title: How do I keep a local copy of a large JSON file updated?
body: <p>I'm writing a php-based website, and it requires a json table from some other website. It's a relatively large file that hardly ever gets updated, so preferably I'd like to keep a local copy and use that, rather than constantly request their server for the same file.</p>
  
  <p>But I do need the latest version of their json file, otherwise a lot of my links to their site will break.</p>
  
  <p>I'm new to web-development so I'm not sure how to approach this. I've read up on things like Redis and Memcaching, but I'm not sure if that's what I'm looking for or how to get it working.</p>
  
  <p>How can I keep my local version of their json file up to date, or is there a better approach?</p>