change user implementation

documentation/readme.md

@@ -316,3 +316,14 @@ conn.query("INSERT INTO testTransaction values ('test2')", (err) => {
 TODO difference
 - error print command + parameters
 - changedRows resultset that depend on language not defined (available if disabling foundRows).
+
+### Change connection user
+
+This permit to resets the connection and re-authenticates with the given credentials. 
+
+```javascript
+conn.changeUser({user: 'changeUser', password: 'mypassword'}, (err) => {
+  //connection user is now changed. 
+});
+```
+

src/cmd/change-user.js

@@ -0,0 +1,188 @@
+"use strict";
+
+const Utils = require("../misc/utils");
+const Iconv = require("iconv-lite");
+const Capabilities = require("../const/capabilities");
+const NativePasswordAuth = require("./handshake/auth/native_password_auth");
+const Collations = require("../const/collations");
+const Handshake = require("./handshake/handshake");
+
+
+/**
+ * send a COM_CHANGE_USER: resets the connection and re-authenticates with the given credentials
+ * see https://mariadb.com/kb/en/library/com_change_user/
+ */
+class ChangeUser extends Handshake {
+  constructor(connEvents, options, onResult) {
+    super(connEvents, () => {}, () => {}, onResult);
+    this.opts = options;
+    this.onResult = onResult;
+  }
+
+  start(out, opts, info) {
+    this.configAssign(opts, this.opts);
+    let authToken;
+    switch (info.defaultPluginName) {
+      case "mysql_native_password":
+      case "":
+        authToken = NativePasswordAuth.encryptPassword(this.opts.password, info.seed);
+        break;
+
+      case "mysql_clear_password":
+        if (!this.opts.password) {
+          authToken = Buffer.alloc(0);
+        } else {
+          authToken = Buffer.from(this.opts.password);
+        }
+        break;
+
+      default:
+        authToken = Buffer.alloc(0);
+        break;
+    }
+
+
+    out.startPacket(this);
+    out.writeInt8(0x11);
+    out.writeString(this.opts.user || "");
+    out.writeInt8(0);
+
+    if (info.serverCapabilities & Capabilities.SECURE_CONNECTION) {
+      out.writeInt8(authToken.length);
+      out.writeBuffer(authToken, 0, authToken.length);
+    } else {
+      out.writeBuffer(authToken, 0, authToken.length);
+      out.writeInt8(0);
+    }
+
+    if (info.clientCapabilities & Capabilities.CONNECT_WITH_DB) {
+      out.writeString(this.opts.database);
+      out.writeInt8(0);
+      info.database = this.opts.database;
+    }
+
+    out.writeInt16(this.opts.collation.index);
+
+    if (info.clientCapabilities & Capabilities.PLUGIN_AUTH) {
+      out.writeString(info.defaultPluginName);
+      out.writeInt8(0);
+    }
+
+    if (info.serverCapabilities & Capabilities.CONNECT_ATTRS) {
+      let connectAttributes = this.opts.connectAttributes || {};
+      let attrNames = Object.keys(connectAttributes);
+      out.writeInt8(0xfc);
+      let initPos = out.pos; //save position, assuming connection attributes length will be less than 2 bytes length
+      out.writeInt16(0);
+
+      const encoding = this.opts.collation.encoding;
+
+      writeParam(out, "_client_name", encoding);
+      writeParam(out, "MariaDB connector/Node", encoding);
+
+      let packageJson = require("../../package.json");
+      writeParam(out, "_client_version", encoding);
+      writeParam(out, packageJson.version, encoding);
+
+      writeParam(out, "_node_version", encoding);
+      writeParam(out, process.versions.node, encoding);
+
+      for (let k = 0; k < attrNames.length; ++k) {
+        writeParam(out, attrNames[k], encoding);
+        writeParam(out, connectAttributes[attrNames[k]], encoding);
+      }
+      //write end size
+      out.buf[initPos] = out.pos - initPos - 2;
+      out.buf[initPos + 1] = (out.pos - initPos - 2) >> 8;
+    }
+
+    out.flushBuffer(true);
+    this.emit("send_end");
+
+    return this.handshakeResult;
+  }
+
+
+  /**
+   * Assign global configuration option used by result-set to current query option.
+   * a little faster than Object.assign() since doest copy all information
+   *
+   * @param connOpts  connection global configuration
+   * @param opt       current options
+   */
+  configAssign(connOpts, opt) {
+    if (!opt) {
+      this.opts = connOpts;
+      return;
+    }
+
+    this.opts.password = opt.password ? opt.password : connOpts.password;
+    this.opts.user = opt.user ? opt.user : connOpts.user;
+    this.opts.database = opt.database ? opt.database : connOpts.database;
+    this.opts.connectAttributes = opt.connectAttributes ? opt.connectAttributes : connOpts.connectAttributes;
+
+    if (this.opts.charset && typeof this.opts.charset === "string") {
+      this.opts.collation = Collations.fromName(this.opts.charset.toUpperCase());
+      if (this.opts.collation === undefined)
+        throw new RangeError("Unknown charset '" + this.opts.charset + "'");
+      const initialCallback = this.onResult;
+      this.onResult = (err) => {
+        if (!err) connOpts.collation = this.opts.collation;
+        initialCallback(err);
+      }
+
+    } else {
+      this.opts.collation = Collations.fromIndex(this.opts.charsetNumber) || connOpts.collation;
+    }
+  }
+
+  /**
+   * Read ping response packet.
+   * packet can be :
+   * - an ERR_Packet
+   * - a OK_Packet
+   *
+   * @param packet  query response
+   * @param out     output writer
+   * @param opts    connection options
+   * @param info    connection info
+   * @returns {null}
+   */
+  readChangeUserResponsePacket(packet, out, opts, info) {
+    switch (packet.peek()) {
+      //*********************************************************************************************************
+      //* OK response
+      //*********************************************************************************************************
+      case 0x00:
+        packet.skip(1); //skip header
+        info.status = packet.readUInt16();
+        if (this.onResult) process.nextTick(this.onResult, null);
+        this.emit("end");
+        return null;
+
+      //*********************************************************************************************************
+      //* ERROR response
+      //*********************************************************************************************************
+      case 0xff:
+        const err = packet.readError(info);
+        this.throwError(err);
+        return null;
+
+      default:
+        const errUnexpected = Utils.createError("unexpected packet", false, info);
+        this.throwError(errUnexpected);
+        return null;
+    }
+  }
+}
+
+
+function writeParam(out, val, encoding) {
+  let param = Buffer.isEncoding(encoding)
+    ? Buffer.from(val, encoding)
+    : Iconv.encode(val, encoding);
+  out.writeLengthCoded(param.length);
+  out.writeBuffer(param, 0, param.length);
+}
+
+module.exports = ChangeUser;

src/connection.js

@@ -17,6 +17,7 @@ const Quit = require("./cmd/quit");
 const Ping = require("./cmd/ping");
 const Utils = require("./misc/utils");
 const Query = require("./cmd/query");
+const ChangeUser = require("./cmd/change-user");
 
 class Connection {
   constructor(options) {
@@ -90,7 +91,17 @@ class Connection {
   }
 
   changeUser(options, callback) {
-    //TODO
+    let _options, _cb;
+    if (typeof options === "function") {
+      _cb = options;
+      _options = undefined;
+    } else {
+      _options = options;
+      _cb = callback;
+    }
+
+    const cmd = new ChangeUser(this._events, _options, _cb);
+    return this._addCommand(cmd, false);
   }
 
   /**

test/integration/test-change-user.js

@@ -0,0 +1,64 @@
+"use strict";
+
+const base = require("../base.js");
+const assert = require("chai").assert;
+const Collations = require("../../src/const/collations.js");
+
+describe("change user", () => {
+
+
+  afterEach(() => {
+    shareConn.query("DROP USER 'changeUser'@'%'", err => {});
+  });
+
+  it("basic change user", function(done) {
+    const conn = base.createConnection();
+    conn.connect(err => {
+      if (err) done(err);
+
+      conn.query("SELECT CURRENT_USER", (err, res) => {
+        const currUser = res[0]["CURRENT_USER"];
+        conn.query("CREATE USER 'changeUser'@'%'");
+        conn.query("GRANT ALL PRIVILEGES ON *.* TO 'changeUser'@'%' IDENTIFIED BY 'mypassword'");
+        conn.changeUser({user: 'changeUser', password: 'mypassword'}, (err) => {
+          if (err) {
+            done(err);
+          } else {
+            conn.query("SELECT CURRENT_USER", (err, res) => {
+              const user = res[0]["CURRENT_USER"];
+              assert.equal(user, "changeUser@%");
+              assert.isTrue(user !== currUser);
+              conn.end();
+              done();
+            });
+          }
+        })
+      });
+    });
+  });
+
+  it("change user with collation", function(done) {
+    const conn = base.createConnection();
+    conn.connect(err => {
+      if (err) done(err);
+
+      conn.query("CREATE USER 'changeUser'@'%'");
+      conn.query("GRANT ALL PRIVILEGES ON *.* TO 'changeUser'@'%' IDENTIFIED BY 'mypassword2'");
+      conn.changeUser({user: 'changeUser', password: 'mypassword2', charset: 'UTF8_VIETNAMESE_CI'}, (err) => {
+        if (err) {
+          done(err);
+        } else {
+          conn.query("SELECT CURRENT_USER", (err, res) => {
+            const user = res[0]["CURRENT_USER"];
+            assert.equal(user, "changeUser@%");
+            assert.equal(conn.opts.collation.name, 'UTF8_VIETNAMESE_CI');
+            conn.end();
+            done();
+          });
+        }
+      })
+    })
+  });
+
+
+});