Issue #1356 - Improve detection of the issuer of the request

src/shared/Utils.h

 #ifndef UTILS_H
 #define UTILS_H
 
 #include <algorithm>
 #include <locale>
 #include <functional>
 #include <string>
 
 #define WM_ALREADY_UP_TO_DATE WM_APP+1
 #define WM_UPDATE_CHECK_ERROR WM_APP+2
@@ skipping 32 matching lines @@
 T TrimString(T text)
 {
   // Via http://stackoverflow.com/questions/216823/whats-the-best-way-to-trim-stdstring
   T trimmed(text);
   std::function<bool(T::value_type)> isspace = std::bind(&std::isspace<T::value_type>, std::placeholders::_1, std::locale::classic());
   trimmed.erase(trimmed.begin(), std::find_if(trimmed.begin(), trimmed.end(), std::not1(isspace)));
   trimmed.erase(std::find_if(trimmed.rbegin(), trimmed.rend(), std::not1(isspace)).base(), trimmed.end());
   return trimmed;
 }
 
+template <class T>
+T ExtractHTTPHeader(const T& allHeaders, const T& targetHeaderName, const T& delimiter)
+{
+  auto targetHeaderBeginsAt = allHeaders.find(targetHeaderName);
+  if (targetHeaderBeginsAt == T::npos)
+  {
+    return T();
+  }
+  targetHeaderBeginsAt += targetHeaderName.length();
+  auto targetHeaderEndsAt = allHeaders.find(delimiter, targetHeaderBeginsAt);
+  if (targetHeaderEndsAt == T::npos)
+  {
+    return T();
+  }
+  return allHeaders.substr(targetHeaderBeginsAt, targetHeaderEndsAt - targetHeaderBeginsAt);
+}
+
 #endif // UTILS_H