Extract MimeUtils

[signal-cli] / lib / src / main / java / org / asamk / signal / manager / util / MimeUtils.java

diff --git a/lib/src/main/java/org/asamk/signal/manager/util/MimeUtils.java b/lib/src/main/java/org/asamk/signal/manager/util/MimeUtils.java
new file mode 100644 (file)
index 0000000..17d8134
--- /dev/null
+++ b/lib/src/main/java/org/asamk/signal/manager/util/MimeUtils.java
@@ -0,0 +1,51 @@
+package org.asamk.signal.manager.util;
+
+import java.io.BufferedInputStream;
+import java.io.File;
+import java.io.FileInputStream;
+import java.io.IOException;
+import java.io.InputStream;
+import java.net.URLConnection;
+import java.nio.file.Files;
+import java.util.Optional;
+
+public class MimeUtils {
+
+    public static final String LONG_TEXT = "text/x-signal-plain";
+    public static final String PLAIN_TEXT = "text/plain";
+    public static final String OCTET_STREAM = "application/octet-stream";
+
+    public static Optional<String> getFileMimeType(final File file) throws IOException {
+        var mime = Files.probeContentType(file.toPath());
+        if (mime != null) {
+            return Optional.of(mime);
+        }
+
+        try (final InputStream bufferedStream = new BufferedInputStream(new FileInputStream(file))) {
+            return getStreamMimeType(bufferedStream);
+        }
+    }
+
+    public static Optional<String> getStreamMimeType(final InputStream inputStream) throws IOException {
+        return Optional.ofNullable(URLConnection.guessContentTypeFromStream(inputStream));
+    }
+
+    public static Optional<String> guessExtensionFromMimeType(String mimeType) {
+        return Optional.ofNullable(switch (mimeType) {
+            case "application/vnd.android.package-archive" -> "apk";
+            case "application/json" -> "json";
+            case "image/png" -> "png";
+            case "image/jpeg" -> "jpg";
+            case "image/heic" -> "heic";
+            case "image/heif" -> "heif";
+            case "image/webp" -> "webp";
+            case "image/gif" -> "gif";
+            case "audio/aac" -> "aac";
+            case "video/mp4" -> "mp4";
+            case "text/x-vcard" -> "vcf";
+            case PLAIN_TEXT, LONG_TEXT -> "txt";
+            case OCTET_STREAM -> "bin";
+            default -> null;
+        });
+    }
+}