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描述文字

mysqljs/mysql: A pure node.js JavaScript Client implementing the MySQL protocol.

原作者: [db:作者] 来自: 网络 收藏 邀请

开源软件名称：

mysqljs/mysql

开源软件地址：

https://github.com/mysqljs/mysql

开源编程语言：

JavaScript 100.0%

开源软件介绍：

mysql

NPM Version NPM Downloads Node.js Version Linux Build Windows Build Test Coverage

Table of Contents

Install

This is a Node.js module available through the npm registry.

Before installing, download and install Node.js. Node.js 0.6 or higher is required.

Installation is done using the npm install command:

$ npm install mysql

For information about the previous 0.9.x releases, visit the v0.9 branch.

Sometimes I may also ask you to install the latest version from Github to check if a bugfix is working. In this case, please do:

$ npm install mysqljs/mysql

Introduction

This is a node.js driver for mysql. It is written in JavaScript, does not require compiling, and is 100% MIT licensed.

Here is an example on how to use it:

var mysql      = require('mysql');
var connection = mysql.createConnection({
  host     : 'localhost',
  user     : 'me',
  password : 'secret',
  database : 'my_db'
});

connection.connect();

connection.query('SELECT 1 + 1 AS solution', function (error, results, fields) {
  if (error) throw error;
  console.log('The solution is: ', results[0].solution);
});

connection.end();

From this example, you can learn the following:

  • Every method you invoke on a connection is queued and executed in sequence.
  • Closing the connection is done using end() which makes sure all remaining queries are executed before sending a quit packet to the mysql server.

Contributors

Thanks goes to the people who have contributed code to this module, see the GitHub Contributors page.

Additionally I'd like to thank the following people:

  • Andrey Hristov (Oracle) - for helping me with protocol questions.
  • Ulf Wendel (Oracle) - for helping me with protocol questions.

Sponsors

The following companies have supported this project financially, allowing me to spend more time on it (ordered by time of contribution):

Community

If you'd like to discuss this module, or ask questions about it, please use one of the following:

Establishing connections

The recommended way to establish a connection is this:

var mysql      = require('mysql');
var connection = mysql.createConnection({
  host     : 'example.org',
  user     : 'bob',
  password : 'secret'
});

connection.connect(function(err) {
  if (err) {
    console.error('error connecting: ' + err.stack);
    return;
  }

  console.log('connected as id ' + connection.threadId);
});

However, a connection can also be implicitly established by invoking a query:

var mysql      = require('mysql');
var connection = mysql.createConnection(...);

connection.query('SELECT 1', function (error, results, fields) {
  if (error) throw error;
  // connected!
});

Depending on how you like to handle your errors, either method may be appropriate. Any type of connection error (handshake or network) is considered a fatal error, see the Error Handling section for more information.

Connection options

When establishing a connection, you can set the following options:

  • host: The hostname of the database you are connecting to. (Default: localhost)
  • port: The port number to connect to. (Default: 3306)
  • localAddress: The source IP address to use for TCP connection. (Optional)
  • socketPath: The path to a unix domain socket to connect to. When used host and port are ignored.
  • user: The MySQL user to authenticate as.
  • password: The password of that MySQL user.
  • database: Name of the database to use for this connection (Optional).
  • charset: The charset for the connection. This is called "collation" in the SQL-level of MySQL (like utf8_general_ci). If a SQL-level charset is specified (like utf8mb4) then the default collation for that charset is used. (Default: 'UTF8_GENERAL_CI')
  • timezone: The timezone configured on the MySQL server. This is used to type cast server date/time values to JavaScript Date object and vice versa. This can be 'local', 'Z', or an offset in the form +HH:MM or -HH:MM. (Default: 'local')
  • connectTimeout: The milliseconds before a timeout occurs during the initial connection to the MySQL server. (Default: 10000)
  • stringifyObjects: Stringify objects instead of converting to values. (Default: false)
  • insecureAuth: Allow connecting to MySQL instances that ask for the old (insecure) authentication method. (Default: false)
  • typeCast: Determines if column values should be converted to native JavaScript types. (Default: true)
  • queryFormat: A custom query format function. See Custom format.
  • supportBigNumbers: When dealing with big numbers (BIGINT and DECIMAL columns) in the database, you should enable this option (Default: false).
  • bigNumberStrings: Enabling both supportBigNumbers and bigNumberStrings forces big numbers (BIGINT and DECIMAL columns) to be always returned as JavaScript String objects (Default: false). Enabling supportBigNumbers but leaving bigNumberStrings disabled will return big numbers as String objects only when they cannot be accurately represented with [JavaScript Number objects] (https://tc39.es/ecma262/#sec-ecmascript-language-types-number-type) (which happens when they exceed the [-2^53, +2^53] range), otherwise they will be returned as Number objects. This option is ignored if supportBigNumbers is disabled.
  • dateStrings: Force date types (TIMESTAMP, DATETIME, DATE) to be returned as strings rather than inflated into JavaScript Date objects. Can be true/false or an array of type names to keep as strings. (Default: false)
  • debug: Prints protocol details to stdout. Can be true/false or an array of packet type names that should be printed. (Default: false)
  • trace: Generates stack traces on Error to include call site of library entrance ("long stack traces"). Slight performance penalty for most calls. (Default: true)
  • localInfile: Allow LOAD DATA INFILE to use the LOCAL modifier. (Default: true)
  • multipleStatements: Allow multiple mysql statements per query. Be careful with this, it could increase the scope of SQL injection attacks. (Default: false)
  • flags: List of connection flags to use other than the default ones. It is also possible to blacklist default ones. For more information, check Connection Flags.
  • ssl: object with ssl parameters or a string containing name of ssl profile. See SSL options.

In addition to passing these options as an object, you can also use a url string. For example:

var connection = mysql.createConnection('mysql://user:pass@host/db?debug=true&charset=BIG5_CHINESE_CI&timezone=-0700');

Note: The query values are first attempted to be parsed as JSON, and if that fails assumed to be plaintext strings.

SSL options

The ssl option in the connection options takes a string or an object. When given a string, it uses one of the predefined SSL profiles included. The following profiles are included:

When connecting to other servers, you will need to provide an object with any of the following options:

Here is a simple example:

var connection = mysql.createConnection({
  host : 'localhost',
  ssl  : {
    ca : fs.readFileSync(__dirname + '/mysql-ca.crt')
  }
});

You can also connect to a MySQL server without properly providing the appropriate CA to trust. You should not do this.

var connection = mysql.createConnection({
  host : 'localhost',
  ssl  : {
    // DO NOT DO THIS
    // set up your ca correctly to trust the connection
    rejectUnauthorized: false
  }
});

Connection flags

If, for any reason, you would like to change the default connection flags, you can use the connection option flags. Pass a string with a comma separated list of items to add to the default flags. If you don't want a default flag to be used prepend the flag with a minus sign. To add a flag that is not in the default list, just write the flag name, or prefix it with a plus (case insensitive).

var connection = mysql.createConnection({
  // disable FOUND_ROWS flag, enable IGNORE_SPACE flag
  flags: '-FOUND_ROWS,IGNORE_SPACE'
});

The following flags are available:

  • COMPRESS - Enable protocol compression. This feature is not currently supported by the Node.js implementation so cannot be turned on. (Default off)
  • CONNECT_WITH_DB - Ability to specify the database on connection. (Default on)
  • FOUND_ROWS - Send the found rows instead of the affected rows as affectedRows. (Default on)
  • IGNORE_SIGPIPE - Don't issue SIGPIPE if network failures. This flag has no effect on this Node.js implementation. (Default on)
  • IGNORE_SPACE - Let the parser ignore spaces before the ( in queries. (Default on)
  • INTERACTIVE - Indicates to the MySQL server this is an "interactive" client. This will use the interactive timeouts on the MySQL server and report as interactive in the process list. (Default off)
  • LOCAL_FILES - Can use LOAD DATA LOCAL. This flag is controlled by the connection option localInfile. (Default on)
  • LONG_FLAG - Longer flags in Protocol::ColumnDefinition320. (Default on)
  • LONG_PASSWORD - Use the improved version of Old Password Authentication. (Default on)
  • MULTI_RESULTS - Can handle multiple resultsets for queries. (Default on)
  • MULTI_STATEMENTS - The client may send multiple statement per query or statement prepare (separated by ;). This flag is controlled by the connection option multipleStatements. (Default off)
  • NO_SCHEMA
  • ODBC Special handling of ODBC behaviour. This flag has no effect on this Node.js implementation. (Default on)
  • PLUGIN_AUTH - Uses the plugin authentication mechanism when connecting to the MySQL server. This feature is not currently supported by the Node.js implementation so cannot be turned on. (Default off)
  • PROTOCOL_41 - Uses the 4.1 protocol. (Default on)
  • PS_MULTI_RESULTS - Can handle multiple resultsets for execute. (Default on)
  • REMEMBER_OPTIONS - This is specific to the C client, and has no effect on this Node.js implementation. (Default off)
  • RESERVED - Old flag for the 4.1 protocol. (Default on)
  • SECURE_CONNECTION - Support native 4.1 authentication. (Default on)
  • SSL - Use SSL after handshake to encrypt data in transport. This feature is controlled though the ssl connection option, so the flag has no effect. (Default off)
  • SSL_VERIFY_SERVER_CERT - Verify the server certificate during SSL set up. This feature is controlled though the ssl.rejectUnauthorized connection option, so the flag has no effect. (Default off)
  • TRANSACTIONS - Asks for the transaction status flags. (Default on)

Terminating connections

There are two ways to end a connection. Terminating a connection gracefully is done by calling the end() method:

connection.end(function(err) {
  // The connection is terminated now
});

This will make sure all previously enqueued queries are still executed before sending a COM_QUIT packet to the MySQL server. If a fatal error occurs before the COM_QUIT packet can be sent, an err argument will be provided to the callback, but the connection will be terminated regardless of that.

An alternative way to end the connection is to call the destroy() method. This will cause an immediate termination of the underlying socket. Additionally destroy() guarantees that no more events or callbacks will be triggered for the connection.

connection.destroy();

Unlike end() the destroy() method does not take a callback argument.

Pooling connections

Rather than creating and managing connections one-by-one, this module also provides built-in connection pooling using mysql.createPool(config). Read more about connection pooling.

Create a pool and use it directly:

var mysql = require('mysql');
var pool  = mysql.createPool({
  connectionLimit : 10,
  host            : 'example.org',
  user            : 'bob',
  password        : 'secret',
  database        : 'my_db'
});

pool.query('SELECT 1 + 1 AS solution', function (error, results, fields) {
  if (error) throw error;
  console.log('The solution is: ', results[0].solution);
});

This is a shortcut for the pool.getConnection() -> connection.query() -> connection.release() code flow. Using pool.getConnection() is useful to share connection state for subsequent queries. This is because two calls to pool.query() may use two different connections and run in parallel. This is the basic structure:

var mysql = require('mysql');
var pool  = mysql.createPool(...);

pool.getConnection(function(err, connection) {
  if (err) throw err; // not connected!

  // Use the connection
  connection.query('SELECT something FROM sometable', function (error, results, fields) {
    // When done with the connection, release it.
    connection.release();

    // Handle error after the release.
    if (error) throw error;

    // Don't use the connection here, it has been returned to the pool.
  });
});

If you would like to close the connection and remove it from the pool, use connection.destroy() instead. The pool will create a new connection the next time one is needed.

Connections are lazily created by the pool. If you configure the pool to allow up to 100 connections, but only ever use 5 simultaneously, only 5 connections will be made. Connections are also cycled round-robin style, with connections being taken from the top of the pool and returning to the bottom.

When a previous connection is retrieved from the pool, a ping packet is sent to the server to check if the connection is still good.

Pool options

Pools accept all the same options as a connection. When creating a new connection, the options are simply passed to the connection constructor. In addition to those options pools accept a few extras:

  • acquireTimeout: The milliseconds before a timeout occurs during the connection acquisition. This is slightly different from connectTimeout, because acquiring a pool connection does not always involve making a connection. If a connection request is queued, the time the request spends in the queue does not count towards this timeout. (Default: 10000)
  • waitForConnections: Determines the pool's action when no connections are available and the limit has been reached. If true, the pool will queue the connection request and call it when one becomes available. If false, the pool will immediately call back with an error. (Default: true)
  • connectionLimit: The maximum number of connections to create at once. (Default: 10)
  • queueLimit: The maximum number of connection requests the pool will queue before returning an error from getConnection. If set to 0, there is no limit to the number of queued connection requests. (Default: 0)

Pool events

acquire

The pool will emit an acquire event when a connection is acquired from the pool. This is called after all acquiring activity has been performed on the connection, right before the connection is handed to the callback of the acquiring code.

pool.on('acquire', function (connection) {
  console.log('Connection %d acquired', connection.threadId);
});

connection

The pool will emit a connection event when a new connection is made within the pool. If you need to set session variables on the connection before it gets used, you can listen to the connection event.

pool.on('connection', function (connection) {
  connection.query('SET SESSION auto_increment_increment=1')
});

enqueue

The pool will emit an enqueue event when a callback has been queued to wait for an available connection.

pool.on('enqueue', function () {
  console.log('Waiting for available connection slot');
});

release

The pool will emit a release event when a connection is released back to the pool. This is called after all release activity has been performed on the connection, so the connection will be listed as free at the time of the event.

pool.on('release', function (connection) {
  console.log('Connection %d released', connection.threadId);
});

Closing all the connections in a pool

When you are done using the pool, you have to end all the connections or the Node.js event loop will stay active until the connections are closed by the MySQL server. This is typically done if the pool is used in a script or when trying to gracefully shutdown a server. To end all the connections in the pool, use the end method on the pool:

pool.end(function (err) {
  // all connections in the pool have ended
});

The end method takes an optional callback that you can use to know when all the connections are ended.

Once pool.end is called, pool.getConnection and other operations can no longer be performed. Wait until all connections in the pool are released before calling pool.end. If you use the shortcut method pool.query, in place of pool.getConnection → connection.query → connection.release, wait until it completes.

pool.end calls connection.end on every active connection in the pool. This queues a QUIT packet on the connection and sets a flag to prevent pool.getConnection from creating new connections. All commands / queries already in progress will complete, but new commands won't execute.

PoolCluster

PoolCluster provides multiple hosts connection. (group & retry & selector)


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