Which verb should be used for custom actions?

Let's say we have a site where we have a list of items. On each of these items you can start a couple of different process that will result in somekind of output related to the item in question. How should you design for the most appropriate use of the http verbs? What I would like to have is multiple links per item and each link trigger one of the actions, but in my scenario that doesn't ma开发者_Python百科tch the HTTP-VERB get, which will be used if I am using links. On the other hand, I don't want to have buttons which all are in a separate form with different actions.

It's somewhat hard to explain but hopefully you understand, it should be some best practices to apply here.

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You should NOT use GET. GET requests should be safe which means they are intended only for information retrieval and should not change the state of the server. (i.e. things like logging are OK, but things that actually update the state of the application are a no-no.) Think of a crawler going over your application. Anything you wouldn't mind a crawler going through is fine for GET, but that doesn't sound like your situation (because you said, "start a couple of different processes", but I could be misinterpreting your use case).

That leaves PUT, DELETE and POST. PUT and DELETE must be idempotent, meaning that multiple identical requests should have the same effect as a single request. So if you had a request that updated a person's name, for example, if you called it once or 100 times, the person's name would still be the same, so it is idempotent.

POST is the most flexible verb. If the processes you are kicking off are not safe or idempotent (or even if they are) you can use POST, which simply doesn't guarantee anything about safety or idempotency. The disadvantages there are:

• If you use POST when GET is more semantically correct, it is less communicative of the intent of your request, since POST usually means you are sending a payload.
• You just couldn't take advantage of the web's caching infrastructure that makes it so scalable.

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In the past, I have used POST with query args to specify custom actions. It made sense in my use case because I had a majority of custom actions needing to pass a payload. Since you do not want to use buttons, you can use GET with query args to specify the different actions, but you have to be very careful that the action you are taking does not have any side effects and is idempotent. As noted in the comment by @jhericks below, there are many things in the network that assume that GET's are safe and may repeat GET's.

From a pure RESTful perspective though, this is not ideal. Your items will have a specific URI and GET on the URI will return the items representation. Running actions on the item is effectively a change in the state of the item representation and that should be done with a POST(or a PUT depending on who you ask and if your web server supports PUT). In real life though, using query args is an easy work around and it may make sense to your use case.

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Im not sure i fully understand your question.

But here's a quick paragraph which might help you.

REST is about making smart clients and simple servers. GET, PUT, DELETE represent the basic operations of file access at the lowest level. What you should be doing is completely ignoring anything the server can offer and be offloading that work onto clients.

So, the question is, why is the server being triggered to do many things. why can't the client do all of these things itself.

Mike Brown