feat: add sqlstring and supports-color modules

- Introduced sqlstring module for SQL escape and formatting.
- Added supports-color module to detect terminal color support.
- Created dashboard and login views with Bootstrap styling.
- Implemented user schema in SQL with mock data for testing.

backend/node_modules/mysql2/lib/commands/auth_switch.js

@@ -0,0 +1,111 @@
+// This file was modified by Oracle on July 5, 2021.
+// Errors generated by asynchronous authentication plugins are now being
+// handled and subsequently emitted at the command level.
+// Modifications copyright (c) 2021, Oracle and/or its affiliates.
+
+'use strict';
+
+const Packets = require('../packets/index.js');
+const sha256_password = require('../auth_plugins/sha256_password');
+const caching_sha2_password = require('../auth_plugins/caching_sha2_password.js');
+const mysql_native_password = require('../auth_plugins/mysql_native_password.js');
+const mysql_clear_password = require('../auth_plugins/mysql_clear_password.js');
+
+const standardAuthPlugins = {
+  sha256_password: sha256_password({}),
+  caching_sha2_password: caching_sha2_password({}),
+  mysql_native_password: mysql_native_password({}),
+  mysql_clear_password: mysql_clear_password({}),
+};
+
+function warnLegacyAuthSwitch() {
+  console.warn(
+    'WARNING! authSwitchHandler api is deprecated, please use new authPlugins api'
+  );
+}
+
+function authSwitchPluginError(error, command) {
+  // Authentication errors are fatal
+  error.code = 'AUTH_SWITCH_PLUGIN_ERROR';
+  error.fatal = true;
+
+  command.emit('error', error);
+}
+
+function authSwitchRequest(packet, connection, command) {
+  const { pluginName, pluginData } =
+    Packets.AuthSwitchRequest.fromPacket(packet);
+  let authPlugin =
+    connection.config.authPlugins && connection.config.authPlugins[pluginName];
+
+  // legacy plugin api don't allow to override mysql_native_password
+  // if pluginName is mysql_native_password it's using standard auth4.1 auth
+  if (
+    connection.config.authSwitchHandler &&
+    pluginName !== 'mysql_native_password'
+  ) {
+    const legacySwitchHandler = connection.config.authSwitchHandler;
+    warnLegacyAuthSwitch();
+    legacySwitchHandler({ pluginName, pluginData }, (err, data) => {
+      if (err) {
+        return authSwitchPluginError(err, command);
+      }
+      connection.writePacket(new Packets.AuthSwitchResponse(data).toPacket());
+    });
+    return;
+  }
+  if (!authPlugin) {
+    authPlugin = standardAuthPlugins[pluginName];
+  }
+  if (!authPlugin) {
+    throw new Error(
+      `Server requests authentication using unknown plugin ${pluginName}. See ${'TODO: add plugins doco here'} on how to configure or author authentication plugins.`
+    );
+  }
+  connection._authPlugin = authPlugin({ connection, command });
+  Promise.resolve(connection._authPlugin(pluginData))
+    .then((data) => {
+      if (data) {
+        connection.writePacket(new Packets.AuthSwitchResponse(data).toPacket());
+      }
+    })
+    .catch((err) => {
+      authSwitchPluginError(err, command);
+    });
+}
+
+function authSwitchRequestMoreData(packet, connection, command) {
+  const { data } = Packets.AuthSwitchRequestMoreData.fromPacket(packet);
+
+  if (connection.config.authSwitchHandler) {
+    const legacySwitchHandler = connection.config.authSwitchHandler;
+    warnLegacyAuthSwitch();
+    legacySwitchHandler({ pluginData: data }, (err, data) => {
+      if (err) {
+        return authSwitchPluginError(err, command);
+      }
+      connection.writePacket(new Packets.AuthSwitchResponse(data).toPacket());
+    });
+    return;
+  }
+
+  if (!connection._authPlugin) {
+    throw new Error(
+      'AuthPluginMoreData received but no auth plugin instance found'
+    );
+  }
+  Promise.resolve(connection._authPlugin(data))
+    .then((data) => {
+      if (data) {
+        connection.writePacket(new Packets.AuthSwitchResponse(data).toPacket());
+      }
+    })
+    .catch((err) => {
+      authSwitchPluginError(err, command);
+    });
+}
+
+module.exports = {
+  authSwitchRequest,
+  authSwitchRequestMoreData,
+};

backend/node_modules/mysql2/lib/commands/binlog_dump.js

@@ -0,0 +1,109 @@
+'use strict';
+
+const Command = require('./command');
+const Packets = require('../packets');
+
+const eventParsers = [];
+
+class BinlogEventHeader {
+  constructor(packet) {
+    this.timestamp = packet.readInt32();
+    this.eventType = packet.readInt8();
+    this.serverId = packet.readInt32();
+    this.eventSize = packet.readInt32();
+    this.logPos = packet.readInt32();
+    this.flags = packet.readInt16();
+  }
+}
+
+class BinlogDump extends Command {
+  constructor(opts) {
+    super();
+    // this.onResult = callback;
+    this.opts = opts;
+  }
+
+  start(packet, connection) {
+    const newPacket = new Packets.BinlogDump(this.opts);
+    connection.writePacket(newPacket.toPacket(1));
+    return BinlogDump.prototype.binlogData;
+  }
+
+  binlogData(packet) {
+    // ok - continue consuming events
+    // error - error
+    // eof - end of binlog
+    if (packet.isEOF()) {
+      this.emit('eof');
+      return null;
+    }
+    // binlog event header
+    packet.readInt8();
+    const header = new BinlogEventHeader(packet);
+    const EventParser = eventParsers[header.eventType];
+    let event;
+    if (EventParser) {
+      event = new EventParser(packet);
+    } else {
+      event = {
+        name: 'UNKNOWN',
+      };
+    }
+    event.header = header;
+    this.emit('event', event);
+    return BinlogDump.prototype.binlogData;
+  }
+}
+
+class RotateEvent {
+  constructor(packet) {
+    this.pposition = packet.readInt32();
+    // TODO: read uint64 here
+    packet.readInt32(); // positionDword2
+    this.nextBinlog = packet.readString();
+    this.name = 'RotateEvent';
+  }
+}
+
+class FormatDescriptionEvent {
+  constructor(packet) {
+    this.binlogVersion = packet.readInt16();
+    this.serverVersion = packet.readString(50).replace(/\u0000.*/, ''); // eslint-disable-line no-control-regex
+    this.createTimestamp = packet.readInt32();
+    this.eventHeaderLength = packet.readInt8(); // should be 19
+    this.eventsLength = packet.readBuffer();
+    this.name = 'FormatDescriptionEvent';
+  }
+}
+
+class QueryEvent {
+  constructor(packet) {
+    const parseStatusVars = require('../packets/binlog_query_statusvars.js');
+    this.slaveProxyId = packet.readInt32();
+    this.executionTime = packet.readInt32();
+    const schemaLength = packet.readInt8();
+    this.errorCode = packet.readInt16();
+    const statusVarsLength = packet.readInt16();
+    const statusVars = packet.readBuffer(statusVarsLength);
+    this.schema = packet.readString(schemaLength);
+    packet.readInt8(); // should be zero
+    this.statusVars = parseStatusVars(statusVars);
+    this.query = packet.readString();
+    this.name = 'QueryEvent';
+  }
+}
+
+class XidEvent {
+  constructor(packet) {
+    this.binlogVersion = packet.readInt16();
+    this.xid = packet.readInt64();
+    this.name = 'XidEvent';
+  }
+}
+
+eventParsers[2] = QueryEvent;
+eventParsers[4] = RotateEvent;
+eventParsers[15] = FormatDescriptionEvent;
+eventParsers[16] = XidEvent;
+
+module.exports = BinlogDump;

backend/node_modules/mysql2/lib/commands/change_user.js

@@ -0,0 +1,68 @@
+// This file was modified by Oracle on September 21, 2021.
+// The changes involve saving additional authentication factor passwords
+// in the command scope and enabling multi-factor authentication in the
+// client-side when the server supports it.
+// Modifications copyright (c) 2021, Oracle and/or its affiliates.
+
+'use strict';
+
+const Command = require('./command.js');
+const Packets = require('../packets/index.js');
+const ClientConstants = require('../constants/client');
+const ClientHandshake = require('./client_handshake.js');
+const CharsetToEncoding = require('../constants/charset_encodings.js');
+
+class ChangeUser extends Command {
+  constructor(options, callback) {
+    super();
+    this.onResult = callback;
+    this.user = options.user;
+    this.password = options.password;
+    // "password1" is an alias of "password"
+    this.password1 = options.password;
+    this.password2 = options.password2;
+    this.password3 = options.password3;
+    this.database = options.database;
+    this.passwordSha1 = options.passwordSha1;
+    this.charsetNumber = options.charsetNumber;
+    this.currentConfig = options.currentConfig;
+    this.authenticationFactor = 0;
+  }
+  start(packet, connection) {
+    const newPacket = new Packets.ChangeUser({
+      flags: connection.config.clientFlags,
+      user: this.user,
+      database: this.database,
+      charsetNumber: this.charsetNumber,
+      password: this.password,
+      passwordSha1: this.passwordSha1,
+      authPluginData1: connection._handshakePacket.authPluginData1,
+      authPluginData2: connection._handshakePacket.authPluginData2,
+    });
+    this.currentConfig.user = this.user;
+    this.currentConfig.password = this.password;
+    this.currentConfig.database = this.database;
+    this.currentConfig.charsetNumber = this.charsetNumber;
+    connection.clientEncoding = CharsetToEncoding[this.charsetNumber];
+    // clear prepared statements cache as all statements become invalid after changeUser
+    connection._statements.clear();
+    connection.writePacket(newPacket.toPacket());
+    // check if the server supports multi-factor authentication
+    const multiFactorAuthentication =
+      connection.serverCapabilityFlags &
+      ClientConstants.MULTI_FACTOR_AUTHENTICATION;
+    if (multiFactorAuthentication) {
+      // if the server supports multi-factor authentication, we enable it in
+      // the client
+      this.authenticationFactor = 1;
+    }
+    return ChangeUser.prototype.handshakeResult;
+  }
+}
+
+ChangeUser.prototype.handshakeResult =
+  ClientHandshake.prototype.handshakeResult;
+ChangeUser.prototype.calculateNativePasswordAuthToken =
+  ClientHandshake.prototype.calculateNativePasswordAuthToken;
+
+module.exports = ChangeUser;

backend/node_modules/mysql2/lib/commands/client_handshake.js

@@ -0,0 +1,241 @@
+// This file was modified by Oracle on June 17, 2021.
+// Handshake errors are now maked as fatal and the corresponding events are
+// emitted in the command instance itself.
+// Modifications copyright (c) 2021, Oracle and/or its affiliates.
+
+// This file was modified by Oracle on September 21, 2021.
+// Handshake workflow now supports additional authentication factors requested
+// by the server.
+// Modifications copyright (c) 2021, Oracle and/or its affiliates.
+
+'use strict';
+
+const Command = require('./command.js');
+const Packets = require('../packets/index.js');
+const ClientConstants = require('../constants/client.js');
+const CharsetToEncoding = require('../constants/charset_encodings.js');
+const auth41 = require('../auth_41.js');
+
+function flagNames(flags) {
+  const res = [];
+  for (const c in ClientConstants) {
+    if (flags & ClientConstants[c]) {
+      res.push(c.replace(/_/g, ' ').toLowerCase());
+    }
+  }
+  return res;
+}
+
+class ClientHandshake extends Command {
+  constructor(clientFlags) {
+    super();
+    this.handshake = null;
+    this.clientFlags = clientFlags;
+    this.authenticationFactor = 0;
+  }
+
+  start() {
+    return ClientHandshake.prototype.handshakeInit;
+  }
+
+  sendSSLRequest(connection) {
+    const sslRequest = new Packets.SSLRequest(
+      this.clientFlags,
+      connection.config.charsetNumber
+    );
+    connection.writePacket(sslRequest.toPacket());
+  }
+
+  sendCredentials(connection) {
+    if (connection.config.debug) {
+      // eslint-disable-next-line
+      console.log(
+        'Sending handshake packet: flags:%d=(%s)',
+        this.clientFlags,
+        flagNames(this.clientFlags).join(', ')
+      );
+    }
+    this.user = connection.config.user;
+    this.password = connection.config.password;
+    // "password1" is an alias to the original "password" value
+    // to make it easier to integrate multi-factor authentication
+    this.password1 = connection.config.password;
+    // "password2" and "password3" are the 2nd and 3rd factor authentication
+    // passwords, which can be undefined depending on the authentication
+    // plugin being used
+    this.password2 = connection.config.password2;
+    this.password3 = connection.config.password3;
+    this.passwordSha1 = connection.config.passwordSha1;
+    this.database = connection.config.database;
+    this.authPluginName = this.handshake.authPluginName;
+    const handshakeResponse = new Packets.HandshakeResponse({
+      flags: this.clientFlags,
+      user: this.user,
+      database: this.database,
+      password: this.password,
+      passwordSha1: this.passwordSha1,
+      charsetNumber: connection.config.charsetNumber,
+      authPluginData1: this.handshake.authPluginData1,
+      authPluginData2: this.handshake.authPluginData2,
+      compress: connection.config.compress,
+      connectAttributes: connection.config.connectAttributes,
+    });
+    connection.writePacket(handshakeResponse.toPacket());
+  }
+
+  calculateNativePasswordAuthToken(authPluginData) {
+    // TODO: dont split into authPluginData1 and authPluginData2, instead join when 1 & 2 received
+    const authPluginData1 = authPluginData.slice(0, 8);
+    const authPluginData2 = authPluginData.slice(8, 20);
+    let authToken;
+    if (this.passwordSha1) {
+      authToken = auth41.calculateTokenFromPasswordSha(
+        this.passwordSha1,
+        authPluginData1,
+        authPluginData2
+      );
+    } else {
+      authToken = auth41.calculateToken(
+        this.password,
+        authPluginData1,
+        authPluginData2
+      );
+    }
+    return authToken;
+  }
+
+  handshakeInit(helloPacket, connection) {
+    this.on('error', (e) => {
+      connection._fatalError = e;
+      connection._protocolError = e;
+    });
+    this.handshake = Packets.Handshake.fromPacket(helloPacket);
+    if (connection.config.debug) {
+      // eslint-disable-next-line
+      console.log(
+        'Server hello packet: capability flags:%d=(%s)',
+        this.handshake.capabilityFlags,
+        flagNames(this.handshake.capabilityFlags).join(', ')
+      );
+    }
+    connection.serverCapabilityFlags = this.handshake.capabilityFlags;
+    connection.serverEncoding = CharsetToEncoding[this.handshake.characterSet];
+    connection.connectionId = this.handshake.connectionId;
+    const serverSSLSupport =
+      this.handshake.capabilityFlags & ClientConstants.SSL;
+    // multi factor authentication is enabled with the
+    // "MULTI_FACTOR_AUTHENTICATION" capability and should only be used if it
+    // is supported by the server
+    const multiFactorAuthentication =
+      this.handshake.capabilityFlags &
+      ClientConstants.MULTI_FACTOR_AUTHENTICATION;
+    this.clientFlags = this.clientFlags | multiFactorAuthentication;
+    // use compression only if requested by client and supported by server
+    connection.config.compress =
+      connection.config.compress &&
+      this.handshake.capabilityFlags & ClientConstants.COMPRESS;
+    this.clientFlags = this.clientFlags | connection.config.compress;
+    if (connection.config.ssl) {
+      // client requires SSL but server does not support it
+      if (!serverSSLSupport) {
+        const err = new Error('Server does not support secure connection');
+        err.code = 'HANDSHAKE_NO_SSL_SUPPORT';
+        err.fatal = true;
+        this.emit('error', err);
+        return false;
+      }
+      // send ssl upgrade request and immediately upgrade connection to secure
+      this.clientFlags |= ClientConstants.SSL;
+      this.sendSSLRequest(connection);
+      connection.startTLS((err) => {
+        // after connection is secure
+        if (err) {
+          // SSL negotiation error are fatal
+          err.code = 'HANDSHAKE_SSL_ERROR';
+          err.fatal = true;
+          this.emit('error', err);
+          return;
+        }
+        // rest of communication is encrypted
+        this.sendCredentials(connection);
+      });
+    } else {
+      this.sendCredentials(connection);
+    }
+    if (multiFactorAuthentication) {
+      // if the server supports multi-factor authentication, we enable it in
+      // the client
+      this.authenticationFactor = 1;
+    }
+    return ClientHandshake.prototype.handshakeResult;
+  }
+
+  handshakeResult(packet, connection) {
+    const marker = packet.peekByte();
+    // packet can be OK_Packet, ERR_Packet, AuthSwitchRequest, AuthNextFactor
+    // or AuthMoreData
+    if (marker === 0xfe || marker === 1 || marker === 0x02) {
+      const authSwitch = require('./auth_switch');
+      try {
+        if (marker === 1) {
+          authSwitch.authSwitchRequestMoreData(packet, connection, this);
+        } else {
+          // if authenticationFactor === 0, it means the server does not support
+          // the multi-factor authentication capability
+          if (this.authenticationFactor !== 0) {
+            // if we are past the first authentication factor, we should use the
+            // corresponding password (if there is one)
+            connection.config.password =
+              this[`password${this.authenticationFactor}`];
+            // update the current authentication factor
+            this.authenticationFactor += 1;
+          }
+          // if marker === 0x02, it means it is an AuthNextFactor packet,
+          // which is similar in structure to an AuthSwitchRequest packet,
+          // so, we can use it directly
+          authSwitch.authSwitchRequest(packet, connection, this);
+        }
+        return ClientHandshake.prototype.handshakeResult;
+      } catch (err) {
+        // Authentication errors are fatal
+        err.code = 'AUTH_SWITCH_PLUGIN_ERROR';
+        err.fatal = true;
+
+        if (this.onResult) {
+          this.onResult(err);
+        } else {
+          this.emit('error', err);
+        }
+        return null;
+      }
+    }
+    if (marker !== 0) {
+      const err = new Error('Unexpected packet during handshake phase');
+      // Unknown handshake errors are fatal
+      err.code = 'HANDSHAKE_UNKNOWN_ERROR';
+      err.fatal = true;
+
+      if (this.onResult) {
+        this.onResult(err);
+      } else {
+        this.emit('error', err);
+      }
+      return null;
+    }
+    // this should be called from ClientHandshake command only
+    // and skipped when called from ChangeUser command
+    if (!connection.authorized) {
+      connection.authorized = true;
+      if (connection.config.compress) {
+        const enableCompression =
+          require('../compressed_protocol.js').enableCompression;
+        enableCompression(connection);
+      }
+    }
+    if (this.onResult) {
+      this.onResult(null);
+    }
+    return null;
+  }
+}
+module.exports = ClientHandshake;

backend/node_modules/mysql2/lib/commands/close_statement.js

@@ -0,0 +1,18 @@
+'use strict';
+
+const Command = require('./command');
+const Packets = require('../packets/index.js');
+
+class CloseStatement extends Command {
+  constructor(id) {
+    super();
+    this.id = id;
+  }
+
+  start(packet, connection) {
+    connection.writePacket(new Packets.CloseStatement(this.id).toPacket(1));
+    return null;
+  }
+}
+
+module.exports = CloseStatement;

backend/node_modules/mysql2/lib/commands/command.js

@@ -0,0 +1,54 @@
+'use strict';
+
+const EventEmitter = require('events').EventEmitter;
+const Timers = require('timers');
+
+class Command extends EventEmitter {
+  constructor() {
+    super();
+    this.next = null;
+  }
+
+  // slow. debug only
+  stateName() {
+    const state = this.next;
+    for (const i in this) {
+      if (this[i] === state && i !== 'next') {
+        return i;
+      }
+    }
+    return 'unknown name';
+  }
+
+  execute(packet, connection) {
+    if (!this.next) {
+      this.next = this.start;
+      connection._resetSequenceId();
+    }
+    if (packet && packet.isError()) {
+      const err = packet.asError(connection.clientEncoding);
+      err.sql = this.sql || this.query;
+      if (this.queryTimeout) {
+        Timers.clearTimeout(this.queryTimeout);
+        this.queryTimeout = null;
+      }
+      if (this.onResult) {
+        this.onResult(err);
+        this.emit('end');
+      } else {
+        this.emit('error', err);
+        this.emit('end');
+      }
+      return true;
+    }
+    // TODO: don't return anything from execute, it's ugly and error-prone. Listen for 'end' event in connection
+    this.next = this.next(packet, connection);
+    if (this.next) {
+      return false;
+    }
+    this.emit('end');
+    return true;
+  }
+}
+
+module.exports = Command;

backend/node_modules/mysql2/lib/commands/execute.js

@@ -0,0 +1,112 @@
+'use strict';
+
+const Command = require('./command.js');
+const Query = require('./query.js');
+const Packets = require('../packets/index.js');
+
+const getBinaryParser = require('../parsers/binary_parser.js');
+const getStaticBinaryParser = require('../parsers/static_binary_parser.js');
+
+class Execute extends Command {
+  constructor(options, callback) {
+    super();
+    this.statement = options.statement;
+    this.sql = options.sql;
+    this.values = options.values;
+    this.onResult = callback;
+    this.parameters = options.values;
+    this.insertId = 0;
+    this.timeout = options.timeout;
+    this.queryTimeout = null;
+    this._rows = [];
+    this._fields = [];
+    this._result = [];
+    this._fieldCount = 0;
+    this._rowParser = null;
+    this._executeOptions = options;
+    this._resultIndex = 0;
+    this._localStream = null;
+    this._unpipeStream = function () {};
+    this._streamFactory = options.infileStreamFactory;
+    this._connection = null;
+  }
+
+  buildParserFromFields(fields, connection) {
+    if (this.options.disableEval) {
+      return getStaticBinaryParser(fields, this.options, connection.config);
+    }
+
+    return getBinaryParser(fields, this.options, connection.config);
+  }
+
+  start(packet, connection) {
+    this._connection = connection;
+    this.options = Object.assign({}, connection.config, this._executeOptions);
+    this._setTimeout();
+    const executePacket = new Packets.Execute(
+      this.statement.id,
+      this.parameters,
+      connection.config.charsetNumber,
+      connection.config.timezone
+    );
+    //For reasons why this try-catch is here, please see
+    // https://github.com/sidorares/node-mysql2/pull/689
+    //For additional discussion, see
+    // 1. https://github.com/sidorares/node-mysql2/issues/493
+    // 2. https://github.com/sidorares/node-mysql2/issues/187
+    // 3. https://github.com/sidorares/node-mysql2/issues/480
+    try {
+      connection.writePacket(executePacket.toPacket(1));
+    } catch (error) {
+      this.onResult(error);
+    }
+    return Execute.prototype.resultsetHeader;
+  }
+
+  readField(packet, connection) {
+    let fields;
+    // disabling for now, but would be great to find reliable way to parse fields only once
+    // fields reported by prepare can be empty at all or just incorrect - see #169
+    //
+    // perfomance optimisation: if we already have this field parsed in statement header, use one from header
+    // const field = this.statement.columns.length == this._fieldCount ?
+    //  this.statement.columns[this._receivedFieldsCount] : new Packets.ColumnDefinition(packet);
+    const field = new Packets.ColumnDefinition(
+      packet,
+      connection.clientEncoding
+    );
+    this._receivedFieldsCount++;
+    this._fields[this._resultIndex].push(field);
+    if (this._receivedFieldsCount === this._fieldCount) {
+      fields = this._fields[this._resultIndex];
+      this.emit('fields', fields, this._resultIndex);
+      return Execute.prototype.fieldsEOF;
+    }
+    return Execute.prototype.readField;
+  }
+
+  fieldsEOF(packet, connection) {
+    // check EOF
+    if (!packet.isEOF()) {
+      return connection.protocolError('Expected EOF packet');
+    }
+    this._rowParser = new (this.buildParserFromFields(
+      this._fields[this._resultIndex],
+      connection
+    ))();
+    return Execute.prototype.row;
+  }
+}
+
+Execute.prototype.done = Query.prototype.done;
+Execute.prototype.doneInsert = Query.prototype.doneInsert;
+Execute.prototype.resultsetHeader = Query.prototype.resultsetHeader;
+Execute.prototype._findOrCreateReadStream =
+  Query.prototype._findOrCreateReadStream;
+Execute.prototype._streamLocalInfile = Query.prototype._streamLocalInfile;
+Execute.prototype._setTimeout = Query.prototype._setTimeout;
+Execute.prototype._handleTimeoutError = Query.prototype._handleTimeoutError;
+Execute.prototype.row = Query.prototype.row;
+Execute.prototype.stream = Query.prototype.stream;
+
+module.exports = Execute;

backend/node_modules/mysql2/lib/commands/index.js

@@ -0,0 +1,27 @@
+'use strict';
+
+const ClientHandshake = require('./client_handshake.js');
+const ServerHandshake = require('./server_handshake.js');
+const Query = require('./query.js');
+const Prepare = require('./prepare.js');
+const CloseStatement = require('./close_statement.js');
+const Execute = require('./execute.js');
+const Ping = require('./ping.js');
+const RegisterSlave = require('./register_slave.js');
+const BinlogDump = require('./binlog_dump.js');
+const ChangeUser = require('./change_user.js');
+const Quit = require('./quit.js');
+
+module.exports = {
+  ClientHandshake,
+  ServerHandshake,
+  Query,
+  Prepare,
+  CloseStatement,
+  Execute,
+  Ping,
+  RegisterSlave,
+  BinlogDump,
+  ChangeUser,
+  Quit,
+};

backend/node_modules/mysql2/lib/commands/ping.js

@@ -0,0 +1,36 @@
+'use strict';
+
+const Command = require('./command');
+const CommandCode = require('../constants/commands');
+const Packet = require('../packets/packet');
+
+// TODO: time statistics?
+// usefull for queue size and network latency monitoring
+// store created,sent,reply timestamps
+class Ping extends Command {
+  constructor(callback) {
+    super();
+    this.onResult = callback;
+  }
+
+  start(packet, connection) {
+    const ping = new Packet(
+      0,
+      Buffer.from([1, 0, 0, 0, CommandCode.PING]),
+      0,
+      5
+    );
+    connection.writePacket(ping);
+    return Ping.prototype.pingResponse;
+  }
+
+  pingResponse() {
+    // TODO: check it's OK packet. error check already done in caller
+    if (this.onResult) {
+      process.nextTick(this.onResult.bind(this));
+    }
+    return null;
+  }
+}
+
+module.exports = Ping;

backend/node_modules/mysql2/lib/commands/prepare.js

@@ -0,0 +1,143 @@
+'use strict';
+
+const Packets = require('../packets/index.js');
+const Command = require('./command.js');
+const CloseStatement = require('./close_statement.js');
+const Execute = require('./execute.js');
+
+class PreparedStatementInfo {
+  constructor(query, id, columns, parameters, connection) {
+    this.query = query;
+    this.id = id;
+    this.columns = columns;
+    this.parameters = parameters;
+    this.rowParser = null;
+    this._connection = connection;
+  }
+
+  close() {
+    return this._connection.addCommand(new CloseStatement(this.id));
+  }
+
+  execute(parameters, callback) {
+    if (typeof parameters === 'function') {
+      callback = parameters;
+      parameters = [];
+    }
+    return this._connection.addCommand(
+      new Execute({ statement: this, values: parameters }, callback)
+    );
+  }
+}
+
+class Prepare extends Command {
+  constructor(options, callback) {
+    super();
+    this.query = options.sql;
+    this.onResult = callback;
+    this.id = 0;
+    this.fieldCount = 0;
+    this.parameterCount = 0;
+    this.fields = [];
+    this.parameterDefinitions = [];
+    this.options = options;
+  }
+
+  start(packet, connection) {
+    const Connection = connection.constructor;
+    this.key = Connection.statementKey(this.options);
+    const statement = connection._statements.get(this.key);
+    if (statement) {
+      if (this.onResult) {
+        this.onResult(null, statement);
+      }
+      return null;
+    }
+    const cmdPacket = new Packets.PrepareStatement(
+      this.query,
+      connection.config.charsetNumber,
+      this.options.values
+    );
+    connection.writePacket(cmdPacket.toPacket(1));
+    return Prepare.prototype.prepareHeader;
+  }
+
+  prepareHeader(packet, connection) {
+    const header = new Packets.PreparedStatementHeader(packet);
+    this.id = header.id;
+    this.fieldCount = header.fieldCount;
+    this.parameterCount = header.parameterCount;
+    if (this.parameterCount > 0) {
+      return Prepare.prototype.readParameter;
+    }
+    if (this.fieldCount > 0) {
+      return Prepare.prototype.readField;
+    }
+    return this.prepareDone(connection);
+  }
+
+  readParameter(packet, connection) {
+    // there might be scenarios when mysql server reports more parameters than
+    // are actually present in the array of parameter definitions.
+    // if EOF packet is received we switch to "read fields" state if there are
+    // any fields reported by the server, otherwise we finish the command.
+    if (packet.isEOF()) {
+      if (this.fieldCount > 0) {
+        return Prepare.prototype.readField;
+      }
+      return this.prepareDone(connection);
+    }
+    const def = new Packets.ColumnDefinition(packet, connection.clientEncoding);
+    this.parameterDefinitions.push(def);
+    if (this.parameterDefinitions.length === this.parameterCount) {
+      return Prepare.prototype.parametersEOF;
+    }
+    return this.readParameter;
+  }
+
+  readField(packet, connection) {
+    if (packet.isEOF()) {
+      return this.prepareDone(connection);
+    }
+    const def = new Packets.ColumnDefinition(packet, connection.clientEncoding);
+    this.fields.push(def);
+    if (this.fields.length === this.fieldCount) {
+      return Prepare.prototype.fieldsEOF;
+    }
+    return Prepare.prototype.readField;
+  }
+
+  parametersEOF(packet, connection) {
+    if (!packet.isEOF()) {
+      return connection.protocolError('Expected EOF packet after parameters');
+    }
+    if (this.fieldCount > 0) {
+      return Prepare.prototype.readField;
+    }
+    return this.prepareDone(connection);
+  }
+
+  fieldsEOF(packet, connection) {
+    if (!packet.isEOF()) {
+      return connection.protocolError('Expected EOF packet after fields');
+    }
+    return this.prepareDone(connection);
+  }
+
+  prepareDone(connection) {
+    const statement = new PreparedStatementInfo(
+      this.query,
+      this.id,
+      this.fields,
+      this.parameterDefinitions,
+      connection
+    );
+    connection._statements.set(this.key, statement);
+    if (this.onResult) {
+      this.onResult(null, statement);
+    }
+    return null;
+  }
+}
+
+module.exports = Prepare;

backend/node_modules/mysql2/lib/commands/query.js

@@ -0,0 +1,329 @@
+'use strict';
+
+const process = require('process');
+const Timers = require('timers');
+
+const Readable = require('stream').Readable;
+
+const Command = require('./command.js');
+const Packets = require('../packets/index.js');
+const getTextParser = require('../parsers/text_parser.js');
+const staticParser = require('../parsers/static_text_parser.js');
+const ServerStatus = require('../constants/server_status.js');
+
+const EmptyPacket = new Packets.Packet(0, Buffer.allocUnsafe(4), 0, 4);
+
+// http://dev.mysql.com/doc/internals/en/com-query.html
+class Query extends Command {
+  constructor(options, callback) {
+    super();
+    this.sql = options.sql;
+    this.values = options.values;
+    this._queryOptions = options;
+    this.namedPlaceholders = options.namedPlaceholders || false;
+    this.onResult = callback;
+    this.timeout = options.timeout;
+    this.queryTimeout = null;
+    this._fieldCount = 0;
+    this._rowParser = null;
+    this._fields = [];
+    this._rows = [];
+    this._receivedFieldsCount = 0;
+    this._resultIndex = 0;
+    this._localStream = null;
+    this._unpipeStream = function () {};
+    this._streamFactory = options.infileStreamFactory;
+    this._connection = null;
+  }
+
+  then() {
+    const err =
+      "You have tried to call .then(), .catch(), or invoked await on the result of query that is not a promise, which is a programming error. Try calling con.promise().query(), or require('mysql2/promise') instead of 'mysql2' for a promise-compatible version of the query interface. To learn how to use async/await or Promises check out documentation at https://sidorares.github.io/node-mysql2/docs#using-promise-wrapper, or the mysql2 documentation at https://sidorares.github.io/node-mysql2/docs/documentation/promise-wrapper";
+    // eslint-disable-next-line
+    console.log(err);
+    throw new Error(err);
+  }
+
+  /* eslint no-unused-vars: ["error", { "argsIgnorePattern": "^_" }] */
+  start(_packet, connection) {
+    if (connection.config.debug) {
+      // eslint-disable-next-line
+      console.log('        Sending query command: %s', this.sql);
+    }
+    this._connection = connection;
+    this.options = Object.assign({}, connection.config, this._queryOptions);
+    this._setTimeout();
+
+    const cmdPacket = new Packets.Query(
+      this.sql,
+      connection.config.charsetNumber
+    );
+    connection.writePacket(cmdPacket.toPacket(1));
+    return Query.prototype.resultsetHeader;
+  }
+
+  done() {
+    this._unpipeStream();
+    // if all ready timeout, return null directly
+    if (this.timeout && !this.queryTimeout) {
+      return null;
+    }
+    // else clear timer
+    if (this.queryTimeout) {
+      Timers.clearTimeout(this.queryTimeout);
+      this.queryTimeout = null;
+    }
+    if (this.onResult) {
+      let rows, fields;
+      if (this._resultIndex === 0) {
+        rows = this._rows[0];
+        fields = this._fields[0];
+      } else {
+        rows = this._rows;
+        fields = this._fields;
+      }
+      if (fields) {
+        process.nextTick(() => {
+          this.onResult(null, rows, fields);
+        });
+      } else {
+        process.nextTick(() => {
+          this.onResult(null, rows);
+        });
+      }
+    }
+    return null;
+  }
+
+  doneInsert(rs) {
+    if (this._localStreamError) {
+      if (this.onResult) {
+        this.onResult(this._localStreamError, rs);
+      } else {
+        this.emit('error', this._localStreamError);
+      }
+      return null;
+    }
+    this._rows.push(rs);
+    this._fields.push(void 0);
+    this.emit('fields', void 0);
+    this.emit('result', rs);
+    if (rs.serverStatus & ServerStatus.SERVER_MORE_RESULTS_EXISTS) {
+      this._resultIndex++;
+      return this.resultsetHeader;
+    }
+    return this.done();
+  }
+
+  resultsetHeader(packet, connection) {
+    const rs = new Packets.ResultSetHeader(packet, connection);
+    this._fieldCount = rs.fieldCount;
+    if (connection.config.debug) {
+      // eslint-disable-next-line
+      console.log(
+        `        Resultset header received, expecting ${rs.fieldCount} column definition packets`
+      );
+    }
+    if (this._fieldCount === 0) {
+      return this.doneInsert(rs);
+    }
+    if (this._fieldCount === null) {
+      return this._streamLocalInfile(connection, rs.infileName);
+    }
+    this._receivedFieldsCount = 0;
+    this._rows.push([]);
+    this._fields.push([]);
+    return this.readField;
+  }
+
+  _streamLocalInfile(connection, path) {
+    if (this._streamFactory) {
+      this._localStream = this._streamFactory(path);
+    } else {
+      this._localStreamError = new Error(
+        `As a result of LOCAL INFILE command server wants to read ${path} file, but as of v2.0 you must provide streamFactory option returning ReadStream.`
+      );
+      connection.writePacket(EmptyPacket);
+      return this.infileOk;
+    }
+
+    const onConnectionError = () => {
+      this._unpipeStream();
+    };
+    const onDrain = () => {
+      this._localStream.resume();
+    };
+    const onPause = () => {
+      this._localStream.pause();
+    };
+    const onData = function (data) {
+      const dataWithHeader = Buffer.allocUnsafe(data.length + 4);
+      data.copy(dataWithHeader, 4);
+      connection.writePacket(
+        new Packets.Packet(0, dataWithHeader, 0, dataWithHeader.length)
+      );
+    };
+    const onEnd = () => {
+      connection.removeListener('error', onConnectionError);
+      connection.writePacket(EmptyPacket);
+    };
+    const onError = (err) => {
+      this._localStreamError = err;
+      connection.removeListener('error', onConnectionError);
+      connection.writePacket(EmptyPacket);
+    };
+    this._unpipeStream = () => {
+      connection.stream.removeListener('pause', onPause);
+      connection.stream.removeListener('drain', onDrain);
+      this._localStream.removeListener('data', onData);
+      this._localStream.removeListener('end', onEnd);
+      this._localStream.removeListener('error', onError);
+    };
+    connection.stream.on('pause', onPause);
+    connection.stream.on('drain', onDrain);
+    this._localStream.on('data', onData);
+    this._localStream.on('end', onEnd);
+    this._localStream.on('error', onError);
+    connection.once('error', onConnectionError);
+    return this.infileOk;
+  }
+
+  readField(packet, connection) {
+    this._receivedFieldsCount++;
+    // Often there is much more data in the column definition than in the row itself
+    // If you set manually _fields[0] to array of ColumnDefinition's (from previous call)
+    // you can 'cache' result of parsing. Field packets still received, but ignored in that case
+    // this is the reason _receivedFieldsCount exist (otherwise we could just use current length of fields array)
+    if (this._fields[this._resultIndex].length !== this._fieldCount) {
+      const field = new Packets.ColumnDefinition(
+        packet,
+        connection.clientEncoding
+      );
+      this._fields[this._resultIndex].push(field);
+      if (connection.config.debug) {
+        /* eslint-disable no-console */
+        console.log('        Column definition:');
+        console.log(`          name: ${field.name}`);
+        console.log(`          type: ${field.columnType}`);
+        console.log(`         flags: ${field.flags}`);
+        /* eslint-enable no-console */
+      }
+    }
+    // last field received
+    if (this._receivedFieldsCount === this._fieldCount) {
+      const fields = this._fields[this._resultIndex];
+      this.emit('fields', fields);
+      if (this.options.disableEval) {
+        this._rowParser = staticParser(fields, this.options, connection.config);
+      } else {
+        this._rowParser = new (getTextParser(
+          fields,
+          this.options,
+          connection.config
+        ))(fields);
+      }
+      return Query.prototype.fieldsEOF;
+    }
+    return Query.prototype.readField;
+  }
+
+  fieldsEOF(packet, connection) {
+    // check EOF
+    if (!packet.isEOF()) {
+      return connection.protocolError('Expected EOF packet');
+    }
+    return this.row;
+  }
+
+  /* eslint no-unused-vars: ["error", { "argsIgnorePattern": "^_" }] */
+  row(packet, _connection) {
+    if (packet.isEOF()) {
+      const status = packet.eofStatusFlags();
+      const moreResults = status & ServerStatus.SERVER_MORE_RESULTS_EXISTS;
+      if (moreResults) {
+        this._resultIndex++;
+        return Query.prototype.resultsetHeader;
+      }
+      return this.done();
+    }
+    let row;
+    try {
+      row = this._rowParser.next(
+        packet,
+        this._fields[this._resultIndex],
+        this.options
+      );
+    } catch (err) {
+      this._localStreamError = err;
+      return this.doneInsert(null);
+    }
+    if (this.onResult) {
+      this._rows[this._resultIndex].push(row);
+    } else {
+      this.emit('result', row, this._resultIndex);
+    }
+    return Query.prototype.row;
+  }
+
+  infileOk(packet, connection) {
+    const rs = new Packets.ResultSetHeader(packet, connection);
+    return this.doneInsert(rs);
+  }
+
+  stream(options) {
+    options = options || {};
+    options.objectMode = true;
+    const stream = new Readable(options);
+    stream._read = () => {
+      this._connection && this._connection.resume();
+    };
+    this.on('result', (row, resultSetIndex) => {
+      if (!stream.push(row)) {
+        this._connection.pause();
+      }
+      stream.emit('result', row, resultSetIndex); // replicate old emitter
+    });
+    this.on('error', (err) => {
+      stream.emit('error', err); // Pass on any errors
+    });
+    this.on('end', () => {
+      stream.push(null); // pushing null, indicating EOF
+    });
+    this.on('fields', (fields) => {
+      stream.emit('fields', fields); // replicate old emitter
+    });
+    stream.on('end', () => {
+      stream.emit('close');
+    });
+    return stream;
+  }
+
+  _setTimeout() {
+    if (this.timeout) {
+      const timeoutHandler = this._handleTimeoutError.bind(this);
+      this.queryTimeout = Timers.setTimeout(timeoutHandler, this.timeout);
+    }
+  }
+
+  _handleTimeoutError() {
+    if (this.queryTimeout) {
+      Timers.clearTimeout(this.queryTimeout);
+      this.queryTimeout = null;
+    }
+
+    const err = new Error('Query inactivity timeout');
+    err.errorno = 'PROTOCOL_SEQUENCE_TIMEOUT';
+    err.code = 'PROTOCOL_SEQUENCE_TIMEOUT';
+    err.syscall = 'query';
+
+    if (this.onResult) {
+      this.onResult(err);
+    } else {
+      this.emit('error', err);
+    }
+  }
+}
+
+Query.prototype.catch = Query.prototype.then;
+
+module.exports = Query;

backend/node_modules/mysql2/lib/commands/quit.js

@@ -0,0 +1,29 @@
+'use strict';
+
+const Command = require('./command.js');
+const CommandCode = require('../constants/commands.js');
+const Packet = require('../packets/packet.js');
+
+class Quit extends Command {
+  constructor(callback) {
+    super();
+    this.onResult = callback;
+  }
+
+  start(packet, connection) {
+    connection._closing = true;
+    const quit = new Packet(
+      0,
+      Buffer.from([1, 0, 0, 0, CommandCode.QUIT]),
+      0,
+      5
+    );
+    if (this.onResult) {
+      this.onResult();
+    }
+    connection.writePacket(quit);
+    return null;
+  }
+}
+
+module.exports = Quit;

backend/node_modules/mysql2/lib/commands/register_slave.js

@@ -0,0 +1,27 @@
+'use strict';
+
+const Command = require('./command');
+const Packets = require('../packets');
+
+class RegisterSlave extends Command {
+  constructor(opts, callback) {
+    super();
+    this.onResult = callback;
+    this.opts = opts;
+  }
+
+  start(packet, connection) {
+    const newPacket = new Packets.RegisterSlave(this.opts);
+    connection.writePacket(newPacket.toPacket(1));
+    return RegisterSlave.prototype.registerResponse;
+  }
+
+  registerResponse() {
+    if (this.onResult) {
+      process.nextTick(this.onResult.bind(this));
+    }
+    return null;
+  }
+}
+
+module.exports = RegisterSlave;

backend/node_modules/mysql2/lib/commands/server_handshake.js

@@ -0,0 +1,203 @@
+'use strict';
+
+const CommandCode = require('../constants/commands.js');
+const Errors = require('../constants/errors.js');
+
+const Command = require('./command.js');
+const Packets = require('../packets/index.js');
+
+class ServerHandshake extends Command {
+  constructor(args) {
+    super();
+    this.args = args;
+    /*
+    this.protocolVersion = args.protocolVersion || 10;
+    this.serverVersion   = args.serverVersion;
+    this.connectionId    = args.connectionId,
+    this.statusFlags     = args.statusFlags,
+    this.characterSet    = args.characterSet,
+    this.capabilityFlags = args.capabilityFlags || 512;
+    */
+  }
+
+  start(packet, connection) {
+    const serverHelloPacket = new Packets.Handshake(this.args);
+    this.serverHello = serverHelloPacket;
+    serverHelloPacket.setScrambleData((err) => {
+      if (err) {
+        connection.emit('error', new Error('Error generating random bytes'));
+        return;
+      }
+      connection.writePacket(serverHelloPacket.toPacket(0));
+    });
+    return ServerHandshake.prototype.readClientReply;
+  }
+
+  readClientReply(packet, connection) {
+    // check auth here
+    const clientHelloReply = Packets.HandshakeResponse.fromPacket(packet);
+    // TODO check we don't have something similar already
+    connection.clientHelloReply = clientHelloReply;
+    if (this.args.authCallback) {
+      this.args.authCallback(
+        {
+          user: clientHelloReply.user,
+          database: clientHelloReply.database,
+          address: connection.stream.remoteAddress,
+          authPluginData1: this.serverHello.authPluginData1,
+          authPluginData2: this.serverHello.authPluginData2,
+          authToken: clientHelloReply.authToken,
+        },
+        (err, mysqlError) => {
+          // if (err)
+          if (!mysqlError) {
+            connection.writeOk();
+          } else {
+            // TODO create constants / errorToCode
+            // 1045 = ER_ACCESS_DENIED_ERROR
+            connection.writeError({
+              message: mysqlError.message || '',
+              code: mysqlError.code || 1045,
+            });
+            connection.close();
+          }
+        }
+      );
+    } else {
+      connection.writeOk();
+    }
+    return ServerHandshake.prototype.dispatchCommands;
+  }
+
+  _isStatement(query, name) {
+    const firstWord = query.split(' ')[0].toUpperCase();
+    return firstWord === name;
+  }
+
+  dispatchCommands(packet, connection) {
+    // command from client to server
+    let knownCommand = true;
+    const encoding = connection.clientHelloReply.encoding;
+    const commandCode = packet.readInt8();
+    switch (commandCode) {
+      case CommandCode.STMT_PREPARE:
+        if (connection.listeners('stmt_prepare').length) {
+          const query = packet.readString(undefined, encoding);
+          connection.emit('stmt_prepare', query);
+        } else {
+          connection.writeError({
+            code: Errors.HA_ERR_INTERNAL_ERROR,
+            message: 'No query handler for prepared statements.',
+          });
+        }
+        break;
+      case CommandCode.STMT_EXECUTE:
+        if (connection.listeners('stmt_execute').length) {
+          const { stmtId, flags, iterationCount, values } =
+            Packets.Execute.fromPacket(packet, encoding);
+          connection.emit(
+            'stmt_execute',
+            stmtId,
+            flags,
+            iterationCount,
+            values
+          );
+        } else {
+          connection.writeError({
+            code: Errors.HA_ERR_INTERNAL_ERROR,
+            message: 'No query handler for execute statements.',
+          });
+        }
+        break;
+      case CommandCode.QUIT:
+        if (connection.listeners('quit').length) {
+          connection.emit('quit');
+        } else {
+          connection.stream.end();
+        }
+        break;
+      case CommandCode.INIT_DB:
+        if (connection.listeners('init_db').length) {
+          const schemaName = packet.readString(undefined, encoding);
+          connection.emit('init_db', schemaName);
+        } else {
+          connection.writeOk();
+        }
+        break;
+      case CommandCode.QUERY:
+        if (connection.listeners('query').length) {
+          const query = packet.readString(undefined, encoding);
+          if (
+            this._isStatement(query, 'PREPARE') ||
+            this._isStatement(query, 'SET')
+          ) {
+            connection.emit('stmt_prepare', query);
+          } else if (this._isStatement(query, 'EXECUTE')) {
+            connection.emit('stmt_execute', null, null, null, null, query);
+          } else connection.emit('query', query);
+        } else {
+          connection.writeError({
+            code: Errors.HA_ERR_INTERNAL_ERROR,
+            message: 'No query handler',
+          });
+        }
+        break;
+      case CommandCode.FIELD_LIST:
+        if (connection.listeners('field_list').length) {
+          const table = packet.readNullTerminatedString(encoding);
+          const fields = packet.readString(undefined, encoding);
+          connection.emit('field_list', table, fields);
+        } else {
+          connection.writeError({
+            code: Errors.ER_WARN_DEPRECATED_SYNTAX,
+            message:
+              'As of MySQL 5.7.11, COM_FIELD_LIST is deprecated and will be removed in a future version of MySQL.',
+          });
+        }
+        break;
+      case CommandCode.PING:
+        if (connection.listeners('ping').length) {
+          connection.emit('ping');
+        } else {
+          connection.writeOk();
+        }
+        break;
+      default:
+        knownCommand = false;
+    }
+    if (connection.listeners('packet').length) {
+      connection.emit('packet', packet.clone(), knownCommand, commandCode);
+    } else if (!knownCommand) {
+      // eslint-disable-next-line no-console
+      console.log('Unknown command:', commandCode);
+    }
+    return ServerHandshake.prototype.dispatchCommands;
+  }
+}
+
+module.exports = ServerHandshake;
+
+// TODO: implement server-side 4.1 authentication
+/*
+4.1 authentication: (http://bazaar.launchpad.net/~mysql/mysql-server/5.5/view/head:/sql/password.c)
+
+  SERVER:  public_seed=create_random_string()
+           send(public_seed)
+
+  CLIENT:  recv(public_seed)
+           hash_stage1=sha1("password")
+           hash_stage2=sha1(hash_stage1)
+           reply=xor(hash_stage1, sha1(public_seed,hash_stage2)
+
+           // this three steps are done in scramble()
+
+           send(reply)
+
+
+  SERVER:  recv(reply)
+           hash_stage1=xor(reply, sha1(public_seed,hash_stage2))
+           candidate_hash2=sha1(hash_stage1)
+           check(candidate_hash2==hash_stage2)
+
+server stores sha1(sha1(password)) ( hash_stag2)
+*/