[#174] Add fallback path to search

Fallback path to search is needed because
some software may keep FileName attribute
and ignore FilePath attribute during file
upload. Therefore, if this feature is
enabled under certain conditions (for more
information, see gate-configuration.md) a
search will be performed for the FileName
attribute.

Signed-off-by: Roman Loginov <r.loginov@yadro.com>

cmd/http-gw/app.go

@@ -95,21 +95,22 @@ type (
 		dialerSource      *internalnet.DialerSource
 		workerPoolSize    int
 
-		mu                   sync.RWMutex
-		defaultTimestamp     bool
-		zipCompression       bool
-		clientCut            bool
-		returnIndexPage      bool
-		indexPageTemplate    string
-		bufferMaxSizeForPut  uint64
-		namespaceHeader      string
-		defaultNamespaces    []string
-		corsAllowOrigin      string
-		corsAllowMethods     []string
-		corsAllowHeaders     []string
-		corsExposeHeaders    []string
-		corsAllowCredentials bool
-		corsMaxAge           int
+		mu                     sync.RWMutex
+		defaultTimestamp       bool
+		zipCompression         bool
+		clientCut              bool
+		returnIndexPage        bool
+		indexPageTemplate      string
+		bufferMaxSizeForPut    uint64
+		namespaceHeader        string
+		defaultNamespaces      []string
+		corsAllowOrigin        string
+		corsAllowMethods       []string
+		corsAllowHeaders       []string
+		corsExposeHeaders      []string
+		corsAllowCredentials   bool
+		corsMaxAge             int
+		enableFilepathFallback bool
 	}
 
 	CORS struct {
@@ -189,6 +190,7 @@ func (s *appSettings) update(v *viper.Viper, l *zap.Logger) {
 	corsExposeHeaders := v.GetStringSlice(cfgCORSExposeHeaders)
 	corsAllowCredentials := v.GetBool(cfgCORSAllowCredentials)
 	corsMaxAge := fetchCORSMaxAge(v)
+	enableFilepathFallback := v.GetBool(cfgFeaturesEnableFilepathFallback)
 
 	s.mu.Lock()
 	defer s.mu.Unlock()
@@ -208,6 +210,7 @@ func (s *appSettings) update(v *viper.Viper, l *zap.Logger) {
 	s.corsExposeHeaders = corsExposeHeaders
 	s.corsAllowCredentials = corsAllowCredentials
 	s.corsMaxAge = corsMaxAge
+	s.enableFilepathFallback = enableFilepathFallback
 }
 
 func (s *loggerSettings) DroppedLogsInc() {
@@ -305,6 +308,12 @@ func (s *appSettings) FormContainerZone(ns string) (zone string, isDefault bool)
 	return ns + ".ns", false
 }
 
+func (s *appSettings) EnableFilepathFallback() bool {
+	s.mu.RLock()
+	defer s.mu.RUnlock()
+	return s.enableFilepathFallback
+}
+
 func (a *app) initResolver() {
 	var err error
 	a.resolver, err = resolver.NewContainerResolver(a.getResolverConfig())