From 5f1230aac542f30640451fe3b34e91a0cd867dd0 Mon Sep 17 00:00:00 2001
From: Gianmaria Del Monte <g.macmount@gmail.com>
Date: Fri, 22 Oct 2021 09:10:33 +0200
Subject: [PATCH] Filter provider by only showing allowed users

---
 pkg/storage/registry/static/static.go | 41 +++++++++++++++++++++++++--
 1 file changed, 38 insertions(+), 3 deletions(-)

diff --git a/pkg/storage/registry/static/static.go b/pkg/storage/registry/static/static.go
index 58d3845013e..e0ad098d819 100644
--- a/pkg/storage/registry/static/static.go
+++ b/pkg/storage/registry/static/static.go
@@ -32,6 +32,7 @@ import (
 	"github.com/cs3org/reva/pkg/storage"
 	"github.com/cs3org/reva/pkg/storage/registry/registry"
 	"github.com/cs3org/reva/pkg/storage/utils/templates"
+	ua "github.com/mileusna/useragent"
 	"github.com/mitchellh/mapstructure"
 	"github.com/pkg/errors"
 )
@@ -43,9 +44,10 @@ func init() {
 var bracketRegex = regexp.MustCompile(`\[(.*?)\]`)
 
 type rule struct {
-	Mapping string            `mapstructure:"mapping"`
-	Address string            `mapstructure:"address"`
-	Aliases map[string]string `mapstructure:"aliases"`
+	Mapping           string            `mapstructure:"mapping"`
+	Address           string            `mapstructure:"address"`
+	Aliases           map[string]string `mapstructure:"aliases"`
+	AllowedUserAgents []string          `mapstructure:"allowed_user_agents"`
 }
 
 type config struct {
@@ -138,6 +140,23 @@ func (b *reg) GetHome(ctx context.Context) (*registrypb.ProviderInfo, error) {
 	return nil, errors.New("static: home not found")
 }
 
+func userAgentIsAllowed(ua *ua.UserAgent, userAgents []string) bool {
+	for _, userAgent := range userAgents {
+		switch userAgent {
+		case "web":
+			if ua.IsChrome() || ua.IsEdge() || ua.IsFirefox() || ua.IsSafari() ||
+				ua.IsInternetExplorer() || ua.IsOpera() || ua.IsOperaMini() {
+				return true
+			}
+		case "desktop":
+			if ua.Desktop {
+				return true
+			}
+		}
+	}
+	return false
+}
+
 func (b *reg) FindProviders(ctx context.Context, ref *provider.Reference) ([]*registrypb.ProviderInfo, error) {
 	// find longest match
 	var match *registrypb.ProviderInfo
@@ -147,6 +166,22 @@ func (b *reg) FindProviders(ctx context.Context, ref *provider.Reference) ([]*re
 	if ref.ResourceId != nil {
 		if ref.ResourceId.StorageId != "" {
 			for prefix, rule := range b.c.Rules {
+
+				// check if the provider is allowed to be shown according to the
+				// user agent that made the request
+				// if the list of AllowedUserAgents is empty, this means that
+				// every agents that made the request could see the provider
+
+				if len(rule.AllowedUserAgents) != 0 {
+					ua, ok := ctxpkg.ContextGetUserAgent(ctx)
+					if !ok {
+						continue
+					}
+					if !userAgentIsAllowed(ua, rule.AllowedUserAgents) {
+						continue // skip this provider
+					}
+				}
+
 				addr := getProviderAddr(ctx, rule)
 				r, err := regexp.Compile("^" + prefix + "$")
 				if err != nil {