package http import ( "fmt" "net/http" "sort" "github.com/rs/zerolog/log" "github.com/traefik/traefik/v2/pkg/rules" "github.com/vulcand/predicate" ) // Muxer handles routing with rules. type Muxer struct { routes routes parser predicate.Parser } // NewMuxer returns a new muxer instance. func NewMuxer() (*Muxer, error) { var matchers []string for matcher := range httpFuncs { matchers = append(matchers, matcher) } parser, err := rules.NewParser(matchers) if err != nil { return nil, fmt.Errorf("error while creating parser: %w", err) } return &Muxer{ parser: parser, }, nil } // ServeHTTP forwards the connection to the matching HTTP handler. // Serves 404 if no handler is found. func (m *Muxer) ServeHTTP(rw http.ResponseWriter, req *http.Request) { for _, route := range m.routes { if route.matchers.match(req) { route.handler.ServeHTTP(rw, req) return } } http.NotFoundHandler().ServeHTTP(rw, req) } // AddRoute add a new route to the router. func (m *Muxer) AddRoute(rule string, priority int, handler http.Handler) error { parse, err := m.parser.Parse(rule) if err != nil { return fmt.Errorf("error while parsing rule %s: %w", rule, err) } buildTree, ok := parse.(rules.TreeBuilder) if !ok { return fmt.Errorf("error while parsing rule %s", rule) } var matchers matchersTree err = matchers.addRule(buildTree()) if err != nil { return fmt.Errorf("error while adding rule %s: %w", rule, err) } if priority == 0 { priority = len(rule) } m.routes = append(m.routes, &route{ handler: handler, matchers: matchers, priority: priority, }) sort.Sort(m.routes) return nil } // ParseDomains extract domains from rule. func ParseDomains(rule string) ([]string, error) { var matchers []string for matcher := range httpFuncs { matchers = append(matchers, matcher) } parser, err := rules.NewParser(matchers) if err != nil { return nil, fmt.Errorf("error while creating parser: %w", err) } parse, err := parser.Parse(rule) if err != nil { return nil, fmt.Errorf("error while parsing rule %s: %w", rule, err) } buildTree, ok := parse.(rules.TreeBuilder) if !ok { return nil, fmt.Errorf("error while parsing rule %s", rule) } return buildTree().ParseMatchers([]string{"Host"}), nil } // routes implements sort.Interface. type routes []*route // Len implements sort.Interface. func (r routes) Len() int { return len(r) } // Swap implements sort.Interface. func (r routes) Swap(i, j int) { r[i], r[j] = r[j], r[i] } // Less implements sort.Interface. func (r routes) Less(i, j int) bool { return r[i].priority > r[j].priority } // route holds the matchers to match HTTP route, // and the handler that will serve the request. type route struct { // matchers tree structure reflecting the rule. matchers matchersTree // handler responsible for handling the route. handler http.Handler // priority is used to disambiguate between two (or more) rules that would all match for a given request. // Computed from the matching rule length, if not user-set. priority int } // matchersTree represents the matchers tree structure. type matchersTree struct { // matcher is a matcher func used to match HTTP request properties. // If matcher is not nil, it means that this matcherTree is a leaf of the tree. // It is therefore mutually exclusive with left and right. matcher func(*http.Request) bool // operator to combine the evaluation of left and right leaves. operator string // Mutually exclusive with matcher. left *matchersTree right *matchersTree } func (m *matchersTree) match(req *http.Request) bool { if m == nil { // This should never happen as it should have been detected during parsing. log.Warn().Msg("Rule matcher is nil") return false } if m.matcher != nil { return m.matcher(req) } switch m.operator { case "or": return m.left.match(req) || m.right.match(req) case "and": return m.left.match(req) && m.right.match(req) default: // This should never happen as it should have been detected during parsing. log.Warn().Str("operator", m.operator).Msg("Invalid rule operator") return false } } func (m *matchersTree) addRule(rule *rules.Tree) error { switch rule.Matcher { case "and", "or": m.operator = rule.Matcher m.left = &matchersTree{} err := m.left.addRule(rule.RuleLeft) if err != nil { return fmt.Errorf("error while adding rule %s: %w", rule.Matcher, err) } m.right = &matchersTree{} return m.right.addRule(rule.RuleRight) default: err := rules.CheckRule(rule) if err != nil { return fmt.Errorf("error while checking rule %s: %w", rule.Matcher, err) } err = httpFuncs[rule.Matcher](m, rule.Value...) if err != nil { return fmt.Errorf("error while adding rule %s: %w", rule.Matcher, err) } if rule.Not { matcherFunc := m.matcher m.matcher = func(req *http.Request) bool { return !matcherFunc(req) } } } return nil }