XrdS3: add simplie 'getBucketName' function extracting bucket name fr…

…om virtual host URI

src/XrdS3/XrdS3Utils.cc

@@ -289,6 +289,22 @@ std::string S3Utils::timestampToRFC7231(const struct tm *gmt) {
   return std::string(buffer);
 }
 
+//------------------------------------------------------------------------------
+//! extract bucket name out of virtual host
+//! @param FQHN
+//! @return the name of the bucket or an empty string
+//------------------------------------------------------------------------------
+std::string S3Utils::getBucketName(const std::string& host)
+{
+  auto ndot = std::count(host.begin(), host.end(), '.');
+  if ( ndot > 2)  {
+    // return bucket name
+    return host.substr(0, host.find('.'));
+  } else {
+    return "";
+  }
+}
+
 //------------------------------------------------------------------------------
 //! make a path
 //!

src/XrdS3/XrdS3Utils.hh

@@ -136,6 +136,8 @@ class S3Utils {
   static std::string timestampToRFC7231(const time_t &t);
   static std::string timestampToRFC7231(const tm *t);
 
+  static std::string getBucketName(const std::string& host);
+
   static int makePath(char *path, mode_t mode);
 
   static void RmPath(std::filesystem::path path,