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Why should you delete using an HTTP POST or DELETE, rather than GET?

Asked 2009-04-24T14:25:23.010
44

I have been working through Microsoft's ASP.NET MVC tutorials, ending up at this page

http://www.asp.net/learn/mvc/tutorial-32-cs.aspx

The following statement is made towards the bottom of this page:

In general, you don’t want to perform an HTTP GET operation when invoking an action that modifies the state of your web application. When performing a delete, you want to perform an HTTP POST, or better yet, an HTTP DELETE operation.

Is this true? Can anyone offer a more detailed explanation for the rationale behind this statement?

Edit

Wikipedia states the following:

Some methods (for example, HEAD, GET, OPTIONS and TRACE) are defined as safe, which means they are intended only for information retrieval and should not change the state of the server.

By contrast, methods such as POST, PUT and DELETE are intended for actions which may cause side effects either on the server

asp.net-mvc http http-delete
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12

Please see my answer here. It applies equally to this question.

  • Prefetch: A lot of web browsers will use prefetching. Which means that it will load a page before you click on the link. Anticipating that you will click on that link later.
  • Bots: There are several bots that scan and index the internet for information. They will only issue GET requests. You don't want to delete something from a GET request for this reason.
  • Caching: GET HTTP requests are not supposed to change state and they should be idempotent. Idempotent means that issuing a request once, or issuing it multiple times gives the same result. I.e. there are no side effects. For this reason GET HTTP requests are tightly tied to caching.
  • HTTP standard says so: The HTTP standard says what each HTTP method is for. Several programs are built to use the HTTP standard, and they assume that you will use it the way you are supposed to. So you will have undefined behavior from a slew of random programs if you don't follow.
answered 2009-04-24T14:29:28.350

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