LinkGenerator won't build link outside of desired action method

Question

I want to return a url as a property in my Group. I can do it from the GetGroup() method when returning a single Group but I only get null when I run the code in the GetGroups() method (returning a collection of Groups). I thought maybe I was misusing the iterator but I'm able to update the objects in the collection with hard coded values. It just seems like LinkGenerator doesn't find my uri when called from GetGroups().

I'm not sure if I have a routing problem or just not understanding how this works.

[Authorize]
[ApiController]
[ApiVersionNeutral]
[ApiConventionType(typeof(DefaultApiConventions))]
[Route("v{version:apiVersion}/{providerId}/[controller]")]
public class GroupsController : ControllerBase
{
    //...omitted code...

    public GroupsController(IGroupsService groupsService, LinkGenerator linkGenerator)
    {
        this.groupsService = groupsService;
        this.linkGenerator = linkGenerator;
    }

    // GET: api/0000/groups/1000
    // Get a group
    [HttpGet("{groupId}", Name="GetGroup")]
    [ApiConventionMethod(typeof(DefaultApiConventions), nameof(DefaultApiConventions.Get))]
    public async Task<ActionResult<Group>> GetGroup(int providerId, int groupId)
    {
        Group group = await this.groupsService.GetGroup(providerId, providerId, groupId);
        if (group == null)
            return NotFound();
        else
            group.Url = linkGenerator.GetUriByAction(HttpContext, action: "GetGroup", controller: "Groups", values: new { providerId, groupId });

        return Ok(group);
    }


    // GET: api/0000/groups
    // Get all groups
    [HttpGet]
    [ApiConventionMethod(typeof(DefaultApiConventions), nameof(DefaultApiConventions.Get))]
    public async Task<ActionResult<IEnumerable<Group>>> GetGroups(int providerId)
    {
        IEnumerable<Group> groups = await groupsService.GetGroups(providerId, providerId);
        if (groups == null)
            return NotFound();
        else
        {
            foreach (Group g in groups)
            {
                g.Url = linkGenerator.GetUriByAction(HttpContext, action: "GetGroup", controller: "Groups", values: new { providerId = g.ProviderID, groupId = g.GroupID });
            }
        }
        return Ok(groups);
    }
//...omitted code...

}

Based on the issue experienced here does that mean that the last suggested answer did not work? — Nkosi, Nov 26 '19 at 22:21
You have route attribute with name. yet still use `...ByAction`. Why not use `Url.RouteUrl("GetGroup", new { providerId = g.ProviderID, groupId = g.GroupID });` — Nkosi, Nov 26 '19 at 22:25
You addressed my approach question and it worked when returning a single Group, but my issue is now related to multiple Groups. I couldn't figure out how to address this in the last question's comments. I get the same results with Url.RouteUrl(). Also RouteUrl() doesn't give me the FQDN so that's an issue. — William Jens, Nov 27 '19 at 14:32

score 0 · Answer 1 · answered Nov 27 '19 at 21:41

0

Adding [FromRoute] before int providerId appears to have fixed it. I have no idea why. I switched to using Url.AbsoluteRouteUrl(), but it was definitely [FromRoute] that fixed it.

answered Nov 27 '19 at 21:41

William Jens

422
2
6
15

LinkGenerator won't build link outside of desired action method

1 Answers1