diff --git a/router.go b/router.go index 9fe3ac8..e7a1829 100644 --- a/router.go +++ b/router.go @@ -23,18 +23,30 @@ type Router struct { routes []route } +// endpoint is comes at the end of each valid path in the tree. It contains the information you +// need to call the endpoint, including path parameter names. +type endpoint struct { + callback http.HandlerFunc + path string + pathParams []string +} + +// route is not part of the tree, but is saved on the router to represent all the available +// routes in the tree. type route struct { callback http.HandlerFunc method string path string } +// segment is a tree node. It can have children, or endpoints, or both attached to it. It also +// has a special child called "parameter" which represents a path parameter. If a route string +// doesn't match any of the children, and there is a parameter child present, it will match that +// parameter child. type segment struct { - children map[string]*segment - methods map[string]http.HandlerFunc - path string - parameter *segment - parameterName string + children map[string]*segment + endpoints map[string]*endpoint + parameter *segment } // NotFoundHandler is the default function for handling routes that are not found. If you wish to @@ -49,12 +61,12 @@ var NotFoundHandler http.Handler = http.HandlerFunc( // method already have a callback registered to them, an error is returned. func (r *Router) AddRoute(method string, path string, callback http.HandlerFunc) (err error) { keys := setupKeys(strings.Split(path, "/")) + pathParams := []string{} if r.root == nil { r.root = &segment{} r.root.children = map[string]*segment{} - r.root.methods = map[string]http.HandlerFunc{} - r.root.path = "/" + r.root.endpoints = map[string]*endpoint{} } curr := r.root @@ -64,7 +76,12 @@ func (r *Router) AddRoute(method string, path string, callback http.HandlerFunc) continue } - if child, ok := curr.children[key]; !ok { + if isParameter(key) { + pathParams = append(pathParams, key[2:]) + + } + + if child, _ := getChild(key, curr); child == nil { seg := addSegment(curr, key) curr = seg } else { @@ -72,18 +89,43 @@ func (r *Router) AddRoute(method string, path string, callback http.HandlerFunc) } } - if _, ok := curr.methods[method]; ok { + if _, ok := curr.endpoints[method]; ok { err = errors.New("path already exists") return } - curr.methods[method] = callback + curr.endpoints[method] = &endpoint{callback, path, pathParams} r.routes = append(r.routes, route{callback, method, path}) return } +// PathParams takes a path and returns the values for any path parameters +// in the path. +func (r *Router) PathParams(method string, reqPath string) (params map[string]string, err error) { + end, err := r.getEndpoint(method, reqPath) + path := end.path + + reqParts := strings.Split(reqPath, "/") + reqKeys := setupKeys(reqParts) + + pathParts := strings.Split(path, "/") + pathKeys := setupKeys(pathParts) + + params = map[string]string{} + + for i, pathKey := range pathKeys { + if isParameter(pathKey) { + name := pathKey[2:] + value := reqKeys[i][1:] + params[name] = value + } + } + + return +} + // Get is a convinience method which calls Router.AddRoute with the "GET" method. func (r *Router) Get(path string, callback http.HandlerFunc) { r.AddRoute(http.MethodGet, path, callback) @@ -99,33 +141,16 @@ func (r *Router) Get(path string, callback http.HandlerFunc) { func (r *Router) Handler(req *http.Request) (h http.Handler, pattern string) { method := req.Method path := req.URL.Path - root := r.root - curr := root - - segments := strings.Split(path, "/") - keys := setupKeys(segments) if r.NotFoundHandler == nil { h = NotFoundHandler } - for _, v := range keys { - if v == "/" { - continue - } + endpoint, err := r.getEndpoint(method, path) - seg := getChild(v, curr) - - if seg == nil { - return - } - - curr = seg - } - - if cb, ok := curr.methods[method]; ok { - h = cb - pattern = curr.path + if err == nil { + h = endpoint.callback + pattern = endpoint.path } return @@ -137,25 +162,26 @@ func (r *Router) Handler(req *http.Request) (h http.Handler, pattern string) { // // In the case of this router, all it needs to do is lookup the Handler that has been saved at a given // path and then call its ServeHTTP. -func (r Router) ServeHTTP(w http.ResponseWriter, req *http.Request) { +func (r *Router) ServeHTTP(w http.ResponseWriter, req *http.Request) { handler, _ := r.Handler(req) handler.ServeHTTP(w, req) return } +// addSegment create a new segment either as a child or as a parameter depending on whether the key +// qualifies as a parameter. A pointer to the created segment is then returned. func addSegment(curr *segment, key string) (seg *segment) { - if curr.parameterName == key { + if curr.parameter != nil { seg = curr.parameter } else if child, ok := curr.children[key]; !ok { // child does not match... var isParam bool - seg, isParam = newSegment(curr.path, key) + seg, isParam = newSegment(key) if isParam { curr.parameter = seg - curr.parameterName = key[2:] } else { curr.children[key] = seg @@ -170,33 +196,60 @@ func addSegment(curr *segment, key string) (seg *segment) { return } -func getChild(key string, curr *segment) (child *segment) { +// getChild takes a path part and finds the appropriate segment child for it. If it is an exact match to a +// child on the segment, then that child segment is returned. If it is not a match, then the parameter child +// is returned. If there is no parameter child, nil is returned. isParam is true if the parameter child is +// being returned. +func getChild(key string, curr *segment) (child *segment, isParam bool) { if seg, ok := curr.children[key]; ok { // is there an exact match? - child = seg + } else if curr.parameter != nil { // could this be a parameter? child = curr.parameter - + isParam = true } return } -func newSegment(parentPath string, key string) (seg *segment, isParam bool) { - var path string +// getEndpoint takes a path and traverses the tree until it finds the endpoint associated with that path. +// If no endpoint if found, an error is returned. +func (r *Router) getEndpoint(method string, path string) (end *endpoint, err error) { + curr := r.root + segments := strings.Split(path, "/") + keys := setupKeys(segments) - if parentPath == "/" { - path = key + for _, v := range keys { + if v == "/" { + continue + } - } else { - path = parentPath + key + seg, _ := getChild(v, curr) + + if seg == nil { + return + } + + curr = seg } + if _, ok := curr.endpoints[method]; !ok { + err = errors.New("route not found") + } + + end = curr.endpoints[method] + + return +} + +// TODO: refactor out newSegment as it's not longer needed. + +// newSegment constructs a new, empty segment and reports back if the key is a parameter. +func newSegment(key string) (seg *segment, isParam bool) { seg = &segment{} seg.children = map[string]*segment{} - seg.methods = map[string]http.HandlerFunc{} - seg.path = path + seg.endpoints = map[string]*endpoint{} if isParameter(key) { isParam = true @@ -205,6 +258,8 @@ func newSegment(parentPath string, key string) (seg *segment, isParam bool) { return } +// setupKeys takes an array of strings representing the parts of a path, and returns a new slice +// made up of the parts with "/" prepended to each. func setupKeys(slice []string) (keys []string) { keys = append(keys, "/") for _, v := range slice { @@ -217,8 +272,8 @@ func setupKeys(slice []string) (keys []string) { } // isParameter returns true if the key is more than one character long and starts with a ':' -func isParameter(key string) (isVar bool) { - if len([]rune(key)) <= 2 { +func isParameter(key string) (isParam bool) { + if len([]rune(key)) <= 1 { return // avoid empty variables, i.e. /somepath/:/someotherpath } @@ -226,7 +281,7 @@ func isParameter(key string) (isVar bool) { return } - isVar = true + isParam = true return } diff --git a/router_test.go b/router_test.go index 8c27469..2faa5ee 100644 --- a/router_test.go +++ b/router_test.go @@ -11,7 +11,7 @@ import ( var testLevel = 1 func TestAddRouter(t *testing.T) { - describeTests("Test AddRouter function") + describeTests("Test AddRouter method") router := Router{} @@ -22,7 +22,7 @@ func TestAddRouter(t *testing.T) { } func TestServeHTTP(t *testing.T) { - describeTests("Test ServeHTTP function") + describeTests("Test ServeHTTP method") router := Router{} @@ -31,6 +31,14 @@ func TestServeHTTP(t *testing.T) { testMatchesPathParam(router, t) } +func TestPathParams(t *testing.T) { + describeTests("Test PathParams method") + + router := Router{} + + testParamValues(router, t) +} + func addAndCheckRoute(r *Router, method string, path string, callback http.HandlerFunc) (err error) { routeCount := len(r.routes) @@ -71,7 +79,7 @@ func addAndCheckRoute(r *Router, method string, path string, callback http.Handl // checkLookup prints out the various saved routes. It's not needed for any test, but is a helpful debugging tool. func checkLookup(curr *segment) { - fmt.Printf("%p { path: \"%s\", methods: %v, children: %v, parameter: %v, parameterName: \"%s\"}\n", curr, curr.path, curr.methods, curr.children, curr.parameter, curr.parameterName) + fmt.Printf("%p { methods: %v, children: %v, parameter: %v\"}\n", curr, curr.endpoints, curr.children, curr.parameter) for _, v := range curr.children { checkLookup(v) @@ -226,6 +234,52 @@ func testMatchesRoot(router Router, t *testing.T) { } } +func testParamValues(router Router, t *testing.T) { + defer testOutcome("returns param names and values", t) + + method := http.MethodOptions + path := "/users/:userID/edit/:status" + userID := "46" + status := "inactive" + expectedBody := "done" + expectedStatus := 200 + reqPath := fmt.Sprintf("/users/%s/edit/%s", userID, status) + + router.AddRoute(method, path, func(w http.ResponseWriter, r *http.Request) { + requestPath := r.URL.Path + requestMethod := r.Method + + params, err := router.PathParams(requestMethod, requestPath) + + if err != nil { + t.Error("An error occurred while getting path parameters") + } + + if len(params) != 2 { + t.Errorf("Received the wrong number of parameters. Expected 2, recieved %d", len(params)) + } + + if params["userID"] != userID { + t.Errorf("userID should be %s, but it is %s", userID, params["userID"]) + } + + if params["status"] != status { + t.Errorf("status should be %s, but it is %s", status, params["status"]) + } + + w.WriteHeader(expectedStatus) + w.Write([]byte(expectedBody)) + }) + + err := matchAndCheckRoute(&router, method, reqPath, expectedBody, expectedStatus) + + if err != nil { + t.Error("Did not find the expected callback handler", err) + + return + } +} + func testOutcome(message string, t *testing.T) { var status string