The difference between XPOST and XPUT

The two commands are not at all the same. The first one (with PUT) will update a full document, not only the field you're sending.

The second one (with POST) will do a partial update and only update the fields you're sending, and not touch the other ones already present in the document.

firstly, -X is a flag of curl. please see -X in the man page. It is same as --request. You can specify which HTTP method to use (POST, GET, PUT, DELETE etc)http://curl.haxx.se/docs/manpage.html

Regarding POST and PUT, they are HTTP methods or "verbs".

ElasticSearch provides us with a REST API. According to REST practices, POST is for create and PUT is for updating a record.

Please see: http://www.restapitutorial.com/lessons/httpmethods.html

HTTP PUT:

PUT puts a file or resource at a specific URI, and exactly at that URI. If there's already a file or resource at that URI, PUT replaces that file or resource. If there is no file or resource there, PUT creates one. PUT is idempotent, but paradoxically PUT responses are not cacheable.

HTTP 1.1 RFC location for PUT

HTTP POST:

POST sends data to a specific URI and expects the resource at that URI to handle the request. The web server at this point can determine what to do with the data in the context of the specified resource. The POST method is not idempotent, however POST responses are cacheable so long as the server sets the appropriate Cache-Control and Expires headers.

The official HTTP RFC specifies POST to be:

Annotation of existing resources;Posting a message to a bulletin board, newsgroup, mailing list, or similar group of articles;Providing a block of data, such as the result of submitting a form, to a data-handling process;Extending a database through an append operation.HTTP 1.1 RFC location for POST

Difference between POST and PUT:

The RFC itself explains the core difference:

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. If the server desires that the request be applied to a different URI, it MUST send a 301 (Moved Permanently) response; the user agent MAY then make its own decision regarding whether or not to redirect the request.Using the right method, unrelated aside:

One benefit of REST ROA vs SOAP is that when using HTTP REST ROA, it encourages the proper usage of the HTTP verbs/methods. So for example you would only use PUT when you want to create a resource at that exact location. And you would never use GET to create or modify a resource.