From 3a64336d9f287c433e97fde18cfd0041cbc1d5f9 Mon Sep 17 00:00:00 2001
From: CalDescent <caldescent@protonmail.com>
Date: Sat, 18 Mar 2023 17:57:07 +0000
Subject: [PATCH] If the MIME type can't be determined from the file's
 contents, fall back to using the filename.

---
 .../org/qortal/api/resource/ArbitraryResource.java  | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/src/main/java/org/qortal/api/resource/ArbitraryResource.java b/src/main/java/org/qortal/api/resource/ArbitraryResource.java
index 84e2d3b0..c4c19652 100644
--- a/src/main/java/org/qortal/api/resource/ArbitraryResource.java
+++ b/src/main/java/org/qortal/api/resource/ArbitraryResource.java
@@ -14,6 +14,8 @@ import io.swagger.v3.oas.annotations.security.SecurityRequirement;
 import io.swagger.v3.oas.annotations.tags.Tag;
 
 import java.io.*;
+import java.net.FileNameMap;
+import java.net.URLConnection;
 import java.nio.file.Files;
 import java.nio.file.Paths;
 import java.util.ArrayList;
@@ -1397,7 +1399,16 @@ public class ArbitraryResource {
 				java.nio.file.Path filePath = Paths.get(outputPath.toString(), files[0]);
 				ContentInfoUtil util = new ContentInfoUtil();
 				ContentInfo info = util.findMatch(filePath.toFile());
-				String mimeType = (info != null) ? info.getMimeType() : null;
+				String mimeType;
+				if (info != null) {
+					// Attempt to extract MIME type from file contents
+					mimeType = info.getMimeType();
+				}
+				else {
+					// Fall back to using the filename
+					FileNameMap fileNameMap = URLConnection.getFileNameMap();
+					mimeType = fileNameMap.getContentTypeFor(filename);
+				}
 				fileProperties.filename = filename;
 				fileProperties.mimeType = mimeType;
 			}