gin/routergroup.go

// Copyright 2014 Manu Martinez-Almeida.  All rights reserved.
// Use of this source code is governed by a MIT style
// license that can be found in the LICENSE file.

package gin

import (
	"net/http"
	"path"
	"regexp"
	"strings"
)

type (
	RoutesInterface interface {
		routesInterface
		Group(string, ...HandlerFunc) *RouterGroup
	}

	routesInterface interface {
		Use(...HandlerFunc) routesInterface

		Handle(string, string, ...HandlerFunc) routesInterface
		Any(string, ...HandlerFunc) routesInterface
		GET(string, ...HandlerFunc) routesInterface
		POST(string, ...HandlerFunc) routesInterface
		DELETE(string, ...HandlerFunc) routesInterface
		PATCH(string, ...HandlerFunc) routesInterface
		PUT(string, ...HandlerFunc) routesInterface
		OPTIONS(string, ...HandlerFunc) routesInterface
		HEAD(string, ...HandlerFunc) routesInterface

		StaticFile(string, string) routesInterface
		Static(string, string) routesInterface
		StaticFS(string, http.FileSystem) routesInterface
	}

	// Used internally to configure router, a RouterGroup is associated with a prefix
	// and an array of handlers (middlewares)
	RouterGroup struct {
		Handlers HandlersChain
		BasePath string
		engine   *Engine
		root     bool
	}
)

var _ RoutesInterface = &RouterGroup{}

// Adds middlewares to the group, see example code in github.
func (group *RouterGroup) Use(middlewares ...HandlerFunc) routesInterface {
	group.Handlers = append(group.Handlers, middlewares...)
	return group.returnObj()
}

// Creates a new router group. You should add all the routes that have common middlwares or the same path prefix.
// For example, all the routes that use a common middlware for authorization could be grouped.
func (group *RouterGroup) Group(relativePath string, handlers ...HandlerFunc) *RouterGroup {
	return &RouterGroup{
		Handlers: group.combineHandlers(handlers),
		BasePath: group.calculateAbsolutePath(relativePath),
		engine:   group.engine,
	}
}

// Handle registers a new request handle and middlewares with the given path and method.
// The last handler should be the real handler, the other ones should be middlewares that can and should be shared among different routes.
// See the example code in github.
//
// For GET, POST, PUT, PATCH and DELETE requests the respective shortcut
// functions can be used.
//
// This function is intended for bulk loading and to allow the usage of less
// frequently used, non-standardized or custom methods (e.g. for internal
// communication with a proxy).
func (group *RouterGroup) handle(httpMethod, relativePath string, handlers HandlersChain) routesInterface {
	absolutePath := group.calculateAbsolutePath(relativePath)
	handlers = group.combineHandlers(handlers)
	group.engine.addRoute(httpMethod, absolutePath, handlers)
	return group.returnObj()
}

func (group *RouterGroup) Handle(httpMethod, relativePath string, handlers ...HandlerFunc) routesInterface {
	if matches, err := regexp.MatchString("^[A-Z]+$", httpMethod); !matches || err != nil {
		panic("http method " + httpMethod + " is not valid")
	}
	return group.handle(httpMethod, relativePath, handlers)
}

// POST is a shortcut for router.Handle("POST", path, handle)
func (group *RouterGroup) POST(relativePath string, handlers ...HandlerFunc) routesInterface {
	return group.handle("POST", relativePath, handlers)
}

// GET is a shortcut for router.Handle("GET", path, handle)
func (group *RouterGroup) GET(relativePath string, handlers ...HandlerFunc) routesInterface {
	return group.handle("GET", relativePath, handlers)
}

// DELETE is a shortcut for router.Handle("DELETE", path, handle)
func (group *RouterGroup) DELETE(relativePath string, handlers ...HandlerFunc) routesInterface {
	return group.handle("DELETE", relativePath, handlers)
}

// PATCH is a shortcut for router.Handle("PATCH", path, handle)
func (group *RouterGroup) PATCH(relativePath string, handlers ...HandlerFunc) routesInterface {
	return group.handle("PATCH", relativePath, handlers)
}

// PUT is a shortcut for router.Handle("PUT", path, handle)
func (group *RouterGroup) PUT(relativePath string, handlers ...HandlerFunc) routesInterface {
	return group.handle("PUT", relativePath, handlers)
}

// OPTIONS is a shortcut for router.Handle("OPTIONS", path, handle)
func (group *RouterGroup) OPTIONS(relativePath string, handlers ...HandlerFunc) routesInterface {
	return group.handle("OPTIONS", relativePath, handlers)
}

// HEAD is a shortcut for router.Handle("HEAD", path, handle)
func (group *RouterGroup) HEAD(relativePath string, handlers ...HandlerFunc) routesInterface {
	return group.handle("HEAD", relativePath, handlers)
}

func (group *RouterGroup) Any(relativePath string, handlers ...HandlerFunc) routesInterface {
	// GET, POST, PUT, PATCH, HEAD, OPTIONS, DELETE, CONNECT, TRACE
	group.handle("GET", relativePath, handlers)
	group.handle("POST", relativePath, handlers)
	group.handle("PUT", relativePath, handlers)
	group.handle("PATCH", relativePath, handlers)
	group.handle("HEAD", relativePath, handlers)
	group.handle("OPTIONS", relativePath, handlers)
	group.handle("DELETE", relativePath, handlers)
	group.handle("CONNECT", relativePath, handlers)
	group.handle("TRACE", relativePath, handlers)
	return group.returnObj()
}

func (group *RouterGroup) StaticFile(relativePath, filepath string) routesInterface {
	if strings.Contains(relativePath, ":") || strings.Contains(relativePath, "*") {
		panic("URL parameters can not be used when serving a static file")
	}
	handler := func(c *Context) {
		c.File(filepath)
	}
	group.GET(relativePath, handler)
	group.HEAD(relativePath, handler)
	return group.returnObj()
}

// Static serves files from the given file system root.
// Internally a http.FileServer is used, therefore http.NotFound is used instead
// of the Router's NotFound handler.
// To use the operating system's file system implementation,
// use :
//     router.Static("/static", "/var/www")
func (group *RouterGroup) Static(relativePath, root string) routesInterface {
	return group.StaticFS(relativePath, Dir(root, false))
}

func (group *RouterGroup) StaticFS(relativePath string, fs http.FileSystem) routesInterface {
	if strings.Contains(relativePath, ":") || strings.Contains(relativePath, "*") {
		panic("URL parameters can not be used when serving a static folder")
	}
	handler := group.createStaticHandler(relativePath, fs)
	urlPattern := path.Join(relativePath, "/*filepath")

	// Register GET and HEAD handlers
	group.GET(urlPattern, handler)
	group.HEAD(urlPattern, handler)
	return group.returnObj()
}

func (group *RouterGroup) createStaticHandler(relativePath string, fs http.FileSystem) HandlerFunc {
	absolutePath := group.calculateAbsolutePath(relativePath)
	fileServer := http.StripPrefix(absolutePath, http.FileServer(fs))
	_, nolisting := fs.(*onlyfilesFS)
	return func(c *Context) {
		if nolisting {
			c.Writer.WriteHeader(404)
		}
		fileServer.ServeHTTP(c.Writer, c.Request)
	}
}

func (group *RouterGroup) combineHandlers(handlers HandlersChain) HandlersChain {
	finalSize := len(group.Handlers) + len(handlers)
	if finalSize >= int(AbortIndex) {
		panic("too many handlers")
	}
	mergedHandlers := make(HandlersChain, finalSize)
	copy(mergedHandlers, group.Handlers)
	copy(mergedHandlers[len(group.Handlers):], handlers)
	return mergedHandlers
}

func (group *RouterGroup) calculateAbsolutePath(relativePath string) string {
	return joinPaths(group.BasePath, relativePath)
}

func (group *RouterGroup) returnObj() routesInterface {
	if group.root {
		return group.engine
	} else {
		return group
	}
}