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package middleware
import (
"net/http"
"strings"
)
// RouteHeaders is a neat little header-based router that allows you to direct
// the flow of a request through a middleware stack based on a request header.
//
// For example, lets say you'd like to setup multiple routers depending on the
// request Host header, you could then do something as so:
//
// r := chi.NewRouter()
// rSubdomain := chi.NewRouter()
// r.Use(middleware.RouteHeaders().
// Route("Host", "example.com", middleware.New(r)).
// Route("Host", "*.example.com", middleware.New(rSubdomain)).
// Handler)
// r.Get("/", h)
// rSubdomain.Get("/", h2)
//
// Another example, imagine you want to setup multiple CORS handlers, where for
// your origin servers you allow authorized requests, but for third-party public
// requests, authorization is disabled.
//
// r := chi.NewRouter()
// r.Use(middleware.RouteHeaders().
// Route("Origin", "https://app.skyweaver.net", cors.Handler(cors.Options{
// AllowedOrigins: []string{"https://api.skyweaver.net"},
// AllowedMethods: []string{"GET", "POST", "PUT", "DELETE", "OPTIONS"},
// AllowedHeaders: []string{"Accept", "Authorization", "Content-Type"},
// AllowCredentials: true, // <----------<<< allow credentials
// })).
// Route("Origin", "*", cors.Handler(cors.Options{
// AllowedOrigins: []string{"*"},
// AllowedMethods: []string{"GET", "POST", "PUT", "DELETE", "OPTIONS"},
// AllowedHeaders: []string{"Accept", "Content-Type"},
// AllowCredentials: false, // <----------<<< do not allow credentials
// })).
// Handler)
func RouteHeaders() HeaderRouter {
return HeaderRouter{}
}
type HeaderRouter map[string][]HeaderRoute
func (hr HeaderRouter) Route(header, match string, middlewareHandler func(next http.Handler) http.Handler) HeaderRouter {
header = strings.ToLower(header)
k := hr[header]
if k == nil {
hr[header] = []HeaderRoute{}
}
hr[header] = append(hr[header], HeaderRoute{MatchOne: NewPattern(match), Middleware: middlewareHandler})
return hr
}
func (hr HeaderRouter) RouteAny(header string, match []string, middlewareHandler func(next http.Handler) http.Handler) HeaderRouter {
header = strings.ToLower(header)
k := hr[header]
if k == nil {
hr[header] = []HeaderRoute{}
}
patterns := []Pattern{}
for _, m := range match {
patterns = append(patterns, NewPattern(m))
}
hr[header] = append(hr[header], HeaderRoute{MatchAny: patterns, Middleware: middlewareHandler})
return hr
}
func (hr HeaderRouter) RouteDefault(handler func(next http.Handler) http.Handler) HeaderRouter {
hr["*"] = []HeaderRoute{{Middleware: handler}}
return hr
}
func (hr HeaderRouter) Handler(next http.Handler) http.Handler {
return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
if len(hr) == 0 {
// skip if no routes set
next.ServeHTTP(w, r)
}
// find first matching header route, and continue
for header, matchers := range hr {
headerValue := r.Header.Get(header)
if headerValue == "" {
continue
}
headerValue = strings.ToLower(headerValue)
for _, matcher := range matchers {
if matcher.IsMatch(headerValue) {
matcher.Middleware(next).ServeHTTP(w, r)
return
}
}
}
// if no match, check for "*" default route
matcher, ok := hr["*"]
if !ok || matcher[0].Middleware == nil {
next.ServeHTTP(w, r)
return
}
matcher[0].Middleware(next).ServeHTTP(w, r)
})
}
type HeaderRoute struct {
Middleware func(next http.Handler) http.Handler
MatchOne Pattern
MatchAny []Pattern
}
func (r HeaderRoute) IsMatch(value string) bool {
if len(r.MatchAny) > 0 {
for _, m := range r.MatchAny {
if m.Match(value) {
return true
}
}
} else if r.MatchOne.Match(value) {
return true
}
return false
}
type Pattern struct {
prefix string
suffix string
wildcard bool
}
func NewPattern(value string) Pattern {
p := Pattern{}
if i := strings.IndexByte(value, '*'); i >= 0 {
p.wildcard = true
p.prefix = value[0:i]
p.suffix = value[i+1:]
} else {
p.prefix = value
}
return p
}
func (p Pattern) Match(v string) bool {
if !p.wildcard {
return p.prefix == v
}
return len(v) >= len(p.prefix+p.suffix) && strings.HasPrefix(v, p.prefix) && strings.HasSuffix(v, p.suffix)
}
|
