How to get Swagger UI to display similar Spring Boot REST endpoints? - spring

Question

I have a controller class with two endpoints
#RestController
#RequestMapping
public class TestController {
#RequestMapping(
value= "/test",
method = RequestMethod.GET)
#ResponseBody
public String getTest() {
return "test without params";
}
#RequestMapping(
value= "/test",
params = {"param"},
method = RequestMethod.GET)
#ResponseBody
public String getTest(#PathParam("param") int param) {
return "test with param";
}
}
One has a parameter, one doesn't, and the both work.
If I use curl or a web browser to hit the endpoints
http://localhost:8081/test
returns
test without params
and
http://localhost:8081/test?param=1
returns
test with param
but the swagger ui only shows the one without a parameter.
If I change the value in the request mapping for the request with a parameter to
#RequestMapping(
value= "/testbyparam",
params = {"param"},
method = RequestMethod.GET)
Swagger UI displays both endpoints correctly, but I'd rather not define my endpoints based on what swagger will or won't display.
Is there any way for me to get swagger ui to properly display endpoints with matching values, but different parameters?
Edit for Clarification:
The endpoints work perfectly fine; /test and /test?param=1 both work perfectly, the issue is that swagger-ui won't display them.
I would like for swagger ui to display the endpoints I have defined, but if it can't, then I'll just have to live with swagger-ui missing some of my endpoints.
Edit with reference:
The people answering here: Proper REST formatted URL with date ranges
explicitly say not to seperate the query string with a slash
They also said "There shouldn't be a slash before the query string."

Answer 1

The issue is in your Request Mapping, The second method declaration is overriding the first method. As Resource Mapping value is same.
Try changing the second method to below. As you want to give input in QueryParam rather than path variable, you should use #RequestParam not #PathParam.
Note that you have to give /test/, In order to tell Spring that your mapping is not ambiguous. Hope it helps.
#RequestMapping(
value= "/test/",
method = RequestMethod.GET)
#ResponseBody
public String getTest (#RequestParam("param") int param) {
return "test with param"+param;
}

Answer 2

Upon reading clarifications, the issue here is that swagger-ui is doing the correct thing.
You have two controller endpoints, but they are for the same RESOURCE /test that takes a set of optional query parameters.
Effectively, all mapped controller endpoints that have the same method (GET) and request mapping (/test) represent a single logical resource. GET operation on the test resource, and a set of optional parameters which may affect the results of invoking that operation.
The fact that you've implemented this as two separate controller endpoints is an implementation detail and does not change the fact that there is a single /test resource that can be operated upon.
What would be the benefit to consumers of your API by listing this as two separate endpoints in swagger UI vs a single endpoint with optional parameters? Perhaps it could constrain the set of allowed valid query parameters (if you set ?foo you MUST set &bar) but this can also be done in descriptive text, and is a much more standard approach. Personally, I am unfamiliar with any publicly documented api that distinguishes multiple operations for the same resource differentiated by query params.

Answer 3

As per Open API Specification 3
OpenAPI defines a unique operation as a combination of a path and an
HTTP method. This means that two GET or two POST methods for the same
path are not allowed – even if they have different parameters
(parameters have no effect on uniqueness).
Reference - https://swagger.io/docs/specification/paths-and-operations/
This was also raised as an issue but it was closed because OAS3 doesn't allow that -
https://github.com/springdoc/springdoc-openapi/issues/859

Answer 4

Try including the param in the path as below.
#GetMapping("/test/{param}")
public String getTest(#PathVariable final int param) {
return "test with param";
}

Answer 5

I'm unclear exactly what you're attempting to do, but I'll give two solutions:
If you want to have PATH parameters e.g. GET /test & GET /test/123 you can do:
#GetMapping("/test")
public String getTest() {
return "test without params";
}
#GetMapping("test/{param}")
public String getTest(#PathVariable("param") int param) {
return "test with param";
}
If you want query parameters (GET /test and GET /test?param=123) then you need a single endpoint that takes an optional parameter:
#GetMapping("test")
public String getTest(#RequestParam("param") Integer param) {
if(param == null) {
return "test without params";
} else {
return "test with param";
}
}