Last days I’ve been playing with couchDB and PHP. There are several ways to use couchDB with PHP. There also are extensions but I want to build a simple library and I will show now the code.
CouchDB has a great RestFul API so I we want to use CouchDB we only need to perform http requests. I have done a small class to do the requests. You can see the code here. It’s a simple class that uses PHP’s curl functions.
I come from relational database world. NoSQL is new for me. Maybe I’m wrong but I want to use INSERT, UPDATE, DELETE and SELECT statements in CouchDB in the same way I use them in Relational database.
The class is focused in the HTTP Document API. There is a great tutorial here that explains the API. Now I’ll show the interface I’ve made to perform the statements with CouchDB.
The examples assumes there are CouchDB host at localhost:5987. Also as I’ve said before the class focused only in HTTP Document API so first of all I create a new database called users using CouchDB’s web interface (http://localhost:5984/_utils/). Now let’s start:
INSERT
$couchDb = new Nov_CouchDb('localhost', 5984);
$couchDb->db('users')->insert('gonzalo', array('password' => "g1"));
SELECT
$data = $couchDb->db('users')->select('gonzalo')->asArray();
print_r($data);
UPDATE
$couchDb->db('users')->update('gonzalo', array('password' => 'g2'));
DELETE
$out = $couchDb->db('users')->delete('gonzalo')->asArray();
print_r($out);
Basically Nov_CouchDb has a constructor that stores connection information into private member variables:
class Nov_CouchDb
{
private $_protocol;
private $_host;
private $_port;
private $_user;
private $_password;
public function __construct($host, $port=Nov_Http::DEF_PORT , $protocol=Nov_Http::HTTP, $user = null, $password=null)
{
$this->_host = $host;
$this->_port = $port;
$this->_protocol = $protocol;
$this->_user = $user;
$this->_password = $password;
}
}
There are also a public function called db. This function stores the database and returns the instance of the class (I like chainable functions)
...
private $_db;
/**
* @param string $db
* @return Nov_CouchDb
*/
public function db($db)
{
$this->_db = $db;
return $this;
}
...
And finally the main functions:
SELECT
public function select($key)
{
try {
$out = Nov_Http::connect($this->_host, $this->_port, $this->_protocol)
->setCredentials($this->_user, $this->_password)
->doGet("{$this->_db}/{$key}");
} catch (Nov_Http_Exception $e) {
$this->_manageExceptions($e);
}
return new Nov_CouchDb_Resulset($out);
}
INSERT
/**
* @param string $key
* @param array $values
* @return Nov_CouchDb_Resulset
*/
public function insert($key, $values)
{
try {
$out = Nov_Http::connect($this->_host, $this->_port, $this->_protocol)
->setCredentials($this->_user, $this->_password)
->setHeaders(array('Content-Type' => 'application/json'))
->doPut("{$this->_db}/{$key}", json_encode($values));
} catch (Nov_Http_Exception $e) {
$this->_manageExceptions($e);
}
return new Nov_CouchDb_Resulset($out);
}
UPDATE
/**
* @param string $key
* @param array $values
* @return Nov_CouchDb_Resulset
*/
public function update($key, $values)
{
try {
$http = Nov_Http::connect($this->_host, $this->_port, $this->_protocol)
->setCredentials($this->_user, $this->_password);
$out = $http->doGet("{$this->_db}/{$key}");
$reg = json_decode($out);
$out = $http->setHeaders(array('Content-Type' => 'application/json'))
->doPut("{$this->_db}/{$key}", json_encode($reg));
} catch (Nov_Http_Exception $e) {
$this->_manageExceptions($e);
}
return new Nov_CouchDb_Resulset($out);
}
DELETE
/**
* @param string $key
* @return Nov_CouchDb_Resulset
*/
public function delete($key)
{
try {
$http = Nov_Http::connect($this->_host, $this->_port, $this->_protocol)
->setCredentials($this->_user, $this->_password);
$out = $http->doGet("{$this->_db}/{$key}");
$reg = json_decode($out);
$out = $http->doDelete("{$this->_db}/{$key}", array('rev' => $reg->_rev));
} catch (Nov_Http_Exception $e) {
$this->_manageExceptions($e);
}
return new Nov_CouchDb_Resulset($out);
}
insert, update, delete and select returns an instance of Nov_CouchDb_Resulset. CouchDb API returns a json string. But sometimes I want a PHP array or maybe an object. I use Nov_CouchDb_Resulset to perform those transformations:
// Different outputs
$data = $couchDb->db('users')->select('dummy')->asArray();
print_r($data);
$data = $couchDb->db('users')->select('dummy')->asObject();
print_r($data);
$data = $couchDb->db('users')->select('dummy')->asJson();
print_r($data);
EXCEPTIONS
CouuchDB API is a RestFul API so it uses HTTP exceptions when something wrong happens. I’ve done three exceptions. One generic and other two with the most common exception in relational databases: NoDataFound and DupValOnIndex. this is because I want do things like the following ones:
try {
$couchDb->db('users')->update('gonzalo', array('password' => 'g2'));
} catch (Nov_CouchDb_Exception_NoDataFound $e) {
echo "No data found \n";
}
$couchDb->db('users')->insert('gonzalo1', array('password' => "g1"));
try {
$couchDb->db('users')->insert('gonzalo1', array('password' => "g1"));
} catch (Nov_CouchDb_Exception_DupValOnIndex $e) {
echo "Dup Val On Index \n";
}
try {
$couchDb->db('users')->delete('gonzalo');
} catch (Nov_CouchDb_Exception_NoDataFound $e) {
echo "No data found \n";
}
The source code is available on google code here
Gonzalo Ayuso - Web Architect 