Improve handling of compression inclusion for objects (#19234)

cmd/object-api-utils.go

@@ -577,22 +577,35 @@ func excludeForCompression(header http.Header, object string, cfg compress.Confi
 	}
 
 	// Filter compression includes.
-	exclude := len(cfg.Extensions) > 0 || len(cfg.MimeTypes) > 0
+	if len(cfg.Extensions) == 0 && len(cfg.MimeTypes) == 0 {
+		// Nothing to filter, include everything.
+		return false
+	}
+
 	if len(cfg.Extensions) > 0 && hasStringSuffixInSlice(objStr, cfg.Extensions) {
-		exclude = false
+		// Matched an extension to compress, do not exclude.
+		return false
 	}
 
 	if len(cfg.MimeTypes) > 0 && hasPattern(cfg.MimeTypes, contentType) {
-		exclude = false
+		// Matched an MIME type to compress, do not exclude.
+		return false
 	}
-	return exclude
+
+	// Did not match any inclusion filters, exclude from compression.
+	return true
 }
 
 // Utility which returns if a string is present in the list.
-// Comparison is case insensitive.
+// Comparison is case insensitive. Explicit short-circuit if
+// the list contains the wildcard "*".
 func hasStringSuffixInSlice(str string, list []string) bool {
 	str = strings.ToLower(str)
 	for _, v := range list {
+		if v == "*" {
+			return true
+		}
+
 		if strings.HasSuffix(str, strings.ToLower(v)) {
 			return true
 		}

docs/compression/README.md

@@ -59,6 +59,14 @@ export MINIO_COMPRESSION_EXTENSIONS=".txt,.log,.csv,.json,.tar,.xml,.bin"
 export MINIO_COMPRESSION_MIME_TYPES="text/*,application/json,application/xml"
 ```
 
+> [!NOTE]
+> To enable compression for all content when using environment variables, set either or both of the extensions and MIME types to `*` instead of an empty string:
+> ```bash
+> export MINIO_COMPRESSION_ENABLE="on"
+> export MINIO_COMPRESSION_EXTENSIONS="*"
+> export MINIO_COMPRESSION_MIME_TYPES="*"
+> ```
+
 ### 3. Compression + Encryption
 
 Combining encryption and compression is not safe in all setups.