Add method to determine a file type

ProjectLighthouse.Tests/ExampleFiles/TestFarc.farc

@@ -0,0 +1 @@
+FSHbFARC

ProjectLighthouse.Tests/ExampleFiles/TestScript.ff

@@ -0,0 +1,3 @@
+FSH
+
+this is not my stuff to upload so its just gonna be a file like this for now :/

ProjectLighthouse.Tests/ProjectLighthouse.Tests.csproj

@@ -23,7 +23,9 @@
     </ItemGroup>
 
     <ItemGroup>
-      <ProjectReference Include="..\ProjectLighthouse\ProjectLighthouse.csproj" />
+        <ProjectReference Include="..\ProjectLighthouse\ProjectLighthouse.csproj" />
+        <Content Include="ExampleFiles\**">
+            <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
+        </Content>
     </ItemGroup>
-
 </Project>

ProjectLighthouse.Tests/Tests/FileTypeTests.cs

@@ -0,0 +1,53 @@
+using System;
+using System.IO;
+using System.Net;
+using System.Text;
+using ProjectLighthouse.Types.Files;
+using Xunit;
+
+namespace ProjectLighthouse.Tests {
+    public class FileTypeTests {
+        [Fact]
+        public void ShouldRecognizeLevel() {
+            LbpFile file = new(File.ReadAllBytes("ExampleFiles/TestLevel.lvl"));
+            Assert.True(file.FileType == LbpFileType.Level);
+        }
+
+        [Fact]
+        public void ShouldRecognizeScript() {
+            LbpFile file = new(File.ReadAllBytes("ExampleFiles/TestScript.ff"));
+            Assert.True(file.FileType == LbpFileType.Script);
+        }
+
+        [Fact]
+        public void ShouldRecognizeTexture() {
+            LbpFile file = new(File.ReadAllBytes("ExampleFiles/TestTexture.tex"));
+            Assert.True(file.FileType == LbpFileType.Texture);
+        }
+
+        [Fact]
+        public void ShouldRecognizeFileArchive() {
+            LbpFile file = new(File.ReadAllBytes("ExampleFiles/TestFarc.farc"));
+            Assert.True(file.FileType == LbpFileType.FileArchive);
+        }
+
+        [Fact]
+        public void ShouldNotRecognizeFileArchiveAsScript() {
+            LbpFile file = new(File.ReadAllBytes("ExampleFiles/TestFarc.farc"));
+            Assert.False(file.FileType == LbpFileType.Script);
+            Assert.True(file.FileType == LbpFileType.FileArchive);
+        }
+
+        [Fact]
+        public void ShouldRecognizeNothingAsUnknown() {
+            LbpFile file = new(Array.Empty<byte>());
+            Assert.True(file.FileType == LbpFileType.Unknown);
+        }
+
+        [Fact]
+        public void ShouldRecognizeGarbageAsUnknown() {
+            LbpFile file = new(Encoding.ASCII.GetBytes("free pc only $900"));
+            Assert.True(file.FileType == LbpFileType.Unknown);
+        }
+    }
+}

ProjectLighthouse/Controllers/PublishController.cs

@@ -49,6 +49,7 @@ namespace ProjectLighthouse.Controllers {
             await database.SaveChangesAsync();
             slot.LocationId = l.Id;
             slot.CreatorId = user.UserId;
+            if(slot.BackgroundHash == null) slot.BackgroundHash = "";
 
             database.Slots.Add(slot);
             await database.SaveChangesAsync();

ProjectLighthouse/Helpers/BinaryHelper.cs

@@ -1,3 +1,4 @@
+using System;
 using System.Collections.Generic;
 using System.IO;
 using System.Text;
@@ -21,5 +22,17 @@ namespace ProjectLighthouse.Helpers {
                 readByte = reader.ReadByte();
             } while(readByte != byteToReadTo);
         }
+
+        public static byte[] ReadLastBytes(BinaryReader reader, int count, bool restoreOldPosition = true) {
+            long oldPosition = reader.BaseStream.Position;
+
+            if(reader.BaseStream.Length < count) return Array.Empty<byte>();
+            
+            reader.BaseStream.Position = reader.BaseStream.Length - count;
+            byte[] data = reader.ReadBytes(count);
+            
+            if(restoreOldPosition) reader.BaseStream.Position = oldPosition;
+            return data;
+        }
     }
 }

ProjectLighthouse/Helpers/FileHelper.cs

@@ -0,0 +1,38 @@
+using System;
+using System.IO;
+using System.Text;
+using ProjectLighthouse.Types.Files;
+
+namespace ProjectLighthouse.Helpers {
+    public static class FileHelper {
+        public static bool IsFileSafe(LbpFile file) {
+            if(file.FileType == LbpFileType.Unknown) file.FileType = DetermineFileType(file.Data);
+            
+            return file.FileType switch {
+                LbpFileType.Texture => true,
+                LbpFileType.Script => false,
+                LbpFileType.Level => true,
+                LbpFileType.FileArchive => false,
+                LbpFileType.Unknown => false,
+                _ => throw new ArgumentOutOfRangeException(nameof(file), "Unknown file type."),
+            };
+        }
+
+        public static LbpFileType DetermineFileType(byte[] data) {
+            using MemoryStream ms = new(data);
+            using BinaryReader reader = new(ms);
+
+            string footer = Encoding.ASCII.GetString(BinaryHelper.ReadLastBytes(reader, 4));
+            if(footer == "FARC") return LbpFileType.FileArchive;
+
+            byte[] header = reader.ReadBytes(3);
+
+            return Encoding.ASCII.GetString(header) switch {
+                "TEX" => LbpFileType.Texture,
+                "FSH" => LbpFileType.Script,
+                "LVL" => LbpFileType.Level,
+                _ => LbpFileType.Unknown,
+            };
+        }
+    }
+}

ProjectLighthouse/Types/Files/LbpFile.cs

@@ -0,0 +1,22 @@
+using System.IO;
+using ProjectLighthouse.Helpers;
+
+namespace ProjectLighthouse.Types.Files {
+    public class LbpFile {
+        public LbpFile(byte[] data) {
+            this.Data = data;
+            this.FileType = FileHelper.DetermineFileType(data);
+        }
+        
+        /// <summary>
+        /// The type of file.
+        /// </summary>
+        public LbpFileType FileType;
+
+        /// <summary>
+        /// A buffer of the file's data.
+        /// </summary>
+        public readonly byte[] Data;
+
+    }
+}

ProjectLighthouse/Types/Files/LbpFileType.cs

@@ -0,0 +1,9 @@
+namespace ProjectLighthouse.Types.Files {
+    public enum LbpFileType {
+        Script, // .ff, FSH
+        Texture, // TEX
+        Level, // LVL
+        FileArchive, // .farc, (ends with FARC)
+        Unknown,
+    }
+}