Difference when declaring variables in Mysql / SQL

You may have notice that there is a lot of differences in writing queries in SQL vs. Mysql; One of this difference concerns the definition of variables:

One way to do it in SQL :

DECLARE @ID VARCHAR(15)
SELECT  @ID ='000000001'

SELECT * from [TABLE] (nolock) WHERE  ID = @cID;

(we could use SET instead of SELECT - here, we have used VARCHAR but  any other kind of variable could have been used!!)

The equivalent in Mysql will be the following :

SELECT @ID:= '000000001';

SELECT * from [TABLE] (nolock) WHERE  ID = @cID;

Managing errors with cURL library access

Having one URL ($sURL), we would like to get the associated file content (this can be any file, not only an  XML file):

Here is the PHP code using cURL library with the 'cur_exec' function to get the content, and the 'curl_errno' function to get the possible error message !!!

<?php
$sUrl = "http://tycaron.blogspot.fr/2014/10/managing-errors-with-curl-library-access.ht";
$bError = false;
$sXml = GetCurl_Response($sUrl);
 if ($sXml === false)
{
        $bError = true;
        $aErrors[] = GetCurl_Error($sUrl);
}

if ($bError) var_dump($aErrors);

/*
 * get the file content related to an URL
* @param  string $url
* @return string
*/
function GetCurl_Response($url)
{
  // create curl resource
  $curl = curl_init($url);

  // var_dump($curl);
  curl_setopt($curl, CURLOPT_FAILONERROR, true);
  curl_setopt($curl, CURLOPT_FOLLOWLOCATION, true);
  curl_setopt($curl, CURLOPT_RETURNTRANSFER, true);
  curl_setopt($curl, CURLOPT_SSL_VERIFYHOST, false);
  curl_setopt($curl, CURLOPT_SSL_VERIFYPEER, false);
  $result = curl_exec($curl);


  //close curl resource to free up system resources
  curl_close($curl);
  return $result;
}

/*
 * get cURL error (return 'false' if no error)
 * @return string
*/
function GetCurl_Error($url)
{
  // create curl resource
  $curl = curl_init($url);

  // var_dump($curl);
  curl_setopt($curl, CURLOPT_FAILONERROR, true);
  curl_setopt($curl, CURLOPT_FOLLOWLOCATION, true);
  curl_setopt($curl, CURLOPT_RETURNTRANSFER, true);
  curl_setopt($curl, CURLOPT_SSL_VERIFYHOST, false);
  curl_setopt($curl, CURLOPT_SSL_VERIFYPEER, false);
  $result = curl_exec($curl);
 if ($result===false)
   $error_curl = 'Erreur Curl : ' .curl_error($curl).' ('.curl_errno($curl).')';
  else
   $error_curl = false;

  //close curl resource to free up system resources
  curl_close($curl);
  return $error_curl ;
}

?>

Having made volontarily an error when writing URL, the output error message will then be :
array(1) { [0]=> string(66) "Erreur Curl : The requested URL returned error: 404 Not Found (22)" }

Rewriting URL

When dealing with resful webservice, one of the principle for the architecture is to use "cleaning URL" or the also called Semantic URL  ; one way to do that is to add some rules to redirect URL within an .htaccess file;

Say you have a resource "users",. I could set up a number of URIs like so:

/api/users     when called with GET, lists users
/api/users     when called with POST, creates user record
/api/users/1   when called with GET, shows user record
               when called with PUT, updates user record
               when called with DELETE, deletes user record

To have a correct representation of a RESTful architecture, one can define  an .htaccess file to so that it redirects any of these URIs to one file, 'user.php' :

.htaccess
Options +FollowSymLinks
RewriteEngine On
RewriteRule ^api/([0-9a-zA-Z]+)/([0-9_-]+)$ user.php [L]

user.php

<?php

    $path = $_SERVER['REQUEST_URI'];

    $url_elements = explode('/', $path);

    $verb = $_SERVER['REQUEST_METHOD'];

    echo $verb."<br>";

    echo "ID = ".$url_elements[5]."<br>";

    echo "NAME = ".$url_elements[6]."<br>";;

    

?>

In doing so, while accessing the following URL http://localhost/api/user/12, the screen will print out :

ID = user
NAME = 12

Calling a database stored procedure from PHP

If a stored procedure retuns a 'select' query within a database, a PHP function calling that stored procedure will be similar to :

function ExecStoreProcSelect()
{
$oStatement = $this->mssql->prepare("Exec [Procedure name]  @Json= :Json ;");
  $oStatement ->bindValue(':Json', $sJson, \PDO::PARAM_STR);

$bResult = $oStatement->execute();
if (!$bResult)
{
return false;
}
return $oStatement->fetchAll(\PDO::FETCH_ASSOC);
/* OR 
  $sSelect = "SELECT @@ROWCOUNT as nb_line_return"; // give the nb of line being returned during the last instruction

  $aResults = $this->mssqlBosql->query($sSelect)->fetch(\PDO::FETCH_ASSOC);
  if ($aResults['nb_line_return'] < 1) { return array('errors' => array('No return by the stored   procedure !')); }
  else { return true; }
*/
} 

If no return is expected from the stored procedure, this function could be simplify like this :

function ExecStoreProcUpdate()
{
$oStatement = $this->mssql->prepare("Exec [Procedure name];");
$bResult = $oStatement->execute();
if (!$bResult)
{
return false;
}
return true;
} 


In mysql, the syntax will be slightly different (cf . http://www.mysqltutorial.org/php-calling-mysql-stored-procedures/) using CALL instead of EXEC :

for a stored procedure like this one :

"
DELIMITER $$

CREATE PROCEDURE GetCustomerLevel(

    in  p_customerNumber int(11),

    out p_customerLevel  varchar(10))

BEGIN

    DECLARE creditlim double;

    SELECT creditlimit INTO creditlim

    FROM customers

    WHERE customerNumber = p_customerNumber;

    IF creditlim > 50000 THEN

    SET p_customerLevel = 'PLATINUM';

    ELSEIF (creditlim <= 50000 AND creditlim >= 10000) THEN

        SET p_customerLevel = 'GOLD';

    ELSEIF creditlim < 10000 THEN

        SET p_customerLevel = 'SILVER';

    END IF; 

END$$

"

The access through PHP can be done via :

require_once 'dbconfig.php';

$customerNumber = 103;

try {

    $conn = new PDO("mysql:host=$host;dbname=$dbname", $username, $password);

    // execute the stored procedure

    $sql = 'CALL GetCustomerLevel(:id,@level)';

    $stmt = $conn->prepare($sql);

    $stmt->bindParam(':id', $customerNumber, PDO::PARAM_INT);

    $stmt->execute();

    $stmt->closeCursor();

    // execute the second query to get customer's level

    $r = $conn->query("SELECT @level AS level")->fetch(PDO::FETCH_ASSOC);

    if ($r) {

        echo sprintf('Customer #%d is %s', $customerNumber, $r['level']);

    }

} catch (PDOException $pe) {

    die("Error occurred:" . $pe->getMessage());

}

The use of "===" instead "==" to test the result of a function

When managing one error, which is returning from a function, I have been faced with the importance of using "= = =" instead of " =  = " ;

Imagine the following case: a function with database query within a foreach with a control from the query return (here, we have just a 'select' but it could have been an 'insert',  an 'update', a 'delete' etc..)


[..]
foreach ($parcels as $aparcel)
{
$events = $this->getEvents($aparcel[id]);
if ($events === false)
        {
$_aMsgs['errors'][$i] = "Error in the resulting data getParcelsEvents";
$i = $i + 1;
continue;
       }
       else { //using $events for doing stuff even if empty
     
       }
}
[..]

protected function getEvents($parcelsid)
{

   $sQuery = "select [fields]
   from [table] (nolock)
   where no_colis = '$parcelsid';";

$oStatement = mysql->prepare($sQuery);

$bResult = $oStatement->execute();
if (!$bResult)
{
//echo $sQuery.PHP_EOL;
return false;
}
return $oStatement->fetchAll(\PDO::FETCH_ASSOC);
}


At start, I was using "if ($events = = false)" to control the results from the getEvents function, but, doing so,  one empty result from the database query was considered as an error - that was not the behavior that I was expected ; the solution was to use "=  =  =" to be sure to test only the "false" returning case and not that empty case !!!

From now on, I am using mostly the triple "=" when dealing return of a function!

How to convert Objects to Arrays or Arrays to Objects in multi-dimensional arrays and objects ?

Dealing with the consumption de SOAP webservices, I have been encountered some trouble when extracting data with a mix of multidimensional arrays and objects ; a way to simplefy this extraction was to transform objects into array or arrays into objects using a recursive method:

Here below, one will find two recursive functions to convert multi-dimensional Objects To Array and Multidimensional Aarrays to Objects :

Function to Convert stdClass Objects to Multidimensional Arrays:

    function objectToArray($d) {
        if (is_object($d)) {
            // Gets the properties of the given object
            // with get_object_vars function
            $d = get_object_vars($d);
        }
 
        if (is_array($d)) {
            /*
            * Return array converted to object
            * Using __FUNCTION__ (Magic constant)
            * for recursive call
            */
            return array_map(__FUNCTION__, $d);
        }
        else {
            // Return array
            return $d;
        }
    }

Function to Convert Multidimensional Arrays to stdClass Objects:

    function arrayToObject($d) {
        if (is_array($d)) {
            /*
            * Return array converted to object
            * Using __FUNCTION__ (Magic constant)
            * for recursive call
            */
            return (object) array_map(__FUNCTION__, $d);
        }
        else {
            // Return object
            return $d;
        }
    }

Example:

<?php
      // Create new stdClass Object
      $init = new stdClass;
      $init->debut = "14:00";
      $init->fin = "18:00";

      $init2 = array();
      $init2[0]= new stdClass;
      $init2[0]->debut = "09:00";
      $init2[0]->fin = "12:00";
      $init2[1]= new stdClass;
      $init2[1]->debut = "14:00";
      $init2[1]->fin = "19:00";

      var_dump($init);
      var_dump($init2);
     // Convert objects to array and then array to  backobject

      $array = $this->objectToArray($init);
      $array2 = $this->objectToArray($init2);
      var_dump($array);
      var_dump($array2);
      $object = $this->arrayToObject($array);

      $object2 = $this->arrayToObject($array2);

      var_dump($array2);
  
    function objectToArray($d) {
        if (is_object($d)) {
            // Gets the properties of the given object
            // with get_object_vars function
            $d = get_object_vars($d);
        }
 
        if (is_array($d)) {
            /*
            * Return object converted to array 

            * Using __FUNCTION__ (Magic constant)
            * for recursive call
            */
            return array_map(__FUNCTION__, $d);
        }
        else {
            // Return array
            return $d;
        }
    }
    
    
    function arrayToObject($d) {
        if (is_array($d)) {
            /*
            * Return array converted to object
            * Using __FUNCTION__ (Magic constant)
            * for recursive call
            */
            return (object) array_map(__FUNCTION__, $d);
        }
        else {
            // Return object
            return $d;
        }
    }
?>

cf. http://www.if-not-true-then-false.com/2009/php-tip-convert-stdclass-object-to-multidimensional-array-and-convert-multidimensional-array-to-stdclass-object/

Using array_map within a class function is not straight forward : the reference to the function has to be written like this : array_map(array($this,__FUNCTION__), $d);

Here is an example of this usage :

<?php

    $Chrono = new Relais();
    $Chrono->convert();

    class Relais {

        public function convert()
        {
            // Create new stdClass Object
            $init = new stdClass;
            $init->debut = "14:00";
            $init->fin = "18:00";

            $init2 = array();
            $init2[0]= new stdClass;
            $init2[0]->debut = "09:00";
            $init2[0]->fin = "12:00";
            $init2[1]= new stdClass;
            $init2[1]->debut = "14:00";
            $init2[1]->fin = "19:00";

           // var_dump($init);
            //var_dump($init2);
            // Convert array to object and then object back to array
            $array = $this->objectToArray($init);
            $array2 = $this->objectToArray($init2);
            var_dump($array);
            var_dump($array2);
            $object = $this->arrayToObject($array);
            $object2 = $this->arrayToObject($array2);
           // var_dump($object);
            var_dump($object2);
        }
        private function objectToArray($d) {
            if (is_object($d)) {
                // Gets the properties of the given object
                // with get_object_vars function
                $d = get_object_vars($d);
            }

            if (is_array($d)) {
                /*
                * Return object converted to array 
                * Using __FUNCTION__ (Magic constant)
                * for recursive call
                */
                return array_map(array($this,__FUNCTION__), $d);
            }
            else {
                // Return array
                return $d;
            }
        }             

        private function arrayToObject($d) {
            if (is_array($d)) {
                /*
                * Return array converted to object
                * Using __FUNCTION__ (Magic constant)
                * for recursive call
                */
                return (object) array_map(array($this,__FUNCTION__), $d);
            }
            else {
                // Return object
                return $d;
            }
        }
    }
    

?>

How to consume a REST/JSON webservice ?

In this post, I will give a way to consume a RESTFUL webservice, using the example given in the previous post for the webservice to be consumed :


 <?php

    $arg = '2';
    $function = 'double';
  
    //$function = 'doubleds';

    $base_url = 'http://localhost:8080/creation_service_rest.php';
    $query_string = '';
  
    $params = array (
        'function' => $function,
        'arg' => $arg,
    );
    //http://localhost/wp_phped/eros/eros/creation_service_rest.php?function=double&arg=2
  
    $query_string = get_urlrequest($params);

    $url = $base_url . "?" . $query_string;

  // $json =  file_get_contents($url);
   $content = URLToContent($url);

   $tab = json_decode($content, true);

 
   if (!empty($tab['response']['value'])) echo "Le double de $arg est ".$tab['response']['value'];
   else
   {
       if (!empty($tab['error']['code']))echo 'ERREUR : code '. $tab['error']['code'].' - '. utf8_decode($tab['error']['message']);
   }
 
 
    function URLToContent($url)
    {
        // create curl resource
        $curl = curl_init($url);

        curl_setopt($curl, CURLOPT_FAILONERROR, true);
        curl_setopt($curl, CURLOPT_FOLLOWLOCATION, true);
        curl_setopt($curl, CURLOPT_RETURNTRANSFER, true);
        curl_setopt($curl, CURLOPT_SSL_VERIFYHOST, false);
        curl_setopt($curl, CURLOPT_SSL_VERIFYPEER, false);
        $result = curl_exec($curl);

        //close curl resource to free up system resources
        curl_close($curl);  
        return $result;
    }

    function get_urlrequest($params) {
        $query_string = '';
        foreach ($params as $key => $value) {
            $query_string .= "$key=" . urlencode($value) . "&";
        }
        $query_string = substr($query_string,0,strlen($query_string) - 1);
      
        return $query_string;
      
     
    }
?>

This example is partly based on the one shown in  http://notos.fr/blog/index.php?article23/exemple-de-web-services-en-php

One could use instead the following functions to replace URLToContent and get_urlrequest functions, respectively:

function curl_get($url) {
      $client = curl_init($url);
      curl_setopt($client, CURLOPT_RETURNTRANSFER, true);
     $response = curl_exec($client);
     curl_close($client);
     return $response;
}


function build_query_string(array $params) {
       $query_string = http_build_query($params);
       return $query_string;
}


The next step will be to include both functions in one include ( for example : RestFulWS.php ):

One Example with consuming an RSS feed from BBC news : 

 <?php
require_once 'RestFulWS.php';
$url = 'http://feeds.bbci.co.uk/news/rss.xml';

$response = curl_get($url);
$xml = simplexml_load_string($response);

echo $response;

foreach ($xml->channel->item as $item) {
echo $item->title . "\n";
}

Extracted from the book "RESTful PHP Web Services" by Samisa Abeysinghe, 2008

?>

Creation of a REST/JSON webservice

Here below, I will show how to create a webservice with data in JSON format through a simple example (a function which gives the double of a given number):


 code for creation_service_rest.php

<?php


function double($val)

{

   return $val * 2;

}

if($_GET['arg']!='' && $_GET['function']=='double')

{

   $value = @call_user_func($_GET['function'], $_GET['arg']);

   $result['response']['value']=$value;
   $result['error']['code'] = '0';
   $result['error']['message'] = '0K';

}

else

{

   $result['response']['value']=NULL;
   $result['error']['code'] = '1';
   $result['error']['message'] = "Requête Invalide". ' avec function '.$_GET['function'].' et argument '.$_GET['arg'];

}

 echo json_encode($result);
?>

cf. http://notos.fr/blog/index.php?article23/exemple-de-web-services-en-php 

Calling a REST Web service method through URL

Instead of using the soapclient library from PHP, a  REST (Representational State Transfer) webservice can be consumed by passing method and parameters directly through  the URL.
Here below, a function "Acces_REST_WS" has been defined to get the response of a web service (through the example of Chronopost webservice giving the information of a relay point from a relay idendifier)  giving the URL of  the webservice along with the applied method and parameters  :

<?php
    $sUrl ="https://www.chronopost.fr/recherchebt-ws-cxf/PointRelaisServiceWS/rechercheDetailPointChronopostInter?";
 
   $parameters = http_build_query(array(
'accountNumber' => 'XXXXXX',
'password' => 'XXXXXX',
'identifiant' => '2711R',
'countryCode' => 'FR',
'language' => 'FR'
), '&');

    $reponse = Acces_Rest_WS($sUrl,$parameters);

    function Acces_Rest_WS($sUrl, $parameters)
    {
        $aErrors = array();
        $bError = false;
     
        $url =$sUrl.$parameters;
     
        $result = URLToXml($url);
     
        // transformer le fichier XML en tableau
        $listePointRelais = json_decode(XmlToJson($result), true);

        //tester les codes erreurs
        $errorCode = $listePointRelais['soapBody']['ns1rechercheDetailPointChronopostInterResponse']['return']['errorCode'];

        if ($errorCode != '0')
        {
            // en cas d'erreur, rechercher le message d'erreur
            $bError = true;
            $errormessage = $listePointRelais['soapBody']['ns1rechercheDetailPointChronopostInterResponse']['return']['errorMessage'];
            $aErrors[] = $errorCode." : ".$errormessage ;
        }

        // absence d'erreur
        if (false === $bError)
        {
            $listePointRelais = $listePointRelais['soapBody'] ['ns1rechercheDetailPointChronopostInterResponse']['return']['listePointRelais'];
            $listePointRelais = isset($listePointRelais) ? $listePointRelais : array();
            if (!isset($listePointRelais[0]))
            {
                $listePointRelais = array(
                    0 => $listePointRelais
                );
            }
            $relays = array();

            foreach ($listePointRelais as $PointRelais)
            {
                if (!isset($PointRelais['identifiant']))
                {
                    continue;
                }
                $relay = array(
                    'label' => $PointRelais['nom'],
                    'code' => $PointRelais['identifiant'],
                    'id' => $PointRelais['identifiant'],
                    'address_line1' => $PointRelais['adresse1'],
                    'address_postal_code' => $PointRelais['codePostal'],
                    'address_city' => $PointRelais['localite'],
                    'relay_type' => 'ChronoRelais',
                    'lat' => isset($PointRelais['coordGeolocalisationLatitude']) ? $PointRelais['coordGeolocalisationLatitude'] : null,
                    'lng' => isset($PointRelais['coordGeolocalisationLongitude']) ? $PointRelais['coordGeolocalisationLongitude'] : null,
                    'country_code' => $PointRelais['codePays'],
                    'hours' => array()
                );

                $jours = array (0 =>'sun',1=>'mon',2=>'tue',3 =>'wed',4=>'thu',5=>'fri',6=>'sat');

                foreach ($PointRelais['listeHoraireOuverture'] as $day)
                {
                    $jour= $jours[$day['jour']];

                    if (isset($day['listeHoraireOuverture']))
                    {
                        $relay['hours'][$jour] = array(
                            'am' => isset($day['listeHoraireOuverture'][0]) ? array(
                                $day['listeHoraireOuverture'][0]['debut'],
                                $day['listeHoraireOuverture'][0]['fin']
                            ) : null,
                            'pm' => isset($day['listeHoraireOuverture'][1]) ? array(
                                $day['listeHoraireOuverture'][1]['debut'],
                                $day['listeHoraireOuverture'][1]['fin']
                            ) : null
                        );
                    }
                    else
                    {
                        $relay['hours'][$jour] = null;
                    }
                }
            }
        }

      return   array(
            'request' => array(
                'url' => $sUrl,
                'options' => array(),
                'parameters' => $parameters
            ),
            'response' => $relay,
            'errors' => $aErrors
        );
    }
    function XmlToJson($fileContents)
    {
        $fileContents = str_replace(array(
            "\n",
            "\r",
            "\t"
        ), '', $fileContents);
        $fileContents = trim(str_replace('"', "'", $fileContents));
        $fileContents = preg_replace("/(<\/?)(\w+):([^>]*>)/", "$1$2$3", $fileContents);
        $fileContents = preg_replace('/xmlns[^=]*="[^"]*"/i', '', $fileContents);
        $fileContents = preg_replace('/[a-zA-Z]+:([a-zA-Z]+[=>])/', '$1', $fileContents);
        $simpleXml = @simplexml_load_string($fileContents);
     
        //$tab = (array) $simpleXml;
     
        $json = json_encode($simpleXml);
        return $json;
    }
 
    function URLToXml($url)
    {
       // create curl resource
        $curl = curl_init($url);

        curl_setopt($curl, CURLOPT_FAILONERROR, true);
        curl_setopt($curl, CURLOPT_FOLLOWLOCATION, true);
        curl_setopt($curl, CURLOPT_RETURNTRANSFER, true);
        curl_setopt($curl, CURLOPT_SSL_VERIFYHOST, false);
        curl_setopt($curl, CURLOPT_SSL_VERIFYPEER, false);
        $result = curl_exec($curl);
     
        //close curl resource to free up system resources
        curl_close($curl);  
        return $result;
    }
?>

How to transform XML file into an array ?

The method I have been using to solve that issue is to convert data in these three steps:
1- apply  the function called "simplexml_load_string" to transform an XML content into XML object
2- convert the XML object into JSON format with the "json_encode" function
3- convert the JSON data to an array using  the "json_decode" function


Here the function I have been using when working with webservices  (through URL):

    $tab = json_decode(XmlToJson($xml), true);

    function XmlToJson($fileContents)
    {
        $fileContents = str_replace(array(
            "\n",
            "\r",
            "\t"
        ), '', $fileContents);
        $fileContents = trim(str_replace('"', "'", $fileContents));
        $fileContents = preg_replace("/(<\/?)(\w+):([^>]*>)/", "$1$2$3", $fileContents);
        $fileContents = preg_replace('/xmlns[^=]*="[^"]*"/i', '', $fileContents);
        $fileContents = preg_replace('/[a-zA-Z]+:([a-zA-Z]+[=>])/', '$1', $fileContents);
        $simpleXml = @simplexml_load_string($fileContents);
       
        //$tab = (array) $simpleXml;
       
        $json = json_encode($simpleXml);
        return $json;
    }

How to get XML/JSON content from a specified URL address ?

 XML (along with JSON) becomes the standart format to render data through internet (cf. consumption of web services).

One way to solve that issue is to use the cURL library (the client URL library) :

Here below is the PHP function I have been using in such case :

/**
* @param str $url
* @return str $content
*/
    function URLToXml($url)
    {
       // create curl resource
        $curl = curl_init($url);

        curl_setopt($curl, CURLOPT_FAILONERROR, true);
        curl_setopt($curl, CURLOPT_FOLLOWLOCATION, true);
        curl_setopt($curl, CURLOPT_RETURNTRANSFER, true);
        curl_setopt($curl, CURLOPT_SSL_VERIFYHOST, false);
        curl_setopt($curl, CURLOPT_SSL_VERIFYPEER, false);
        $content = curl_exec($curl);
     
        //close curl resource to free up system resources

        curl_close($curl);

        return $content;
    }


Note :
"For accessing services we need an HTTP client. We can also use file_get_contents (http://www.php.net/file_get_contents) to access not only local files but
also those located on remote servers over HTTP.
However, file_get_contents uses GET, you would need considerable extra work to use a different verb like POST. Also, fopen wrappers need to be enabled to let file_get_contents() access remote files. System administrators may disable fopen wrappers due to security concerns.

The solution to the limitations associated with file_get_contents is to use an HTTP client library such as CURL (http://www.php.net/curl). CURL PHP API is a wrapper of libcurl (http://curl.haxx.se/libcurl/), a library that allows you to communicate using many different types of protocols. It supports HTTP verbs such as POST and PUT in addition to GET.

 [..]
HTTP verbs and how they apply while using REST web services:
GET : Retrieves a resource identified by a URI.
POST : Sends a resource to the server. Updates the resource in the location identified by the URI.
PUT : Sends a resource to the server, to be stored in the location identified by the URI.
DELETE : Deletes a resource identified by a URI.
HEAD : Retrieves the metadata of a resource identified by the URI.
"
(extracted from RESTful PHP Web Services, Samisa Abeysinghe
October 2008)

        

Using anonymous class to instantiate object

use \Domain\ModelOrder as ModelOrder;

class ClassA extends classB
{
public function __construct(Context $context = null)
{
$this->modelOrder = function ($context)
{
return new ModelOrder($context);
};

parent::__construct($context);
}

protected function test()
{
$ordermethodA = $this->modelOrder->getmethodA();

return true;
}
}

Autoloading Classes

Many developers writing object-oriented applications create one PHP source file per class definition. One of the biggest annoyances is having to write a long list of needed includes at the beginning of each script (one for each class).
In PHP 5, this is no longer necessary. You may define an __autoload()  function which is automatically called in case you are trying to use a class/interface which hasn't been defined yet. By calling this function the scripting engine is given a last chance to load the class before PHP fails with an error.

Example #1 Autoload example

This example attempts to load the classes MyClass1 and MyClass2 from the files MyClass1.php and MyClass2.php respectively.

<?phpfunction __autoload($class_name) {
    include $class_name . '.php';
}
$obj  = new MyClass1();$obj2 = new MyClass2(); 
?>

Cf. http://php.net/manual/en/language.oop5.autoload.php#language.oop5.autoload

Using Fluent Interface for method chaining

In the fluent interface, one setter method returns the current object ; this is implemented  for doing method cascading (or method chaining) ; please refer to wikipedia for further explanation  http://en.wikipedia.org/wiki/Fluent_interface

In PHP, one can return the current object by using the $this special variable which represent the instance. Hence return $this; will make the method return the instance. The example below define a class Employee and three methods to set its name, surname and salary. Each return the instance of the Employee class allowing to chain methods.

<?php
class Employee
{
    public $name;
    public $surName; 
    public $salary;
 
    public function setName($name)
    {
        $this->name = $name;
 
        return $this;
    }
 
    public function setSurname($surname)
    {
        $this->surName = $surname;
 
        return $this;
    }
 
    public function setSalary($salary)
    {
        $this->salary = $salary;
 
        return $this;
    }
 
    public function __toString()
    {
        $employeeInfo = 'Name: ' . $this->name . PHP_EOL;
        $employeeInfo .= 'Surname: ' . $this->surName . PHP_EOL;
        $employeeInfo .= 'Salary: ' . $this->salary . PHP_EOL;
 
        return $employeeInfo;
    }
}
 
# Create a new instance of the Employee class:
$employee = new Employee();
 
# Employee Tom Smith has a salary of 100:
echo $employee->setName('Tom')
              ->setSurname('Smith')
              ->setSalary('100');
 
# Display:
# Name: Tom
# Surname: Smith
# Salary: 100