yarr/server/server.go

package server

import (
	"context"
	"regexp"
	"net/http"
)

type Route struct {
	url string
	urlRegex *regexp.Regexp
	handler func(http.ResponseWriter, *http.Request)
}

type Handler struct {
}

func p(path string, handler func(http.ResponseWriter, *http.Request)) Route {
	var urlRegexp string
	urlRegexp = regexp.MustCompile(`[\*\:]\w+`).ReplaceAllStringFunc(path, func(m string) string {
		if m[0:1] == `*` {
			return "(?P<" + m[1:] + ">.+)"
		}
		return "(?P<" + m[1:] + ">[^/]+)"
	})
	urlRegexp = "^" + urlRegexp + "$"
	return Route{
		url: path,
		urlRegex: regexp.MustCompile(urlRegexp),
		handler: handler,
	}
}

var routes []Route = []Route{
	p("/", Index),
	p("/static/*path", Static),
	p("/api/folders", FolderList),
	p("/api/folders/:id", Folder),
	p("/api/feeds", FeedList),
	p("/api/feeds/:id", Feed),
}

func Vars(req *http.Request) map[string]string {
	if rv := req.Context().Value(0); rv != nil {
		return rv.(map[string]string)
	}
	return nil
}

func (h Handler) ServeHTTP(rw http.ResponseWriter, req *http.Request) {
	for _, route := range routes {
		if route.urlRegex.MatchString(req.URL.Path) {
			if route.urlRegex.NumSubexp() > 0 {
				vars := make(map[string]string)
				matches := route.urlRegex.FindStringSubmatchIndex(req.URL.Path)
				for i, key := range route.urlRegex.SubexpNames()[1:] {
					vars[key] = req.URL.Path[matches[i*2+2]:matches[i*2+3]]
				}
				ctx := context.WithValue(req.Context(), 0, vars)
				req = req.WithContext(ctx)	
			}
			route.handler(rw, req)
			return
		}
	}
	rw.WriteHeader(http.StatusNotFound)
}

func New() *http.Server {
	h := Handler{}
	s := &http.Server{Addr: "127.0.0.1:8000", Handler: h}
	return s
}