fiber/routing/router.go

// ⚡️ Fiber is an Express inspired web framework written in Go with ☕️
// 🤖 Github Repository: https://github.com/gofiber/fiber
// 📌 API Documentation: https://docs.gofiber.io

package routing

import (
	"fmt"
	"github.com/gofiber/fiber/v3"
	"html"
	"sort"
	"strconv"
	"strings"
	"sync/atomic"
	"time"

	"github.com/gofiber/utils/v2"
	"github.com/valyala/fasthttp"
)

type ExpressjsRouter struct {
	// Route stack divided by HTTP methods
	stack [][]*Route
	// Route stack divided by HTTP methods and route prefixes
	treeStack []map[string][]*Route
	// customConstraints is a list of external constraints
	customConstraints []CustomConstraint

	fiber.CommonRouterI
	fiber.Router
}

func New(RequestMethods []string) *ExpressjsRouter {
	return &ExpressjsRouter{
		stack:     make([][]*Route, len(RequestMethods)),
		treeStack: make([]map[string][]*Route, len(RequestMethods)),
	}
}

// FindNextHandler is a method that find the next handler in the stack
func (router *ExpressjsRouter) FindNextHandler(method string, path string) fiber.Handler {
	// TODO: implement this
	return nil
}

func (router *ExpressjsRouter) GetAllRoutes() []any {
	return nil
}

//region Customer ExpressjsRouter methods

// RegisterCustomConstraint allows to register custom constraint.
func (router *ExpressjsRouter) RegisterCustomConstraint(constraint CustomConstraint) {
	router.customConstraints = append(router.customConstraints, constraint)
}

//endregion

// Route is a struct that holds all metadata for each registered handler.
type Route struct {
	// ### important: always keep in sync with the copy method "app.copyRoute" ###
	// Data for routing
	pos         uint32      // Position in stack -> important for the sort of the matched routes
	use         bool        // USE matches path prefixes
	mount       bool        // Indicated a mounted app on a specific route
	star        bool        // Path equals '*'
	root        bool        // Path equals '/'
	path        string      // Prettified path
	routeParser routeParser // Parameter parser
	group       *Group      // Group instance. used for routes in groups

	// Public fields
	Method string `json:"method"` // HTTP method
	Name   string `json:"name"`   // Route's name
	//nolint:revive // Having both a Path (uppercase) and a path (lowercase) is fine
	Path     string          `json:"path"`   // Original registered route path
	Params   []string        `json:"params"` // Case sensitive param keys
	Handlers []fiber.Handler `json:"-"`      // Ctx handlers

	// TODO: check it
	fiber.Route
}

func (r *Route) match(detectionPath, path string, params *[fiber.MaxParams]string) bool {
	// root detectionPath check
	if r.root && detectionPath == "/" {
		return true
		// '*' wildcard matches any detectionPath
	} else if r.star {
		if len(path) > 1 {
			params[0] = path[1:]
		} else {
			params[0] = ""
		}
		return true
	}
	// Does this route have parameters
	if len(r.Params) > 0 {
		// Match params
		if match := r.routeParser.getMatch(detectionPath, path, params, r.use); match {
			// Get params from the path detectionPath
			return match
		}
	}
	// Is this route a Middleware?
	if r.use {
		// Single slash will match or detectionPath prefix
		if r.root || strings.HasPrefix(detectionPath, r.path) {
			return true
		}
		// Check for a simple detectionPath match
	} else if len(r.path) == len(detectionPath) && r.path == detectionPath {
		return true
	}
	// No match
	return false
}

func (app *fiber.App) nextCustom(c fiber.CustomCtx) (bool, error) { //nolint: unparam // bool param might be useful for testing
	// Get stack length
	tree, ok := app.treeStack[c.getMethodINT()][c.getTreePath()]
	if !ok {
		tree = app.treeStack[c.getMethodINT()][""]
	}
	lenr := len(tree) - 1

	//region TODO: interface for this part which loop over the routes and make the matching
	// Loop over the route stack starting from previous index
	for c.getIndexRoute() < lenr {
		// Increment route index
		c.setIndexRoute(c.getIndexRoute() + 1)

		// Get *Route
		route := tree[c.getIndexRoute()]

		// Check if it matches the request path
		match := route.match(c.getDetectionPath(), c.Path(), c.getValues())

		// No match, next route
		if !match {
			continue
		}
		// Pass route reference and param values
		c.setRoute(route)

		// Non use handler matched
		if !c.getMatched() && !route.use {
			c.setMatched(true)
		}

		// Execute first handler of route
		c.setIndexHandler(0)
		err := route.Handlers[0](c)
		return match, err // Stop scanning the stack
	}
	//endregion

	// If c.Next() does not match, return 404
	err := fiber.NewError(fiber.StatusNotFound, "Cannot "+c.Method()+" "+c.getPathOriginal())

	// If no match, scan stack again if other methods match the request
	// Moved from app.handler because middleware may break the route chain
	if !c.getMatched() && app.methodExistCustom(c) {
		err = fiber.ErrMethodNotAllowed
	}
	return false, err
}

func (app *fiber.App) next(c *fiber.DefaultCtx) (bool, error) {
	// Get stack length
	tree, ok := app.treeStack[c.methodINT][c.treePath]
	if !ok {
		tree = app.treeStack[c.methodINT][""]
	}
	lenTree := len(tree) - 1

	// Loop over the route stack starting from previous index
	for c.indexRoute < lenTree {
		// Increment route index
		c.indexRoute++

		// Get *Route
		route := tree[c.indexRoute]

		var match bool
		var err error
		// skip for mounted apps
		if route.mount {
			continue
		}

		// Check if it matches the request path
		match = route.match(c.detectionPath, c.path, &c.values)
		if !match {
			// No match, next route
			continue
		}
		// Pass route reference and param values
		c.route = route

		// Non use handler matched
		if !c.matched && !route.use {
			c.matched = true
		}

		// Execute first handler of route
		c.indexHandler = 0
		if len(route.Handlers) > 0 {
			err = route.Handlers[0](c)
		}
		return match, err // Stop scanning the stack
	}

	// If c.Next() does not match, return 404
	err := fiber.NewError(fiber.StatusNotFound, "Cannot "+c.method+" "+html.EscapeString(c.pathOriginal))
	if !c.matched && app.methodExist(c) {
		// If no match, scan stack again if other methods match the request
		// Moved from app.handler because middleware may break the route chain
		err = fiber.ErrMethodNotAllowed
	}
	return false, err
}

func (router *ExpressjsRouter) ConfigureRoute(config fiber.Config, prefix string, route *Route) *Route {
	prefixedPath := fiber.GetGroupPath(prefix, route.Path)
	prettyPath := prefixedPath
	// Case-sensitive routing, all to lowercase
	if !config.CaseSensitive {
		prettyPath = utils.ToLower(prettyPath)
	}
	// Strict routing, remove trailing slashes
	if !config.StrictRouting && len(prettyPath) > 1 {
		prettyPath = strings.TrimRight(prettyPath, "/")
	}

	route.Path = prefixedPath
	route.path = RemoveEscapeChar(prettyPath)
	route.routeParser = parseRoute(prettyPath, router.customConstraints...)
	route.root = false
	route.star = false

	return route
}

func (router *ExpressjsRouter) CopyRoute(route *Route) *Route {
	return &Route{
		// CommonRouterI booleans
		use:   route.use,
		mount: route.mount,
		star:  route.star,
		root:  route.root,

		// Path data
		path:        route.path,
		routeParser: route.routeParser,

		// misc
		pos: route.pos,

		// Public data
		Path:     route.Path,
		Params:   route.Params,
		Name:     route.Name,
		Method:   route.Method,
		Handlers: route.Handlers,
	}
}

// TODO: make it changeable -> api for outside
func (app *fiber.App) register(methods []string, pathRaw string, group *Group, handler fiber.Handler, middleware ...fiber.Handler) {
	handlers := middleware
	if handler != nil {
		handlers = append(handlers, handler)
	}

	for _, method := range methods {
		// Uppercase HTTP methods
		method = utils.ToUpper(method)
		// Check if the HTTP method is valid unless it's USE
		if method != fiber.methodUse && app.methodInt(method) == -1 {
			panic(fmt.Sprintf("add: invalid http method %s\n", method))
		}
		// is mounted app
		isMount := group != nil && group.app != app
		// A route requires atleast one ctx handler
		if len(handlers) == 0 && !isMount {
			panic(fmt.Sprintf("missing handler/middleware in route: %s\n", pathRaw))
		}
		// Cannot have an empty path
		if pathRaw == "" {
			pathRaw = "/"
		}
		// Path always start with a '/'
		if pathRaw[0] != '/' {
			pathRaw = "/" + pathRaw
		}
		// Create a stripped path in-case sensitive / trailing slashes
		pathPretty := pathRaw
		// Case-sensitive routing, all to lowercase
		if !app.config.CaseSensitive {
			pathPretty = utils.ToLower(pathPretty)
		}
		// Strict routing, remove trailing slashes
		if !app.config.StrictRouting && len(pathPretty) > 1 {
			pathPretty = strings.TrimRight(pathPretty, "/")
		}
		// Is layer a middleware?
		isUse := method == fiber.methodUse
		// Is path a direct wildcard?
		isStar := pathPretty == "/*"
		// Is path a root slash?
		isRoot := pathPretty == "/"
		// Parse path parameters
		parsedRaw := parseRoute(pathRaw)
		parsedPretty := parseRoute(pathPretty)

		// Create route metadata without pointer
		route := Route{
			// CommonRouterI booleans
			use:   isUse,
			mount: isMount,
			star:  isStar,
			root:  isRoot,

			// Path data
			path:        RemoveEscapeChar(pathPretty),
			routeParser: parsedPretty,
			Params:      parsedRaw.params,

			// Group data
			group: group,

			// Public data
			Path:     pathRaw,
			Method:   method,
			Handlers: handlers,
		}
		// Increment global handler count
		atomic.AddUint32(&app.handlersCount, uint32(len(handlers)))

		// Middleware route matches all HTTP methods
		if isUse {
			// Add route to all HTTP methods stack
			for _, m := range app.config.RequestMethods {
				// Create a route copy to avoid duplicates during compression
				r := route
				app.addRoute(m, &r, isMount)
			}
		} else {
			// Add route to stack
			app.addRoute(method, &route, isMount)
		}
	}
}

func (app *fiber.App) registerStatic(prefix, root string, config ...fiber.Static) {
	// For security, we want to restrict to the current work directory.
	if root == "" {
		root = "."
	}
	// Cannot have an empty prefix
	if prefix == "" {
		prefix = "/"
	}
	// Prefix always start with a '/' or '*'
	if prefix[0] != '/' {
		prefix = "/" + prefix
	}
	// in case-sensitive routing, all to lowercase
	if !app.config.CaseSensitive {
		prefix = utils.ToLower(prefix)
	}
	// Strip trailing slashes from the root path
	if len(root) > 0 && root[len(root)-1] == '/' {
		root = root[:len(root)-1]
	}
	// Is prefix a direct wildcard?
	isStar := prefix == "/*"
	// Is prefix a root slash?
	isRoot := prefix == "/"
	// Is prefix a partial wildcard?
	if strings.Contains(prefix, "*") {
		// /john* -> /john
		isStar = true
		prefix = strings.Split(prefix, "*")[0]
		// Fix this later
	}
	prefixLen := len(prefix)
	if prefixLen > 1 && prefix[prefixLen-1:] == "/" {
		// /john/ -> /john
		prefixLen--
		prefix = prefix[:prefixLen]
	}
	const cacheDuration = 10 * time.Second
	// Fileserver settings
	fs := &fasthttp.FS{
		Root:                 root,
		AllowEmptyRoot:       true,
		GenerateIndexPages:   false,
		AcceptByteRange:      false,
		Compress:             false,
		CompressedFileSuffix: app.config.CompressedFileSuffix,
		CacheDuration:        cacheDuration,
		IndexNames:           []string{"index.html"},
		PathRewrite: func(fctx *fasthttp.RequestCtx) []byte {
			path := fctx.Path()
			if len(path) >= prefixLen {
				if isStar && app.getString(path[0:prefixLen]) == prefix {
					path = append(path[0:0], '/')
				} else {
					path = path[prefixLen:]
					if len(path) == 0 || path[len(path)-1] != '/' {
						path = append(path, '/')
					}
				}
			}
			if len(path) > 0 && path[0] != '/' {
				path = append([]byte("/"), path...)
			}
			return path
		},
		PathNotFound: func(fctx *fasthttp.RequestCtx) {
			fctx.Response.SetStatusCode(fiber.StatusNotFound)
		},
	}

	// Set config if provided
	var cacheControlValue string
	var modifyResponse fiber.Handler
	if len(config) > 0 {
		maxAge := config[0].MaxAge
		if maxAge > 0 {
			cacheControlValue = "public, max-age=" + strconv.Itoa(maxAge)
		}
		fs.CacheDuration = config[0].CacheDuration
		fs.Compress = config[0].Compress
		fs.AcceptByteRange = config[0].ByteRange
		fs.GenerateIndexPages = config[0].Browse
		if config[0].Index != "" {
			fs.IndexNames = []string{config[0].Index}
		}
		modifyResponse = config[0].ModifyResponse
	}
	fileHandler := fs.NewRequestHandler()
	handler := func(c fiber.Ctx) error {
		// Don't execute middleware if Next returns true
		if len(config) != 0 && config[0].Next != nil && config[0].Next(c) {
			return c.Next()
		}
		// Serve file
		fileHandler(c.Context())
		// Sets the response Content-Disposition header to attachment if the Download option is true
		if len(config) > 0 && config[0].Download {
			c.Attachment()
		}
		// Return request if found and not forbidden
		status := c.Context().Response.StatusCode()
		if status != fiber.StatusNotFound && status != fiber.StatusForbidden {
			if len(cacheControlValue) > 0 {
				c.Context().Response.Header.Set(fiber.HeaderCacheControl, cacheControlValue)
			}
			if modifyResponse != nil {
				return modifyResponse(c)
			}
			return nil
		}
		// Reset response to default
		c.Context().SetContentType("") // Issue #420
		c.Context().Response.SetStatusCode(fiber.StatusOK)
		c.Context().Response.SetBodyString("")
		// Next middleware
		return c.Next()
	}

	// Create route metadata without pointer
	route := Route{
		// CommonRouterI booleans
		use:  true,
		root: isRoot,
		path: prefix,
		// Public data
		Method:   fiber.MethodGet,
		Path:     prefix,
		Handlers: []fiber.Handler{handler},
	}
	// Increment global handler count
	atomic.AddUint32(&app.handlersCount, 1)
	// Add route to stack
	app.addRoute(fiber.MethodGet, &route)
	// Add HEAD route
	app.addRoute(fiber.MethodHead, &route)
}

// TODO: add to registering module
func (app *fiber.App) addRoute(method string, route *Route, isMounted ...bool) {
	// Check mounted routes
	var mounted bool
	if len(isMounted) > 0 {
		mounted = isMounted[0]
	}

	// Get unique HTTP method identifier
	m := app.methodInt(method)

	// prevent identically route registration
	l := len(app.stack[m])
	if l > 0 && app.stack[m][l-1].Path == route.Path && route.use == app.stack[m][l-1].use && !route.mount && !app.stack[m][l-1].mount {
		preRoute := app.stack[m][l-1]
		preRoute.Handlers = append(preRoute.Handlers, route.Handlers...)
	} else {
		// Increment global route position
		route.pos = atomic.AddUint32(&app.routesCount, 1)
		route.Method = method
		// Add route to the stack
		app.stack[m] = append(app.stack[m], route)
		app.routesRefreshed = true
	}

	// Execute onRoute hooks & change latestRoute if not adding mounted route
	if !mounted {
		app.mutex.Lock()
		app.latestRoute = route
		if err := app.hooks.executeOnRouteHooks(*route); err != nil {
			panic(err)
		}
		app.mutex.Unlock()
	}
}

// buildTree build the prefix tree from the previously registered routes
func (app *fiber.App) buildTree() *fiber.App {
	if !app.routesRefreshed {
		return app
	}

	// loop all the methods and stacks and create the prefix tree
	for m := range app.config.RequestMethods {
		tsMap := make(map[string][]*Route)
		for _, route := range app.stack[m] {
			treePath := ""
			if len(route.routeParser.segs) > 0 && len(route.routeParser.segs[0].Const) >= 3 {
				treePath = route.routeParser.segs[0].Const[:3]
			}
			// create tree stack
			tsMap[treePath] = append(tsMap[treePath], route)
		}
		app.treeStack[m] = tsMap
	}

	// loop the methods and tree stacks and add global stack and sort everything
	for m := range app.config.RequestMethods {
		tsMap := app.treeStack[m]
		for treePart := range tsMap {
			if treePart != "" {
				// merge global tree routes in current tree stack
				tsMap[treePart] = fiber.uniqueRouteStack(append(tsMap[treePart], tsMap[""]...))
			}
			// sort tree slices with the positions
			slc := tsMap[treePart]
			sort.Slice(slc, func(i, j int) bool { return slc[i].pos < slc[j].pos })
		}
	}
	app.routesRefreshed = false

	return app
}