What is the purpose of using “PUT” method in a form with PHP?

Question

I wanted to know, why form method PUT is used?

• What is the exact purpose ?

• What will be real time scenario in which we can use it ?

• Is it more safe than GET or POST ?

Answer 1

If you take a look at page 55 of RFC 2616 (“Hypertext Transfer Protocol – HTTP/1.1”), Section 9.6 (“PUT”) , you'll see what PUT is actually for:

The PUT method requests that the enclosed entity be stored under the supplied Request-URI. There's also a handy paragraph to explain the difference between POST and PUT:

The fundamental difference between the POST and PUT requests is reflected in the different meaning of the Request-URI. The URI in a POST request identifies the resource that will handle the enclosed entity. That resource might be a data-accepting process, a gateway to some other protocol, or a separate entity that accepts annotations. In contrast, the URI in a PUT request identifies the entity enclosed with the request – the user agent knows what URI is intended and the server MUST NOT attempt to apply the request to some other resource.

When should we use PUT and when should we use POST?

Use PUT when you can update a resource completely through a specific resource. For instance, if you know that an article resides at http://example.org/article/1234 , you can PUT a new resource representation of this article directly through a PUT on this URL.

If you do not know the actual resource location, for instance, when you add a new article, but do not have any idea where to store it, you can POST it to an URL, and let the server decide the actual URL.

Use the HTTP PUT method when:

• The client includes all aspect of the resource including the unique identifier to uniquely identify the resource. Example: creating a new employee.
• The client provides all the information for a resource to be able to modify that resource.This implies that the server side does not update any aspect of the resource (such as an update date).

In both cases, these operations can be performed multiple times with the same results. That is the resource will not be changed by requesting the operation more than once. Hence, a true idempotent operation.

References

• http://restcookbook.com/HTTP%20Methods/put-vs-post/
• http://www.filecatalyst.com/rest-http-post-vs-http-put
• http://php.net/manual/en/features.file-upload.put-method.php