#node-pg-native

High performance native bindings between node.js and PostgreSQL via libpq with a simple API.

install

You need PostgreSQL client libraries & tools installed. An easy way to check is to type pg_config. If pg_config is in your path, you should be good to go. If it's not in your path you'll need to consult operating specific instructions on how to go about getting it there.

Some ways I've done it in the past:

• On OS X: brew install postgres
• On Ubuntu: apt-get install libpq-dev
• On RHEL/CentOS: yum install postgresql-devel
• On Windows:

1. Install Visual Studio C++ (successfully built with Express 2010). Express is free.
2. Add your Postgre Installation's bin folder to the system path (i.e. C:\Program Files\PostgreSQL\9.3\bin).
3. Make sure that both libpq.dll and pg_config.exe are in that folder.

Afterwards pg_config should be in your path. Then...

$ npm i pg-native

use

async

var Client = require('pg-native')

var client = new Client();
client.connect(function(err) {
  if(err) throw err

  //text queries
  client.query('SELECT NOW() AS the_date', function(err, rows) {
    if(err) throw err

    console.log(rows[0].the_date) //Tue Sep 16 2014 23:42:39 GMT-0400 (EDT)

    //parameterized statements
    client.query('SELECT $1::text as twitter_handle', ['@briancarlson'], function(err, rows) {
      if(err) throw err

      console.log(rows[0].twitter_handle) //@briancarlson
    })

    //prepared statements
    client.prepare('get_twitter', 'SELECT $1::text as twitter_handle', 1, function(err) {
      if(err) throw err

      //execute the prepared, named statement
      client.execute('get_twitter', ['@briancarlson'], function(err, rows) {
        if(err) throw err

        console.log(rows[0].twitter_handle) //@briancarlson

        //execute the prepared, named statement again
        client.execute('get_twitter', ['@realcarrotfacts'], function(err, rows) {
          if(err) throw err

          console.log(rows[0].twitter_handle) //@realcarrotfacts
          
          client.end(function() {
            console.log('ended')
          })
        })
      })
    })
  })
})

sync

Because pg-native is bound to libpq it is able to provide sync operations for both connecting and queries. This is a bad idea in non-blocking systems like web servers, but is exteremly convienent in scripts and bootstrapping applications - much the same way fs.readFileSync comes in handy.

var Client = require('pg-native')

var client = new Client()
client.connectSync()

//text queries
var rows = client.querySync('SELECT NOW() AS the_date')
console.log(rows[0].the_date) //Tue Sep 16 2014 23:42:39 GMT-0400 (EDT)

//parameterized queries
var rows = client.querySync('SELECT $1::text as twitter_handle', ['@briancarlson'])
console.log(rows[0].twitter_handle) //@briancarlson

//prepared statements
client.prepareSync('get_twitter', 'SELECT $1::text as twitter_handle', 1)

var rows = client.executeSync('get_twitter', ['@briancarlson'])
console.log(rows[0].twitter_handle) //@briancarlson

var rows = client.executeSync('get_twitter', ['@realcarrotfacts'])
console.log(rows[0].twitter_handle) //@realcarrotfacts

api

constructor

• constructor Client()

Constructs and returns a new Client instance

async functions

• client.connect(<params:string>, callback:function(err:Error))

Connect to a PostgreSQL backend server.

params is optional and is in any format accepted by libpq. The connection string is passed as is to libpq, so any format supported by libpq will be supported here. Likewise, any format unsupported by libpq will not work. If no parameters are supplied libpq will use environment variables to connect.

Returns an Error to the callback if the connection was unsuccessful. callback is required.

example

var client = new Client()
client.connect(function(err) {
  if(err) throw err
  
  console.log('connected!')
})

var client2 = new Client()
client2.connect('postgresql://user:password@host:5432/database?param=value', function(err) {
  if(err) throw err
  
  console.log('connected with connection string!')
})

• client.query(queryText:string, <values:string[]>, callback:Function(err:Error, rows:Object[]))

Execute a query with the text of queryText and optional parameters specified in the values array. All values are passed to the PostgreSQL backend server and executed as a parameterized statement. The callback is required and is called with an Error object in the event of a query error, otherwise it is passed an array of result objects. Each element in this array is a dictionary of results with keys for column names and their values as the values for those columns.

example

var client = new Client()
client.connect(function(err) {
  if (err) throw err
  
  client.query('SELECT NOW()', function(err, rows) {
    if (err) throw err
    
    console.log(rows) // [{ "now": "Tue Sep 16 2014 23:42:39 GMT-0400 (EDT)" }]
    
    client.query('SELECT $1::text as name', ['Brian'], function(err, rows) {
      if (err) throw err
      
      console.log(rows) // [{ "name": "Brian" }]
      
      client.end()
    })
  })
})

• client.prepare(statementName:string, queryText:string, nParams:int, callback:Function(err:Error))

Prepares a named statement for later execution. You must supply the name of the statement via statementName, the command to prepare via queryText and the number of parameters in queryText via nParams. Calls the callback with an Error if there was an error.

example

var client = new Client()
client.connection(function(err) {
  if(err) throw err
  
  client.prepare('prepared_statement', 'SELECT $1::text as name', 1, function(err) {
    if(err) throw err
    
    console.log('statement prepared')
    client.end()
  })
  
})

• client.execute(statementName:string, <values:string[]>, callback:Function(err:err, rows:Object[]))

Executes a previously prepared statement on this client with the name of statementName, passing it the optional array of query parameters as a values array. The callback is mandatory and is called with and Error if the execution failed, or with the same array of results as would be passed to the callback of a client.query result.

example

var client = new Client()
client.connection(function(err) {
  if(err) throw err
  
  client.prepare('i_like_beans', 'SELECT $1::text as beans', 1, function(err) {
    if(err) throw err
    
    client.execute('i_like_beans', ['Brak'], function(err, rows) {
      if(err) throw err
      
      console.log(rows) // [{ "i_like_beans": "Brak" }]
      client.end()
    })
  })
})

• client.end(<callback:Function()>

Ends the connection. Calls the optional callback when the connection is terminated.

example

var client = new Client()
client.connect(function(err) {
  if(err) throw err
  client.end(function() {
    console.log('client ended') // client ended
  })
})

• client.cancel(callback:function(err))

Cancels the active query on the client. Callback receives an error if there was an error sending the cancel request.

example

var client = new Client()
client.connectSync()
//sleep for 100 seconds
client.query('select pg_sleep(100)', function(err) {
  console.log(err) // [Error: ERROR: canceling statement due to user request]
})
client.cancel(function(err) {
  console.log('cancel dispatched')
})

sync functions

• client.connectSync(params:string)

Connect to a PostgreSQL backend server. Params is in any format accepted by libpq. Throws an Error if the connection was unsuccessful.

• client.querySync(queryText:string, <values:string[]>) -> results:Object[]

Executes a query with a text of queryText and optional parameters as values. Uses a parameterized query if values are supplied. Throws an Error if the query fails, otherwise returns an array of results.

• client.prepareSync(statementName:string, queryText:string, nParams:int)

Prepares a name statement with name of statementName and a query text of queryText. You must specify the number of params in the query with the nParams argument. Throws an Error if the statement is un-preparable, otherwise returns an array of results.

• client.executeSync(statementName:string, <values:string[]>) -> results:Object[]

Executes a previously prepared statement on this client with the name of statementName, passing it the optional array of query paramters as a values array. Throws an Error if the execution fails, otherwas returns an array of results.

testing

$ npm test

To run the tests you need a PostgreSQL backend reachable by typing psql with no connection parameters in your terminal. The tests use environment variables to connect to the backend.

An example of supplying a specific host the tests:

$ PGHOST=blabla.mydatabasehost.com npm test

license

The MIT License (MIT)

Copyright (c) 2014 Brian M. Carlson

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.