File: simpleserver.php

<?php
session_start();
//require_once('SimpleServer.class.php');
header('Content-type: application/json');

/***
 * REQUEST FORMAT
 * JSON encoded string supplied as the POST parameter 'data'
 *		action 		getData, putData or listData
 * 		objectname  (getData & putData) name of a file in the designated directory
 *	    objectdata	(putdata)the data to be stored in that file
 * 
 * REPLY FORMAT
 * JSON encoded string containing the following properties
 * 		errnum    	  	numeric code (Server else SQL92)
 * 		error 			textual desxription of error
 * 		severity		errorlevel
 * 		objectdata  	as retrieved from file
 ***/
 

	if(!isset($_REQUEST['data']) ) 
	{
		echo '{
	"errorMessage":"SSRV: No request received",
	"errorNum":"SSRV:1",
	"severity":2
}';
		die();
	}

	$server = new SimpleServer();
	echo json_encode($server->evaluate($_REQUEST['data']), JSON_PRETTY_PRINT);

			
/***
 * Class simpleserver.php - serves JSON files
 * 
 * the file must start <?php /* and end appropriately too, must already
 * exist and must be valid JSON. The call may be POST or GET.
 * 
 * @param string fn the name of the file to get
 * @returns object PHP type
 ***/
 
 class SimpleServer {
	private $fn;
	private $json;
	private $FPATH = "/home/chris/json/";
	private $response;
	
	function __construct() {
		$this->response = new stdClass();
		$this->response->errorMessage ='OK';
		$this->response->errorNo = 0;
		$this->response->severity = 0;
		$this->response->resultData = new stdClass();
	}
    
    function evaluate($data) {
		$data = $this->testjson($data);
		
		if(!isset($data->action)) {	$this->send('{"errorMessage":"SSRV:Invalid action type","errorNo":25,"severity":2}');	}

		switch($data->action) 
		{
			case 'getData':	
			
				if(!isset($data->objectName) && !isset($data->queryName)) 
				{	
					$this->send('{"errorMessage":"SSRV:Invalid name","errorNo":26,"severity":2}');
				}
				if(!isset($data->objectName))
				{
					$data->objectName = $data->queryName;
				}
				$this->response->resultData = $this->get($data->objectName);
				break;
				
			case 'putData':
				$this->response->resultData = $this->put($data->objectData, $data->objectName);
				break;
				
			case 'list':
				$this->response->resultData =  $this->getList();
				break;
				
			default:
				$this->response->errorMessage = "SSRV:Invalid action type: {$data->action}";
				$this->response->errorNo = 24;
				$this->response->severity = 2;
		}
		return $this->response; 

	}
	
	function get($fn) {
		$fn = $this->FPATH . $fn;
		//does the file even exist?
		if (!file_exists($fn)) 
		{
			$this->response->errorMessage = "SSRV:File does not exist ".$fn;
			$this->response->errorNo = 20;
			$this->response->severity = 2;
			return (object) [];
		}
		
		$json = file_get_contents($fn);
		$_SESSION['simpleserver'] = [];
		$_SESSION['simpleserver']['lastfile'] = $fn;
		$result = new stdClass();
		return $this->testJSON($json);
	}
	
	function put($json, $fn) {
		$fn = $this->FPATH . $fn;
		
		if(!isset($_SESSION['simpleserver']) || !isset($_SESSION['simpleserver']['lastfile'])) {
			$this->response->errorMessage = "SSRV:Invalid invocation - get file first";
			$this->response->errorNo = 21;
			$this->response->severity = 2;
			return (object) [];
		}
			
		if ($fn != $_SESSION['simpleserver']['lastfile']) {
			$this->response->errorMessage = "SSRV:Invalid invocation - wrong file name";
			$this->response->errorNo = 22;
			$this->response->severity = 2;
			return (object) [];
		}
		
		try 
		{
			file_put_contents($fn, json_encode($json, JSON_PRETTY_PRINT));
			$this->response->errorMessage = 'Your data has been saved';
			return (object)[];
		} 
		catch (Exception $e) 
		{
			$this->response->errorMessage ="SSRV:Error saving file:".$e;
			$this->response->errorNo = 23;
			$this->response->severity = 2;
			return (object) [];
		}
	}
	
	function getList()	{
		$searchpath = $this->FPATH. '*';
		$files = glob($searchpath);
		$resultData = [];
		$crop = strlen($this->FPATH);

		foreach($files as $file) {
			$name = substr($file, $crop);
			$resultData[] = (object) ["queryName"=>$name];
		}

		return $resultData;
	}
	

	/***
	 * testjson - receive a JSON string - convert to PHP object	
	 * 
	 * @note set repsonse error codes if there is an error - check
	 *           $this->response->severity if error status needs to be known
	 * @para string JSON
	 * @return object PHP version of JSON string or empty object on error
	 * 
	 ***/
	function testJSON($json,$candie=false) {
		
		$temp = json_decode($json);

		if ($this->response->errorNo == JSON_ERROR_NONE)
		{
			return $temp;
		}
		else
		{
			$this->response->errorMessage = "JSON: " . json_last_error_msg();
	        $this->response->errorNo = json_last_error();
	        $this->response->severity = 2;
			return (object) [];
		}
	}
}