mysql
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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.
Community
If you’d like to discuss this module, or ask questions about it, please use one of the following:
- Mailing list: https://groups.google.com/forum/#!forum/node-mysql
- IRC Channel: #node.js (on freenode.net, I pay attention to any message
including the term
mysql
)
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.
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:
"Amazon RDS"
: this profile is for connecting to an Amazon RDS server and contains the certificates from https://rds.amazonaws.com/doc/rds-ssl-ca-cert.pem and https://s3.amazonaws.com/rds-downloads/rds-combined-ca-bundle.pem
When connecting to other servers, you will need to provide an object with any of the following options:
ca
: The certificate(s) to trust instead of the ones Node.js is configured to trust. This refers to the value of the certificate(s) and not a filename of the certificate(s). This is passed as theca
option for the underlyingtls.createSecureContext()
call (or underlyingcrypto.createCredentials()
if using Node.js below 0.12).cert
: The client certificate to use in the SSL handshake. This is passed as thecert
option for the underlyingtls.createSecureContext()
call (or underlyingcrypto.createCredentials()
if using Node.js below 0.12).ciphers
: The ciphers to use to use in the SSL handshake instead of the default ones for Node.js. This is passed as theciphers
option fortls.createSecureContext()
call (or underlyingcrypto.createCredentials()
if using Node.js below 0.12).maxVersion
: This is passed as themaxVersion
option for the underlyingtls.createSecureContext()
call.minVersion
: This is passed as theminVersion
option for the underlyingtls.createSecureContext()
call.key
: This is passed as thekey
option fortls.createSecureContext()
call (or underlyingcrypto.createCredentials()
if using Node.js below 0.12).passphrase
: This is passed as thepassphrase
option fortls.createSecureContext()
call (or underlyingcrypto.createCredentials()
if using Node.js below 0.12).rejectUnauthorized
: The server certificate is verified against the list of supplied CAs and the hostname, and if no match is found, the SSL connection will fail. (Default:true
)
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
}
});
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 fromconnectTimeout
, 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. Iftrue
, the pool will queue the connection request and call it when one becomes available. Iffalse
, 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 fromgetConnection
. If set to0
, 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)
// create
var poolCluster = mysql.createPoolCluster();
// add configurations (the config is a pool config object)
poolCluster.add(config); // add configuration with automatic name
poolCluster.add('MASTER', masterConfig); // add a named configuration
poolCluster.add('SLAVE1', slave1Config);
poolCluster.add('SLAVE2', slave2Config);
// remove configurations
poolCluster.remove('SLAVE2'); // By nodeId
poolCluster.remove('SLAVE*'); // By target group : SLAVE1-2
// Target Group : ALL(anonymous, MASTER, SLAVE1-2), Selector : round-robin(default)
poolCluster.getConnection(function (err, connection) {});
// Target Group : MASTER, Selector : round-robin
poolCluster.getConnection('MASTER', function (err, connection) {});
// Target Group : SLAVE1-2, Selector : order
// If can't connect to SLAVE1, return SLAVE2. (remove SLAVE1 in the cluster)
poolCluster.on('remove', function (nodeId) {
console.log('REMOVED NODE : ' + nodeId); // nodeId = SLAVE1
});
// A pattern can be passed with * as wildcard
poolCluster.getConnection('SLAVE*', 'ORDER', function (err, connection) {});
// The pattern can also be a regular expression
poolCluster.getConnection(/^SLAVE[12]$/, function (err, connection) {});
// of namespace : of(pattern, selector)
poolCluster.of('*').getConnection(function (err, connection) {});
var pool = poolCluster.of('SLAVE*', 'RANDOM');
pool.getConnection(function (err, connection) {});
pool.getConnection(function (err, connection) {});
pool.query(function (error, results, fields) {});
// close all connections
poolCluster.end(function (err) {
// all connections in the pool cluster have ended
});
PoolCluster options
canRetry
: Iftrue
,PoolCluster
will attempt to reconnect when connection fails. (Default:true
)removeNodeErrorCount
: If connection fails, node’serrorCount
increases. WhenerrorCount
is greater thanremoveNodeErrorCount
, remove a node in thePoolCluster
. (Default:5
)restoreNodeTimeout
: If connection fails, specifies the number of milliseconds before another connection attempt will be made. If set to0
, then node will be removed instead and never re-used. (Default:0
)defaultSelector
: The default selector. (Default:RR
)RR
: Select one alternately. (Round-Robin)RANDOM
: Select the node by random function.ORDER
: Select the first node available unconditionally.
var clusterConfig = {
removeNodeErrorCount: 1, // Remove the node immediately when connection fails.
defaultSelector: 'ORDER'
};
var poolCluster = mysql.createPoolCluster(clusterConfig);
Switching users and altering connection state
MySQL offers a changeUser command that allows you to alter the current user and other aspects of the connection without shutting down the underlying socket:
connection.changeUser({user : 'john'}, function(err) {
if (err) throw err;
});
The available options for this feature are:
user
: The name of the new user (defaults to the previous one).password
: The password of the new user (defaults to the previous one).charset
: The new charset (defaults to the previous one).database
: The new database (defaults to the previous one).
A sometimes useful side effect of this functionality is that this function also resets any connection state (variables, transactions, etc.).
Errors encountered during this operation are treated as fatal connection errors by this module.
Server disconnects
You may lose the connection to a MySQL server due to network problems, the
server timing you out, the server being restarted, or crashing. All of these
events are considered fatal errors, and will have the err.code =
'PROTOCOL_CONNECTION_LOST'
. See the Error Handling section
for more information.
Re-connecting a connection is done by establishing a new connection. Once terminated, an existing connection object cannot be re-connected by design.
With Pool, disconnected connections will be removed from the pool freeing up space for a new connection to be created on the next getConnection call.
With PoolCluster, disconnected connections will count as errors against the
related node, incrementing the error code for that node. Once there are more than
removeNodeErrorCount
errors on a given node, it is removed from the cluster.
When this occurs, the PoolCluster may emit a POOL_NONEONLINE
error if there are
no longer any matching nodes for the pattern. The restoreNodeTimeout
config can
be set to restore offline nodes after a given timeout.
Performing queries
The most basic way to perform a query is to call the .query()
method on an object
(like a Connection
, Pool
, or PoolNamespace
instance).
The simplest form of .query()
is .query(sqlString, callback)
, where a SQL string
is the first argument and the second is a callback:
connection.query('SELECT * FROM `books` WHERE `author` = "David"', function (error, results, fields) {
// error will be an Error if one occurred during the query
// results will contain the results of the query
// fields will contain information about the returned results fields (if any)
});
The second form .query(sqlString, values, callback)
comes when using
placeholder values (see escaping query values):
connection.query('SELECT * FROM `books` WHERE `author` = ?', ['David'], function (error, results, fields) {
// error will be an Error if one occurred during the query
// results will contain the results of the query
// fields will contain information about the returned results fields (if any)
});
The third form .query(options, callback)
comes when using various advanced
options on the query, like escaping query values,
joins with overlapping column names,
timeouts, and type casting.
connection.query({
sql: 'SELECT * FROM `books` WHERE `author` = ?',
timeout: 40000, // 40s
values: ['David']
}, function (error, results, fields) {
// error will be an Error if one occurred during the query
// results will contain the results of the query
// fields will contain information about the returned results fields (if any)
});
Note that a combination of the second and third forms can be used where the
placeholder values are passed as an argument and not in the options object.
The values
argument will override the values
in the option object.
connection.query({
sql: 'SELECT * FROM `books` WHERE `author` = ?',
timeout: 40000, // 40s
},
['David'],
function (error, results, fields) {
// error will be an Error if one occurred during the query
// results will contain the results of the query
// fields will contain information about the returned results fields (if any)
}
);
If the query only has a single replacement character (?
), and the value is
not null
, undefined
, or an array, it can be passed directly as the second
argument to .query
:
connection.query(
'SELECT * FROM `books` WHERE `author` = ?',
'David',
function (error, results, fields) {
// error will be an Error if one occurred during the query
// results will contain the results of the query
// fields will contain information about the returned results fields (if any)
}
);
Preparing Queries
You can use mysql.format to prepare a query with multiple insertion points, utilizing the proper escaping for ids and values. A simple example of this follows:
var sql = "SELECT * FROM ?? WHERE ?? = ?";
var inserts = ['users', 'id', userId];
sql = mysql.format(sql, inserts);
Following this you then have a valid, escaped query that you can then send to the database safely. This is useful if you are looking to prepare the query before actually sending it to the database. As mysql.format is exposed from SqlString.format you also have the option (but are not required) to pass in stringifyObject and timezone, allowing you provide a custom means of turning objects into strings, as well as a location-specific/timezone-aware Date.
Custom format
If you prefer to have another type of query escape format, there’s a connection configuration option you can use to define a custom format function. You can access the connection object if you want to use the built-in .escape()
or any other connection function.
Here’s an example of how to implement another format:
connection.config.queryFormat = function (query, values) {
if (!values) return query;
return query.replace(/\:(\w+)/g, function (txt, key) {
if (values.hasOwnProperty(key)) {
return this.escape(values[key]);
}
return txt;
}.bind(this));
};
connection.query("UPDATE posts SET title = :title", { title: "Hello MySQL" });
Getting the number of affected rows
You can get the number of affected rows from an insert, update or delete statement.
connection.query('DELETE FROM posts WHERE title = "wrong"', function (error, results, fields) {
if (error) throw error;
console.log('deleted ' + results.affectedRows + ' rows');
})
Getting the number of changed rows
You can get the number of changed rows from an update statement.
“changedRows” differs from “affectedRows” in that it does not count updated rows whose values were not changed.
connection.query('UPDATE posts SET ...', function (error, results, fields) {
if (error) throw error;
console.log('changed ' + results.changedRows + ' rows');
})
Getting the connection ID
You can get the MySQL connection ID (“thread ID”) of a given connection using the threadId
property.
connection.connect(function(err) {
if (err) throw err;
console.log('connected as id ' + connection.threadId);
});
Executing queries in parallel
The MySQL protocol is sequential, this means that you need multiple connections to execute queries in parallel. You can use a Pool to manage connections, one simple approach is to create one connection per incoming http request.
Streaming query rows
Sometimes you may want to select large quantities of rows and process each of them as they are received. This can be done like this:
var query = connection.query('SELECT * FROM posts');
query
.on('error', function(err) {
// Handle error, an 'end' event will be emitted after this as well
})
.on('fields', function(fields) {
// the field packets for the rows to follow
})
.on('result', function(row) {
// Pausing the connnection is useful if your processing involves I/O
connection.pause();
processRow(row, function() {
connection.resume();
});
})
.on('end', function() {
// all rows have been received
});
Please note a few things about the example above:
- Usually you will want to receive a certain amount of rows before starting to
throttle the connection using
pause()
. This number will depend on the amount and size of your rows. pause()
/resume()
operate on the underlying socket and parser. You are guaranteed that no more'result'
events will fire after callingpause()
.- You MUST NOT provide a callback to the
query()
method when streaming rows. - The
'result'
event will fire for both rows as well as OK packets confirming the success of a INSERT/UPDATE query. - It is very important not to leave the result paused too long, or you may
encounter
Error: Connection lost: The server closed the connection.
The time limit for this is determined by the net_write_timeout setting on your MySQL server.
Additionally you may be interested to know that it is currently not possible to stream individual row columns, they will always be buffered up entirely. If you have a good use case for streaming large fields to and from MySQL, I’d love to get your thoughts and contributions on this.
Piping results with Streams
The query object provides a convenience method .stream([options])
that wraps
query events into a Readable Stream
object. This stream can easily be piped downstream and provides automatic
pause/resume, based on downstream congestion and the optional highWaterMark
.
The objectMode
parameter of the stream is set to true
and cannot be changed
(if you need a byte stream, you will need to use a transform stream, like
objstream for example).
For example, piping query results into another stream (with a max buffer of 5 objects) is simply:
connection.query('SELECT * FROM posts')
.stream({highWaterMark: 5})
.pipe(...);
Stored procedures
You can call stored procedures from your queries as with any other mysql driver. If the stored procedure produces several result sets, they are exposed to you the same way as the results for multiple statement queries.
Joins with overlapping column names
When executing joins, you are likely to get result sets with overlapping column names.
By default, node-mysql will overwrite colliding column names in the order the columns are received from MySQL, causing some of the received values to be unavailable.
However, you can also specify that you want your columns to be nested below the table name like this:
var options = {sql: '...', nestTables: true};
connection.query(options, function (error, results, fields) {
if (error) throw error;
/* results will be an array like this now:
[{
table1: {
fieldA: '...',
fieldB: '...',
},
table2: {
fieldA: '...',
fieldB: '...',
},
}, ...]
*/
});
Or use a string separator to have your results merged.
var options = {sql: '...', nestTables: '_'};
connection.query(options, function (error, results, fields) {
if (error) throw error;
/* results will be an array like this now:
[{
table1_fieldA: '...',
table1_fieldB: '...',
table2_fieldA: '...',
table2_fieldB: '...',
}, ...]
*/
});
Ping
A ping packet can be sent over a connection using the connection.ping
method. This
method will send a ping packet to the server and when the server responds, the callback
will fire. If an error occurred, the callback will fire with an error argument.
connection.ping(function (err) {
if (err) throw err;
console.log('Server responded to ping');
})
Timeouts
Every operation takes an optional inactivity timeout option. This allows you to specify appropriate timeouts for operations. It is important to note that these timeouts are not part of the MySQL protocol, and rather timeout operations through the client. This means that when a timeout is reached, the connection it occurred on will be destroyed and no further operations can be performed.
// Kill query after 60s
connection.query({sql: 'SELECT COUNT(*) AS count FROM big_table', timeout: 60000}, function (error, results, fields) {
if (error && error.code === 'PROTOCOL_SEQUENCE_TIMEOUT') {
throw new Error('too long to count table rows!');
}
if (error) {
throw error;
}
console.log(results[0].count + ' rows');
});
Error handling
This module comes with a consistent approach to error handling that you should review carefully in order to write solid applications.
Most errors created by this module are instances of the JavaScript Error object. Additionally they typically come with two extra properties:
err.code
: String, contains the MySQL server error symbol if the error is a MySQL server error (e.g.'ER_ACCESS_DENIED_ERROR'
), a Node.js error code if it is a Node.js error (e.g.'ECONNREFUSED'
), or an internal error code (e.g.'PROTOCOL_CONNECTION_LOST'
).err.errno
: Number, contains the MySQL server error number. Only populated from MySQL server error.err.fatal
: Boolean, indicating if this error is terminal to the connection object. If the error is not from a MySQL protocol operation, this property will not be defined.err.sql
: String, contains the full SQL of the failed query. This can be useful when using a higher level interface like an ORM that is generating the queries.err.sqlState
: String, contains the five-character SQLSTATE value. Only populated from MySQL server error.err.sqlMessage
: String, contains the message string that provides a textual description of the error. Only populated from MySQL server error.
Fatal errors are propagated to all pending callbacks. In the example below, a fatal error is triggered by trying to connect to a blocked port. Therefore the error object is propagated to both pending callbacks:
var connection = require('mysql').createConnection({
port: 1 // example blocked port
});
connection.connect(function(err) {
console.log(err.code); // 'ECONNREFUSED'
console.log(err.fatal); // true
});
connection.query('SELECT 1', function (error, results, fields) {
console.log(error.code); // 'ECONNREFUSED'
console.log(error.fatal); // true
});
Normal errors however are only delegated to the callback they belong to. So in the example below, only the first callback receives an error, the second query works as expected:
connection.query('USE name_of_db_that_does_not_exist', function (error, results, fields) {
console.log(error.code); // 'ER_BAD_DB_ERROR'
});
connection.query('SELECT 1', function (error, results, fields) {
console.log(error); // null
console.log(results.length); // 1
});
Last but not least: If a fatal errors occurs and there are no pending
callbacks, or a normal error occurs which has no callback belonging to it, the
error is emitted as an 'error'
event on the connection object. This is
demonstrated in the example below:
connection.on('error', function(err) {
console.log(err.code); // 'ER_BAD_DB_ERROR'
});
connection.query('USE name_of_db_that_does_not_exist');
Note: 'error'
events are special in node. If they occur without an attached
listener, a stack trace is printed and your process is killed.
tl;dr: This module does not want you to deal with silent failures. You should always provide callbacks to your method calls. If you want to ignore this advice and suppress unhandled errors, you can do this:
// I am Chuck Norris:
connection.on('error', function() {});
Exception Safety
This module is exception safe. That means you can continue to use it, even if one of your callback functions throws an error which you’re catching using ‘uncaughtException’ or a domain.
Type casting
For your convenience, this driver will cast mysql types into native JavaScript types by default. The default behavior can be changed through various Connection options. The following mappings exist:
Number
- TINYINT
- SMALLINT
- INT
- MEDIUMINT
- YEAR
- FLOAT
- DOUBLE
- BIGINT
Date
- TIMESTAMP
- DATE
- DATETIME
Buffer
- TINYBLOB
- MEDIUMBLOB
- LONGBLOB
- BLOB
- BINARY
- VARBINARY
- BIT (last byte will be filled with 0 bits as necessary)
String
Note text in the binary character set is returned as Buffer
, rather
than a string.
- CHAR
- VARCHAR
- TINYTEXT
- MEDIUMTEXT
- LONGTEXT
- TEXT
- ENUM
- SET
- DECIMAL (may exceed float precision)
- TIME (could be mapped to Date, but what date would be set?)
- GEOMETRY (never used those, get in touch if you do)
It is not recommended (and may go away / change in the future) to disable type casting, but you can currently do so on either the connection:
var connection = require('mysql').createConnection({typeCast: false});
Or on the query level:
var options = {sql: '...', typeCast: false};
var query = connection.query(options, function (error, results, fields) {
if (error) throw error;
// ...
});
Custom type casting
You can also pass a function and handle type casting yourself. You’re given some column information like database, table and name and also type and length. If you just want to apply a custom type casting to a specific type you can do it and then fallback to the default.
The function is provided two arguments field
and next
and is expected to
return the value for the given field by invoking the parser functions through
the field
object.
The field
argument is a Field
object and contains data about the field that
need to be parsed. The following are some of the properties on a Field
object:
db
- a string of the database the field came from.table
- a string of the table the field came from.name
- a string of the field name.type
- a string of the field type in all caps.length
- a number of the field length, as given by the database.
The next
argument is a function
that, when called, will return the default
type conversion for the given field.
When getting the field data, the following helper methods are present on the
field
object:
.string()
- parse the field into a string..buffer()
- parse the field into aBuffer
..geometry()
- parse the field as a geometry value.
The MySQL protocol is a text-based protocol. This means that over the wire, all
field types are represented as a string, which is why only string-like functions
are available on the field
object. Based on the type information (like INT
),
the type cast should convert the string field into a different JavaScript type
(like a number
).
Here’s an example of converting TINYINT(1)
to boolean:
connection = mysql.createConnection({
typeCast: function (field, next) {
if (field.type === 'TINY' && field.length === 1) {
return (field.string() === '1'); // 1 = true, 0 = false
} else {
return next();
}
}
});
WARNING: YOU MUST INVOKE the parser using one of these three field functions in your custom typeCast callback. They can only be called once.
Debugging and reporting problems
If you are running into problems, one thing that may help is enabling the
debug
mode for the connection:
var connection = mysql.createConnection({debug: true});
This will print all incoming and outgoing packets on stdout. You can also restrict debugging to packet types by passing an array of types to debug:
var connection = mysql.createConnection({debug: ['ComQueryPacket', 'RowDataPacket']});
to restrict debugging to the query and data packets.
If that does not help, feel free to open a GitHub issue. A good GitHub issue will have:
- The minimal amount of code required to reproduce the problem (if possible)
- As much debugging output and information about your environment (mysql version, node version, os, etc.) as you can gather.
Security issues
Security issues should not be first reported through GitHub or another public forum, but kept private in order for the collaborators to assess the report and either (a) devise a fix and plan a release date or (b) assert that it is not a security issue (in which case it can be posted in a public forum, like a GitHub issue).
The primary private forum is email, either by emailing the module’s author or opening a GitHub issue simply asking to whom a security issues should be addressed to without disclosing the issue or type of issue.
An ideal report would include a clear indication of what the security issue is and how it would be exploited, ideally with an accompanying proof of concept (“PoC”) for collaborators to work against and validate potentional fixes against.
Running tests
The test suite is split into two parts: unit tests and integration tests. The unit tests run on any machine while the integration tests require a MySQL server instance to be setup.
Running unit tests
$ FILTER=unit npm test