Cacher.php

<?php
/**
 * Created by Will Bowman, 2016, twitter.com/asked_io & asked.io.
 */

$Cacher = new Cacher;

$Cacher->add('js/analytics.js', 'http://www.google-analytics.com/analytics.js');

$Cacher->fetch()->withErrors();

/**
 * Cache remote files to a local file.
 */
class Cacher
{
    /**
     * Files and Urls to save.
     * @var array
     */
    protected $scripts = [];

    /**
     * List of errors.
     * @var array
     */
    protected $errors = [];

    /**
     * File name.
     * @var string
     */
    protected $file;

    /**
     * Url.
     * @var string
     */
    protected $url;

    /**
     * Contents of a file
     * @var string
     */
    protected $contents;

    /**
     * Fetch urls and save to a file.
     * @return self
     */
    public function fetch()
    {
        foreach ($this->scripts as $file => $url) {
            $this->setData($file, $url);
            $this->save();
        }

        return $this;
    }

    /**
     * Add file and url to fetch.
     * @param string $file path/to/file.js
     * @param string $url  http://example.org/file.js
     * @return self
     */
    public function add($file, $url)
    {
        $this->scripts = array_merge($this->scripts, [$file => $url]);

        return $this;
    }

    /**
     * Get errors.
     * @return array
     */
    public function getErrors()
    {
        return $this->errors;
    }

    /**
     * Check if there are errors.
     * @return boolean
     */
    public function hasErrors()
    {
        return !empty($this->errors);
    }

    /**
     * Fetch with error reporting.
     * @return boolean
     */
    public function withErrors()
    {
        if (!$this->hasErrors()) {
            return false;
        }

        foreach ($this->getErrors() as $error) {
            echo sprintf('%s[91m %s ERROR: %s %s[0m%s', chr(27), strtoupper($error['type']), $error['file'], chr(27), PHP_EOL);
        }

        return true;
    }

    /**
     * Set data to be parsed.
     * @param string $file path/to/file.js
     * @param string $url  http://example.org/file.js
     */
    private function setData($file, $url)
    {
        $this->file = $file;
        $this->url = $url;
        $this->contents = null;
    }

    /**
     * Add an error.
     * @param  string $type type of error.
     * @return void
     */
    private function addError($type)
    {
        array_push($this->errors, [
            'type' => $type ,
            'file' => $this->file,
        ]);
    }

    /**
     * Save a file.
     * @return boolean
     */
    private function save()
    {
        if (!$this->getContents()) {
            $this->addError('get');
            return false;
        }

        if (!$this->checkFolder()) {
            $this->addError('folder');
            return false;
        }

        if (!$this->putContents()) {
            $this->addError('put');
            return false;
        }

        return true;
    }

    /**
     * Get contents of a file.
     * @return boolean
     */
    private function getContents()
    {
        try {
            $this->contents = file_get_contents($this->url);
        } catch (Exception $exception) {
            return false;
        }

        return true;
    }

    /**
     * Check if a folder exists and is writable.
     * @return boolean
     */
    private function checkFolder()
    {
        $path = pathinfo($this->file, PATHINFO_DIRNAME);

        if (!is_dir($path) || !is_writable($path)) {
            return false;
        }

        return true;
    }

    /**
     * Save contents to a file.
     * @return boolean
     */
    private function putContents()
    {
        try {
            file_put_contents($this->file, $this->contents);
        } catch (Exception $exception) {
            return false;
        }

        return true;
    }
}