Added Filter and Filter Regexpes to spec and code.

They don't do anything yet.
For KSP-CKAN#129.

CKAN.schema

@@ -152,6 +152,14 @@
                         "description" : "Where file should be installed to",
                         "$ref" : "#/definitions/install_to"
                     },
+                    "filter" : {
+                        "description" : "List of files and directories that should be filtered from the install",
+                        "$ref" : "#/definitions/one_or_more_strings"
+                    },
+                    "filter_regexp" : {
+                        "description" : "List of regexps that should filter files from this install",
+                        "$ref" : "#/definitions/one_or_more_strings"
+                    },
                     "requires" : {
                         "description" : "A required mod for this install part",
                         "$ref" : "#/definitions/identifier"
@@ -303,6 +311,17 @@
                     "uniqueItems" : true
                 }
             ]
+        },
+        "one_or_more_strings" : {
+            "description" : "One or more strings",
+            "oneOf"       : [
+                { "type" : "string" },
+                {
+                    "type"        : "array",
+                    "items"       : { "type" : "string" },
+                    "uniqueItems" : true
+                }
+            ]
         }
     }
 }

CKAN/CKAN/Module.cs

@@ -51,12 +51,19 @@ public class ResourcesDescriptor
         public KerbalStuffResourceDescriptor kerbalstuff;
     }
 
+    // [JsonObject(MemberSerialization.OptIn)]
     public class ModuleInstallDescriptor : InstallableDescriptor
     {
-        public string description;
-        public bool optional;
-        public bool overwrite;
-        public string requires;
+        public string description; // Discouraged, maybe...
+        public bool optional;      // Discouraged GH #113
+        public bool overwrite;     // Discouraged GH #113
+        public string requires;    // Discouraged GH #113
+
+        [JsonConverter(typeof (JsonSingleOrArrayConverter<string>))]
+        public List<string> filter;
+
+        [JsonConverter(typeof (JsonSingleOrArrayConverter<string>))]
+        public List<string> filter_regexp;
     }
 
     public enum License

CKAN/CKAN/ModuleInstaller.cs

@@ -610,15 +610,15 @@ internal static List<InstallableFile> FindInstallableFiles(InstallableDescriptor
             }
 
             // Is there a better way to extract a tree?
-            string filter = "^" + stanza.file + "(/|$)";
+            string wanted_filter = "^" + stanza.file + "(/|$)";
 
             // O(N^2) solution, as we're walking the zipfile for each stanza.
             // Surely there's a better way, although this is fast enough we may not care.
 
             foreach (ZipEntry entry in zipfile)
             {
                 // Skip things we don't want.
-                if (!Regex.IsMatch(entry.Name, filter))
+                if (!Regex.IsMatch(entry.Name, wanted_filter))
                 {
                     continue;
                 }

CKAN/Tests/CKAN/Module.cs

@@ -33,6 +33,18 @@ public void MetaData()
             Assert.AreEqual("https://github.com/KSP-KOS/KOS/issues", module.resources.bugtracker.ToString());
         }
 
+        [Test]
+        public void FilterRead()
+        {
+            CkanModule module = CkanModule.FromJson(TestData.DogeCoinFlag_101());
+
+            // Assert known things about this mod.
+            Assert.IsNotNull(module.install[0].filter);
+            Assert.IsNotNull(module.install[0].filter_regexp);
+
+            Assert.AreEqual(2, module.install[0].filter.Count);
+        }
+
     }
 }
 

CKAN/Tests/TestData.cs

@@ -78,7 +78,9 @@ public static string DogeCoinFlag_101()
                     ""install"": [
                         {
                         ""file"": ""DogeCoinFlag-1.01/GameData/DogeCoinFlag"",
-                        ""install_to"": ""GameData""
+                        ""install_to"": ""GameData"",
+                        ""filter"" : [ ""Thumbs.db"", ""INSTALL.md"" ],
+                        ""filter_regexp"" : ""\\.bak$""
                         }
                     ],
                     ""resources"": {

Spec.md

@@ -239,7 +239,20 @@ mandatory directives:
   Paths will be preserved, but directories will *only*
   be created when installing to `GameData` or `Tutorial`.
 
-An install directive may also include the following optional fields:
+Optionally, an install directive may filter the files to install using:
+
+- `filter` : A string, or list of strings, of file parts that should not
+  be installed. These are treated as literal things which must match a
+  file name or directory. Examples of filters may be `Thumbs.db`,
+  or `Source`. Filters are considered case-insensitive.
+- `filter_regexp` : A string, or list of strings, which are treated as
+  case-sensitive C# regular expressions whch are matched against the
+  full paths from the installing zip-file. If a file matches the regular
+  expression, it is not installed.
+
+An install directive may also include the following optional fields.
+Use of these fields are *discouraged*, and they may become deprecated
+in the future.
 
 - `depends`: Indicates this install directive should only be triggered
   if the required mod has already been installed.