They both seem to be sending data to the server inside the body, so what makes them different?
19 Answers
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 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.
Additionally, and a bit more concisely, RFC 7231 Section 4.3.4 PUT states (emphasis added),
4.3.4. PUT
The PUT method requests that the state of the target resource be
created
orreplaced
with the state defined by the representation enclosed in the request message payload.
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.
Only semantics.
An HTTP PUT
is supposed to accept the body of the request, and then store that at the resource identified by the URI.
An HTTP POST
is more general. It is supposed to initiate an action on the server. That action could be to store the request body at the resource identified by the URI, or it could be a different URI, or it could be a different action.
PUT is like a file upload. A put to a URI affects exactly that URI. A POST to a URI could have any effect at all.
To give examples of REST-style resources:
POST /books
with a bunch of book information might create a new book, and respond with the new URL identifying that book: /books/5
.
PUT /books/5
would have to either create a new book with the id of 5, or replace the existing book with ID 5.
In non-resource style, POST
can be used for just about anything that has a side effect. One other difference is that PUT
should be idempotent - multiple PUTs
of the same data to the same URL should be fine, whereas multiple POSTs
might create multiple objects or whatever it is your POST
action does.
- GET: Retrieves data from the server. Should have no other effect.
- PUT: Replaces target resource with the request payload. Can be used to update or create a new resources.
- PATCH: Similar to PUT, but used to update only certain fields within an existing resource.
- POST: Performs resource-specific processing on the payload. Can be used for different actions including creating a new resource, uploading a file or submitting a web form.
- DELETE: Removes data from the server.
- TRACE: Provides a way to test what server receives. It simply returns what was sent.
- OPTIONS: Allows a client to get information about the request methods supported by a service. The relevant response header is Allow with supported methods. Also used in CORS as preflight request to inform server about actual request method and ask about custom headers.
- HEAD: Returns only the response headers.
- CONNECT: Used by browser when it knows it talks to a proxy and the final URI begins with https://. The intent of CONNECT is to allow end-to-end encrypted TLS session, so the data is unreadable to a proxy.
PUT is meant as a a method for "uploading" stuff to a particular URI, or overwriting what is already in that URI.
POST, on the other hand, is a way of submitting data RELATED to a given URI.
Refer to the HTTP RFC
Please see: http://zacharyvoase.com/2009/07/03/http-post-put-diff/
I’ve been getting pretty annoyed lately by a popular misconception by web developers that a POST is used to create a resource, and a PUT is used to update/change one.
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.
It doesn’t mention anything about the difference between updating/creating, because that’s not what it’s about. It’s about the difference between this:
obj.set_attribute(value) # A POST request.
And this:
obj.attribute = value # A PUT request.
So please, stop the spread of this popular misconception. Read your RFCs.
Define operations in terms of HTTP methods
The HTTP protocol defines a number of methods that assign semantic meaning to a request. The common HTTP methods used by most RESTful web APIs are:
GET retrieves a representation of the resource at the specified URI. The body of the response message contains the details of the requested resource.
POST creates a new resource at the specified URI. The body of the request message provides the details of the new resource. Note that POST can also be used to trigger operations that don't actually create resources.
PUT either creates or replaces the resource at the specified URI. The body of the request message specifies the resource to be created or updated.
PATCH performs a partial update of a resource. The request body specifies the set of changes to apply to the resource.
DELETE removes the resource at the specified URI.
The effect of a specific request should depend on whether the resource is a collection or an individual item. The following table summarizes the common conventions adopted by most RESTful implementations using the e-commerce example. Not all of these requests might be implemented—it depends on the specific scenario.
Resource | POST | GET | PUT | DELETE |
---|---|---|---|---|
/customers | Create a new customer | Retrieve all customers | Bulk update of customers | Remove all customers |
/customers/1 | Error | Retrieve the details for customer 1 | Update the details of customer 1 if it exists | Remove customer 1 |
/customers/1/orders | Create a new order for customer 1 | Retrieve all orders for customer 1 | Bulk update of orders for customer 1 | Remove all orders for customer 1 |
The differences between POST, PUT, and PATCH can be confusing.
A POST request creates a resource. The server assigns a URI for the new resource and returns that URI to the client. In the REST model
, you frequently apply POST
requests to collections. The new resource is added to the collection. A POST
request can also be used to submit data for processing to an existing resource, without any new resource being created.
A PUT request creates a resource or updates an existing resource. The client specifies the URI for the resource. The request body contains a complete representation of the resource. If a resource with this URI already exists, it is replaced. Otherwise, a new resource is created, if the server supports doing so. PUT
requests are most frequently applied to resources that are individual items, such as a specific customer, rather than collections. A server might support updates but not creation via PUT
. Whether to support creation via PUT
depends on whether the client can meaningfully assign a URI to a resource before it exists. If not, then use POST
to create resources and PUT or PATCH
to update.
A PATCH request performs a partial update to an existing resource. The client specifies the URI for the resource. The request body specifies a set of changes to apply to the resource. This can be more efficient than using PUT
, because the client only sends the changes, not the entire representation of the resource. Technically PATCH
can also create a new resource (by specifying a set of updates to a "null" resource), if the server supports this.
PUT
requests must be idempotent. If a client submits the same PUT
request multiple times, the results should always be the same (the same resource will be modified with the same values). POST and PATCH
requests are not guaranteed to be idempotent.
A POST is considered something of a factory type method. You include data with it to create what you want and whatever is on the other end knows what to do with it. A PUT is used to update existing data at a given URL, or to create something new when you know what the URI is going to be and it doesn't already exist (as opposed to a POST which will create something and return a URL to it if necessary).
It should be pretty straightforward when to use one or the other, but complex wordings are a source of confusion for many of us.
When to use them:
Use
PUT
when you want to modify a singular resource that is already a part of resource collection.PUT
replaces the resource in its entirety. Example:PUT /resources/:resourceId
Sidenote: Use
PATCH
if you want to update a part of the resource.
- Use
POST
when you want to add a child resource under a collection of resources.
Example:POST => /resources
In general:
- Generally, in practice, always use
PUT
for UPDATE operations. - Always use
POST
for CREATE operations.
Example:
GET
/company/reports => Get all reportsGET
/company/reports/{id} => Get the report information identified by "id"POST
/company/reports => Create a new reportPUT
/company/reports/{id} => Update the report information identified by "id"PATCH
/company/reports/{id} => Update a part of the report information identified by "id"DELETE
/company/reports/{id} => Delete report by "id"
The difference between POST and PUT is that PUT is idempotent, that means, calling the same PUT request multiple times will always produce the same result(that is no side effect), while on the other hand, calling a POST request repeatedly may have (additional) side effects of creating the same resource multiple times.
GET
: Requests using GET only retrieve data , that is it requests a representation of the specified resource
POST
: It sends data to the server to create a resource. The type of the body of the request is indicated by the Content-Type header. It often causes a change in state or side effects on the server
PUT
: Creates a new resource or replaces a representation of the target resource with the request payload
PATCH
: It is used to apply partial modifications to a resource
DELETE
: It deletes the specified resource
TRACE
: It performs a message loop-back test along the path to the target resource, providing a useful debugging mechanism
OPTIONS
: It is used to describe the communication options for the target resource, the client can specify a URL for the OPTIONS method, or an asterisk (*) to refer to the entire server.
HEAD
: It asks for a response identical to that of a GET request, but without the response body
CONNECT
: It establishes a tunnel to the server identified by the target resource , can be used to access websites that use SSL (HTTPS)
It would be worth mentioning that POST
is subject to some common Cross-Site Request Forgery (CSRF) attacks while PUT
isn't.
The CSRF below are not possible with PUT
when the victim visits attackersite.com
.
The effect of the attack is that the victim unintentionally deletes a user just because it (the victim) was logged-in as admin
on target.site.com
, before visiting attackersite.com
:
Malicious code on attackersite.com
:
Case 1: Normal request. saved target.site.com
cookies will automatically be sent by the browser: (note: supporting PUT
only, at the endpoint, is safer because it is not a supported <form>
attribute value)
<!--deletes user with id 5-->
<form id="myform" method="post" action="http://target.site.com/deleteUser" >
<input type="hidden" name="userId" value="5">
</form>
<script>document.createElement('form').submit.call(document.getElementById('myform'));</script>
Case 2: XHR request. saved target.site.com
cookies will automatically be sent by the browser: (note: supporting PUT
only, at the endpoint, is safer because an attempt to send PUT
would trigger a preflight request, whose response would prevent the browser from requesting the deleteUser
page)
//deletes user with id 5
var xhr = new XMLHttpRequest();
xhr.open("POST", "http://target.site.com/deleteUser");
xhr.withCredentials=true;
xhr.send(["userId=5"]);
MDN Ref : [..]Unlike “simple requests” (discussed above), --[[ Means: POST/GET/HEAD ]]--, for "preflighted" requests the browser first sends an HTTP request using the OPTIONS method[..]
cors in action : [..]Certain types of requests, such as DELETE or PUT, need to go a step further and ask for the server’s permission before making the actual request[..]what is called a preflight request[..]
REST-ful usage
POST
is used to create a new resource and then returns the resource URI
EX
REQUEST : POST ..../books
{
"book":"booName",
"author":"authorName"
}
This call may create a new book and returns that book URI
Response ...THE-NEW-RESOURCE-URI/books/5
PUT
is used to replace a resource, if that resource is exist then simply update it, but if that resource doesn't exist then create it,
REQUEST : PUT ..../books/5
{
"book":"booName",
"author":"authorName"
}
With PUT
we know the resource identifier, but POST
will return the new resource identifier
Non REST-ful usage
POST
is used to initiate an action on the server side, this action may or may not create a resource, but this action will have side affects always it will change something on the server
PUT
is used to place or replace literal content at a specific URL
Another difference in both REST-ful and non REST-ful styles
POST
is Non-Idempotent Operation: It will cause some changes if executed multiple times with the same request.
PUT
is Idempotent Operation: It will have no side-effects if executed multiple times with the same request.
Actually there's no difference other than their title. There's actually a basic difference between GET and the others. With a "GET"-Request method, you send the data in the url-address-line, which are separated first by a question-mark, and then with a & sign.
But with a "POST"-request method, you can't pass data through the url, but you have to pass the data as an object in the so called "body" of the request. On the server side, you have then to read out the body of the received content in order to get the sent data. But there's on the other side no possibility to send content in the body, when you send a "GET"-Request.
The claim, that "GET" is only for getting data and "POST" is for posting data, is absolutely wrong. Noone can prevent you from creating new content, deleting existing content, editing existing content or do whatever in the backend, based on the data, that is sent by the "GET" request or by the "POST" request. And nobody can prevent you to code the backend in a way, that with a "POST"-Request, the client asks for some data.
With a request, no matter which method you use, you call a URL and send or don't send some data to specify, which information you want to pass to the server to deal with your request, and then the client gets an answer from the server. The data can contain whatever you want to send, the backend is allowed to do whatever it wants with the data and the response can contain any information, that you want to put in there.
There are only these two BASIC METHODS. GET and POST. But it's their structure, which makes them different and not what you code in the backend. In the backend you can code whatever you want to, with the received data. But with the "POST"-request you have to send/retrieve the data in the body and not in the url-addressline, and with a "GET" request, you have to send/retrieve data in the url-addressline and not in the body. That's all.
All the other methods, like "PUT", "DELETE" and so on, they have the same structure as "POST".
The POST Method is mainly used, if you want to hide the content somewhat, because whatever you write in the url-addressline, this will be saved in the cache and a GET-Method is the same as writing a url-addressline with data. So if you want to send sensitive data, which is not always necessarily username and password, but for example some ids or hashes, which you don't want to be shown in the url-address-line, then you should use the POST method.
Also the URL-Addressline's length is limited to 1024 symbols, whereas the "POST"-Method is not restricted. So if you have a bigger amount of data, you might not be able to send it with a GET-Request, but you'll need to use the POST-Request. So this is also another plus point for the POST-request.
But dealing with the GET-request is way easier, when you don't have complicated text to send. Otherwise, and this is another plus point for the POST method, is, that with the GET-method you need to url-encode the text, in order to be able to send some symbols within the text or even spaces. But with a POST method you have no restrictions and your content doesn't need to be changed or manipulated in any way.
Both PUT and POST are Rest Methods .
PUT - If we make the same request twice using PUT using same parameters both times, the second request will not have any effect. This is why PUT is generally used for the Update scenario,calling Update more than once with the same parameters doesn't do anything more than the initial call hence PUT is idempotent.
POST is not idempotent , for instance Create will create two separate entries into the target hence it is not idempotent so CREATE is used widely in POST.
Making the same call using POST with same parameters each time will cause two different things to happen, hence why POST is commonly used for the Create scenario
The request methods GET, PUT and DELETE are CRUD (create, read, update and delete) operations—that is data management operations—on the state of a target resource (the one identified by the request URI):
- GET should read the state of the target resource;
- PUT should create or update the state of the target resource;
- DELETE should delete the state of the target resource.
The request method POST is a different beast. It should not create the state of the target resource like PUT because it is a process operation with a higher-level goal than CRUD (cf. RFC 7231, § 4.3.3). The process may create a resource but different from the target resource, otherwise the lower-level goal request method PUT should be used, so even in this case that does not make it a CRUD operation.
The difference between CRUD operations (GET, PUT and DELETE in HTTP) and non-CRUD operations (POST in HTTP) is the difference between abstract data types and objects that Alan Kay was stressing in most of his talks and his ACM paper The Early History of Smalltalk:
What I got from Simula was that you could now replace bindings and assignments with goals. The last thing you wanted any programmer to do is mess with internal state even if presented figuratively. Instead, the objects should be presented as sites of higher level behaviors more appropriate for use as dynamic components.
[…] It is unfortunate that much of what is called "object-oriented programming" today is simply old style programming with fancier constructs. Many programs are loaded with "assignment-style" operations now done by more expensive attached procedures.
[…] Assignment statements—even abstract ones—express very low-level goals, and more of them will be needed to get anything done. […] Another way to think of all this is: though the late-binding of automatic storage allocations doesn’t do anything a programmer can’t do, its presence leads both to simpler and more powerful code. OOP is a late binding strategy for many things and all of them together hold off fragility and size explosion much longer than the older methodologies.