELOG.txt

@@ -2,6 +2,7 @@ v4.2.0 (2018-XX-XX)
 -------------------
 [new] Added TVP support for msnodesqlv8 driver
 [new] Added support for information messages in msnodesqlv8 driver
+[new] Added support for request cancellation in msnodesqlv8 driver
 [fix] Fixed Tedious deprecation warnings
 [fix] Fixed ResourceRequest timed out error
 [fix] All query and batch methods now have the same interface

lib/msnodesqlv8.js

@@ -313,6 +313,12 @@ class Request extends base.Request {
         if (!err) {
           debug('connection(%d): borrowed to request #%d', IDS.get(connection), IDS.get(this))
 
+          if (this.canceled) {
+            debug('request(%d): canceled', IDS.get(this))
+            this.parent.release(connection)
+            return callback(new base.RequestError('Canceled.', 'ECANCEL'))
+          }
+
           const done = (err, rowCount) => {
             if (err) {
               if ((typeof err.sqlstate === 'string') && (err.sqlstate.toLowerCase() === '08s01')) {
@@ -429,6 +435,12 @@ class Request extends base.Request {
 
         debug('connection(%d): borrowed to request #%d', IDS.get(connection), IDS.get(this))
 
+        if (this.canceled) {
+          debug('request(%d): canceled', IDS.get(this))
+          this.parent.release(connection)
+          return callback(new base.RequestError('Canceled.', 'ECANCEL'))
+        }
+
         const params = []
         for (let name in this.parameters) {
           let param = this.parameters[name]
@@ -443,6 +455,14 @@ class Request extends base.Request {
           query_str: command,
           query_timeout: config.requestTimeout / 1000 // msnodesqlv8 timeouts are in seconds (<1 second not supported)
         }, params)
+
+        this._cancel = () => {
+          debug('request(%d): cancel', IDS.get(this))
+          req.cancelQuery(err => {
+            if (err) debug('request(%d): failed to cancel', IDS.get(this), err)
+          })
+        }
+
         req.on('meta', metadata => {
           if (row) {
             if (isChunkedRecordset) {
@@ -570,7 +590,9 @@ class Request extends base.Request {
 
           err = new base.RequestError(err)
           err.code = 'EREQUEST'
+          err.state = err.sqlstate
 
+          delete this._cancel
           this.parent.release(connection)
 
           debug('request(%d): failed', IDS.get(this), err)
@@ -626,6 +648,7 @@ class Request extends base.Request {
             }
           }
 
+          delete this._cancel
           this.parent.release(connection)
 
           debug('request(%d): completed', IDS.get(this))
@@ -713,14 +736,6 @@ class Request extends base.Request {
       })
     })
   }
-
-  /*
-  Cancel currently executed request.
-  */
-
-  cancel () {
-    return false // Request canceling is not implemented by msnodesql driver.
-  }
 }
 
 module.exports = Object.assign({

lib/tedious.js

@@ -466,7 +466,7 @@ class Request extends base.Request {
             errors.push(err)
           }
 
-          this._cancel = null
+          delete this._cancel
 
           let error
           if (errors.length && !this.stream) {
@@ -621,7 +621,7 @@ class Request extends base.Request {
             }
           }
 
-          this._cancel = null
+          delete this._cancel
 
           let error
           if (errors.length && !this.stream) {
@@ -912,7 +912,7 @@ class Request extends base.Request {
             errors.push(err)
           }
 
-          this._cancel = null
+          delete this._cancel
 
           let error
           if (errors.length && !this.stream) {

test/msnodesqlv8/msnodesqlv8.js

@@ -67,7 +67,7 @@ describe('msnodesqlv8', function () {
     it('prepared statement in transaction', done => TESTS['prepared statement in transaction'](done))
     it('transaction with rollback', done => TESTS['transaction with rollback'](done))
     it.skip('transaction with commit (temporarily disabled because of issues introduced in 0.5.3)', done => TESTS['transaction with commit'](done))
-    it.skip('cancel request (not supported by msnodesqlv8)', done => TESTS['cancel request'](done))
+    it('cancel request', done => TESTS['cancel request'](done))
     it('request timeout', done => TESTS['request timeout'](done))
     it('dataLength type correction', done => TESTS['dataLength type correction'](done))
     it.skip('chunked json support (requires SQL Server 2016)', done => TESTS['chunked json support'](done))