画像ファイル対応 (LINE -> Slack) (#12)

* 画像ファイル対応 (LINE -> Slack ) * fix
YDKK · Sep 27, 2020 · a72e6dc · a72e6dc
1 parent f0c243b
commit a72e6dc
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Showing 5 changed files with 97 additions and 28 deletions.
diff --git a/SlackLineBridge/Controllers/ProxyController.cs b/SlackLineBridge/Controllers/ProxyController.cs
@@ -0,0 +1,52 @@
+using System;
+using System.Collections.Generic;
+using System.IO;
+using System.Linq;
+using System.Net;
+using System.Net.Http;
+using System.Net.Mime;
+using System.Threading.Tasks;
+using Microsoft.AspNetCore.Http;
+using Microsoft.AspNetCore.Mvc;
+using Microsoft.Net.Http.Headers;
+using SlackLineBridge.Services;
+
+namespace SlackLineBridge.Controllers
+{
+    [Route("[controller]")]
+    [ApiController]
+    public class ProxyController : ControllerBase
+    {
+        IHttpClientFactory _clientFactory;
+        string _lineChannelSecret;
+        public ProxyController(IHttpClientFactory clientFactory, string lineChannelSecret)
+        {
+            _clientFactory = clientFactory;
+            _lineChannelSecret = lineChannelSecret;
+        }
+
+        [HttpGet("line/{token}/{id}")]
+        public async Task<IActionResult> Line(string id, string token)
+        {
+            if (token != LineMessageProcessingService.GetHMACHex(id, _lineChannelSecret))
+            {
+                return new StatusCodeResult((int)HttpStatusCode.Forbidden);
+            }
+
+            var client = _clientFactory.CreateClient("Line");
+
+            var result = await client.GetAsync($"https://api-data.line.me/v2/bot/message/{id}/content");
+            if (result.IsSuccessStatusCode)
+            {
+                var stream = await result.Content.ReadAsStreamAsync();
+                var contentType = result.Content.Headers.GetValues("Content-Type").First();
+
+                return new FileStreamResult(stream, contentType);
+            }
+            else
+            {
+                return new StatusCodeResult((int)result.StatusCode);
+            }
+        }
+    }
+}
diff --git a/SlackLineBridge/Controllers/WebhookController.cs b/SlackLineBridge/Controllers/WebhookController.cs
@@ -26,14 +26,14 @@ public class WebhookController : ControllerBase
         private readonly LineChannels _lineChannels;
         private readonly SlackLineBridges _bridges;
         private readonly IHttpClientFactory _clientFactory;
-        private readonly ConcurrentQueue<(string signature, string body)> _lineRequestQueue;
+        private readonly ConcurrentQueue<(string signature, string body, string host)> _lineRequestQueue;
 
         public WebhookController(
             ILogger<WebhookController> logger,
             IOptionsSnapshot<SlackChannels> slackChannels,
             IOptionsSnapshot<LineChannels> lineChannels,
             IOptionsSnapshot<SlackLineBridges> bridges,
-            ConcurrentQueue<(string signature, string body)> lineRequestQueue,
+            ConcurrentQueue<(string signature, string body, string host)> lineRequestQueue,
             IHttpClientFactory clientFactory)
         {
             _logger = logger;
@@ -134,7 +134,7 @@ public async Task<StatusCodeResult> Line()
 
             using var reader = new StreamReader(Request.Body);
 
-            _lineRequestQueue.Enqueue((Request.Headers["X-Line-Signature"], await reader.ReadToEndAsync()));
+            _lineRequestQueue.Enqueue((Request.Headers["X-Line-Signature"], await reader.ReadToEndAsync(), Request.Host.ToString()));
 
             return Ok();
         }

diff --git a/SlackLineBridge/Services/LineMessageProcessingService.cs b/SlackLineBridge/Services/LineMessageProcessingService.cs
@@ -10,6 +10,7 @@
 using System.Linq;
 using System.Net.Http;
 using System.Security.Cryptography;
+using System.Security.Policy;
 using System.Text;
 using System.Text.Json;
 using System.Threading;
@@ -24,15 +25,15 @@ public class LineMessageProcessingService : BackgroundService
         private readonly IOptionsMonitor<SlackLineBridges> _bridges;
         private readonly IHttpClientFactory _clientFactory;
         private readonly ILogger<LineMessageProcessingService> _logger;
-        private readonly ConcurrentQueue<(string signature, string body)> _queue;
+        private readonly ConcurrentQueue<(string signature, string body, string host)> _queue;
         private readonly string _lineChannelSecret;
 
         public LineMessageProcessingService(
             IOptionsMonitor<SlackChannels> slackChannels,
             IOptionsMonitor<LineChannels> lineChannels,
             IOptionsMonitor<SlackLineBridges> bridges,
             IHttpClientFactory clientFactory,
-            ConcurrentQueue<(string signature, string body)> lineRequestQueue,
+            ConcurrentQueue<(string signature, string body, string host)> lineRequestQueue,
             string lineChannelSecret,
             ILogger<LineMessageProcessingService> logger)
         {
@@ -56,7 +57,7 @@ protected override async Task ExecuteAsync(CancellationToken stoppingToken)
                 {
                     _logger.LogInformation("Processing request from line: " + request.body);
 
-                    var signature = GetHMAC(request.body, _lineChannelSecret);
+                    var signature = GetHMACBase64(request.body, _lineChannelSecret);
                     _logger.LogDebug($"LINE signature check (expected:{request.signature}, calculated:{signature})");
                     if (request.signature != signature)
                     {
@@ -88,17 +89,33 @@ protected override async Task ExecuteAsync(CancellationToken stoppingToken)
 
                                     var message = e.GetProperty("message");
                                     var type = message.GetProperty("type").GetString();
-                                    var text = type switch
+                                    var text = "";
+                                    string imageUrl = null;
+                                    var id = "";
+                                    if (message.TryGetProperty("id", out var idElement))
                                     {
-                                        "text" => message.GetProperty("text").GetString(),
-                                        _ => $"<{type}>",
-                                    };
+                                        id = idElement.GetString();
+                                    }
 
-                                    string stickerUrl = null;
-                                    if (type == "sticker")
+                                    switch (type)
                                     {
-                                        var stickerId = message.GetProperty("stickerId").GetString();
-                                        stickerUrl = $"https://stickershop.line-scdn.net/stickershop/v1/sticker/{stickerId}/android/sticker.png";
+                                        case "text":
+                                            text = message.GetProperty("text").GetString();
+                                            break;
+                                        case "sticker":
+                                            var stickerId = message.GetProperty("stickerId").GetString();
+                                            imageUrl = $"https://stickershop.line-scdn.net/stickershop/v1/sticker/{stickerId}/android/sticker.png";
+                                            break;
+                                        case "image":
+                                            imageUrl = $"https://{request.host}/proxy/line/{GetHMACHex(id, _lineChannelSecret)}/{id}";
+                                            break;
+                                        default:
+                                            text = $"<{type}>";
+                                            if (!string.IsNullOrEmpty(id))
+                                            {
+                                                text += $"\nhttps://{request.host}/proxy/line/{GetHMACHex(id, _lineChannelSecret)}/{id}";
+                                            }
+                                            break;
                                     }
 
                                     foreach (var bridge in bridges)
@@ -110,7 +127,7 @@ protected override async Task ExecuteAsync(CancellationToken stoppingToken)
                                             continue;
                                         }
 
-                                        await SendToSlack(slackChannel.WebhookUrl, slackChannel.ChannelId, pictureUrl, userName, text, stickerUrl);
+                                        await SendToSlack(slackChannel.WebhookUrl, slackChannel.ChannelId, pictureUrl, userName, text, imageUrl);
                                     }
                                 }
                                 break;
@@ -136,7 +153,7 @@ protected override async Task ExecuteAsync(CancellationToken stoppingToken)
             _logger.LogDebug($"LineMessageProcessing background task is stopped.");
         }
 
-        private async Task SendToSlack(string webhookUrl, string channelId, string pictureUrl, string userName, string text, string stickerUrl)
+        private async Task SendToSlack(string webhookUrl, string channelId, string pictureUrl, string userName, string text, string imageUrl)
         {
             var client = _clientFactory.CreateClient();
 
@@ -153,13 +170,13 @@ private async Task SendToSlack(string webhookUrl, string channelId, string pictu
                 message.icon_url = pictureUrl;
             }
 
-            if (!string.IsNullOrEmpty(stickerUrl))
+            if (!string.IsNullOrEmpty(imageUrl))
             {
                 message.blocks = new[]{new
                     {
                         type = "image",
-                        image_url = stickerUrl,
-                        alt_text = "sticker"
+                        image_url = imageUrl,
+                        alt_text = "image"
                     } };
             }
 
@@ -246,21 +263,19 @@ private string GetLineEventSourceId(JsonElement e)
             return resultProfile;
         }
 
-        private static string GetHMAC(string text, string key)
+        private static byte[] CalcHMAC(string text, string key)
         {
             var encoding = new UTF8Encoding();
 
             var textBytes = encoding.GetBytes(text);
             var keyBytes = encoding.GetBytes(key);
 
-            byte[] hashBytes;
+            using var hash = new HMACSHA256(keyBytes);
+            return hash.ComputeHash(textBytes);
+        }
 
-            using (var hash = new HMACSHA256(keyBytes))
-            {
-                hashBytes = hash.ComputeHash(textBytes);
-            }
+        private static string GetHMACBase64(string text, string key) => Convert.ToBase64String(CalcHMAC(text, key));
 
-            return Convert.ToBase64String(hashBytes);
-        }
+        public static string GetHMACHex(string text, string key) => BitConverter.ToString(CalcHMAC(text, key)).Replace("-", "").ToLower();
     }
 }
diff --git a/SlackLineBridge/SlackLineBridge.csproj b/SlackLineBridge/SlackLineBridge.csproj
@@ -7,7 +7,9 @@
 
   <ItemGroup>
     <PackageReference Include="AWS.Logger.AspNetCore" Version="2.1.1" />
+    <PackageReference Include="Microsoft.Extensions.Logging.Debug" Version="3.0.0" />
     <PackageReference Include="Microsoft.VisualStudio.Azure.Containers.Tools.Targets" Version="1.9.5" />
+    <PackageReference Include="Microsoft.VisualStudio.Web.CodeGeneration.Design" Version="3.0.0" />
   </ItemGroup>
 
 </Project>
diff --git a/SlackLineBridge/Startup.cs b/SlackLineBridge/Startup.cs
@@ -55,7 +55,7 @@ public void ConfigureServices(IServiceCollection services)
             services.Configure<SlackChannels>(x => x.Channels = Configuration.GetSection("slackChannels").Get<SlackChannel[]>());
             services.Configure<LineChannels>(x => x.Channels = Configuration.GetSection("lineChannels").Get<LineChannel[]>());
             services.Configure<SlackLineBridges>(x => x.Bridges = Configuration.GetSection("slackLineBridges").Get<Models.Configurations.SlackLineBridge[]>());
-            services.AddSingleton<ConcurrentQueue<(string signature, string body)>>(); //lineRequestQueue
+            services.AddSingleton<ConcurrentQueue<(string signature, string body, string host)>>(); //lineRequestQueue
             services.AddSingleton(Configuration["lineChannelSecret"]);
             services.AddHostedService<LineMessageProcessingService>();
             services.AddHostedService<BackgroundAccessingService>();