// FilterParam adds the middleware filter iff the URL parameter exists.
func (r *Router) FilterParam(param string, filter http.HandlerFunc) {
r.Filter(func(w http.ResponseWriter, req *http.Request) {
c := context.Get(req)
if len(c.Params.Get(param)) > 0 {
filter(w, req)
}
})
}
// Required by http.Handler interface. This method is invoked by the
// http server and will handle all page routing
func (r *Router) ServeHTTP(rw http.ResponseWriter, req *http.Request) {
r.RLock()
defer r.RUnlock()
//wrap the response writer in our custom interface
w := &responseWriter{writer: rw, Router: r}
//find a matching Route
for _, route := range r.routes {
//if the methods don't match, skip this handler
//i.e if request.Method is 'PUT' Route.Method must be 'PUT'
if req.Method != route.method {
continue
}
//check if Route pattern matches url
if !route.regex.MatchString(req.URL.Path) {
continue
}
//get submatches (params)
matches := route.regex.FindStringSubmatch(req.URL.Path)
//double check that the Route matches the URL pattern.
if len(matches[0]) != len(req.URL.Path) {
continue
}
//create the http.Requests context
c := context.Get(req)
//add url parameters to the context
for i, match := range matches[1:] {
c.Params.Set(route.params[i], match)
}
//execute middleware filters
for _, filter := range r.filters {
filter(w, req)
if w.started {
return
}
}
//invoke the request handler
route.handler(w, req)
return
}
//if no matches to url, throw a not found exception
if w.started == false {
http.NotFound(w, req)
}
}
// TestFilter tests that a route is filtered prior to handling
func TestRouteFilter(t *testing.T) {
r, _ := http.NewRequest("GET", "/person/anderson/thomas?learn=kungfu", nil)
w := httptest.NewRecorder()
mux := New()
mux.Filter(HandlerSetVar)
mux.Get("/person/:last/:first", HandlerOk)
mux.ServeHTTP(w, r)
c := context.Get(r)
password := c.Values.Get("password")
if password != "z1on" {
t.Errorf("session variable set to [%s]; want [%s]", password, "z1on")
}
if w.Body.String() != "hello world" {
t.Errorf("Body set to [%s]; want [%s]", w.Body.String(), "hello world")
}
}
// TestRouteOk tests that the route is correctly handled, and the URL parameters
// are added to the Context.
func TestRouteOk(t *testing.T) {
r, _ := http.NewRequest("GET", "/person/anderson/thomas?learn=kungfu", nil)
w := httptest.NewRecorder()
mux := New()
mux.Get("/person/:last/:first", HandlerOk)
mux.ServeHTTP(w, r)
c := context.Get(r)
lastNameParam := c.Params.Get("last")
firstNameParam := c.Params.Get("first")
if lastNameParam != "anderson" {
t.Errorf("url param set to [%s]; want [%s]", lastNameParam, "anderson")
}
if firstNameParam != "thomas" {
t.Errorf("url param set to [%s]; want [%s]", firstNameParam, "thomas")
}
if w.Body.String() != "hello world" {
t.Errorf("Body set to [%s]; want [%s]", w.Body.String(), "hello world")
}
}
func HandlerSetVar(w http.ResponseWriter, r *http.Request) {
c := context.Get(r)
c.Values.Set("password", "z1on")
}