Multiple resources under one request: RESTful API design pattern - java

I'm trying to create a GET request, where I have two different requests. Since both resources are related with each other, I'm trying to put them under one 'sub-resource'.
The first one is:
#QueryParam("{customerId}")
public List<customerModel> getCustomer(#QueryParam("customerId") Long customerId) {....}
this fetches the customer's name depending on the customerId
#QueryParam("{customerId}/details")
public List<customerDetailModel> getCustomerDetail(#QueryParam("customerId") Long customerId) {....}
this fetches the detailed information of the customer (phone number, address, etc.)
I'm running the first one with the following (works fine) :
......?customerId=7453112
but I can't reach the second request when I'm hitting the following URL:
......?customerId=7453112/details
Any suggestions?

Resource methods must be annotated with #Path and with a request method designator such as #GET, #POST, #PUT,
#DELETE, #HEAD or #OPTIONS. Your #QueryParam annotation is misplaced.
By the way, for this situation, you should consider using a path parameter instead of a query parameter. Hence you should use #PathParam instead of #QueryParam in the method parameter. For more details on when to use query or path parameters, have a look at this answer
Also, not sure why you are returning a List if you are requesting a resource by its unique identifier. In this situation, you are supposed to return a representation of a single resource (and not a represention of multiple resources).
So your resource class would be as following:
#Path("customers")
#Produces({ MediaType.APPLICATION_JSON, MediaType.APPLICATION_XML })
public class CustomerResource {
#GET
#Path("{customerId}")
public CustomerModel getCustomer(#PathParam("customerId") Long id) {
...
}
#GET
#Path("{customerId}/details")
public CustomerDetailModel getCustomerDetail(#PathParam("customerId") Long id) {
...
}
}
The first endpoint can be requested as following:
GET http://example.com/api/customers/1
And the second endpoint can be requested as following:
GET http://example.com/api/customers/1/details

You need to go with #RequestMapping.
Something like:
#RequestMapping("/{customerId}") and #RequestMapping("/{customerId}/details").
Your URL becomes 7453112/details instead of query params.

You can specify the /details in an #Path annotation, and then use the same query parameter, like this:
#Path("/details/{customerId}")
public List<customerDetailModel> getCustomerDetail(#PathParam("customerId") Long customerId) {....}
Then your URL would look like this:
.../details/7453112
Or if you want to keep using it as a query parameter you can do something like this:
#Path("/details")
public List<customerDetailModel> getCustomerDetail(#QueryParam("customerId") Long customerId) {....}
using this url:
.../details?customerId=xxx

Related

resteasy: #QueryParam to parse nested array structure

I'm using a javascript library called tabulator to display data inside tables on the client side.
The Tabulator js library provides a feature to encode a representation of filters in the query parameters of an ajax request. For example, here's what the query params look like:
https://host/myEndpoint?size=10&page=1&filters%5B0%5D%5Bfield%5D=username&filters%5B0%5D%5Btype%5D=like&filters%5B0%5D%5Bvalue%5D=filteredBy
Here's the same url decoded:
https://host/myEndpoint?size=10&page=1&filters[0][field]=username&filters[0][type]=like&filters[0][value]=filteredBy
If possible, I'd like to have a Resteasy endpoint like this:
#GET
#Path("/myEndpoint")
#Consumes("application/json")
#Produces("application/json")
public Response myEndpoint(#QueryParam("page") Integer page,
#QueryParam("size") Integer size,
#QueryParam("filters") List<Filter> filters) {
resteasy interprets page and size no problem, but filters is always a list of size 0.
My Filter bean has 3 fields named field, type, and value with a constructor with single String argument as described here.
But it doesn't seem like resteasy is recognizing and parsing the filters query param? Is it possible to parse this type of nested array structure query parameters in resteasy?
filters[0][field]=username&filters[0][type]=like&filters[0][value]=filteredB
I'm still hoping that there's a better way, but here's a possible solution that works for me for now at least:
#GET
#Path("/myEndpoint")
#Consumes("application/json")
#Produces("application/json")
public Response myEndpoint(#QueryParam("page") Integer page,
#QueryParam("size") Integer size,
#Context UriInfo uriInfo) {
for(String key : uriInfo.getQueryParameters().keySet()) {
// check if key starts with something like `filters[0]`
// and then parse it however you need.
}
}

#Path in rest-easy with variable?

I am using rest-easy and I want my #Path annotation to obtain it's value from a variable (mayabe a system parameter).
Eg:
#Path(someVar)
#GET
#Produces(MediaType.TEXT_XML)
public String retrieve() {
}
I tried reading and got to know that Path must be a constant value.
Is something like above possible in rest easy ??
Annotations are processed on compile time. You cannot use a variable as an annotation parameter.
You can pass variable value in URL, something like below example
so your URL will be /book/some_isbn_code and the getBook method will receive isbn value in id field.
#Path("/book/{isbn}")
public String getBook(#PathParam("isbn") String id) {

Can RestEasy choose method based on query params?

I've started working with RestEasy and I've come across a problem that I can't seem to find an answer to. If I have 2 methods that both resolve to the same path (in this case /path1/path2/path3), but they both have a different number of query parameters, will RestEasy be able to determine which method to use?
#GET
#NoCache
#Produces({
MediaType.APPLICATION_JSON
})
#Path("/path1/path2/{path3}")
public String getResults1(
#PathParam("path3") String path3,
#QueryParam("query1") #DefaultValue("") String query1,
#QueryParam("query2") String query2,
#QueryParam("query3") #DefaultValue("25") int query3) {
...
}
#GET
#NoCache
#Produces({
MediaType.APPLICATION_JSON
})
#Path("/path1/path2/{path3}")
public String getResults2(
#PathParam("path3") String path3,
#QueryParam("query1") #DefaultValue("") String query1,
#QueryParam("query2") #DefaultValue("5") Integer query2) {
...
}
I've done some testing and yesterday it seemed that everything was working perfectly and that it could choose the right path, but now today I'm starting to see it take the wrong path each time.
Is this something that should be handled, or should I just suck it up and put it in 1 method and do the check myself?
No, you should be handling this in the method. If conflicting resources are found it is implementation independent which method will be matched.
Take a look at your example again:
If you submitted query1 and query2 how would it know if you wanted the method with 2 query parameters or the method with 3 query parameters and you wanted it to default the 3rd to it's default value?

Jersey #Path for plural/single REST nouns in same class

I have a class this is annotated with #Path like so:
#Path("widgets")
#Produces(MediaType.APPLICATION_XML)
public class WidgetResource {
#GET
public Response getWidgets(#QueryParam("limit"))
{
//This class returns the plural noun, a list of widgets
//...}
#GET
#Path("widget/{id}")
public Response getWidgetById(#PathParam("id") long id)
{
//This class returns a single widget by id
//...}
When I fire up a test client the localhost/widgets maps as expected, but when the getWidgetById method is mapped to localhost/widgets/widget/{id}. This is not what I want - I would like to have localhost/widgets and localhost/widget/{id}
I have tried omitting the #Path annotation at the class level, but that prevents Jersey from recognizing this class as a REST Resource (I tried both the ScanningResourceConfig and the ClassNameResourceConfig - both failed to load the class as a resource unless there was a #Path at the class level).
I guess a (ugly) workaround would be to split the methods between classes a WidgetResource class and a WidgetsResource class. I think this is a terrible solution since both of these methods share resources in the same class, but I really need the REST-ful localhost/widget (for a single entity) and localhost/widgets (for plural).
Am I missing something - is there some way for me to have Jersey pick up the class as a Resource class if I just #Path annotate the methods (I couldn't get it to work), if not can I force absolute mapping (#Path(/widget/{id})) or some relative mapping (#Path(../widget/id) - neither of those work in reality - just an analogy of what I'm after. Thanks!
This part is about what you need:
Personally, I find your mapping strange and confusing. Just keep it like this:
#Path("widgets")
#Produces(MediaType.APPLICATION_XML)
public class WidgetResource {
#GET
public Response getWidgets(#QueryParam("limit")) {
//This method returns the plural noun, a list of widgets
// it's also possible to limit the number returned by
// using a query parameter. You could easily implement
// pagination by adding further query parameters like
// 'offset', 'sortOrder', etc.
//...
}
#GET
#Path("{id}")
public Response getWidgetById(#PathParam("id") long id) {
//This method returns a single widget by id
//...
}
}
It seems natural to append the path to a collection with an ID to fetch an object from the collection. There's really no need to make it widgets/widget/{id}. The widget part is obvious and unnecessary.
Here's a really neat tutorial on RESTful APIs: "Teach a dog to REST" by apigee I think it's a really good video. The authors make a couple of good points. And here's a link to a longer version of the same presentation
This part is about what you want:
If you really want to keep the plural/singular dualism (which I really don't recomment), you can annotate your code like this:
But it's really ugly
#Path("/")
#Produces(MediaType.APPLICATION_XML)
public class WidgetResource {
#GET
#Path("widgets")
public Response getWidgets(#QueryParam("limit")) {
//This method returns the plural noun, a list of widgets
//...}
#GET
#Path("widget/{id}")
public Response getWidgetById(#PathParam("id") long id) {
//This method returns a single widget by id
//...
}
}
My suggestion is to have your paths be:
"widgets" and "widgets/id/{id}". Or if you knew you were never going to query by anything other than id, your second one could simply be "widgets/{id}".
I would not switch between plural and singular in your path. Since you accessing the same type of resource for both, your root should be the same. The second form just specifies it more -- a vectoring-based approach for getting more specific.

Defining custom parameter types with JAX-RS to return data by identifier

I am new to Jersey, and I discovered that we can define our own parameter types to handle other types than string, as dates or boolean for instance.
I will work with an ORM to store the data in a database, so that I will be able to map an identifier to an instance of a class, let's say to a User.
Is it a good practise to define a param class which would handle the user id given in parameter (path or query for instance), and return the instance of User corresponding to the id?
If your param is directly mappable to a primitive type then there's no need to define your own. It sounds like you want to accept a user ID as a param, which is likely to be a long, int or String. All of these are automatically mapped.
For example;
#Path("/")
public class UserService {
#GET
#Produces(MediaType.APPLICATION_XML)
#Path("/{id}")
public User getUser(#PathParam("id") String id) {
//Your implementation here
}
}
Well, lets take some example:
stackoverflow.com/users/1235336/
Here we have the path with usedId in it. And if we proceed the link (execute a GET request), we will get the some user enity in response.
So defining a user id as a path parameter and returning some user instance is kind of normal practice.

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