From 13e0b21e95d6c174df6433bb345041806da48591 Mon Sep 17 00:00:00 2001
From: Unnoen <Unnoen@users.noreply.github.com>
Date: Mon, 11 Jan 2021 19:42:03 +1100
Subject: [PATCH] Retry from B-CDN if unable to connect to cache server.

---
 .../Downloaders/WabbajackCDNDownloader.cs     | 30 +++++++++++++++++--
 1 file changed, 28 insertions(+), 2 deletions(-)

diff --git a/Wabbajack.Lib/Downloaders/WabbajackCDNDownloader.cs b/Wabbajack.Lib/Downloaders/WabbajackCDNDownloader.cs
index 688322b5..082fafef 100644
--- a/Wabbajack.Lib/Downloaders/WabbajackCDNDownloader.cs
+++ b/Wabbajack.Lib/Downloaders/WabbajackCDNDownloader.cs
@@ -11,6 +11,7 @@ using Wabbajack.Common.Exceptions;
 using Wabbajack.Common.Serialization.Json;
 using Wabbajack.Lib.AuthorApi;
 using Wabbajack.Lib.Validation;
+using System.Linq;
 
 namespace Wabbajack.Lib.Downloaders
 {
@@ -89,7 +90,7 @@ namespace Wabbajack.Lib.Downloaders
                     if (DomainRemaps.TryGetValue(Url.Host, out var remap))
                     {
                         var builder = new UriBuilder(Url) {Host = remap};
-                        using var response = await client.GetAsync($"{builder}/parts/{part.Index}");
+                        using var response = await GetWithCDNRetry(client, $"{builder}/parts/{part.Index}");
                         if (!response.IsSuccessStatusCode)
                             throw new HttpException((int)response.StatusCode, response.ReasonPhrase ?? "Unknown");
                         await response.Content.CopyToAsync(ostream);
@@ -114,6 +115,31 @@ namespace Wabbajack.Lib.Downloaders
                 return true;
             }
 
+            private async Task<HttpResponseMessage> GetWithCDNRetry(Http.Client client, string url, CancellationToken? token = null)
+            {
+                int retries = 0;
+
+                TOP:
+
+                try
+                {
+                    return await client.GetAsync(url, retry: false, token: token);
+                }
+                catch (Exception ex)
+                {
+                    if (retries > 2)
+                    {
+                        Utils.Log($"Trying CDN...");
+                        var remap = url.Replace(new Uri(url).Host, DomainRemaps.FirstOrDefault(x => x.Value == new Uri(url).Host).Key);
+                        return await client.GetAsync(remap, retry: false, token: token);
+                    }
+                    retries += 1;
+                    Utils.Log($"Error reading {url} retrying [{retries}]");
+                    Utils.Log(ex.ToString());
+                    goto TOP;
+                }
+            }
+
             private async Task<HttpResponseMessage> GetWithMirroredRetry(Http.Client client, string url)
             {
                 int retries = 0;
@@ -157,7 +183,7 @@ namespace Wabbajack.Lib.Downloaders
                 if (DomainRemaps.TryGetValue(Url.Host, out var remap))
                 {
                     var builder = new UriBuilder(Url) {Host = remap};
-                    using var data = await client.GetAsync(builder + "/definition.json.gz", token: token);
+                    using var data = await GetWithCDNRetry(client, builder + "/definition.json.gz", token: token);
                     await using var gz = new GZipStream(await data.Content.ReadAsStreamAsync(),
                         CompressionMode.Decompress);
                     return gz.FromJson<CDNFileDefinition>();