PagedResourcesAssembler generated navigation links ignore non pageable request parameters [DATACMNS-1757]

[spring-projects-issues]

Réda Housni Alaoui opened DATACMNS-1757 and commented

Let's consider the following test:

@Test
  @DisplayName("GET with pageable and additional request parameter")
  public void test2() throws Exception {
    mockMvc
        .perform(
            MockMvcRequestBuilders.get("/api/PagedResourcesAssemblerTest")
                .queryParam("text", "foo")
                .queryParam("page_size", "1")
                .queryParam("page_number", "1"))
        .andExpect(status().isOk())
        .andExpect(jsonPath("$._links.first.href").value(containsString("text=foo")));
  }

@Controller
  @RequestMapping("/PagedResourcesAssemblerTest")
  public static class MyController {

    @GetMapping
    public ResponseEntity<?> get(
        @RequestParam(name = "text", required = false) String text,
        Pageable pageable,
        PagedResourcesAssembler<Element> pageAssembler) {
      Page<Element> page =
          new PageImpl<>(Collections.singletonList(new Element("foo")), pageable, 10);
      return ResponseEntity.ok(pageAssembler.toModel(page));
    }
  }

The described test fails because the generate response body is:

{
  "_embedded": {
    "content": [{
      "name": "foo"
    }]
  },
  "_links": {
    "first": {
      "href": "http://localhost/api/PagedResourcesAssemblerTest?page_number=0&page_size=1"
    },
    "prev": {
      "href": "http://localhost/api/PagedResourcesAssemblerTest?page_number=0&page_size=1"
    },
    "self": {
      "href": "http://localhost/api/PagedResourcesAssemblerTest?page_number=1&page_size=1"
    },
    "next": {
      "href": "http://localhost/api/PagedResourcesAssemblerTest?page_number=2&page_size=1"
    },
    "last": {
      "href": "http://localhost/api/PagedResourcesAssemblerTest?page_number=9&page_size=1"
    }
  },
  "page": {
    "size": 1,
    "totalElements": 10,
    "totalPages": 10,
    "number": 1
  }
}

The navigation links hold the correct page parameters, but they are missing request parameter text.

---

Affects: 2.4 M1 (2020.0.0)

Referenced from: pull request #452

[odrotbohm]

I am inclined to go down a slightly different route than what's suggested in #452. Here's what's actually causing the issue: when PagedResourcesAssembler is resolved for method injection, our HanderMethodArgumentResolver currently equips it with a default URI that is the one created when pointing to the method that is currently invoked. In the course of that, optional request parameters are dropped as we don't consider the request parameters when expanding those potentially optional parameters.

That said, I think wen can just skip the pre-computation entirely as PagedResourcesAssembler will fall back to use the current request's URI as the base for the links to be created. If controller methods want to use anything but that, they're free to calculate that URI and hand a Link into an overload of ….toModel(…) explicitly. I just briefly checked whether that removal works and except a test case checking for some internal state of PRA no test cases fail, also not in Spring Data REST.

I am inclined to back-port this into 2.4 (i.e. Spring Boot 2.4) as well as it's a rather young branch and we can easily tweak things back in case this causes trouble. For Neumann (SR7 approaching) I'd leave the decision up for @mp911de.

[reda-alaoui]

Thank you @odrotbohm !