mariastream
Simplified stream interface for mariaDB, build upon the mariasql module.
Installation
npm install mariastream
Example
// Other modulesvar typepoint = ;var inspectpoint = ; // This modulevar mariastream = ; // Create client and connectvar client = ; client; // There are connection and close events, but you don't have to wait for that client // Create a statement object, this is like prepare query that you can use // multiply times. Except it also works for normal querys without paramenters. // Create a readable object stream, there are also writable stream, duplex stream, // and a simple execute method there will buffer the result. // This module don't do typecasting, but there are modules for that purpose. // NOTE: if you know of a fast way to do automatic typecasting please let me know // Each `data` event or `.read()` call gives an object, // run util.inspect and output it. ; // Outputs: // {id: 1, act: 'sleeping'} // {id: 2, act: 'eating'} // {id: 3, act: 'programming'} // PS: Yeah, I can't eat and do programming at once, I'm a disgrace.
TODO
- Complete tests for abort once mariasql has been fixed
- Complete tests for connected property once mariasql has been fixed
- Write external stream module for type conversion
Documentation
This module is a wrapper around the mariasql module. Therefore if you are in doubt, you should consult thier documentation for more information.
The mariastream
module returns an object constructor that you should use to
create or wrap a connection.
var mariastream = ;
Class: Client
Client = mariastream([options])
To create a client simple call the mariastream
client constructor.
var client = ;
The constructor takes an optional options
object, the idea is that these options
are inherited by each new Statement
object. At the moment only the option useArray
exists. For more information about this option visit the mariasql documentation.
var client = ; // Default is false
Client.connect(settings, [callback])
Client.connect(mariasql, [callback])
When client
object is created it is not connected anything before the .connect
method is executed. The connect methods requires a first argument, there can either
be an object there takes the same options as [mariasql](https://github.com/mscdex/node-mariasql).connect()
method, or it can be a mariasql
instance.
In case of the latter, you must call or have called the .connect()
on the mariasql
instance.
The second argument is an optional callback and will execute once the client is
connected. In case you connected using an already connected mariasql
instance
the callback won't be called.
client;
Client.close([callback])
Closes the connection. Note that all querys must be completed before
the connection will be closed. The optional callback
argument is called
when connection is actually closed.
client;
Client.connected
Returns true if the client is connected.
Client.threadId
If the client is connected, this is the thread id for the connection on the server.
Event: Client.on('error')
Errors can happen (e.q. connection error), unless its form a statement the error will emit on this object.
Event: Client.on('connect')
Emitted when a connection is made.
Event: Client.on('close')
Emitted when the connection is closed.
Class: Statement
Statement = Client.statement(sql, [options])
When you want to query something from a database, you have to create a statement
object. If the SQL query is the same, you can reused this object. This is especially
useful in case the query contains placeholders. The the internal prepare function
won't have to be created multiply times. Once statement
object has been made, you
can then call one of its methods in order to execute the SQL query.
The .statement
method, requires an SQL query, there can contain multiply commands.
The query can also contain placeholders, the syntax of those are defined by the mariasql module. But put in a simple way
if you use ?
signs, then use arrays. If you use :placeholder
then use objects.
var query = client;
The second argument is an optional object, there take the same properties as
the client
constructor. If a property is not defined here, it inherits from
the options set in client
constructor.
Abortable = Statement.execute([params], callback);
Unlike the other statement
methods, this method don't return an object stream
interface. Instread it simply executes the statement and buffer up the resutlt.
Once the statement has been processed or an error occurred the callback will be
called.
query;
The callback
takes 3 arguments, the first is an Error
or null
, the second
and array of the rows, the thrid is an info
object there contain the following
properties:
{ queries: Number, // Number of successful queries insertId: Number, // Last inserted id affectedRows: Number, // Total affected rows numRows: Number // Total selected rows}
It should be noted that unlike the mariasql module, the info object will contain the summed information for all subquerys in the statement.
The .execute
method also takes an optional params
object before the callback
.
This object contain parameters for the prepare statement to use.
ReadStream = Statement.readable([params])
The .readable
method, returns an object ReadStream, where each fetched row
can be accessed from the data
event or the .read()
method.
The method takes an optional params
object, there sets the parameters in the
prepare statement to use.
query ;
DublexStream = Statement.duplex()
The .duplex
method, returns an object DuplexStream. This means that each
.write(params)
will result in the statement
to be processed with the required
params
objects specifing the parameters for the prepare statement to use. The
rows from each statement can then be read though the data
event or a .read()
call.
Its important to note that since 10 writes will be processed simultaneously, there
are no garantie for the order of the returned rows. If the order is important
it is therefore recomended to return a static value (e.q. id
) even if it is known in advance and only return one row (e.q. LIMIT 1
).
var updater = client; updater;updater;
WriteStream = Statement.writable()
This works very much like the .duplex
stream. The important diffrence is that
this is a WriteStream only, meaning that it won't buffer up rows if you don't
need them. Also you can't accidently pipe from this stream only too.
It should be noted that if the statement
this WriteStream will execute do
return rows, you are mostlikely doing it wrong. But now you have all the stream
types you could want.
Class: Abortable
This object is returned by the statement.execute
method. It is the same object that the [mariasql](https://github.com/mscdex/node-mariasql).query
method will return.
Abortable.abort()
The only reason to use this object, is if you would abort the statement execution.
Class: Stream
There are 3 methods there return a stream object, they are called
statement.readable
, statement.duplex
and statement.writable
. Some of them
can be read from others can be written to.
They all have the classic (stream)[http://nodejs.org/api/stream.html] methods, but futhermore they also share these methods:
Stream.info
Contains the same information as the info
object in statement.execute
but is
updated continuely.
{ queries: Number, // Number of successful queries insertId: Number, // Last inserted id affectedRows: Number, // Total affected rows numRows: Number // Total selected rows}
Stream.destroy()
This will abort all active statements in progress related to the stream. In case
of the statement.readable
this is only one active query. But in the case of
stream.wirtable
and steam.duplex
there can up to 10 active queries.
Event: Stream.on('close')
When the stream is done, either becase no more data can be read or written, or if the stream has been aborted this event will emit.
Event: Stream.on('error')
If an error happen while processing the query, this event will emit.
License
The software is license under "MIT"
Copyright (c) 2013 Andreas Madsen
Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.