github.com/hellobchain/third_party@v0.0.0-20230331131523-deb0478a2e52/gorilla/mux/middleware.go (about)

     1  package mux
     2  
     3  import (
     4  	"github.com/hellobchain/newcryptosm/http"
     5  	"strings"
     6  )
     7  
     8  // MiddlewareFunc is a function which receives an http.Handler and returns another http.Handler.
     9  // Typically, the returned handler is a closure which does something with the http.ResponseWriter and http.Request passed
    10  // to it, and then calls the handler passed as parameter to the MiddlewareFunc.
    11  type MiddlewareFunc func(http.Handler) http.Handler
    12  
    13  // middleware interface is anything which implements a MiddlewareFunc named Middleware.
    14  type middleware interface {
    15  	Middleware(handler http.Handler) http.Handler
    16  }
    17  
    18  // Middleware allows MiddlewareFunc to implement the middleware interface.
    19  func (mw MiddlewareFunc) Middleware(handler http.Handler) http.Handler {
    20  	return mw(handler)
    21  }
    22  
    23  // Use appends a MiddlewareFunc to the chain. Middleware can be used to intercept or otherwise modify requests and/or responses, and are executed in the order that they are applied to the Router.
    24  func (r *Router) Use(mwf ...MiddlewareFunc) {
    25  	for _, fn := range mwf {
    26  		r.middlewares = append(r.middlewares, fn)
    27  	}
    28  }
    29  
    30  // useInterface appends a middleware to the chain. Middleware can be used to intercept or otherwise modify requests and/or responses, and are executed in the order that they are applied to the Router.
    31  func (r *Router) useInterface(mw middleware) {
    32  	r.middlewares = append(r.middlewares, mw)
    33  }
    34  
    35  // CORSMethodMiddleware sets the Access-Control-Allow-Methods response header
    36  // on a request, by matching routes based only on paths. It also handles
    37  // OPTIONS requests, by settings Access-Control-Allow-Methods, and then
    38  // returning without calling the next http handler.
    39  func CORSMethodMiddleware(r *Router) MiddlewareFunc {
    40  	return func(next http.Handler) http.Handler {
    41  		return http.HandlerFunc(func(w http.ResponseWriter, req *http.Request) {
    42  			var allMethods []string
    43  
    44  			err := r.Walk(func(route *Route, _ *Router, _ []*Route) error {
    45  				for _, m := range route.matchers {
    46  					if _, ok := m.(*routeRegexp); ok {
    47  						if m.Match(req, &RouteMatch{}) {
    48  							methods, err := route.GetMethods()
    49  							if err != nil {
    50  								return err
    51  							}
    52  
    53  							allMethods = append(allMethods, methods...)
    54  						}
    55  						break
    56  					}
    57  				}
    58  				return nil
    59  			})
    60  
    61  			if err == nil {
    62  				w.Header().Set("Access-Control-Allow-Methods", strings.Join(append(allMethods, "OPTIONS"), ","))
    63  
    64  				if req.Method == "OPTIONS" {
    65  					return
    66  				}
    67  			}
    68  
    69  			next.ServeHTTP(w, req)
    70  		})
    71  	}
    72  }