package middleware import ( "net/http" "strings" "github.com/Sirupsen/logrus" "github.com/docker/docker/api/server/httputils" "github.com/docker/docker/api/types/versions" "golang.org/x/net/context" ) // UserAgentMiddleware is a middleware that // validates the client user-agent. type UserAgentMiddleware struct { serverVersion string } // NewUserAgentMiddleware creates a new UserAgentMiddleware // with the server version. func NewUserAgentMiddleware(s string) UserAgentMiddleware { return UserAgentMiddleware{ serverVersion: s, } } // WrapHandler returns a new handler function wrapping the previous one in the request chain. func (u UserAgentMiddleware) WrapHandler(handler func(ctx context.Context, w http.ResponseWriter, r *http.Request, vars map[string]string) error) func(ctx context.Context, w http.ResponseWriter, r *http.Request, vars map[string]string) error { return func(ctx context.Context, w http.ResponseWriter, r *http.Request, vars map[string]string) error { ctx = context.WithValue(ctx, httputils.UAStringKey, r.Header.Get("User-Agent")) if strings.Contains(r.Header.Get("User-Agent"), "Docker-Client/") { userAgent := strings.Split(r.Header.Get("User-Agent"), "/") // v1.20 onwards includes the GOOS of the client after the version // such as Docker/1.7.0 (linux) if len(userAgent) == 2 && strings.Contains(userAgent[1], " ") { userAgent[1] = strings.Split(userAgent[1], " ")[0] } if len(userAgent) == 2 && !versions.Equal(u.serverVersion, userAgent[1]) { logrus.Debugf("Client and server don't have the same version (client: %s, server: %s)", userAgent[1], u.serverVersion) } } return handler(ctx, w, r, vars) } }