How to work with xml?

Question

PHP

In general, when I wrote applications that worked only with html, css, php and sql, I had no idea why xml or json was needed, how to build applications based on REST or SOAP with json and xml, respectively. These terms literally fell on me and I really want to understand this. Maybe I'm saying something wrong, but nevertheless, having looked at a sufficient number of resources, I found out that you can't do without "data caching" and various apis on the web. I just have a question for people who understand this, what should I read about xml, data caching, how to use all this correctly, how to understand these architectures, because recently I started trying to do something on mvc, and here it turns out there is some other then "scary Restful". Thanks in advance )

Answer 1

php.net/manual/ru/book.simplexml.php

Answer 2

How to work with xml? - with a fresh mind.