Global refactoring

router/router.go

@@ -0,0 +1,108 @@
+package router
+
+import (
+	"net/http"
+	"regexp"
+	"strings"
+
+	nanoid "github.com/matoous/go-nanoid/v2"
+	log "github.com/sirupsen/logrus"
+)
+
+const (
+	xRequestIDHeader = "X-Request-ID"
+)
+
+var (
+	requestIDRe = regexp.MustCompile(`^[A-Za-z0-9_\-]+$`)
+)
+
+type RouteHandler func(string, http.ResponseWriter, *http.Request)
+type PanicHandler func(string, http.ResponseWriter, *http.Request, error)
+
+type route struct {
+	Method  string
+	Prefix  string
+	Handler RouteHandler
+	Exact   bool
+}
+
+type Router struct {
+	prefix       string
+	Routes       []*route
+	PanicHandler PanicHandler
+}
+
+func (r *route) isMatch(req *http.Request) bool {
+	if r.Method != req.Method {
+		return false
+	}
+
+	if r.Exact {
+		return req.URL.Path == r.Prefix
+	}
+
+	return strings.HasPrefix(req.URL.Path, r.Prefix)
+}
+
+func New(prefix string) *Router {
+	return &Router{
+		prefix: prefix,
+		Routes: make([]*route, 0),
+	}
+}
+
+func (r *Router) Add(method, prefix string, handler RouteHandler, exact bool) {
+	r.Routes = append(
+		r.Routes,
+		&route{Method: method, Prefix: r.prefix + prefix, Handler: handler, Exact: exact},
+	)
+}
+
+func (r *Router) GET(prefix string, handler RouteHandler, exact bool) {
+	r.Add(http.MethodGet, prefix, handler, exact)
+}
+
+func (r *Router) OPTIONS(prefix string, handler RouteHandler, exact bool) {
+	r.Add(http.MethodOptions, prefix, handler, exact)
+}
+
+func (r *Router) HEAD(prefix string, handler RouteHandler, exact bool) {
+	r.Add(http.MethodHead, prefix, handler, exact)
+}
+
+func (r *Router) ServeHTTP(rw http.ResponseWriter, req *http.Request) {
+	req = setRequestTime(req)
+
+	reqID := req.Header.Get(xRequestIDHeader)
+
+	if len(reqID) == 0 || !requestIDRe.MatchString(reqID) {
+		reqID, _ = nanoid.New()
+	}
+
+	rw.Header().Set("Server", "imgproxy")
+	rw.Header().Set(xRequestIDHeader, reqID)
+
+	defer func() {
+		if rerr := recover(); rerr != nil {
+			if err, ok := rerr.(error); ok && r.PanicHandler != nil {
+				r.PanicHandler(reqID, rw, req, err)
+			} else {
+				panic(rerr)
+			}
+		}
+	}()
+
+	LogRequest(reqID, req)
+
+	for _, rr := range r.Routes {
+		if rr.isMatch(req) {
+			rr.Handler(reqID, rw, req)
+			return
+		}
+	}
+
+	log.Warningf("Route for %s is not defined", req.URL.Path)
+
+	rw.WriteHeader(404)
+}