[backend/api] Add user follow, unfollow & lookup api methods (ISH-346)

Iceshrimp.Backend/Controllers/UserController.cs

@@ -7,6 +7,7 @@ using Iceshrimp.Backend.Core.Database;
 using Iceshrimp.Backend.Core.Database.Tables;
 using Iceshrimp.Backend.Core.Extensions;
 using Iceshrimp.Backend.Core.Middleware;
+using Iceshrimp.Backend.Core.Services;
 using Microsoft.AspNetCore.Mvc;
 using Microsoft.AspNetCore.RateLimiting;
 using Microsoft.EntityFrameworkCore;
@@ -17,17 +18,18 @@ namespace Iceshrimp.Backend.Controllers;
 [Authenticate]
 [Authorize]
 [EnableRateLimiting("sliding")]
-[Route("/api/iceshrimp/users/{id}")]
+[Route("/api/iceshrimp/users")]
 [Produces(MediaTypeNames.Application.Json)]
 public class UserController(
 	DatabaseContext db,
 	UserRenderer userRenderer,
 	NoteRenderer noteRenderer,
 	UserProfileRenderer userProfileRenderer,
-	ActivityPub.UserResolver userResolver
+	ActivityPub.UserResolver userResolver,
+	UserService userSvc
 ) : ControllerBase
 {
-	[HttpGet]
+	[HttpGet("{id}")]
 	[ProducesResponseType(StatusCodes.Status200OK, Type = typeof(UserResponse))]
 	[ProducesResponseType(StatusCodes.Status404NotFound, Type = typeof(ErrorResponse))]
 	public async Task<IActionResult> GetUser(string id)
@@ -39,12 +41,27 @@ public class UserController(
 		return Ok(await userRenderer.RenderOne(await userResolver.GetUpdatedUser(user)));
 	}
 
-	[HttpGet("profile")]
+	[HttpGet("lookup")]
+	[ProducesResponseType(StatusCodes.Status200OK, Type = typeof(UserResponse))]
+	[ProducesResponseType(StatusCodes.Status404NotFound, Type = typeof(ErrorResponse))]
+	public async Task<IActionResult> LookupUser([FromQuery] string username, [FromQuery] string? host)
+	{
+		username = username.ToLowerInvariant();
+		host     = host?.ToLowerInvariant();
+
+		var user = await db.Users.IncludeCommonProperties()
+		                   .FirstOrDefaultAsync(p => p.UsernameLower == username && p.Host == host) ??
+		           throw GracefulException.NotFound("User not found");
+
+		return Ok(await userRenderer.RenderOne(await userResolver.GetUpdatedUser(user)));
+	}
+
+	[HttpGet("{id}/profile")]
 	[ProducesResponseType(StatusCodes.Status200OK, Type = typeof(UserProfileResponse))]
 	[ProducesResponseType(StatusCodes.Status404NotFound, Type = typeof(ErrorResponse))]
 	public async Task<IActionResult> GetUserProfile(string id)
 	{
-		var localUser = HttpContext.GetUser();
+		var localUser = HttpContext.GetUserOrFail();
 		var user = await db.Users.IncludeCommonProperties()
 		                   .FirstOrDefaultAsync(p => p.Id == id) ??
 		           throw GracefulException.NotFound("User not found");
@@ -52,13 +69,13 @@ public class UserController(
 		return Ok(await userProfileRenderer.RenderOne(await userResolver.GetUpdatedUser(user), localUser));
 	}
 
-	[HttpGet("notes")]
+	[HttpGet("{id}/notes")]
 	[LinkPagination(20, 80)]
 	[ProducesResponseType(StatusCodes.Status200OK, Type = typeof(IEnumerable<NoteResponse>))]
 	[ProducesResponseType(StatusCodes.Status404NotFound, Type = typeof(ErrorResponse))]
 	public async Task<IActionResult> GetUserNotes(string id, PaginationQuery pq)
 	{
-		var localUser = HttpContext.GetUser();
+		var localUser = HttpContext.GetUserOrFail();
 		var user = await db.Users.FirstOrDefaultAsync(p => p.Id == id) ??
 		           throw GracefulException.NotFound("User not found");
 
@@ -74,4 +91,54 @@ public class UserController(
 		return Ok(await noteRenderer.RenderMany(notes.EnforceRenoteReplyVisibility(), localUser,
 		                                        Filter.FilterContext.Accounts));
 	}
+
+	[HttpPost("{id}/follow")]
+	[Authenticate]
+	[Authorize]
+	[ProducesResponseType(StatusCodes.Status200OK)]
+	[ProducesResponseType(StatusCodes.Status400BadRequest, Type = typeof(ErrorResponse))]
+	[ProducesResponseType(StatusCodes.Status403Forbidden, Type = typeof(ErrorResponse))]
+	[ProducesResponseType(StatusCodes.Status404NotFound, Type = typeof(ErrorResponse))]
+	public async Task<IActionResult> FollowUser(string id)
+	{
+		var user = HttpContext.GetUserOrFail();
+		if (user.Id == id)
+			throw GracefulException.BadRequest("You cannot follow yourself");
+
+		var followee = await db.Users.IncludeCommonProperties()
+		                       .Where(p => p.Id == id)
+		                       .PrecomputeRelationshipData(user)
+		                       .FirstOrDefaultAsync() ??
+		               throw GracefulException.RecordNotFound();
+
+		if ((followee.PrecomputedIsBlockedBy ?? true) || (followee.PrecomputedIsBlocking ?? true))
+			throw GracefulException.Forbidden("This action is not allowed");
+
+		if (!(followee.PrecomputedIsFollowedBy ?? false) && !(followee.PrecomputedIsRequestedBy ?? false))
+			await userSvc.FollowUserAsync(user, followee);
+
+		return Ok();
+	}
+
+	[HttpPost("{id}/unfollow")]
+	[ProducesResponseType(StatusCodes.Status200OK)]
+	[ProducesResponseType(StatusCodes.Status400BadRequest, Type = typeof(ErrorResponse))]
+	[ProducesResponseType(StatusCodes.Status404NotFound, Type = typeof(ErrorResponse))]
+	public async Task<IActionResult> UnfollowUser(string id)
+	{
+		var user = HttpContext.GetUserOrFail();
+		if (user.Id == id)
+			throw GracefulException.BadRequest("You cannot unfollow yourself");
+
+		var followee = await db.Users
+		                       .Where(p => p.Id == id)
+		                       .IncludeCommonProperties()
+		                       .PrecomputeRelationshipData(user)
+		                       .FirstOrDefaultAsync() ??
+		               throw GracefulException.RecordNotFound();
+
+		await userSvc.UnfollowUserAsync(user, followee);
+
+		return Ok();
+	}
 }

Iceshrimp.Frontend/Core/ControllerModels/UserControllerModel.cs

@@ -1,6 +1,7 @@
 using Iceshrimp.Frontend.Core.Miscellaneous;
 using Iceshrimp.Frontend.Core.Services;
 using Iceshrimp.Shared.Schemas;
+using Microsoft.AspNetCore.Http;
 
 namespace Iceshrimp.Frontend.Core.ControllerModels;
 
@@ -15,4 +16,12 @@ internal class UserControllerModel(ApiClient api)
 	[LinkPagination(20, 80)]
 	public Task<List<NoteResponse>?> GetUserNotes(string id, PaginationQuery pq) =>
 		api.CallNullable<List<NoteResponse>>(HttpMethod.Get, $"/users/{id}/notes", pq);
+
+	public Task<UserResponse?> LookupUser(string username, string? host)
+	{
+		var query = new QueryString();
+		query.Add("username", username);
+		if (host != null) query.Add("host", host);
+		return api.CallNullable<UserResponse>(HttpMethod.Get, "/users/lookup", query);
+	}
 }