Merge pull request #1052 from KSP-CKAN/resolve_certs

More robust cURL CA bundle file resolution

Netkan/Web.cs

@@ -1,5 +1,7 @@
 using System;
 using System.IO;
+using System.Linq;
+using System.Reflection;
 using System.Text;
 using CurlSharp;
 using log4net;
@@ -22,22 +24,12 @@ public Web()
                 CurlSharp.Curl.GlobalInit(CurlInitFlag.All);
                 init_complete = true;
             }
-            var curl_ca_bundle_crt = "./curl-ca-bundle.crt";
-            if (File.Exists(curl_ca_bundle_crt))
-            {
-                easy = new CurlEasy
-                {
-                    UserAgent = Net.UserAgentString,
-                    CaInfo = curl_ca_bundle_crt
-                };
-            }
-            else
+
+            easy = new CurlEasy
             {
-                easy = new CurlEasy
-                {
-                    UserAgent = Net.UserAgentString,
-                };
-            }
+                UserAgent = Net.UserAgentString,
+                CaInfo = ResolveCurlCaBundle()
+            };
         }
 
         /// <summary>
@@ -82,6 +74,40 @@ public void Dispose()
             CurlSharp.Curl.GlobalCleanup();
             easy.Dispose();
         }
+
+        /// <summary>
+        /// Resolves the location of the cURL CA bundle file to use.
+        /// </summary>
+        /// <returns>The absolute file path to the bundle file or null if none is found.</returns>
+        private static string ResolveCurlCaBundle()
+        {
+            const string caBundleFileName = "curl-ca-bundle.crt";
+            const string ckanSubDirectoryName = "CKAN";
+
+            string bundle = new[]
+            {
+                // Working Directory
+                Environment.CurrentDirectory,
+
+                // Executable Directory
+                Path.GetDirectoryName(Assembly.GetExecutingAssembly().Location),
+
+                // %LOCALAPPDATA%/CKAN
+                Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.LocalApplicationData), ckanSubDirectoryName),
+
+                // %APPDATA%/CKAN
+                Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.ApplicationData), ckanSubDirectoryName),
+
+                // %PROGRAMDATA%/CKAN
+                Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.CommonApplicationData), ckanSubDirectoryName),
+            }
+            .Select(i => Path.Combine(i, caBundleFileName))
+            .FirstOrDefault(File.Exists);
+
+            log.InfoFormat("Using curl-ca bundle: {0}",bundle ?? "(none)");
+
+            return bundle;
+        }
     }
 }