api.php

<?php
header('Access-Control-Allow-Origin: *');
header("Access-Control-Allow-Credentials: true");
header('Access-Control-Allow-Methods: GET, PUT, POST, DELETE, OPTIONS');
header('Access-Control-Max-Age: 1000');
header('Access-Control-Allow-Headers: Origin, Content-Type, X-Auth-Token , Authorization');

/**
 * Declarations
 */
$validCommands = [
	'search',
	'location'
];

$command = isset($_GET['command']) ? $_GET['command'] : null;
$baseUrl = 'https://www.metaweather.com/api/location/';

/**
 * Functions
 */
function quitWithResponse($output, $code = 200) {
	header('Content-Type: text/json');
	http_response_code($code);
	echo $output;
	exit;
}

function quitWithJsonResponse($output, $code = 200) {
	return quitWithResponse(
		json_encode($output),
		$code
	);
}

function mirrorToEndpoint($uri) {
	global $baseUrl;
	$response = @file_get_contents($baseUrl . $uri);

	if ( $response ) {
		return quitWithResponse($response);
	}

	quitWithJsonResponse(['error' => 'Not found'], 404);
}

function requireParameters($params) {
	foreach ($params as $param) {
		if (!isset($_GET[$param])) {
			quitWithJsonResponse(['error' => $param . ' is missing']);
		}
	}
}

/**
 * Commands
 */
function search() {
	requireParameters(['keyword']);
	return mirrorToEndpoint('search/?query=' . $_GET['keyword']);
}

function location() {
	requireParameters(['woeid']);
	return mirrorToEndpoint($_GET['woeid']);
}

/**
 * Execution
 */
if (is_null($command) or !in_array($command, $validCommands)) {
	quitWithJsonResponse(['error' => 'Invalid command'], 422);
}

$command();