Add link-only posts

backend/CircleForms/Contracts/V1/ContractModels/Response/PostResponseContract.cs

@@ -19,6 +19,9 @@ public class PostResponseContract
     [JsonProperty("title")]
     public string Title { get; set; }
 
+    [JsonProperty("access_key")]
+    public string AccessKey { get; set; }
+
     [JsonProperty("description")]
     public string Description { get; set; }
 

backend/CircleForms/Controllers/V1/PostsController.cs

@@ -1,10 +1,13 @@
 using System.Collections.Generic;
 using System.Linq;
+using System.Security.Cryptography;
+using System.Text;
 using System.Threading.Tasks;
 using AutoMapper;
 using CircleForms.Contracts.V1;
 using CircleForms.Contracts.V1.ContractModels.Request;
 using CircleForms.Contracts.V1.ContractModels.Response;
+using CircleForms.Models.Enums;
 using CircleForms.Models.Posts;
 using CircleForms.Models.Posts.Questions;
 using CircleForms.Models.Posts.Questions.Submissions;
@@ -125,6 +128,25 @@ public async Task<IActionResult> Answer(string id, [FromBody] List<SubmissionCon
         return Ok();
     }
 
+    private static string GenerateAccessKey(byte size)
+    {
+        const string chars =
+            "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890";
+        var data = new byte[size];
+        using (var crypto = RandomNumberGenerator.Create())
+        {
+            crypto.GetBytes(data);
+        }
+
+        var result = new StringBuilder(size);
+        foreach (var b in data)
+        {
+            result.Append(chars[b % chars.Length]);
+        }
+
+        return result.ToString();
+    }
+
     /// <summary>
     ///     Add a new post. (Requires auth)
     /// </summary>
@@ -148,6 +170,10 @@ public async Task<IActionResult> Post(PostRequestContract postContract)
             _logger.LogInformation("User {User} posts a post {PostId}", claim, post.ID);
 
             post.AuthorId = claim;
+            if (post.Accessibility == Accessibility.Link)
+            {
+                post.AccessKey = GenerateAccessKey(6);
+            }
 
             for (var i = 0; i < post.Questions.Count; i++)
             {
@@ -181,22 +207,37 @@ public async Task<IActionResult> Post(PostRequestContract postContract)
     [ProducesResponseType(typeof(PostResponseContract), StatusCodes.Status200OK, "application/json")]
     [ProducesResponseType(typeof(PostDetailedResponseContract), StatusCodes.Status200OK, "application/json")]
     [ProducesResponseType(StatusCodes.Status404NotFound)]
-    public async Task<IActionResult> GetDetailed(string id)
+    public async Task<IActionResult> GetDetailed(string id, [FromQuery] string key = "")
     {
         var claim = HttpContext.User.Identity?.Name;
-        var post = await _postRepository.Get(id);
+        var post = await _postRepository.GetCached(id);
         if (post is null)
         {
             return NotFound();
         }
 
+        Post forceRequestedPost = null;
+        if (post.Accessibility == Accessibility.Link)
+        {
+            if (string.IsNullOrEmpty(key) || key.Length != 6)
+            {
+                return NotFound();
+            }
+
+            forceRequestedPost = await _postRepository.Get(id);
+            if (forceRequestedPost.AccessKey != key)
+            {
+                return NotFound();
+            }
+        }
+
         if (string.IsNullOrEmpty(claim) || !long.TryParse(claim, out _))
         {
             return Ok(_mapper.Map<PostDetailedResponseContract>(post));
         }
 
         return post.AuthorId == claim
-            ? Ok(_mapper.Map<PostResponseContract>(await _postRepository.Get(id)))
+            ? Ok(_mapper.Map<PostResponseContract>(forceRequestedPost ?? await _postRepository.Get(id)))
             : Ok(_mapper.Map<PostDetailedResponseContract>(post));
     }
 

backend/CircleForms/Models/Posts/Post.cs

@@ -22,6 +22,9 @@ public Post()
     [JsonProperty("title")]
     public string Title { get; set; }
 
+    [JsonProperty("access_key")]
+    public string AccessKey { get; set; }
+
     [JsonProperty("description")]
     public string Description { get; set; }
 

backend/CircleForms/Services/Database/PostRepository.cs

@@ -4,6 +4,7 @@
 using System.Threading.Tasks;
 using AutoMapper;
 using CircleForms.Models;
+using CircleForms.Models.Enums;
 using CircleForms.Models.Posts;
 using CircleForms.Services.Database.Interfaces;
 using Microsoft.Extensions.Logging;
@@ -56,6 +57,11 @@ await DB.Update<User>()
             return post;
         }
 
+        if (post.Accessibility != Accessibility.Public)
+        {
+            return post;
+        }
+
         _logger.LogInformation("Adding {PostId} to the cached posts set", postId);
         if (!await redisDb.SortedSetAddAsync("posts", postId, publishUnixTime))
         {