similarArtists.php

<?php

	//Get parameters proivded by the slack request
	$command = $_POST['command'];
	$text = $_POST['text'];
	$token = $_POST['token'];
	$channel_name = $_POST['channel_name'];
	$username = "Music bot bleep bloop";

	//We'll use the last.fm API to return some similar artists. This URL string will provide a JSON result to iterate over
	$lastFmUrl = 'http://ws.audioscrobbler.com/2.0/?method=artist.getsimilar&artist=' . $text . '&api_key=9ddaab7dc99dbcfb3f2ed8204ef965ce&limit=10&format=json';
	$content = file_get_contents($lastFmUrl);
	$json = json_decode($content, true);

	//The URL of the webhook generated by slack on setting one up. Follow readme instructions if not sure
    $webhookUrl = "https://hooks.slack.com/services/this-will-be-unique-to-your-webhook";

	//Initialize and set up a new cURL session
	$curl = curl_init($webhookUrl);
	curl_setopt($curl, CURLOPT_POST, true);

	$response = '';

	//Loop over the JSON response from the last.fm similar artist request
	foreach($json['similarartists']['artist'] as $item) 
	{
		//Append the artists to a variable to be later used in our JSON slack response. Include a line break for formatting
		$response .= $item['name'];
		$response .= '\n';
	}

	//Create an array with optional elements that slack recognises
	$payload = array(
		'text' => rawurlencode($response), 	//The main body of the slack message
		'username' => $username,			//The username of the bot
		'channel' => "#".$channel_name		//Which channel it came from, and then needs to post back to. This stops it defualting to the one set up in the webhook
	);
	
	//Encode the response ready to send back to slack
	$jsonPayload = "payload=".json_encode($payload);
	curl_setopt($curl, CURLOPT_POSTFIELDS, $jsonPayload);
	$return = curl_exec($curl);
	
	//Close the cURL session
	curl_close($curl);
?>