REST API Get single latest resource - rest

I'm designing a REST api and interested if anyone can help with best practice in the following scenario.
I have...
GET Customers/{customerId}/Orders - to get all customer orders
GET Customers/{customerId}/Orders/{orderId} - to get a particular order
I need to provide the ability to get a customers most recent order. What is best practice in this scenario? Simply get all and sort by date or provide a specific method?

I need to provide the ability to get a customers most recent order.
Of course you could provide query parameters to filter, sort and slice the orders collection, but why not making it simpler and give the latest order if the client needs it?
You could use something like (returning a representation of a single order):
GET /customers/{customerId}/orders/latest
The above URL will map an order that will change over the time and it's perfectly fine.
Say there is also a case where you need last 5 orders. How would your route(s) look like?
The above approach focus on the ability to get a customers most recent order requirement. If returning the last 5 orders requirement eventually comes up after some time, I would probably introduce another mapping such as /recent that returns a representation of a collection with the recent orders and accepts a query parameter that indicates the amount of orders to be returned (5 would be the default value if the parameter is omitted).
The /latest mapping would still be valid and would return a representation of the very latest order only.
Providing query parameters to filter, sort and slice the orders collection is still a valid approach.
The key is: If you know the client who will consume the API, target it to their needs. Otherwise, make it more generic. And when modifying the API, be careful with breaking changes and versioning the API is also welcome.

I think there is no need for another route.
Pass something like &order=-created_at&limit=1 in your get request
Or &order=created_at&orderby=DESC&limit=1 (note I'm not sure about naming your params so maybe you could use &count=1 instead of &limit=1, ditto order params)
I think it also depends whether you are using pagination or not on that route, so perhaps additional params are required
Customers/{customerId}/Orders?order=-created_at&limit=1

The Github API for the similar use case is using latest, to fetch the single resource which is latest.
https://docs.github.com/en/rest/reference/repos#get-the-latest-release
So to fetch a single resource which is latest you can use.
GET /customers/{customerId}/orders/latest
However would like to know what community think about this.
IMO the resource/latest gives an impression that the response will be a list of resource sorted by latest to oldest.

Related

Is it possible to obtain the ServicePath when querying entities in Orion?

the question I'd like to ask was raised some time ago (FIWARE Orion: How to retrieve the servicePath of an entity?) but as far as I've seen, there is no final answer.
In short, I'd like to retrieve the service path of entities when I exec a GET query to /v2/entitites which returns multiple results.
In our FIWARE instance, we strongly rely on the servicePath element to differentiate between entities with the same id. It is not a good design choice but, unfortunately, we cannot change it as many applications use that id convention at the moment.
There was an attempt three years ago to add a virtual field 'servicePath' to the query result (https://github.com/telefonicaid/fiware-orion/pull/2880) but the pull request was discarded because it didn't include test coverage for that feature and the final NGSIv2 spec didn't include that field.
Is there any plan to implement such feature in the future? I guess the answer is no, what brings me to the next question: is there any other way to do it which does not involve creating subscriptions (we found that the initial notification of a subscription does give you that info, but the notification is limited to 1000 results, what is too low for the number of entities we want to retrieve, and it does not allow pagination either)?
Thanks in advance for your responses.
A possible workaround is to use an attribute (provided by the context producer application) to keep the service path. Somehow, this is the same idea of the builtin attribute proposed in PR #2880.

REST: Filter primary resource by properties on related resource

I'm looking for some guidance/advice/input on the concept of filtering resources when making a REST API call. Let's say I have Users and Posts, and a User creates a Post. If I want to get all Posts, I might have a route as follows:
GET /api/posts
Now if I wanted to get all posts that were created after a certain date, I might add a filter parameter like so
GET /api/posts?created_after=2017-09-01
However, let's say I want to get all posts by Users that were created after a certain date. Is this the right format?
GET /api/posts?user.created_after=2017-09-01
When it comes to filtering, grouping, etc, I'm having a hard time figuring out the right stuff to do for REST APIs, particularly when using a paginated API. If I do this client side (which was my initial thought) then you potentially end up with a variable number of resources per page, based on what meets your criteria. It seems complicated to add all of this logic as query parameters over the API, but I can't see any other way to do it. Is there a standard for this kind of thing?
There is no objective 'right' way. If using user.created_after logically makes sense in the context of your API, then there's nothing really wrong with it.
Personally, I would not use user.created_after.
I would rather prefer one of the following options:
Option I: /api/posts/users/{userid}?created_after=2017-09-01
Option II: /api/posts/?user={userid}&created_after=2017-09-01
The reason is simple: It looks wrong to me to create dynamic query parameters. Instead you can combine the query parameters (Option II) or even define a more specific resource (Option I).
Regarding pagination: the standard approach is something like this: In addition to filter parameters, you define the following parameters: page and pageSize. When constructing the request, client will specify something like page=2&pageSize=25&orderBy=creationDate.
It's important to note that server must always validate the parameters and can potentially ignore or override incorrect parameters (e.g. page doesn't exist, or pageSize is too big may not return an error, but instead returning reasonable output. This really depends on your business case)

REST url proper format

my REST API format:
http://example.com/api/v1.0/products - get all products
http://example.com/api/v1.0/products/3 - get product with id=3
Also, the products can be orginized into a product groups.
What is a proper way to get all product groups according to REST best practices:
http://example.com/api/v1.0/products/groups
or
http://example.com/api/v1.0/productgroups
...
another option ?
I can't agree with Rishabh Soni because http://example.com/api/v1.0/products/groups may lead to ambiguity.
I would put my money on http://example.com/api/v1.0/productgroups or even better http://example.com/api/v1.0/product_groups (better readability).
I've had similar discussion here: Updating RESTful resources against aggregate roots only
Question: About the thing of /products/features or /product-features,
is there any consensus on this? Do you know any good source to ensure
that it's not just a matter of taste?
Answer: I think this is misleading. I would expect to get all features
in all products rather than get all possible features. But, to be
honest, it’s hard to find any source talking directly about this
problem, but there is a bunch of articles where people don’t try to
create nested resources like /products/features, but do this
separately.
So, we can't be sure http://example.com/api/v1.0/products/groups will return all possible groups or just all groups that are connected with all existing products (what about a group that has not been connected with the product yet?).
To avoid this ambiguity, you can add some annotation in documentation. But you can just prepare http://example.com/api/v1.0/product_groups and all is clear.
If you are developing Rest API for your clients than you should not rely on id's. Instead build a meaningful abbreviation and map them to actual id on server side.
If that is not possible, instead of using
http://example.com/api/v1.0/products/3 you can use http://example.com/api/v1.0/products?product_id=3 and then you can provide "product_id" description in the documentation. basically telling the client ways to use product_id.
In short a url must be meaningful and follow a pattern.The variable part must be send by in the url query(part after ? or POST payload)
With this, method to querying the server is also important. If client is trying to get something to the server he should use "GET" http request, similar POST http request if it is uploading new info and "PUT" request if it is updating or creating a new resource.
So by this analogy http://example.com/api/v1.0/products/groups is more appropriate as it is following a pattern(groups in product) while productgroups is more like a keyword with no pattern.
A directory like pattern is more easier to understand. Like in file systems(C:\Program Files\WinRAR), every part gets us to more generalized target.
You can also customize this for specific group- http://example.com/api/v1.0/products/groups?id=3

REST where should end point go?

Suppose there's USERS and ORDERS
for a specific user's order list
You could do
/user/3/order_list
/order/?user=3
Which one is prefered and why?
Optional parameters tend to be easier to put in the query string.
If you want to return a 404 error when the parameter value does not correspond to an existing resource then I would tend towards a path segment parameter. e.g. /customer/232 where 232 is not a valid customer id.
If however you want to return an empty list then when the parameter is not found then query string parameters. e.g. /contacts?name=dave
If a parameter affects an entire URI structure then use a path e.g. a language parameter /en/document/foo.txt versus /document/foo.txt?language=en
If unique identifiers to be in a path rather than a query parameter.
Path is friendly for search engine/browser history/ Navigation.
When I started to create an API, I was thinking about the same question.
Video from apigee. help me a lot.
In a nutshell when you decide to build an API, you should decide which entity is independent and which is only related to someone.
For example, if you have a specific endpoint for orders with create/update/delete operations, then it will be fine to use a second approach /order/?user=3.
In the other way, if orders have only one representation, depends on a user and they don't have any special interaction then you could first approach.
There is also nice article about best practice
The whole point of REST is resources. You should try and map them as closely as possible to the actual requests you're going to get. I'd definitely not call it order_list because that looks like an action (you're "listing" the orders, while GET should be enough to tell you that you're getting something)
So, first of all I think you should have /users instead of /user, Then consider it as a tree structure:
A seller (for lack of a better name) can have multiple users
A user can have multiple orders
An order can have multiple items
So, I'd go for something like:
The seller can see its users with yourdomain.com/my/users
The details of a single user can be seen with yourdomain.com/my/users/3
The orders of a single user can be seen with yourdomain.com/my/users/3/orders
The items of a single order can be seen with yourdomain.com/my/users/3/orders/5

REST parameters vs URI

I'm just learning REST and trying to figure out how to apply it in practice. I have a sampling of data that I want to query, but I'm not sure how the URLs are meant to be formed, i.e. where I put the query. For example, for querying the most recent 100 data records:
GET http://data.com/data/latest/100
GET http://data.com/data?amount=100
which of the previous two queries is the better, and why? And the same for the following:
GET http://data.com/data/latest-days/2
GET http://data.com/data?days=2
GET http://data.com/data?fromDate=01-01-2000
Thanks in advance.
Personally, I would use the query string format in this case. If your /data path is returning all of the data, and you would like to perform this type of query, I believe it makes the most sense. You could also pass query string parameters such as ?since=01-01-2000 to get entries after a specified date or pass column names such as ?category=clothing to retrieve all entries with category equaling clothing.
Additionally, you would want paths such as /data/{id} to be available to retrieve certain entries given their unique id.
It really depends on a lot of things. If you're using any sort of MVC framework, you'd use the URI segments to define your get request to your API which I personally prefer.
It's not a big deal either way, it's all based on preference and how predictable you want the URL to be to your user. In some cases, I'd say go with the REST parameters, but more often than not a URI based GET is quite clean if your setup supports it.