add support for '*' in etag match

Author: harshavardhana

api-put-object.go

@@ -106,7 +106,11 @@ func (opts *PutObjectOptions) SetMatchETag(etag string) {
 	if opts.customHeaders == nil {
 		opts.customHeaders = http.Header{}
 	}
-	opts.customHeaders.Set("If-Match", "\""+etag+"\"")
+	if etag == "*" {
+		opts.customHeaders.Set("If-Match", "*")
+	} else {
+		opts.customHeaders.Set("If-Match", "\""+etag+"\"")
+	}
 }
 
 // SetMatchETagExcept if etag does not match while PUT MinIO returns an
@@ -116,7 +120,11 @@ func (opts *PutObjectOptions) SetMatchETagExcept(etag string) {
 	if opts.customHeaders == nil {
 		opts.customHeaders = http.Header{}
 	}
-	opts.customHeaders.Set("If-None-Match", "\""+etag+"\"")
+	if etag == "*" {
+		opts.customHeaders.Set("If-None-Match", "*")
+	} else {
+		opts.customHeaders.Set("If-None-Match", "\""+etag+"\"")
+	}
 }
 
 // getNumThreads - gets the number of threads to be used in the multipart