Always use the same SourceForge mirror

KSP-CKAN · Sep 5, 2024 · 107303c · 107303c
1 parent f475493
commit 107303c
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Showing 2 changed files with 58 additions and 25 deletions.
diff --git a/Core/Net/Net.cs b/Core/Net/Net.cs
@@ -1,4 +1,5 @@
 using System;
+using System.IO;
 using System.Collections.Generic;
 using System.Linq;
 using System.Net;
@@ -9,6 +10,7 @@
 using ChinhDo.Transactions.FileManager;
 using log4net;
 
+using CKAN.Extensions;
 using CKAN.Configuration;
 
 namespace CKAN
@@ -198,33 +200,37 @@ public static string Download(string url, out string? etag, string? filename = n
         }
 
         public static Uri? ResolveRedirect(Uri     url,
-                                           string? userAgent = "")
+                                           string? userAgent    = null,
+                                           int     maxRedirects = 6)
         {
-            const int maxRedirects = 6;
-            for (int redirects = 0; redirects <= maxRedirects; ++redirects)
+            var urls = url.TraverseNodes(u => new RedirectWebClient(userAgent) is RedirectWebClient rwClient
+                                              && rwClient.OpenRead(u) is Stream s && DisposeStream(s)
+                                              && rwClient.ResponseHeaders is WebHeaderCollection headers
+                                              && headers["Location"] is string location
+                                                  ? Uri.IsWellFormedUriString(location, UriKind.Absolute)
+                                                      ? new Uri(location)
+                                                      : Uri.IsWellFormedUriString(location, UriKind.Relative)
+                                                          ? new Uri(u, location)
+                                                          : throw new Kraken(string.Format(Properties.Resources.NetInvalidLocation,
+                                                                                           location))
+                                                  : null)
+                          // The first element is the input, so e.g. if we want two redirects, that's three elements
+                          .Take(maxRedirects + 1)
+                          .ToArray();
+            if (log.IsDebugEnabled)
             {
-                var rwClient = new RedirectWebClient(userAgent);
-                using (rwClient.OpenRead(url)) { }
-                var location = rwClient.ResponseHeaders?["Location"];
-                if (location == null)
+                foreach ((Uri from, Uri to) in urls.Zip(urls.Skip(1)))
                 {
-                    return url;
-                }
-                else if (Uri.IsWellFormedUriString(location, UriKind.Absolute))
-                {
-                    url = new Uri(location);
-                }
-                else if (Uri.IsWellFormedUriString(location, UriKind.Relative))
-                {
-                    url = new Uri(url, location);
-                    log.DebugFormat("Relative URL {0} is absolute URL {1}", location, url);
-                }
-                else
-                {
-                    throw new Kraken(string.Format(Properties.Resources.NetInvalidLocation, location));
+                    log.DebugFormat("Redirected {0} to {1}", from, to);
                 }
             }
-            return null;
+            return urls.LastOrDefault();
+        }
+
+        private static bool DisposeStream(Stream s)
+        {
+            s.Dispose();
+            return true;
         }
 
         /// <summary>

diff --git a/Netkan/Transformers/SourceForgeTransformer.cs b/Netkan/Transformers/SourceForgeTransformer.cs
@@ -1,6 +1,8 @@
 using System;
 using System.Linq;
+using System.Web;
 using System.Collections.Generic;
+using System.Collections.Specialized;
 
 using Newtonsoft.Json.Linq;
 using log4net;
@@ -74,8 +76,18 @@ private static Metadata TransformOne(JObject            json,
                 { "bugtracker", mod.BugTrackerLink },
             }));
             // SourceForge doesn't send redirects to user agents it considers browser-like
-            json.SafeAdd("download", Net.ResolveRedirect(version.Link, "Wget")
-                                        ?.OriginalString);
+            if (Net.ResolveRedirect(version.Link, "Wget", 1) is Uri firstRedir)
+            {
+                // SourceForge redirects to different mirrors for load-balancing
+                // (IF it considers your user agent string a non-browser, which excludes the CKAN client),
+                // but for us that means CKAN users constantly shifting from one server
+                // to another in unison as the bot changes the URL in the metadata.
+                // https://sourceforge.net/p/forge/documentation/Mirrors/
+                // Tweak the intermediate redirect URL to use the same mirror every time.
+                json.SafeAdd("download", Net.ResolveRedirect(SetQueryKey(firstRedir, "use_mirror", mirror),
+                                                             "Wget", 1)
+                                            ?.OriginalString);
+            }
             json.SafeAdd(Metadata.UpdatedPropertyName, version.Timestamp);
 
             json.Remove("$kref");
@@ -84,7 +96,22 @@ private static Metadata TransformOne(JObject            json,
             return new Metadata(json);
         }
 
+        private static Uri SetQueryKey(Uri url, string key, string value)
+        {
+            if (HttpUtility.ParseQueryString(url.Query) is NameValueCollection newQuery)
+            {
+                newQuery.Set(key, value);
+                return new UriBuilder(url)
+                {
+                    Query = newQuery.ToString(),
+                }.Uri;
+
+            }
+            return url;
+        }
+
         private        readonly ISourceForgeApi api;
-        private static readonly ILog            log = LogManager.GetLogger(typeof(GitlabTransformer));
+        private const           string          mirror = "psychz"; // Brooklyn, United States
+        private static readonly ILog            log    = LogManager.GetLogger(typeof(GitlabTransformer));
     }
 }