A slightly nicer interface to Postgres over node-libpq
npm install pg-native
High performance native bindings between node.js and PostgreSQL via libpq with a simple API.
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 macOS: brew install libpq
- On Ubuntu/Debian: apt-get install libpq-dev g++ make
- On RHEL/CentOS: yum install postgresql-devel
- On Windows:
1. Install Visual Studio C++ (successfully built with Express 2010). Express is free.
2. Install PostgreSQL (http://www.postgresql.org/download/windows/)
3. Add your Postgre Installation's bin folder to the system path (i.e. C:\Program Files\PostgreSQL\9.3\bin).
4. Make sure that both libpq.dll and pg_config.exe are in that folder.
Afterwards pg_config should be in your path. Then...
``sh`
$ npm i pg-native
`js
const Client = require('pg-native')
const 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')
})
})
})
})
})
})
`
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.
`js
const Client = require('pg-native')
const client = new Client()
client.connectSync()
// text queries
const 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
const 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)
const rows = client.executeSync('get_twitter', ['@briancarlson'])
console.log(rows[0].twitter_handle) // @briancarlson
const rows = client.executeSync('get_twitter', ['@realcarrotfacts'])
console.log(rows[0].twitter_handle) // @realcarrotfacts
`
- __constructor Client()__
Constructs and returns a new Client instance
- __client.connect(__
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
`js
const client = new Client()
client.connect(function(err) {
if(err) throw err
console.log('connected!')
})
const 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, __
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
`js`
const 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
`js`
const client = new Client()
client.connect(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, __
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
`js`
const client = new Client()
client.connect(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(__
Ends the connection. Calls the _optional_ callback when the connection is terminated.
##### example
`js`
const 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
`js
const 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')
})
`
- __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, __
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, __
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. Throws an Error if the execution fails, otherwise returns an array of results.
`sh`
$ 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:
`sh``
$ PGHOST=blabla.mydatabasehost.com npm test
The MIT License (MIT)
Copyright (c) 2014 Brian M. Carlson
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