131 lines
3.8 KiB
Go
Executable file
131 lines
3.8 KiB
Go
Executable file
// Copyright 2018-2019 Martin Riedl
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package gohttprouter
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import (
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"fmt"
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"net/http"
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"strings"
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)
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// Router is the main struct for the whole routing logic.
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type Router struct {
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registry map[string]*route
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}
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// RouteHandler is the function construct called by this framework.
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type RouteHandler func(http.ResponseWriter, *http.Request, RoutingInfo)
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// RoutingInfo is returned for each web server method call and includes details abount the execution.
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type RoutingInfo struct {
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Parameters map[string]string
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}
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// Handler interface that must be implemented by custom structs.
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type Handler interface {
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ServeHTTP(http.ResponseWriter, *http.Request, RoutingInfo)
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}
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type defaultHandler struct {
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Func RouteHandler
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}
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func (handler defaultHandler) ServeHTTP(response http.ResponseWriter, request *http.Request, routingInfo RoutingInfo) {
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handler.Func(response, request, routingInfo)
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}
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// New creates a new router instance.
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func New() *Router {
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return &Router{
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registry: make(map[string]*route),
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}
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}
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// Handle registers a new handler using method and path for execution.
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func (router *Router) Handle(method string, path string, handler Handler) error {
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return router.addRoute(method, path, handler)
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}
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// HandleFunc registers a new handler function using method and path for execution.
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func (router *Router) HandleFunc(method string, path string, handler RouteHandler) error {
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newHandler := defaultHandler{Func: handler}
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return router.addRoute(method, path, newHandler)
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}
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func (router *Router) addRoute(method string, path string, handler Handler) error {
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if err := router.validateRoute(path); err != nil {
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return err
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}
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// parse path and set new handler
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route, created, _ := router.findRoute(method, path, true)
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if !created {
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return fmt.Errorf("there is already a handler registered for the path %s", path)
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}
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route.handler = handler
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return nil
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}
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func (router *Router) findRoute(method string, path string, create bool) (route *route, created bool, parameter map[string]string) {
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methodUpper := strings.ToUpper(method)
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// add method, if not already existing
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methodRoute, ok := router.registry[methodUpper]
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if !ok && !create {
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return nil, false, nil
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} else if !ok && create {
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methodRoute = newRoute()
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router.registry[methodUpper] = methodRoute
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created = true
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}
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// parse path and set new handler
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route, pathCreated, parameter := methodRoute.parsePath(path, create)
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created = created || pathCreated
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return
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}
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func (router *Router) validateRoute(path string) error {
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// path must start with a slash
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if strings.Index(path, "/") != 0 {
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return fmt.Errorf("URL path must start with a slash (/)")
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}
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// path must not end with a slash
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if len(path) > 1 && path[len(path)-1] == '/' {
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return fmt.Errorf("URL path must not end with a slash (/)")
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}
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return nil
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}
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func (router *Router) ServeHTTP(response http.ResponseWriter, request *http.Request) {
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// check for exact matching
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route, _, parameter := router.findRoute(request.Method, request.RequestURI, false)
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if route != nil && route.handler != nil {
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route.handler.ServeHTTP(response, request, RoutingInfo{Parameters: parameter})
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return
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}
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// nothing found
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http.NotFound(response, request)
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}
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// Must is a wrapper that panics if an error was returned.
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func Must(err error) {
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if err != nil {
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panic(err)
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}
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}
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