http client with cache

src/Utils.cs

@@ -1,8 +1,14 @@
 using System.ComponentModel;
 using System.Diagnostics;
+using System.IO.Compression;
 using System.IO.Pipes;
+using System.Net;
+using System.Net.Http.Headers;
 using System.Runtime.InteropServices;
+using System.Security.Cryptography;
+using System.Text;
 using System.Text.Json.Nodes;
+using Google.Protobuf;
 using YaeAchievement.Win32;
 using static YaeAchievement.Win32.OpenFileFlags;
 
@@ -10,7 +16,72 @@ namespace YaeAchievement;
 
 public static class Utils {
 
+    private static readonly Lazy<HttpClient> CHttpClient = new (() => {
+        var c = new HttpClient(new HttpClientHandler {
+            Proxy = new WebProxy("http://127.0.0.1:8888")
+        }) {
+            DefaultRequestHeaders = {
+                UserAgent = {
+                    new ProductInfoHeaderValue("YaeAchievement", GlobalVars.AppVersion.ToString(2))
+                }
+            }
+        };
+        return c;
+    });
+
+    public static string GetBucketFileAsString(string path) {
+        return Encoding.UTF8.GetString(GetBucketFileAsByteArray(path));
+    }
+    
+    public static byte[] GetBucketFileAsByteArray(string path) {
+        using var msg = new HttpRequestMessage {
+            Method = HttpMethod.Get,
+            RequestUri = new Uri($"{GlobalVars.BucketHost}/{path}")
+        };
+        CacheItem? ci = null;
+        string?  etag = null;
+        var cacheName = $"./cache/{CalculateMD5(path)[..16]}.miko";
+        if (File.Exists(cacheName)) {
+            using var input = File.OpenRead(cacheName);
+            using var dInput = new GZipStream(input, CompressionMode.Decompress);
+            ci = CacheItem.Parser.ParseFrom(dInput);
+            etag = ci.Etag;
+        }
+        if (etag != null) {
+            msg.Headers.TryAddWithoutValidation("If-None-Match", $"{etag}");
+        }
+        using var response = CHttpClient.Value.Send(msg);
+        if (response.StatusCode == HttpStatusCode.NotModified) {
+            return ci!.Content.ToByteArray();
+        }
+        response.EnsureSuccessStatusCode();
+        etag = response.Headers.ETag!.Tag;
+        var responseBytes = response.Content.ReadAsByteArrayAsync().Result;
+        using var os = File.OpenWrite(cacheName);
+        using var cos = new GZipStream(os, CompressionLevel.SmallestSize);
+        new CacheItem {
+            Etag = etag,
+            Version = 3,
+            Checksum = CalculateMD5(responseBytes),
+            Content = ByteString.CopyFrom(responseBytes)
+        }.WriteTo(cos);
+        return responseBytes;
+    }
+
+    // ReSharper disable once InconsistentNaming
+    private static string CalculateMD5(string text) {
+        return CalculateMD5(Encoding.UTF8.GetBytes(text));
+    }
+    
+    // ReSharper disable once InconsistentNaming
+    private static string CalculateMD5(byte[] bytes) {
+        using var md5 = MD5.Create();
+        var b = md5.ComputeHash(bytes);
+        return Convert.ToHexString(b).ToLower();
+    }
+    
     public static void LoadConfig() {
+        Directory.CreateDirectory("cache");
         var conf = JsonNode.Parse(File.ReadAllText(GlobalVars.ConfigFileName))!;
         var path = conf["genshinPath"];
         if (path == null || CheckGamePathValid(path.GetValue<string>())) {
@@ -112,7 +183,9 @@ public static class Utils {
             while (!proc.HasExited) {
                 var line = reader.ReadLine();
                 if (line?.Length > 0) {
-                    if (onReceive(line)) break;
+                    if (onReceive(line)) {
+                        break;
+                    }
                     server.Disconnect();
                     server.WaitForConnection();
                 }