I'm implementing Asynchronous REST API where file is posted and then it's added to queue for further processing. My questions is what's the best practice in this case of naming the resources.
Resource #1 POST Files where {type} is dynamic.
POST /files/{type}
Posting data to this resource. It's queued and user will receive unique Queue ID. How should the resource of files queue be named ?
Resource #2. GET files queue
OPTION 1. GET /files/queues/{QueueID}
OR
OPTION 2. GET /files/{type}/queues/{QueueID}
Which one makes more sense ? User can upload files with different {type}.
OR should I just use completely different resource of Getting queue items like:
GET /queues
AND
/queues/{QueueID}
Thanks for tips.
It depends on your needs. (Or the client's needs)
I would go with the "/queues/{QueueID}" option, since the queueId itself (without the type) identifies the file, so there is no need to include it.
Additionally I would omit the {type} variable even from the POST method, because you can simply send that information in the HTTP header. (Content-Type)
The "files/{type}" approach is more useful, when you have to display the files grouped by type. Without that need, there is no need to further complicate the resource identifier.
(Note: If the "queue" and "file" items are the same, then you could use GET /files/{QueueId} )
Related
So i have one single http post API called UpsertPerson, where it does two things:
check if Person existed in DB, if it does, update the person , then return Http code 200
if not existed in DB, create the Person, then return http 201.
So is it a good practices by having the same api return different statusCode (200,201) based on different actions(update, create)?
This is what my company does currently , i just feel like its weird. i think we should have two individual api to handle the update and create.
ninja edit my answer doesn't make as much sense because I misread the question, I thought OP used PUT not POST.
Original answer
Yes, this is an excellent practice, The best method for creating new resources is PUT, because it's idempotent and has a very specific meaning (create/replace the resource at the target URI).
The reason many people use POST for creation is for 1 specific reason: In many cases the client cannot determine the target URI of the new resource. The standard example for this is if there's auto-incrementing database ids in the URL. PUT just doesn't really work for that.
So PUT should probably be your default for creation, and POST if the client doesn't control the namespace. In practice most APIs fall in the second category.
And returning 201/200/204 depending on if a resource was created or updated is also an excellent idea.
Revision
I think having a way to 'upsert' an item without knowing the URI can be a useful optimization. I think the general design I use for building APIs is that the standard plumbing should be in place (CRUD, 1 resource per item).
But if the situation demands optimizations, I typically layer those on top of these standards. I wouldn't avoid optimizations, but adopt them on an as-needed basis. It's still nice to know if every resource has a URI, and I have a URI I can just call PUT on it.
But a POST request that either creates or updates something that already exists based on its own body should:
Return 201 Created and a Location header if something new was created.
I would probably return 200 OK + The full resource body of what was updated + a Content-Location header of the existing resource if something was updated.
Alternatively this post endpoint could also return 303 See Other and a Location header pointing to the updated resource.
Alternatively I also like at the very least sending a Link: </updated-resource>; rel="invalidates" header to give a hint to the client that if they had a cache of the resource, that cache is now invalid.
So is it a good practices by having the same api return different statusCode (200,201) based on different actions(update, create)?
Yes, if... the key thing to keep in mind is that HTTP status codes are metadata of the transfer-of-documents-over-a-network domain. So it is appropriate to return a 201 when the result of processing a POST request include the creation of new resources on the web server, because that's what the current HTTP standard says that you should do (see RFC 9110).
i think we should have two individual api to handle the update and create.
"It depends". HTTP really wants you to send request that change documents to the documents that are changed (see RFC 9111). A way to think about it is that your HTTP request handlers are really just a facade that is supposed to make your service look like a general purpose document store (aka a web site).
Using the same resource identifier whether saving a new document or saving a revised document is a pretty normal thing to do.
It's absolutely what you would want to be doing with PUT semantics and an anemic document store.
POST can be a little bit weird, because the target URI for the request is not necessarily the same as the URI for the document that will be created (ie, in resource models where the server, rather than the client, is responsible for choosing the resource identifier). A common example would be to store new documents by sending a request to a collection resource, that updates itself and selects an identifier for the new item resource that you are creating.
(Note: sending requests that update an item to the collection is a weird choice.)
I like to use the correct HTTP methods when I'm creating an API. And usually it's very straightforward. POST for creating entities, PUT for updating them, GET for retrieving etc.
But I have a use-case here where I will create an endpoint that updates the status of multiple objects given 1 identifier.
e.g.:
/api/v1/entity/update-status
But note that I mentioned multiple objects. The initial thought of my team would be to use map it as POST, but it won't actually be creating anything, plus if you were to call the same endpoint multiple times with the same identifier, nothing would change after the first time. Making it idempotent.
With this in mind, my idea was to create it as a PUT or even PATCH endpoint.
What do you smart people think?
I imagine PATCH would be the most correct way. Although if you use a PUT it would also not be incorrect.
The difference between the PUT and PATCH requests is reflected in the
way the server processes the enclosed entity to modify the resource
identified by the Request-URI. In a PUT request, the enclosed entity
is considered to be a modified version of the resource stored on the
origin server, and the client is requesting that the stored version be
replaced. With PATCH, however, the enclosed entity contains a set of
instructions describing how a resource currently residing on the
origin server should be modified to produce a new version. The PATCH
method affects the resource identified by the Request-URI, and it also
MAY have side effects on other resources; i.e., new resources may be
created, or existing ones modified, by the application of a PATCH.
Whilst it is a convention in REST APIs that POST is used to create a resource it doesn't necessarily have to be constrained to this purpose.
Referring back to the definition of POST in RFC 7231:
The POST method requests that the target resource process the representation enclosed in the request according to the resource's own specific semantics. For example, POST is used for the following functions (among others):
Providing a block of data, such as the fields entered into an HTMl form, to a data-handling process
Posting a message to a bulletin board, newsgroup, mailing list, blog, or similar group of articles;
*Creating a new resource that has yet to be identified by the origin server; and *
Appending data to a resource's existing representation(s).
Clearly creation is only one of those purposes and updating existing resources is also legitimate.
The PUT operation is not appropriate for your intended operation because again, per RFC, a PUT is supposed to replace the content of the target resource (URL). The same also applies to PATCH but, since it is intended for partial updates of the target resource you can target it to the URL of the collection.
So I think your viable options are:
POST /api/v1/entity/update-status
PATCH /api/v1/entity
Personally, I would choose to go with the PATCH as I find it semantically more pleasing but the POST is not wrong. Using PATCH doesn't gain you anything in terms of communicating an idempotency guarantee to a consumer. Per RFC 5789: "PATCH is neither safe nor idempotent" which is the same as POST.
I am trying build an api which conforms to the json:api spec.
My api has three resources /task, /item and /result. A task has the fields name, description and state. A item has the fields itemName. A count is kept server-site for the item and the count is returned when a user retrieves the item with a GET request. The count is incremented server-side when the item is updated. There is a one-to-many relationship between task and item. In a sense an item is appended to a task. When the tasks state changes a script runs server-side to do some processing on the associated items. Once the script finishes the output is available in the result resource.
Per the spec, I am using the POST verb to create a task and the PATCH to update a task. I just want one endpoint which handles both the create /update (appending) of an item. But, I'm not sure which verb to use? Can I use PATCH to update the item but also create an item if it doesn't exist?
I also thought that perhaps I should be using the PUT verb. But, my understanding here is that this verb is used to simply replace a resource rather than update it. I don't think this is right for my user-case as an items count is incremented when updated, so replacing it is not what I want todo. But, the count is handled server-side so a user doesn't have the option of "replacing" the count anyway.
my understanding here is that this verb is used to simply replace a resource rather than update it.
This is a common understanding - wrong, but common.
The IANA registry documents the authoritative reference for the semantics of http methods. Most of the common ones are defined by RFC 7231; PATCH is defined by RFC 5789.
PUT is an appropriate choice when the message body is a complete representation of what you want the resource to be. It may be easier to think about "saving a file"; PUT describes what the client expects the document to look like when it has been saved.
It's appropriate to use PUT for either updating a document or creating one, provided that the client knows the identifier for the document (just in the same way that we can use save to create a file, or replace a file, but we need to know the file name).
If you read the text of the specification, you'll see that - while the semantics of the request are to save the new representation "as-is", the server isn't required to do that -- the server, after all, is in control of its own documents -- so there is room to cover read only fields, or fields that should be updated by the server only. You need to have a little bit of care with the response headers to avoid implying that you saved the representation as is, but other than that you should be fine.
One of the reasons, and probably the main one, to use UUID is to avoid having a "centralized" point responsible for creating and assigning ids to resources.
That means that, for REST APIs, the clients could (and should) be able to generate, and give the UUID for a certain resource when they POST that specific resource for the first time. That would minimize problems related with successfully posting a resource for the first time but not getting the ID back as response (connectivity problems for example). That can result in a new post for some of the clients, generating duplicated resources.
My question are:
Having UUID generated by clients and being exposed in the REST API is a best practice?
Are there any other alternatives to that?
REST does not really care if the UUID is generated by the server or by the client. It just needs a unique resource-identifier in form of an URI.
What form the URI has, is not important to clients and servers - only that they are unique and may be obtained by clients (HATEOAS). You need of course also a resource on the server side which is able to create the sub-resource for you and understands that you want to provide the UUID instead of generating an own one. Instead of a UUID you could f.e. also use a url-encoded title of a blog-post or like this question a combination of hash-value and question-title 31584303/rest-api-and-uuid to uniquely identify a resource.
Generating a UUID by a client is in my opinion not used that ofen in practice, but I may be wrong on this matter. The actual question is rather, why should a client really provide an own UUID instead of letting the server create one? The client is, IMO, only interested in getting the data to the server and having some way to retrieve it at some later point, which will be provided through the location header returned in the response of a POST request.
If connection issues are an actual concern, you could let the client send an empty POST to create a resource and send back the location within the header. The content is than added via a PUT request.
There still can be some connection issues involved:
request does not reach the server
response does not reach the client
While the primer one is no issue for the client as well as for the server as no operation is executed and the request can simply be resent, the latter one will actually create a resource at the server side, though the link never reaches the client. Therefore the actual resource is in an unreferencable state unless you provide a way to iterate over all resources, which contains also the empty ones.
A server can have a cleanup thread in the back which removes empty resources after a given amount of time. If a client sends a further empty POST request but this time also receives the URI of the created resource, he can update the state of the resource via PUT. PUT is idempotent. If the server did not receive the request, the client can simply resent it. PUT has the semantic of updating existing or creating a new resource if it is not yet available. So, the server can create the resource in that case with the provided content. If the request did reach the server, a further update does not change the state of the resource.
one advantage of client-generated UUID is: the client knows the resource key even before creating the resource. no need to read the response of the POST/PUT except for errors
For some reasons my application needs to have an API that flows like:
Client calls server to get ID for a new resource.
Then user spends a while filling out the forms for the resource.
Then user clicks save (or not...), and when he does the client saves by writing to /myresource/{id}
What is the RESTful way to design this?
How should the first call look like? On server side, it's a matter of generating an ID and returning it. It has side effects (increments sequence and thus "reserves space"), but it doesn't explicitly create a resource.
If I understand correctly, the 3rd call should be a PUT because it creates something with a known URI.
One way you could do it is:
client POSTs empty body to /myresource/
server answers with status code 302 (Found) with a Location response header set to /myresource/newresourceid (to indicate the ID / URI that should be used to create the resource)
client PUTs the new resource to /myresource/newresourceid once the user is done filling the form.
Seems RESTful enough. ;)
I'm interested to see the other answers to this question as I imagine there's a lot of ways to do this.
If possible I would let your auto-incrementing ID in the database serve as your surrogate key and assign another field to be your business identifier. It could be something like a product code or a GUID.
With this in mind the client can now create the ID themselves which removes the need for step 1 at all. They would do a PUT to a url such as /myresource/MLN5001 or /myresource/3F2504E0-4F89-11D3-9A0C-0305E82C3301 to create the resource. If the ID is already in use return a 409 Conflict with the conflict in the response body. Otherwise return a 201 Created and include the URI to the resource in the response body and location header.
I would go with
GET /myresource/new-id
POST /myresource/{id}
Your walkthrough is pretty clear on the verb:
"to GET [an] ID for a new resource"
you could rename new-id to whatever you think makes it most clear. If you have multiple resources you need to do this for, it would probably be better to split out the generator into its own resource, such as
GET /id-generator/myresource
GET /id-generator/my-other-resource
If there are multiple cases, the user will quickly learn they need to hit id-generator to get their ID. If it's only one case, it's annoying for them to only have to use it infrequently.
I guess you could also do
GET /myresource-id-generator/next
which looks a little clearer, but then if you ever need another ID to be generated you have to make another resource to do it.
ID allocation is non-idempotent — two invokes of the allocation operation will get different IDs — so that should always be a POST. From that point on, the resource should conceptually exist. However, what I'd do at that point is fill it out with reasonable default values (whether that involves doing POSTs or PUTs is rather immaterial to the RESTfulness of the overall design), so the user can then take their time to alter the things that they want to look like they want them to.
The question then becomes one of whether there should be some kind of “release this; I'm done with altering it” operation at the end. Strict RESTfulness says there shouldn't, as if you know the resource identifier (the URL) then you can talk about it. On the other hand, that doesn't mean the hosting server has to tell anyone else about the resource until the creating user is happy with it; general HATEOAS principles say nothing about when others can discover that a resource exists or whether knowing the name lets you read the thing, but it's entirely reasonable to deny to third parties that a resource exists until the owner of the resource turns on the “make this public” flag.