Add the concept of valueHandlers for processing returned rows from qu…

…eries with user provided code

lib/base/index.js

@@ -54,6 +54,13 @@ Object.defineProperty(module.exports, 'Promise', {
   }
 })
 
+Object.defineProperty(module.exports, 'valueHandler', {
+  enumerable: true,
+  value: shared.valueHandler,
+  writable: false,
+  configurable: false
+})
+
 for (const key in TYPES) {
   const value = TYPES[key]
   module.exports.exports[key] = value

lib/msnodesqlv8/index.js

@@ -22,6 +22,13 @@ Object.defineProperty(module.exports, 'Promise', {
   }
 })
 
+Object.defineProperty(module.exports, 'valueHandler', {
+  enumerable: true,
+  value: base.valueHandler,
+  writable: false,
+  configurable: false
+})
+
 base.driver.name = 'msnodesqlv8'
 base.driver.ConnectionPool = ConnectionPool
 base.driver.Transaction = Transaction

lib/msnodesqlv8/request.js

@@ -8,6 +8,7 @@ const { IDS, objectHasProperty } = require('../utils')
 const { TYPES, DECLARATIONS, declare } = require('../datatypes')
 const { PARSERS: UDT } = require('../udt')
 const Table = require('../table')
+const { valueHandler } = require('../shared')
 
 const JSON_COLUMN_ID = 'JSON_F52E2B61-18A1-11d1-B105-00805F49916B'
 const XML_COLUMN_ID = 'XML_F52E2B61-18A1-11d1-B105-00805F49916B'
@@ -122,7 +123,12 @@ const createColumns = function (metadata, arrayRowMode) {
 }
 
 const valueCorrection = function (value, metadata) {
-  if ((metadata.sqlType === 'time') && (value != null)) {
+  const type = metadata && objectHasProperty(metadata, 'sqlType') && objectHasProperty(DECLARATIONS, metadata.sqlType)
+    ? DECLARATIONS[metadata.sqlType]
+    : null
+  if (type && valueHandler.has(type)) {
+    return valueHandler.get(type)(value)
+  } else if ((metadata.sqlType === 'time') && (value != null)) {
     value.setFullYear(1970)
     return value
   } else if ((metadata.sqlType === 'udt') && (value != null)) {

lib/shared.js

@@ -105,3 +105,10 @@ Object.defineProperty(module.exports, 'Promise', {
     PromiseLibrary = value
   }
 })
+
+Object.defineProperty(module.exports, 'valueHandler', {
+  enumerable: true,
+  value: new Map(),
+  writable: false,
+  configurable: false
+})

lib/tedious/index.js

@@ -22,6 +22,13 @@ Object.defineProperty(module.exports, 'Promise', {
   }
 })
 
+Object.defineProperty(module.exports, 'valueHandler', {
+  enumerable: true,
+  value: base.valueHandler,
+  writable: false,
+  configurable: false
+})
+
 base.driver.name = 'tedious'
 base.driver.ConnectionPool = ConnectionPool
 base.driver.Transaction = Transaction

lib/tedious/request.js

@@ -8,6 +8,7 @@ const { IDS, objectHasProperty } = require('../utils')
 const { TYPES, DECLARATIONS, declare, cast } = require('../datatypes')
 const Table = require('../table')
 const { PARSERS: UDT } = require('../udt')
+const { valueHandler } = require('../shared')
 
 const JSON_COLUMN_ID = 'JSON_F52E2B61-18A1-11d1-B105-00805F49916B'
 const XML_COLUMN_ID = 'XML_F52E2B61-18A1-11d1-B105-00805F49916B'
@@ -159,7 +160,10 @@ const createColumns = function (metadata, arrayRowMode) {
 }
 
 const valueCorrection = function (value, metadata) {
-  if ((metadata.type === tds.TYPES.UDT) && (value != null)) {
+  const type = getMssqlType(metadata.type)
+  if (valueHandler.has(type)) {
+    return valueHandler.get(type)(value)
+  } else if ((metadata.type === tds.TYPES.UDT) && (value != null)) {
     if (UDT[metadata.udtInfo.typeName]) {
       return UDT[metadata.udtInfo.typeName](value)
     } else {

test/common/tests.js

@@ -123,6 +123,19 @@ module.exports = (sql, driver) => {
   }
 
   return {
+    'value handler' (done) {
+      let callCount = 0
+      const callArgs = []
+      // assign a "spy" to the valuehandler for varchar
+      sql.valueHandler.set(sql.TYPES.VarChar, function () { callCount++; callArgs.push(arguments); return arguments[0].toUpperCase() })
+      sql.query('SELECT TOP 1 * FROM [streaming]  ').then((result) => {
+        assert.strictEqual(callCount, 1)
+        assert.strictEqual(result.recordset.length, 1)
+        assert.notStrictEqual(result.recordset[0], callArgs[0])
+        assert.notStrictEqual(result.recordset[0], callArgs[0][0].toUpperCase())
+        done()
+      }).catch(done)
+    },
     'stored procedure' (mode, done) {
       const req = new TestRequest()
       req.input('in', sql.Int, null)

test/common/unit.js

@@ -1,6 +1,6 @@
 'use strict'
 
-/* globals describe, it */
+/* globals describe, it, afterEach */
 
 const sql = require('../../')
 const assert = require('assert')
@@ -352,3 +352,37 @@ describe('config cloning', () => {
     assert.notDeepStrictEqual(options, pool.config.options)
   })
 })
+
+describe('value handlers', () => {
+  afterEach('reset valueHandler', () => {
+    sql.valueHandler.clear()
+  })
+  it('can set a value handler', () => {
+    assert.strictEqual(sql.valueHandler instanceof Map, true)
+    assert.strictEqual(sql.valueHandler.size, 0)
+    sql.valueHandler.set(sql.TYPES.Int, (value) => value.toUpperCase())
+    assert.strictEqual(sql.valueHandler.size, 1)
+    assert.strictEqual(sql.valueHandler.has(sql.TYPES.Int), true)
+  })
+  it('can delete a value handler', () => {
+    assert.strictEqual(sql.valueHandler instanceof Map, true)
+    assert.strictEqual(sql.valueHandler.size, 0)
+    sql.valueHandler.set(sql.TYPES.Int, (value) => value.toUpperCase())
+    assert.strictEqual(sql.valueHandler.size, 1)
+    assert.strictEqual(sql.valueHandler.has(sql.TYPES.Int), true)
+    sql.valueHandler.delete(sql.TYPES.Int)
+    assert.strictEqual(sql.valueHandler.has(sql.TYPES.Int), false)
+    assert.strictEqual(sql.valueHandler.size, 0)
+  })
+  it('can reset all value handlers', () => {
+    assert.strictEqual(sql.valueHandler instanceof Map, true)
+    assert.strictEqual(sql.valueHandler.size, 0)
+    sql.valueHandler.set(sql.TYPES.Int, (value) => value.toUpperCase())
+    sql.valueHandler.set(sql.TYPES.BigInt, (value) => value.toUpperCase())
+    assert.strictEqual(sql.valueHandler.size, 2)
+    assert.strictEqual(sql.valueHandler.has(sql.TYPES.Int), true)
+    assert.strictEqual(sql.valueHandler.has(sql.TYPES.BigInt), true)
+    sql.valueHandler.clear()
+    assert.strictEqual(sql.valueHandler.size, 0)
+  })
+})

test/msnodesqlv8/msnodesqlv8.js

@@ -36,13 +36,15 @@ describe('msnodesqlv8', function () {
       })
     })
   )
+  afterEach(() => sql.valueHandler.clear())
 
   describe('basic test suite', function () {
     before(function (done) {
       const cfg = config()
       sql.connect(cfg, done)
     })
 
+    it('value handler', done => TESTS['value handler'](done))
     it('stored procedure (exec)', done => TESTS['stored procedure']('execute', done))
     it('stored procedure (batch)', done => TESTS['stored procedure']('batch', done))
     it('user defined types', done => TESTS['user defined types'](done))

test/tedious/tedious.js

@@ -42,6 +42,7 @@ describe('tedious', () => {
       })
     })
   )
+  afterEach(() => sql.valueHandler.clear())
 
   describe('basic test suite', () => {
     before((done) => {
@@ -50,6 +51,7 @@ describe('tedious', () => {
       sql.connect(cfg, done)
     })
 
+    it('value handler', done => TESTS['value handler'](done))
     it('stored procedure (exec)', done => TESTS['stored procedure']('execute', done))
     it('stored procedure (batch)', done => TESTS['stored procedure']('batch', done))
     it('user defined types', done => TESTS['user defined types'](done))