From afd6fa3f8fbaaefae1633404484bd66137f275ad Mon Sep 17 00:00:00 2001 From: Niall Sheridan Date: Tue, 28 Jun 2016 22:38:48 +0100 Subject: http logging --- vendor/github.com/gorilla/handlers/cors.go | 317 +++++++++++++++++++++++++++++ 1 file changed, 317 insertions(+) create mode 100644 vendor/github.com/gorilla/handlers/cors.go (limited to 'vendor/github.com/gorilla/handlers/cors.go') diff --git a/vendor/github.com/gorilla/handlers/cors.go b/vendor/github.com/gorilla/handlers/cors.go new file mode 100644 index 0000000..1f92d1a --- /dev/null +++ b/vendor/github.com/gorilla/handlers/cors.go @@ -0,0 +1,317 @@ +package handlers + +import ( + "net/http" + "strconv" + "strings" +) + +// CORSOption represents a functional option for configuring the CORS middleware. +type CORSOption func(*cors) error + +type cors struct { + h http.Handler + allowedHeaders []string + allowedMethods []string + allowedOrigins []string + allowedOriginValidator OriginValidator + exposedHeaders []string + maxAge int + ignoreOptions bool + allowCredentials bool +} + +// OriginValidator takes an origin string and returns whether or not that origin is allowed. +type OriginValidator func(string) bool + +var ( + defaultCorsMethods = []string{"GET", "HEAD", "POST"} + defaultCorsHeaders = []string{"Accept", "Accept-Language", "Content-Language", "Origin"} + // (WebKit/Safari v9 sends the Origin header by default in AJAX requests) +) + +const ( + corsOptionMethod string = "OPTIONS" + corsAllowOriginHeader string = "Access-Control-Allow-Origin" + corsExposeHeadersHeader string = "Access-Control-Expose-Headers" + corsMaxAgeHeader string = "Access-Control-Max-Age" + corsAllowMethodsHeader string = "Access-Control-Allow-Methods" + corsAllowHeadersHeader string = "Access-Control-Allow-Headers" + corsAllowCredentialsHeader string = "Access-Control-Allow-Credentials" + corsRequestMethodHeader string = "Access-Control-Request-Method" + corsRequestHeadersHeader string = "Access-Control-Request-Headers" + corsOriginHeader string = "Origin" + corsVaryHeader string = "Vary" + corsOriginMatchAll string = "*" +) + +func (ch *cors) ServeHTTP(w http.ResponseWriter, r *http.Request) { + origin := r.Header.Get(corsOriginHeader) + if !ch.isOriginAllowed(origin) { + ch.h.ServeHTTP(w, r) + return + } + + if r.Method == corsOptionMethod { + if ch.ignoreOptions { + ch.h.ServeHTTP(w, r) + return + } + + if _, ok := r.Header[corsRequestMethodHeader]; !ok { + w.WriteHeader(http.StatusBadRequest) + return + } + + method := r.Header.Get(corsRequestMethodHeader) + if !ch.isMatch(method, ch.allowedMethods) { + w.WriteHeader(http.StatusMethodNotAllowed) + return + } + + requestHeaders := strings.Split(r.Header.Get(corsRequestHeadersHeader), ",") + allowedHeaders := []string{} + for _, v := range requestHeaders { + canonicalHeader := http.CanonicalHeaderKey(strings.TrimSpace(v)) + if canonicalHeader == "" || ch.isMatch(canonicalHeader, defaultCorsHeaders) { + continue + } + + if !ch.isMatch(canonicalHeader, ch.allowedHeaders) { + w.WriteHeader(http.StatusForbidden) + return + } + + allowedHeaders = append(allowedHeaders, canonicalHeader) + } + + if len(allowedHeaders) > 0 { + w.Header().Set(corsAllowHeadersHeader, strings.Join(allowedHeaders, ",")) + } + + if ch.maxAge > 0 { + w.Header().Set(corsMaxAgeHeader, strconv.Itoa(ch.maxAge)) + } + + if !ch.isMatch(method, defaultCorsMethods) { + w.Header().Set(corsAllowMethodsHeader, method) + } + } else { + if len(ch.exposedHeaders) > 0 { + w.Header().Set(corsExposeHeadersHeader, strings.Join(ch.exposedHeaders, ",")) + } + } + + if ch.allowCredentials { + w.Header().Set(corsAllowCredentialsHeader, "true") + } + + if len(ch.allowedOrigins) > 1 { + w.Header().Set(corsVaryHeader, corsOriginHeader) + } + + w.Header().Set(corsAllowOriginHeader, origin) + + if r.Method == corsOptionMethod { + return + } + ch.h.ServeHTTP(w, r) +} + +// CORS provides Cross-Origin Resource Sharing middleware. +// Example: +// +// import ( +// "net/http" +// +// "github.com/gorilla/handlers" +// "github.com/gorilla/mux" +// ) +// +// func main() { +// r := mux.NewRouter() +// r.HandleFunc("/users", UserEndpoint) +// r.HandleFunc("/projects", ProjectEndpoint) +// +// // Apply the CORS middleware to our top-level router, with the defaults. +// http.ListenAndServe(":8000", handlers.CORS()(r)) +// } +// +func CORS(opts ...CORSOption) func(http.Handler) http.Handler { + return func(h http.Handler) http.Handler { + ch := parseCORSOptions(opts...) + ch.h = h + return ch + } +} + +func parseCORSOptions(opts ...CORSOption) *cors { + ch := &cors{ + allowedMethods: defaultCorsMethods, + allowedHeaders: defaultCorsHeaders, + allowedOrigins: []string{corsOriginMatchAll}, + } + + for _, option := range opts { + option(ch) + } + + return ch +} + +// +// Functional options for configuring CORS. +// + +// AllowedHeaders adds the provided headers to the list of allowed headers in a +// CORS request. +// This is an append operation so the headers Accept, Accept-Language, +// and Content-Language are always allowed. +// Content-Type must be explicitly declared if accepting Content-Types other than +// application/x-www-form-urlencoded, multipart/form-data, or text/plain. +func AllowedHeaders(headers []string) CORSOption { + return func(ch *cors) error { + for _, v := range headers { + normalizedHeader := http.CanonicalHeaderKey(strings.TrimSpace(v)) + if normalizedHeader == "" { + continue + } + + if !ch.isMatch(normalizedHeader, ch.allowedHeaders) { + ch.allowedHeaders = append(ch.allowedHeaders, normalizedHeader) + } + } + + return nil + } +} + +// AllowedMethods can be used to explicitly allow methods in the +// Access-Control-Allow-Methods header. +// This is a replacement operation so you must also +// pass GET, HEAD, and POST if you wish to support those methods. +func AllowedMethods(methods []string) CORSOption { + return func(ch *cors) error { + ch.allowedMethods = []string{} + for _, v := range methods { + normalizedMethod := strings.ToUpper(strings.TrimSpace(v)) + if normalizedMethod == "" { + continue + } + + if !ch.isMatch(normalizedMethod, ch.allowedMethods) { + ch.allowedMethods = append(ch.allowedMethods, normalizedMethod) + } + } + + return nil + } +} + +// AllowedOrigins sets the allowed origins for CORS requests, as used in the +// 'Allow-Access-Control-Origin' HTTP header. +// Note: Passing in a []string{"*"} will allow any domain. +func AllowedOrigins(origins []string) CORSOption { + return func(ch *cors) error { + for _, v := range origins { + if v == corsOriginMatchAll { + ch.allowedOrigins = []string{corsOriginMatchAll} + return nil + } + } + + ch.allowedOrigins = origins + return nil + } +} + +// AllowedOriginValidator sets a function for evaluating allowed origins in CORS requests, represented by the +// 'Allow-Access-Control-Origin' HTTP header. +func AllowedOriginValidator(fn OriginValidator) CORSOption { + return func(ch *cors) error { + ch.allowedOriginValidator = fn + return nil + } +} + +// ExposeHeaders can be used to specify headers that are available +// and will not be stripped out by the user-agent. +func ExposedHeaders(headers []string) CORSOption { + return func(ch *cors) error { + ch.exposedHeaders = []string{} + for _, v := range headers { + normalizedHeader := http.CanonicalHeaderKey(strings.TrimSpace(v)) + if normalizedHeader == "" { + continue + } + + if !ch.isMatch(normalizedHeader, ch.exposedHeaders) { + ch.exposedHeaders = append(ch.exposedHeaders, normalizedHeader) + } + } + + return nil + } +} + +// MaxAge determines the maximum age (in seconds) between preflight requests. A +// maximum of 10 minutes is allowed. An age above this value will default to 10 +// minutes. +func MaxAge(age int) CORSOption { + return func(ch *cors) error { + // Maximum of 10 minutes. + if age > 600 { + age = 600 + } + + ch.maxAge = age + return nil + } +} + +// IgnoreOptions causes the CORS middleware to ignore OPTIONS requests, instead +// passing them through to the next handler. This is useful when your application +// or framework has a pre-existing mechanism for responding to OPTIONS requests. +func IgnoreOptions() CORSOption { + return func(ch *cors) error { + ch.ignoreOptions = true + return nil + } +} + +// AllowCredentials can be used to specify that the user agent may pass +// authentication details along with the request. +func AllowCredentials() CORSOption { + return func(ch *cors) error { + ch.allowCredentials = true + return nil + } +} + +func (ch *cors) isOriginAllowed(origin string) bool { + if origin == "" { + return false + } + + if ch.allowedOriginValidator != nil { + return ch.allowedOriginValidator(origin) + } + + for _, allowedOrigin := range ch.allowedOrigins { + if allowedOrigin == origin || allowedOrigin == corsOriginMatchAll { + return true + } + } + + return false +} + +func (ch *cors) isMatch(needle string, haystack []string) bool { + for _, v := range haystack { + if v == needle { + return true + } + } + + return false +} -- cgit v1.2.3