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package router
import (
"errors"
"fmt"
"github.com/franckcuny/web-request"
"net/http"
"regexp"
"strings"
)
type Router struct {
routes []*Route
knownPaths map[string]map[string]bool
withOptions bool
notAllowed bool
}
var defaultHTTPMethods = []string{"GET", "HEAD", "PUT", "POST", "PATCH", "OPTIONS"}
var reMessyPath = regexp.MustCompile("/{2,}")
// Create a new router.
func BuildRouter() *Router {
router := Router{}
router.knownPaths = map[string]map[string]bool{}
return &router
}
// For each path, add a new route to respond to OPTIONS.
func (self *Router) AddOptions() *Router {
self.withOptions = true
routes := self.GetRouteList()
for _, r := range routes {
m := self.GetMethodsForPath(r)
allowed := strings.Join(m, ", ")
defaultFn := func(req *request.Request, resp *request.Response) error {
resp.Status = 204
resp.AddHeader("Allow", allowed)
return nil
}
self.AddRoute(&Route{Method: "OPTIONS", Path: r, Code: defaultFn})
}
return self
}
// For each path, add a route to respond 405 if the method is not implemented.
func (self *Router) AddNotAllowed() *Router {
self.notAllowed = true
routes := self.GetRouteList()
for _, r := range routes {
methods := self.GetMethodsForPath(r)
supportedMethods := map[string]bool{}
for _, m := range methods {
supportedMethods[m] = true
}
allowed := strings.Join(methods, ", ")
defaultFn := func(req *request.Request, resp *request.Response) error {
resp.Status = 405
resp.AddHeader("Allow", allowed)
return nil
}
for _, dm := range defaultHTTPMethods {
if supportedMethods[dm] == false {
self.AddRoute(&Route{Method: dm, Path: r, Code: defaultFn})
}
}
}
return self
}
func (self *Router) routeIsKnown(route *Route) bool {
if self.knownPaths[route.Path] == nil {
self.knownPaths[route.Path] = map[string]bool{}
return false
} else if self.knownPaths[route.Path][route.Method] == false {
return false
}
return true
}
// Add a route to the router.
func (self *Router) AddRoute(route *Route) error {
if self.routeIsKnown(route) == true {
return errors.New(fmt.Sprintf("The route %s with the method %s already exist.", route.Path, route.Method))
}
route.init()
self.routes = append(self.routes, route)
self.knownPaths[route.Path][route.Method] = true
return nil
}
func (self *Router) canonpath(url string) string {
url = reMessyPath.ReplaceAllString(url, "/")
return url
}
// Will try to find a route that match the HTTP Request.
func (self *Router) Match(request *http.Request) (*Match, error) {
matches := []*Match{}
method := request.Method
url := self.canonpath(request.URL.Path)
components := strings.Split(url, "/")
for _, r := range self.routes {
match := r.Match(method, components)
if match != nil {
matches = append(matches, match)
}
}
if len(matches) == 0 {
return nil, nil
} else if len(matches) == 1 {
return matches[0], nil
} else {
return self.disambiguateMatches(request.URL.Path, matches)
}
return nil, nil
}
func (self *Router) disambiguateMatches(path string, matches []*Match) (*Match, error) {
min := -1
found := []*Match{}
for _, m := range matches {
req := m.Route.requiredNamedComponents
vars := len(req)
if min == -1 || vars < min {
found = append(found, m)
min = vars
} else if vars == min {
found = append(found, m)
}
}
if len(found) > 1 {
msg := fmt.Sprintf("Ambiguous match: path %s could match any of:", path)
for _, f := range found {
msg = fmt.Sprintf("%s %s", msg, f.Route.Path)
}
err := errors.New(msg)
return nil, err
}
return found[0], nil
}
// Get a list of routes from the router.
func (self *Router) GetRouteList() []string {
routes := make([]string, len(self.knownPaths))
i := 0
for path, _ := range self.knownPaths {
routes[i] = path
i = i + 1
}
return routes
}
// Check that the router knows a given path.
func (self *Router) HasPath(path string) bool {
if self.knownPaths[path] != nil {
return true
}
return false
}
// Remove a path (and all associated routes) from the router.
func (self *Router) RemovePath(path string) error {
p := self.HasPath(path)
if p == false {
return errors.New("foo")
}
delete(self.knownPaths, path)
newRoutes := []*Route{}
for _, p := range self.routes {
if p.Path != path {
newRoutes = append(newRoutes, p)
}
}
self.routes = newRoutes
return nil
}
// Return all the routes known by the router.
func (self *Router) GetAllRoutes() []*Route {
return self.routes
}
// Return all the routes that implement the given HTTP method.
func (self *Router) GetAllRoutesByMethods(method string) []*Route {
routes := []*Route{}
for _, r := range self.routes {
if r.Method == method {
routes = append(routes, r)
}
}
return routes
}
// Return a list of HTTP methods implemented for a given path.
func (self *Router) GetMethodsForPath(path string) []string {
p := self.knownPaths[path]
m := make([]string, len(p))
i := 0
for k, _ := range p {
m[i] = k
i = i + 1
}
return m
}
|
