Initial check-in

FileManager/UNTESTED/FileUtility.cs

@@ -0,0 +1,101 @@
+using System;
+using System.Collections.Generic;
+using System.IO;
+using System.Linq;
+
+namespace FileManager
+{
+    public static class FileUtility
+    {
+        // a replacement for File.Exists() which allows long paths
+        // not needed in .net-core
+        public static bool FileExists(string path)
+        {
+            var basic = File.Exists(path);
+            if (basic)
+                return true;
+
+            // character cutoff is usually 269 but this isn't a hard number. there are edgecases which shorted the threshold
+            if (path.Length < 260)
+                return false;
+
+            // try long name prefix:
+            //   \\?\
+            // https://blogs.msdn.microsoft.com/jeremykuhne/2016/06/21/more-on-new-net-path-handling/
+            path = @"\\?\" + path;
+
+            return File.Exists(path);
+        }
+
+        /// <param name="proposedPath">acceptable inputs:
+        ///   example.txt
+        ///   C:\Users\username\Desktop\example.txt</param>
+        /// <returns>Returns full name and path of unused filename. including (#)</returns>
+        public static string GetValidFilename(string proposedPath)
+            => GetValidFilename(Path.GetDirectoryName(proposedPath), Path.GetFileNameWithoutExtension(proposedPath), Path.GetExtension(proposedPath));
+
+        public static string GetValidFilename(string dirFullPath, string filename, string extension, params string[] metadataSuffixes)
+        {
+            if (string.IsNullOrWhiteSpace(dirFullPath))
+                throw new ArgumentException($"{nameof(dirFullPath)} may not be null or whitespace", nameof(dirFullPath));
+
+            // file max length = 255. dir max len = 247
+
+            // sanitize
+            filename = GetAsciiTag(filename);
+            // manage length
+            if (filename.Length > 50)
+                filename = filename.Substring(0, 50) + "[...]";
+
+            // append id. it is 10 or 14 char in the common cases
+            if (metadataSuffixes != null && metadataSuffixes.Length > 0)
+                filename += " [" + string.Join("][", metadataSuffixes) + "]";
+
+            // this method may also be used for directory names, so no guarantee of extension
+            if (!string.IsNullOrWhiteSpace(extension))
+                extension = '.' + extension.Trim('.');
+
+            // ensure uniqueness
+            var fullfilename = Path.Combine(dirFullPath, filename + extension);
+            var i = 0;
+            while (FileExists(fullfilename))
+                fullfilename = Path.Combine(dirFullPath, filename + $" ({++i})" + extension);
+
+            return fullfilename;
+        }
+
+        public static string GetAsciiTag(string property)
+        {
+            if (property == null)
+                return "";
+
+            // omit characters which are invalid. EXCEPTION: change colon to underscore
+            property = property.Replace(':', '_');
+
+            // GetInvalidFileNameChars contains everything in GetInvalidPathChars plus ':', '*', '?', '\\', '/'
+            foreach (var ch in Path.GetInvalidFileNameChars())
+                property = property.Replace(ch.ToString(), "");
+            return property;
+        }
+
+        public static string Declaw(string str)
+            => str
+                .Replace("<script", "<sxcript")
+                .Replace(".net", ".nxet")
+                .Replace(".com", ".cxom")
+                .Replace("<link", "<lxink")
+                .Replace("http", "hxttp");
+        public static string RestoreDeclawed(string str)
+            => str
+                ?.Replace("<sxcript", "<script")
+                .Replace(".nxet", ".net")
+                .Replace(".cxom", ".com")
+                .Replace("<lxink", "<link")
+                .Replace("hxttp", "http");
+
+        public static string TitleCompressed(string title)
+            => new string(title
+                .Where(c => (char.IsLetterOrDigit(c)))
+                .ToArray());
+    }
+}