What is the benefit of passing HTTP status with API responses? - api

With your error responses you need to pass some attribute that indicates the error type anyway. So that makes HTTP status code redundant or sometimes even inaccurate.
Any real benefit here, and why it shouldn't just be 200?

Assuming we're talking about a RESTful API:
Because if you return an error message with a HTTP Status Code of 200, the client will assume his request was successful, and maybe not read the response body at all.
If the status code is 200, the client will not be looking for an error message in the response body.
An HTTP status code is not redundant. Pretty much in the same way a book's index is not redundant. First you look at the index for a topic you want to read on, and then you flip to that page and read more on that topic. Similarly, the client first reads the status code to know what happened, and then reads the response body to find out more about it.

Related

HTTP status code for an expired confirmation code

I have an endpoint in my REST API that sends a code the user received per email to verify the email address.
What status code should I better use to return that this code has expired?
Is it 401, 410 or 498?
I would recommend using status code 498 if you wanna show the user that their authorization code is invalid
or use 410 to show that the link is invalid
Edit: Note that 498 is an unofficial status code
HTTP status codes are metadata of the transfer of documents over a network domain. They are a token that instructs general purpose HTTP clients how to interpret the response (especially the other meta data fields).
When considering an unassigned status code (like 498), you want to keep in mind that general purpose components that don't recognize the code are going to treat the response as though it had the x00 response code of the same class (so 498 --> 400, 298 --> 200, and so on).
That said, if your expected context includes clients that do understand the semantics of 498, then this is less of a concern.
I have an endpoint in my REST API that sends a code the user received per email to verify the email address.
What status code should I better use to return that this code has expired?
You can make a good case for either 200 or 410, I think.
In either case, the important thing to the client is going to be the representation in the payload, which is going to be some kind of "so sorry" message and maybe hypermedia controls to restart the process.
The 410 response is primarily intended to assist the task of web maintenance by notifying the recipient that the resource is intentionally unavailable and that the server owners desire that remote links to that resource be removed.
So that could be a reasonable choice, given that you don't particularly want this URI to be reused
If the URL reads something like https://website.com/confirm-email/1738-65b9-7a39-8d1c I would use http status code 410.

Status code inside the body of a REST API response

I have seen a lot applications using REST API returning a status code inside theirs response bodies, although the HTTP response returns the status code just fine. Is there any reason to put the status code also in the body of the response?
Some APIs return a 200 for all requests, even erroneous ones, and put a status code in the response body. This status code might mimic HTTP status codes, but doesn't have to. One could start numbering your response statuses from 1 for all anyone cares.
Other APIs return appropriate HTTP status codes, and indeed, put the same status code in the response. That's just a waste of bandwidth and brain cells, and a cause for lots of head scratching. It's unnecessary. Except...
It might be useful for some kinds of client libraries. When a client application uses a library that abstracts away all the HTTP stuff, it can just return an object to the programmer that contains all information about the response.
Something like:
{
"status": 200,
"data": {
"foo" : "bar"
}
}
And:
{
"status": 401,
"data": null,
"message": "You are not authorized."
}
This way the library author can chuck the HTTP status code into the object's status property, and the caller doesn't have to deal with exception handling.
But then still there's no reason for the API to respond with it both in HTTP status code and response.
Is there any reason to put the status code also in the body of the response?
Yes, in the sense that the status-line is HTTP metadata, describing the semantics of the response message. Like other HTTP metadata, it's not really designed for use by the end client.
Consider the web experience - the browser gets to see the HTTP response message, and can act on it. But what information do you want to share with the user? In cases where you wanted the user to be aware of the HTTP status code, you would include it in the HTML representation also.
Problem Details for HTTP APIs includes an optional status field in its schema to surface that information for the client.

HTTP response body for server command request

I am solving one question with my team about REST API specification.
We have a case where in some requests we are sending only some particular command via HTTP request for example : We are using POST (now considering PATCH request) to endpoint : /server/startSomeOperation . Backend developers told us that this request is only telling hardware to start some functionality on backend that affects the measurement of the user but it really has nothing to return. My question is :
Should we (according to some REST API specification) always return body of such a request when we know that no additional returned data will be needed except HTTP status code? Until now we were strictly following the rule that every request needs to have some sort of body returned but until now every body response even when it was a command to a server made sense.
Should we (according to some REST API specification) always return body of such a request when we know that no additional returned data will be needed except HTTP status code?
No - it is perfectly fine to send a 204 No Content or a 205 Reset Content when the semantics of your response is well aligned with the standard meaning of those codes.
You also have the option of declaring that the "representation of the status of, or results obtained from, the action" is zero bytes long, in which case you could use a 200 OK with a Content-Length header.

HTTP status code to return by a REST API when image size exceeds limit

A POST to a specific end point allows to upload an image except if the image is too large, so I want to return the appropiate http status code response in that case.
A http status code 400 response it does not seem to fit well in this case.
400 Bad Request: "The server cannot or will not process the request due
to something that is perceived to be a client error (e.g., malformed
request syntax, invalid request message framing, or deceptive request
routing).
I think that the image being too large it does not imply that the request is malformed or syntactically incorrect.
Any suggestions?
This seems like it would be an ideal candidate for 413 Payload Too Large. From Section 6.5.11 of RFC 7231:
The 413 (Payload Too Large) status code indicates that the server is
refusing to process a request because the request payload is larger
than the server is willing or able to process.
You can use 420 or even 422, but I would avoid that until you have really good reason to have separate code for it. Usually is better to keep number of different status codes rather small. Check top 10 on that list: http://www.restapitutorial.com/httpstatuscodes.html
You should avoid using more than 10 codes, because your API will become too complex.
So my answer is: use 400 with proper error message returned to the client like: "Image too large, you can upload files up to XX MB"

what should be HTTP status code if resource is not available for requested action?

I am developing a RESTful API. I am confused about setting HTTP status code in this particular scenario. I am not sure what status code should I (server) return.
Let's say my app has a follow user functionality, if I am already following a user and again I send follow request for the same user id then in this case what should be the HTTP status code from server. The status code will be followed by an error message saying something like: "already following the user."
Similar scenario can be considered for unfollow user functionality, if I am not following an user "A", still I send request to unfollow user "A", then what HTTP status code should server return with error message something like "not following user to unfollow"
Certainly 200 response code doesn't seem to be appropriate to me here? or does it?
Please forgive me if I have posted the question at wrong stack exchange site, I posted it in stackoverflow site just because it is related to REST APIs.
EDIT
From client side user needs to send POST request to the URL:
http://www.myserver.com/api/follow/10
along with other necessary parameters ( like API keys, proper headers, etc) which are used for authentication before serving the requests at server side.
similar URL for unfollow action is:
http://www.myserver.com/api/unfollow/10
Right now, I am sending HTTP status code 200 in response if the client sends follow request, let's say, for user id 10 even if he/she is already following the user with id 10. In this case,along with status code (200) I am sending message similar to "already following the user"
Somehow I feel this is not convincing as no resource is created/updated it should return the error message with proper status code something other than 200, may be one from 4XX, not sure.
422 Unprocessable Entity
422 seems to be the proper HTTP status code in this use case.
The description of 422 says:
The 422 (Unprocessable Entity) status code means the server understands the content type of the request entity (hence a 415(Unsupported Media Type) status code is inappropriate), and the syntax of the request entity is correct (thus a 400 (Bad Request) status code is inappropriate) but was unable to process the contained instructions.
The answer depends on your API. You're describing the API in terms of "follow user X" or "unfollow user Y". That makes me think you might be approaching your API design in an RPC style rather than focusing on resources.
If your API uses REST including the HATEOAS principle, then error codes from the 4xx range may be appropriate (but I would recommend against it in this case, see below). In very short: HATEOAS means that your resources provide links to possible "actions". You can read more about it here: http://restcookbook.com/Basics/hateoas/
Apart from that, it seems a good idea to design your API "fault tolerant", i.e. expect the same request sent multiple times (e.g. because users are impatient and click again and again, or the browser crashed and is restarted and reopens all previous tabs, or...).
My personal opinion and recommendation is the following:
follow user X: Your implementation should check if it needs to add the new follower or not. Regardless, if the user is already following or not, send back HTTP status 201 (created) and add the "Location" HTTP header pointing at the resource.
unfollow user X: Your implementation should check if it needs to delete the follower or not. Regardless, if the user is already removed from the followers or not, send back HTTP status 200 (OK).
The general idea is, if a client requests something to be a certain way and that is already the case, the server has two options: Either it responds to the client "The result you wish is already in place. Therefore your request is invalid." or the server can respond "The result you wish is already in place. You have everything you need.".
Going for the second option makes the API more tolerant and helps with idempotency (see http://restcookbook.com/HTTP%20Methods/idempotency/).
I think djlauk's answer covers a lot, but I want to give a little different approach and add some information:
Do not use verbs in the URI
I would not use POST on /follow/ respectively /unfollow/ URIs because this is not very RESTful see this SO question: Why does including an action verb in the URI in a REST implementation violate the protocol? and escpacially this SO answer: How to create REST URLs without verbs?
Do use the correct HTTP verbs for the actions
What you want to do is a creation of an entity ("follow") so for that you can use the HTTP verbs POST or PUT and afterwards the deletion of that entity ("unfollow") where DELETE would be the right fit.
My approach for your API:
I would do the following:
(The first two examples are just for explaining the structure, you don't have to implement them if you don't need them.)
This does get you the user "robert":
GET http://www.myserver.com/api/users/robert/
response: #200
This does get you the users "robert" is following:
GET http://www.myserver.com/api/users/robert/following/
response: #200
And this is how you let "robert" follow "rahul":
PUT http://www.myserver.com/api/users/robert/following/rahul
response: #200
If you send this request again you get the same response:#200 because PUT is idempotent and this is how it should behave (see (2))
When you now want to let "robert" unfollow "rahul" you send:
DELETE http://www.myserver.com/api/users/robert/following/rahul
response: #200
If you send the DELETE request again you get a little different response a #404 , but this is HTTP standard and the clients should understand this.
For the regular answer codes of HTTP methods I can also recommend this source: restapitutorial.com
I would use some of the following:
System.Net.HttpStatusCode.ServiceUnavailable;
System.Net.HttpStatusCode.MethodNotAllowed;
System.Net.HttpStatusCode.BadRequest;
Better if it is one of the first two.
Certainly 200 response code will not work in this situation.
following are the groups in HTTP Status Code:
1xx Informational
2xx Success
3xx Redirection
4xx Client Error
5xx Server Error
Certainly you need to use 4xx.
I think for the condition that you have described here, you can use any of the following:
405 Method Not Allowed
A request was made of a resource using a request method not supported by that resource; for example, using GET on a form which requires data to be presented via POST, or using PUT on a read-only resource.
400 Bad Request
The server cannot or will not process the request due to something that is perceived to be a client error
409 Conflict
Indicates that the request could not be processed because of conflict in the request, such as an edit conflict in the case of multiple updates.
More details are available here:
http://en.wikipedia.org/wiki/List_of_HTTP_status_codes