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481 lines
15 KiB
481 lines
15 KiB
package chi
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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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"sync"
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)
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var _ Router = &Mux{}
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// Mux is a simple HTTP route multiplexer that parses a request path,
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// records any URL params, and executes an end handler. It implements
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// the http.Handler interface and is friendly with the standard library.
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//
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// Mux is designed to be fast, minimal and offer a powerful API for building
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// modular and composable HTTP services with a large set of handlers. It's
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// particularly useful for writing large REST API services that break a handler
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// into many smaller parts composed of middlewares and end handlers.
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type Mux struct {
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// The radix trie router
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tree *node
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// The middleware stack
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middlewares []func(http.Handler) http.Handler
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// Controls the behaviour of middleware chain generation when a mux
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// is registered as an inline group inside another mux.
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inline bool
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parent *Mux
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// The computed mux handler made of the chained middleware stack and
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// the tree router
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handler http.Handler
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// Routing context pool
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pool *sync.Pool
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// Custom route not found handler
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notFoundHandler http.HandlerFunc
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// Custom method not allowed handler
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methodNotAllowedHandler http.HandlerFunc
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}
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// NewMux returns a newly initialized Mux object that implements the Router
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// interface.
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func NewMux() *Mux {
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mux := &Mux{tree: &node{}, pool: &sync.Pool{}}
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mux.pool.New = func() interface{} {
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return NewRouteContext()
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}
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return mux
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}
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// ServeHTTP is the single method of the http.Handler interface that makes
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// Mux interoperable with the standard library. It uses a sync.Pool to get and
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// reuse routing contexts for each request.
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func (mx *Mux) ServeHTTP(w http.ResponseWriter, r *http.Request) {
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// Ensure the mux has some routes defined on the mux
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if mx.handler == nil {
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mx.NotFoundHandler().ServeHTTP(w, r)
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return
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}
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// Check if a routing context already exists from a parent router.
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rctx, _ := r.Context().Value(RouteCtxKey).(*Context)
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if rctx != nil {
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mx.handler.ServeHTTP(w, r)
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return
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}
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// Fetch a RouteContext object from the sync pool, and call the computed
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// mx.handler that is comprised of mx.middlewares + mx.routeHTTP.
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// Once the request is finished, reset the routing context and put it back
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// into the pool for reuse from another request.
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rctx = mx.pool.Get().(*Context)
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rctx.Reset()
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rctx.Routes = mx
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rctx.parentCtx = r.Context()
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// NOTE: r.WithContext() causes 2 allocations
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r = r.WithContext((*directContext)(rctx))
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// Serve the request and once its done, put the request context back in the sync pool
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mx.handler.ServeHTTP(w, r)
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mx.pool.Put(rctx)
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}
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// Use appends a middleware handler to the Mux middleware stack.
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//
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// The middleware stack for any Mux will execute before searching for a matching
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// route to a specific handler, which provides opportunity to respond early,
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// change the course of the request execution, or set request-scoped values for
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// the next http.Handler.
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func (mx *Mux) Use(middlewares ...func(http.Handler) http.Handler) {
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if mx.handler != nil {
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panic("chi: all middlewares must be defined before routes on a mux")
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}
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mx.middlewares = append(mx.middlewares, middlewares...)
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}
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// Handle adds the route `pattern` that matches any http method to
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// execute the `handler` http.Handler.
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func (mx *Mux) Handle(pattern string, handler http.Handler) {
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mx.handle(mALL, pattern, handler)
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}
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// HandleFunc adds the route `pattern` that matches any http method to
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// execute the `handlerFn` http.HandlerFunc.
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func (mx *Mux) HandleFunc(pattern string, handlerFn http.HandlerFunc) {
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mx.handle(mALL, pattern, handlerFn)
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}
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// Method adds the route `pattern` that matches `method` http method to
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// execute the `handler` http.Handler.
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func (mx *Mux) Method(method, pattern string, handler http.Handler) {
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m, ok := methodMap[strings.ToUpper(method)]
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if !ok {
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panic(fmt.Sprintf("chi: '%s' http method is not supported.", method))
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}
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mx.handle(m, pattern, handler)
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}
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// MethodFunc adds the route `pattern` that matches `method` http method to
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// execute the `handlerFn` http.HandlerFunc.
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func (mx *Mux) MethodFunc(method, pattern string, handlerFn http.HandlerFunc) {
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mx.Method(method, pattern, handlerFn)
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}
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// Connect adds the route `pattern` that matches a CONNECT http method to
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// execute the `handlerFn` http.HandlerFunc.
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func (mx *Mux) Connect(pattern string, handlerFn http.HandlerFunc) {
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mx.handle(mCONNECT, pattern, handlerFn)
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}
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// Delete adds the route `pattern` that matches a DELETE http method to
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// execute the `handlerFn` http.HandlerFunc.
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func (mx *Mux) Delete(pattern string, handlerFn http.HandlerFunc) {
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mx.handle(mDELETE, pattern, handlerFn)
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}
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// Get adds the route `pattern` that matches a GET http method to
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// execute the `handlerFn` http.HandlerFunc.
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func (mx *Mux) Get(pattern string, handlerFn http.HandlerFunc) {
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mx.handle(mGET, pattern, handlerFn)
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}
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// Head adds the route `pattern` that matches a HEAD http method to
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// execute the `handlerFn` http.HandlerFunc.
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func (mx *Mux) Head(pattern string, handlerFn http.HandlerFunc) {
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mx.handle(mHEAD, pattern, handlerFn)
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}
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// Options adds the route `pattern` that matches a OPTIONS http method to
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// execute the `handlerFn` http.HandlerFunc.
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func (mx *Mux) Options(pattern string, handlerFn http.HandlerFunc) {
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mx.handle(mOPTIONS, pattern, handlerFn)
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}
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// Patch adds the route `pattern` that matches a PATCH http method to
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// execute the `handlerFn` http.HandlerFunc.
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func (mx *Mux) Patch(pattern string, handlerFn http.HandlerFunc) {
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mx.handle(mPATCH, pattern, handlerFn)
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}
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// Post adds the route `pattern` that matches a POST http method to
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// execute the `handlerFn` http.HandlerFunc.
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func (mx *Mux) Post(pattern string, handlerFn http.HandlerFunc) {
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mx.handle(mPOST, pattern, handlerFn)
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}
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// Put adds the route `pattern` that matches a PUT http method to
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// execute the `handlerFn` http.HandlerFunc.
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func (mx *Mux) Put(pattern string, handlerFn http.HandlerFunc) {
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mx.handle(mPUT, pattern, handlerFn)
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}
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// Trace adds the route `pattern` that matches a TRACE http method to
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// execute the `handlerFn` http.HandlerFunc.
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func (mx *Mux) Trace(pattern string, handlerFn http.HandlerFunc) {
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mx.handle(mTRACE, pattern, handlerFn)
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}
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// NotFound sets a custom http.HandlerFunc for routing paths that could
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// not be found. The default 404 handler is `http.NotFound`.
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func (mx *Mux) NotFound(handlerFn http.HandlerFunc) {
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// Build NotFound handler chain
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m := mx
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hFn := handlerFn
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if mx.inline && mx.parent != nil {
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m = mx.parent
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hFn = Chain(mx.middlewares...).HandlerFunc(hFn).ServeHTTP
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}
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// Update the notFoundHandler from this point forward
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m.notFoundHandler = hFn
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m.updateSubRoutes(func(subMux *Mux) {
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if subMux.notFoundHandler == nil {
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subMux.NotFound(hFn)
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}
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})
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}
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// MethodNotAllowed sets a custom http.HandlerFunc for routing paths where the
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// method is unresolved. The default handler returns a 405 with an empty body.
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func (mx *Mux) MethodNotAllowed(handlerFn http.HandlerFunc) {
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// Build MethodNotAllowed handler chain
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m := mx
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hFn := handlerFn
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if mx.inline && mx.parent != nil {
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m = mx.parent
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hFn = Chain(mx.middlewares...).HandlerFunc(hFn).ServeHTTP
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}
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// Update the methodNotAllowedHandler from this point forward
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m.methodNotAllowedHandler = hFn
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m.updateSubRoutes(func(subMux *Mux) {
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if subMux.methodNotAllowedHandler == nil {
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subMux.MethodNotAllowed(hFn)
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}
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})
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}
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// With adds inline middlewares for an endpoint handler.
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func (mx *Mux) With(middlewares ...func(http.Handler) http.Handler) Router {
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// Similarly as in handle(), we must build the mux handler once additional
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// middleware registration isn't allowed for this stack, like now.
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if !mx.inline && mx.handler == nil {
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mx.updateRouteHandler()
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}
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// Copy middlewares from parent inline muxs
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var mws Middlewares
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if mx.inline {
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mws = make(Middlewares, len(mx.middlewares))
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copy(mws, mx.middlewares)
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}
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mws = append(mws, middlewares...)
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im := &Mux{
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pool: mx.pool, inline: true, parent: mx, tree: mx.tree, middlewares: mws,
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notFoundHandler: mx.notFoundHandler, methodNotAllowedHandler: mx.methodNotAllowedHandler,
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}
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return im
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}
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// Group creates a new inline-Mux with a fresh middleware stack. It's useful
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// for a group of handlers along the same routing path that use an additional
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// set of middlewares. See _examples/.
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func (mx *Mux) Group(fn func(r Router)) Router {
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im := mx.With().(*Mux)
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if fn != nil {
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fn(im)
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}
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return im
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}
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// Route creates a new Mux with a fresh middleware stack and mounts it
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// along the `pattern` as a subrouter. Effectively, this is a short-hand
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// call to Mount. See _examples/.
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func (mx *Mux) Route(pattern string, fn func(r Router)) Router {
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if fn == nil {
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panic(fmt.Sprintf("chi: attempting to Route() a nil subrouter on '%s'", pattern))
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}
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subRouter := NewRouter()
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fn(subRouter)
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mx.Mount(pattern, subRouter)
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return subRouter
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}
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// Mount attaches another http.Handler or chi Router as a subrouter along a routing
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// path. It's very useful to split up a large API as many independent routers and
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// compose them as a single service using Mount. See _examples/.
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//
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// Note that Mount() simply sets a wildcard along the `pattern` that will continue
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// routing at the `handler`, which in most cases is another chi.Router. As a result,
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// if you define two Mount() routes on the exact same pattern the mount will panic.
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func (mx *Mux) Mount(pattern string, handler http.Handler) {
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if handler == nil {
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panic(fmt.Sprintf("chi: attempting to Mount() a nil handler on '%s'", pattern))
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}
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// Provide runtime safety for ensuring a pattern isn't mounted on an existing
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// routing pattern.
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if mx.tree.findPattern(pattern+"*") || mx.tree.findPattern(pattern+"/*") {
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panic(fmt.Sprintf("chi: attempting to Mount() a handler on an existing path, '%s'", pattern))
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}
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// Assign sub-Router's with the parent not found & method not allowed handler if not specified.
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subr, ok := handler.(*Mux)
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if ok && subr.notFoundHandler == nil && mx.notFoundHandler != nil {
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subr.NotFound(mx.notFoundHandler)
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}
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if ok && subr.methodNotAllowedHandler == nil && mx.methodNotAllowedHandler != nil {
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subr.MethodNotAllowed(mx.methodNotAllowedHandler)
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}
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mountHandler := http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
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rctx := RouteContext(r.Context())
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// shift the url path past the previous subrouter
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rctx.RoutePath = mx.nextRoutePath(rctx)
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// reset the wildcard URLParam which connects the subrouter
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n := len(rctx.URLParams.Keys) - 1
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if n >= 0 && rctx.URLParams.Keys[n] == "*" && len(rctx.URLParams.Values) > n {
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rctx.URLParams.Values[n] = ""
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}
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handler.ServeHTTP(w, r)
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})
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if pattern == "" || pattern[len(pattern)-1] != '/' {
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mx.handle(mALL|mSTUB, pattern, mountHandler)
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mx.handle(mALL|mSTUB, pattern+"/", mountHandler)
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pattern += "/"
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}
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method := mALL
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subroutes, _ := handler.(Routes)
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if subroutes != nil {
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method |= mSTUB
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}
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n := mx.handle(method, pattern+"*", mountHandler)
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if subroutes != nil {
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n.subroutes = subroutes
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}
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}
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// Routes returns a slice of routing information from the tree,
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// useful for traversing available routes of a router.
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func (mx *Mux) Routes() []Route {
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return mx.tree.routes()
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}
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// Middlewares returns a slice of middleware handler functions.
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func (mx *Mux) Middlewares() Middlewares {
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return mx.middlewares
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}
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// Match searches the routing tree for a handler that matches the method/path.
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// It's similar to routing a http request, but without executing the handler
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// thereafter.
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//
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// Note: the *Context state is updated during execution, so manage
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// the state carefully or make a NewRouteContext().
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func (mx *Mux) Match(rctx *Context, method, path string) bool {
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m, ok := methodMap[method]
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if !ok {
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return false
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}
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node, _, h := mx.tree.FindRoute(rctx, m, path)
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if node != nil && node.subroutes != nil {
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rctx.RoutePath = mx.nextRoutePath(rctx)
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return node.subroutes.Match(rctx, method, rctx.RoutePath)
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}
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return h != nil
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}
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// NotFoundHandler returns the default Mux 404 responder whenever a route
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// cannot be found.
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func (mx *Mux) NotFoundHandler() http.HandlerFunc {
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if mx.notFoundHandler != nil {
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return mx.notFoundHandler
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}
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return http.NotFound
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}
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// MethodNotAllowedHandler returns the default Mux 405 responder whenever
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// a method cannot be resolved for a route.
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func (mx *Mux) MethodNotAllowedHandler() http.HandlerFunc {
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if mx.methodNotAllowedHandler != nil {
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return mx.methodNotAllowedHandler
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}
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return methodNotAllowedHandler
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}
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// handle registers a http.Handler in the routing tree for a particular http method
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// and routing pattern.
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func (mx *Mux) handle(method methodTyp, pattern string, handler http.Handler) *node {
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if len(pattern) == 0 || pattern[0] != '/' {
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panic(fmt.Sprintf("chi: routing pattern must begin with '/' in '%s'", pattern))
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}
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// Build the computed routing handler for this routing pattern.
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if !mx.inline && mx.handler == nil {
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mx.updateRouteHandler()
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}
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// Build endpoint handler with inline middlewares for the route
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var h http.Handler
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if mx.inline {
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mx.handler = http.HandlerFunc(mx.routeHTTP)
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h = Chain(mx.middlewares...).Handler(handler)
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} else {
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h = handler
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}
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// Add the endpoint to the tree and return the node
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return mx.tree.InsertRoute(method, pattern, h)
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}
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// routeHTTP routes a http.Request through the Mux routing tree to serve
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// the matching handler for a particular http method.
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func (mx *Mux) routeHTTP(w http.ResponseWriter, r *http.Request) {
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// Grab the route context object
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rctx := r.Context().Value(RouteCtxKey).(*Context)
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// The request routing path
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routePath := rctx.RoutePath
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if routePath == "" {
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if r.URL.RawPath != "" {
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routePath = r.URL.RawPath
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} else {
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routePath = r.URL.Path
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}
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}
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// Check if method is supported by chi
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if rctx.RouteMethod == "" {
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rctx.RouteMethod = r.Method
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}
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method, ok := methodMap[rctx.RouteMethod]
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if !ok {
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mx.MethodNotAllowedHandler().ServeHTTP(w, r)
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return
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}
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// Find the route
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if _, _, h := mx.tree.FindRoute(rctx, method, routePath); h != nil {
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h.ServeHTTP(w, r)
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return
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}
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if rctx.methodNotAllowed {
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mx.MethodNotAllowedHandler().ServeHTTP(w, r)
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} else {
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mx.NotFoundHandler().ServeHTTP(w, r)
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}
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}
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func (mx *Mux) nextRoutePath(rctx *Context) string {
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routePath := "/"
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nx := len(rctx.routeParams.Keys) - 1 // index of last param in list
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if nx >= 0 && rctx.routeParams.Keys[nx] == "*" && len(rctx.routeParams.Values) > nx {
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routePath = "/" + rctx.routeParams.Values[nx]
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}
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return routePath
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}
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// Recursively update data on child routers.
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func (mx *Mux) updateSubRoutes(fn func(subMux *Mux)) {
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for _, r := range mx.tree.routes() {
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subMux, ok := r.SubRoutes.(*Mux)
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if !ok {
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continue
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}
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fn(subMux)
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}
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}
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// updateRouteHandler builds the single mux handler that is a chain of the middleware
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// stack, as defined by calls to Use(), and the tree router (Mux) itself. After this
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// point, no other middlewares can be registered on this Mux's stack. But you can still
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// compose additional middlewares via Group()'s or using a chained middleware handler.
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func (mx *Mux) updateRouteHandler() {
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mx.handler = chain(mx.middlewares, http.HandlerFunc(mx.routeHTTP))
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}
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// methodNotAllowedHandler is a helper function to respond with a 405,
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// method not allowed.
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func methodNotAllowedHandler(w http.ResponseWriter, r *http.Request) {
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w.WriteHeader(405)
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w.Write(nil)
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}
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