What is the difference between PUT, POST and PATCH methods in HTTP protocol?
POST
HTTP.POST can be used when the client is sending data to the server and the server will decide the URI for the newly created resource. The POST method is used to request that the origin server accept the entity enclosed in the request as a new subordinate of the resource identified by the Request-URI in the Request-Line.
PUT
HTTP.PUT can be used when the client is sending data to the server and the client is determining the URI for the newly created resource. The PUT method requests that the enclosed entity be stored under the supplied Request-URI. If the Request-URI refers to an already existing resource, the enclosed entity SHOULD be considered as a modified version of the one residing on the origin server. If the Request-URI does not point to an existing resource, and that URI is capable of being defined as a new resource by the requesting user agent, the origin server can create the resource with that URI.
PATCH
HTTP.PATCH can be used when the client is sending one or more changes to be applied by the server. The PATCH method requests that a set of changes described in the request entity be applied to the resource identified by the Request-URI. The set of changes is represented in a format called a patch document.
For more information refer below mentioned URL
Difference between PUT, POST, GET, DELETE and PATCH IN HTTP Verbs:
The most commonly used HTTP verbs POST, GET, PUT, DELETE are similar to CRUD (Create, Read, Update and Delete) operations in database. We specify these HTTP verbs in the capital case. So, the below is the comparison between them.
- create - POST
- read - GET
- update - PUT
- delete - DELETE
PATCH: Submits a partial modification to a resource. If you only need to update one field for the resource, you may want to use the PATCH method.
Note:
Since POST, PUT, DELETE modifies the content, the tests with Fiddler for the below url just mimicks the updations. It doesn't delete or modify actually. We can just see the status codes to check whether insertions, updations, deletions occur.
URL: http://jsonplaceholder.typicode.com/posts/
1) GET:
GET is the simplest type of HTTP request method; the one that browsers use each time you click a link or type a URL into the address bar. It instructs the server to transmit the data identified by the URL to the client. Data should never be modified on the server side as a result of a GET request. In this sense, a GET request is read-only.
Checking with Fiddler or PostMan: We can use Fiddler for checking the response. Open Fiddler and select the Compose tab. Specify the verb and url as shown below and click Execute to check the response.
Verb: GET
url: http://jsonplaceholder.typicode.com/posts/
Response: You will get the response as:
"userId": 1, "id": 1, "title": "sunt aut...", "body": "quia et suscipit..."
In the “happy” (or non-error) path, GET returns a representation in XML or JSON and an HTTP response code of 200 (OK). In an error case, it most often returns a 404 (NOT FOUND) or 400 (BAD REQUEST).
2) POST:
The POST verb is mostly utilized to create new resources. In particular, it's used to create subordinate resources. That is, subordinate to some other (e.g. parent) resource.
On successful creation, return HTTP status 201, returning a Location header with a link to the newly-created resource with the 201 HTTP status.
Checking with Fiddler or PostMan: We can use Fiddler for checking the response. Open Fiddler and select the Compose tab. Specify the verb and url as shown below and click Execute to check the response.
Verb: POST
url: http://jsonplaceholder.typicode.com/posts/
Request Body:
data: { title: 'foo', body: 'bar', userId: 1000, Id : 1000 }
Response: You would receive the response code as 201.
If we want to check the inserted record with Id = 1000 change the verb to Get and use the same url and click Execute.
As said earlier, the above url only allows reads (GET), we cannot read the updated data in real.
3) PUT:
PUT is most-often utilized for update capabilities, PUT-ing to a known resource URI with the request body containing the newly-updated representation of the original resource.
Checking with Fiddler or PostMan: We can use Fiddler for checking the response. Open Fiddler and select the Compose tab. Specify the verb and url as shown below and click Execute to check the response.
Verb: PUT
url: http://jsonplaceholder.typicode.com/posts/1
Request Body:
data: { title: 'foo', body: 'bar', userId: 1, Id : 1 }
Response: On successful update it returns 200 (or 204 if not returning any content in the body) from a PUT.
4) DELETE:
DELETE is pretty easy to understand. It is used to delete a resource identified by a URI.
On successful deletion, return HTTP status 200 (OK) along with a response body, perhaps the representation of the deleted item (often demands too much bandwidth), or a wrapped response (see Return Values below). Either that or return HTTP status 204 (NO CONTENT) with no response body. In other words, a 204 status with no body, or the JSEND-style response and HTTP status 200 are the recommended responses.
Checking with Fiddler or PostMan: We can use Fiddler for checking the response. Open Fiddler and select the Compose tab. Specify the verb and url as shown below and click Execute to check the response.
Verb: DELETE
url: http://jsonplaceholder.typicode.com/posts/1
Response: On successful deletion it returns HTTP status 200 (OK) along with a response body.
Example between PUT and PATCH
PUT
If I had to change my firstname then send PUT request for Update:
{ "first": "Nazmul", "last": "hasan" } So, here in order to update the first name we need to send all the parameters of the data again.
PATCH:
Patch request says that we would only send the data that we need to modify without modifying or effecting other parts of the data. Ex: if we need to update only the first name, we pass only the first name.
Please refer the below links for more information:
https://jsonplaceholder.typicode.com/
https://github.com/typicode/jsonplaceholder#how-to
PUT = replace the ENTIRE RESOURCE with the new representation provided
PATCH = replace parts of the source resource with the values provided AND|OR other parts of the resource are updated that you havent provided (timestamps) AND|OR updating the resource effects other resources (relationships)
Request Types
- create - POST
- read - GET
- create or update - PUT
- delete - DELETE
- update - PATCH
GET/PUT is idempotent PATCH can be sometimes idempotent
What is idempotent - It means if we fire the query multiple times it should not afftect the result of it.(same output.Suppose a cow is pregnant and if we breed it again then it cannot be pregnent multiple times)
get :-
simple get. Get the data from server and show it to user
{
id:1
name:parth
email:x@x.com
}
post :-
create new resource at Database. It means it adds new data. Its not idempotent.
put :-
Create new resource otherwise add to existing. Idempotent because it will update the same resource everytime and output will be the same. ex. - initial data
{
id:1
name:parth
email:x@x.com
}
- perform put-localhost/1 put email:ppp@ppp.com
{
id:1
email:ppp@ppp.com
}
patch
so now came patch request PATCH can be sometimes idempotent
id:1
name:parth
email:x@x.com
}
patch name:w
{
id:1
name:w
email:x@x.com
}
HTTP Method GET yes POST no PUT yes PATCH no* OPTIONS yes HEAD yes DELETE yes
Resources : Idempotent -- What is Idempotency?
The below definition is from the real world example.
Example Overview
For every client data, we are storing an identifier to find that client data and we will send back that identifier to that client for reference.
POST
- If the Client sends data without any identifier using the POST method then we will store it and assign a new identifier.
- If the Client again sends the same data without any identifier using the POST method, then we will store it and assign a new identifier.
- Note: Duplication is allowed here
PUT
- If the Client Sends data with an identifier then we will check whether that identifier exists. If the identifier exists we will update data else we will create it and assign a new identifier.
PATCH
- If the Client Sends data with an identifier then we will check whether that identifier exists. If the identifier exists we will update data else we will throw an exception.
Note: On Put Method, We are not throwing an exception if an identifier is not found. But in Patch method, we are throwing an exception if the identifier is not found.
Do let me know if you have any queries on the above.
来源：https://stackoverflow.com/questions/31089221/what-is-the-difference-between-put-post-and-patch