json-download-counter.php

<?php
	/////////////////////////////////////////////////////////////////
	# Create a Simple JSON Based Download Counter with WordPress
	/////////////////////////////////////////////////////////////////
		
	// Extending from:
	// http://www.kavoir.com/2010/05/simplest-php-hit-counter-or-download-counter-count-the-number-of-times-of-access-visits-or-downloads.html
	function download_count_actions($id = null, $step = 'get', $file = null){
		
		# Note for newbies: Because we know what we're doing, we will prepend the file functions with the at sign (@) to supress known PHP errors
		
		# Set the parameters
		$id = (!empty($id)) ? $id : 0;
		$file = (!empty($file)) ? $file : TEMPLATEPATH . '/download-counter.json';
		
		# Parse the data
		if(file_exists( $file )){
			$file_contents = @file_get_contents($file);
			if(!empty($file_contents)){
				$json_data = (object) json_decode($file_contents);
			} else {
				$json_data = (object) array();
			}
			$hit_count = $json_data->$id;
		}
		$hit_count = (!empty($hit_count)) ? $hit_count : 0;
		 
		# Loop through the actions
		switch($step){
			
			# Grab All Counts
			case 'get_all':
				return $json_data;
					break;
			
			# Add to the count
			case 'add':
				$hit_count++;
					break;
			
			# Subtract from the count
			case 'subtract':
				$hit_count--;
				$hit_count = ($hit_count < 0) ? 0 : $hit_count;
					break;
			
			# Reset the count
			case 'reset':
				$hit_count = 0;
					break;
			
			# Delete All Counts
			case 'delete':
				@unlink( $file );
				return false;
					break;
			
		}
		
		# Save the file
		if(in_array($step, array('add', 'subtract', 'reset'))){
			$json_data->$id = $hit_count;
			$file_contents = json_encode($json_data);
			@file_put_contents($file, $file_contents);
		}
		
		# Return the count
		return $hit_count;
		
	}
	//////////////////////////
	# Get Download Counts
	//////////////////////////
	function get_download_counts($file = null){
		return download_count_actions($id = null, $step = 'get_all', $file);
	}
	//////////////////////////
	# Get Download Count
	//////////////////////////
	function get_download_count($id = null, $file = null){
		return download_count_actions($id, $step = 'get', $file);
	}
	//////////////////////////
	# Add Download Count
	//////////////////////////
	function add_download_count($id = null, $file = null){
		return download_count_actions($id, $step = 'add', $file);
	}
	////////////////////////////
	# Subtract Download Count
	////////////////////////////
	function subtract_download_count($id = null, $file = null){
		return download_count_actions($id, $step = 'subtract', $file);
	}
	////////////////////////////
	# Reset Download Count
	////////////////////////////
	function reset_download_count($id = null, $file = null){
		return download_count_actions($id, $step = 'reset', $file);
	}
	//////////////////////////
	# Delete All Counts
	//////////////////////////
	function delete_download_counts($file = null){
		return download_count_actions($id = null, $step = 'delete', $file);
	}

?>

test-download-counter.php

<?php
	//////////////////////////
	# Download Example
	//////////////////////////
	add_action('init', 'test_download_count');
	function test_download_count(){
		
		////////////////////////////
		# Grab all download counts
		////////////////////////////
		/*
			$download_counts = get_download_counts();
			echo '<pre>';
			print_r( $download_counts );
			echo '</pre>';
			$download_id = 14;
			$download_count = $download_counts->$download_id;
			echo sprintf('<br />Download count for ID %s is %s', $download_id, $download_count);
			exit();
		*/
		
		////////////////////////////
		# Grab the download count
		////////////////////////////
		/*
			$download_id = 14;
			$download_count = get_download_count( $download_id );
			echo sprintf('<br />Download count for ID %s is %s', $download_id, $download_count);
			exit();
		*/
		
		////////////////////////////////
		# Add multiple counts for testing
		////////////////////////////////
		/*
			$array = array(14,21,313,14,2,11,14,4521);
			foreach($array as $download_id){
				add_download_count( $download_id );
			}
			exit();
		*/
		
		////////////////////////////////
		# Delete the download count file
		////////////////////////////////
		/*
			delete_download_counts();
			exit();
		*/
		
		////////////////////////////
		# Add the download count
		////////////////////////////
		/*
			$download_id = 1234;
			add_download_count( $download_id );
			
			# Redirect to the real file to be downloaded
			header('Location: http://www.example.com/download.zip'); 
			exit();
		*/
	}
?>