What "Hypermedia Data Formats" Means in Fielding's Famous Thesis When It Comes to Cookies

Question

Below is given Fielding REST dissertation 6.4.3.2 Cookies

Similarly, the use of cookies to identify custom “shopping carts” in the server-side database can be more efficiently implemented by defining the semantics of the goods for purchases within the hyperlink data formats that allow the user agent to select and store these items in their own customer shopping cart with a URI that will be used for statement when the customer is ready to purchase.

For the bold part, does this mean keeping elements on the page? Such as hidden form elements? If so, I think the customer will lose his purchase when he leaves the page.

So what does it mean hypermedia data formats?

Answer 1

What we are talking about is the format in which data is transmitted, so the client knows how to read it and what to do with it. Thus, with HTML, the format will be "text / html", and with mp4 audio it will be "audio / mp4".

Without such instructions, when data is sent by the server, the client does not know how to interpret the data being sent.

Although data can be defined and interpreted using other methods, hypermedia data formats are part of the HTTP standard and are clearly defined without the need for any external helpers.