It is okay to use POST

http://roy.gbiv.com/untangled/2009/it-is-okay-to-use-post

by dizz • 17 years ago

29 8 17 years ago

roy.gbiv.com

Roy Fielding on the usage of POST within REST, prompted by Tim Bray's recent article

thras3• 17 years ago

Use REST because it's a convention. As far as I can tell, there is no other earthly reason to use it. It certainly doesn't simplify the coding of web applications.

In fact, REST barely exists in the Django world. The problem that Rails solved with CRUD, Django solved with the Admin interface.

ratsbane2• 17 years ago

REST simplifies web applications because it works with the behavior built into the different levels of the web infrastructure. Browsers pop up a dialog box if you try to go back to a page requested with a non-idempotent method (anything but GET or HEAD). Caching servers treat non-idempotent requests differently from idempotent requests, etc.

Understanding what REST actually means and whether something is RESTful isn't always obvious. To me it means use the appropriate HTTP method as defined in the RFCs; use the URL, including query string, as the sole resource descriptor; use the request body only to contain new information. I get a bit tripped up over what I understand to be Roy Fielding's objections to maintaining state through cookies - I continue to do that, but with a vague feeling of unease that I'm missing something.

thras3• 17 years ago

The problem is that REST only makes sense when your UI is all about data entry. Sure, it's great there. You update things, you create things, you delete things, you replace things. Wonderful stuff.

But as soon as your application steps beyond that, you're sunk. The user of a web application only rarely interacts directly with resources. Individual forms can be linked to multiple database objects or none.

What REST can't handle is any level abstraction between CRUD and UI.

davidmathers• 17 years ago

It's ok to have client state in cookies, just not application state.

For instance if you have a shopping cart you can have "items in cart" in a cookie because that's pure client state. You can think of the client as a resource and, say, a "view cart" page as a representation of that resource.

If the cookie in any way tells the application how to behave, then you have sinned against the gods of REST. The most common example is probably the login redirection cookie.

mookid• 17 years ago

hmm

REST is just using HTTP properly (as a transfer protocol) - if you want to implement RPC go use some other protocol that is actually a transport, instead of raping HTTP simply because it will get you through firewalls.

REST is a far superior approach to developing web apps because it actually respects the style of the underlying protocol. It's not that mystical or complicated.

Oh and stop using front controller patterns, they're stupid.

It is okay to use POST

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