271 lines
8 KiB
Go
271 lines
8 KiB
Go
// Package headers Middleware based on https://github.com/unrolled/secure.
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package headers
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import (
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"context"
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"errors"
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"net/http"
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"strconv"
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"strings"
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"github.com/containous/traefik/v2/pkg/config/dynamic"
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"github.com/containous/traefik/v2/pkg/log"
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"github.com/containous/traefik/v2/pkg/middlewares"
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"github.com/containous/traefik/v2/pkg/tracing"
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"github.com/opentracing/opentracing-go/ext"
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"github.com/unrolled/secure"
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)
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const (
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typeName = "Headers"
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)
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type headers struct {
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name string
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handler http.Handler
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}
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// New creates a Headers middleware.
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func New(ctx context.Context, next http.Handler, config dynamic.Headers, name string) (http.Handler, error) {
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// HeaderMiddleware -> SecureMiddleWare -> next
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logger := log.FromContext(middlewares.GetLoggerCtx(ctx, name, typeName))
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logger.Debug("Creating middleware")
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hasSecureHeaders := config.HasSecureHeadersDefined()
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hasCustomHeaders := config.HasCustomHeadersDefined()
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hasCorsHeaders := config.HasCorsHeadersDefined()
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if !hasSecureHeaders && !hasCustomHeaders && !hasCorsHeaders {
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return nil, errors.New("headers configuration not valid")
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}
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var handler http.Handler
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nextHandler := next
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if hasSecureHeaders {
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logger.Debug("Setting up secureHeaders from %v", config)
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handler = newSecure(next, config)
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nextHandler = handler
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}
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if hasCustomHeaders || hasCorsHeaders {
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logger.Debug("Setting up customHeaders/Cors from %v", config)
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handler = NewHeader(nextHandler, config)
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}
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return &headers{
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handler: handler,
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name: name,
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}, nil
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}
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func (h *headers) GetTracingInformation() (string, ext.SpanKindEnum) {
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return h.name, tracing.SpanKindNoneEnum
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}
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func (h *headers) ServeHTTP(rw http.ResponseWriter, req *http.Request) {
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h.handler.ServeHTTP(rw, req)
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}
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type secureHeader struct {
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next http.Handler
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secure *secure.Secure
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}
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// newSecure constructs a new secure instance with supplied options.
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func newSecure(next http.Handler, headers dynamic.Headers) *secureHeader {
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opt := secure.Options{
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BrowserXssFilter: headers.BrowserXSSFilter,
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ContentTypeNosniff: headers.ContentTypeNosniff,
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ForceSTSHeader: headers.ForceSTSHeader,
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FrameDeny: headers.FrameDeny,
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IsDevelopment: headers.IsDevelopment,
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SSLRedirect: headers.SSLRedirect,
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SSLForceHost: headers.SSLForceHost,
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SSLTemporaryRedirect: headers.SSLTemporaryRedirect,
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STSIncludeSubdomains: headers.STSIncludeSubdomains,
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STSPreload: headers.STSPreload,
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ContentSecurityPolicy: headers.ContentSecurityPolicy,
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CustomBrowserXssValue: headers.CustomBrowserXSSValue,
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CustomFrameOptionsValue: headers.CustomFrameOptionsValue,
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PublicKey: headers.PublicKey,
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ReferrerPolicy: headers.ReferrerPolicy,
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SSLHost: headers.SSLHost,
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AllowedHosts: headers.AllowedHosts,
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HostsProxyHeaders: headers.HostsProxyHeaders,
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SSLProxyHeaders: headers.SSLProxyHeaders,
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STSSeconds: headers.STSSeconds,
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FeaturePolicy: headers.FeaturePolicy,
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}
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return &secureHeader{
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next: next,
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secure: secure.New(opt),
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}
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}
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func (s secureHeader) ServeHTTP(rw http.ResponseWriter, req *http.Request) {
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s.secure.HandlerFuncWithNextForRequestOnly(rw, req, s.next.ServeHTTP)
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}
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// Header is a middleware that helps setup a few basic security features.
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// A single headerOptions struct can be provided to configure which features should be enabled,
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// and the ability to override a few of the default values.
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type Header struct {
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next http.Handler
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hasCustomHeaders bool
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hasCorsHeaders bool
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headers *dynamic.Headers
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}
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// NewHeader constructs a new header instance from supplied frontend header struct.
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func NewHeader(next http.Handler, headers dynamic.Headers) *Header {
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hasCustomHeaders := headers.HasCustomHeadersDefined()
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hasCorsHeaders := headers.HasCorsHeadersDefined()
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return &Header{
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next: next,
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headers: &headers,
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hasCustomHeaders: hasCustomHeaders,
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hasCorsHeaders: hasCorsHeaders,
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}
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}
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func (s *Header) ServeHTTP(rw http.ResponseWriter, req *http.Request) {
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// Handle Cors headers and preflight if configured.
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if isPreflight := s.processCorsHeaders(rw, req); isPreflight {
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return
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}
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if s.hasCustomHeaders {
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s.modifyCustomRequestHeaders(req)
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}
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// If there is a next, call it.
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if s.next != nil {
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s.next.ServeHTTP(rw, req)
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}
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}
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// modifyCustomRequestHeaders sets or deletes custom request headers.
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func (s *Header) modifyCustomRequestHeaders(req *http.Request) {
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// Loop through Custom request headers
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for header, value := range s.headers.CustomRequestHeaders {
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if value == "" {
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req.Header.Del(header)
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} else {
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req.Header.Set(header, value)
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}
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}
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}
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// preRequestModifyCorsResponseHeaders sets during request processing time,
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// all the CORS response headers that we already know that are supposed to be set,
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// and which do not depend on a later state of the response.
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// One notable example of a header that can only be modified later on is "Vary",
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// And this is set in the post-response response modifier method
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func (s *Header) preRequestModifyCorsResponseHeaders(rw http.ResponseWriter, req *http.Request) {
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originHeader := req.Header.Get("Origin")
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allowOrigin := s.getAllowOrigin(originHeader)
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if allowOrigin != "" {
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rw.Header().Set("Access-Control-Allow-Origin", allowOrigin)
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}
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if s.headers.AccessControlAllowCredentials {
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rw.Header().Set("Access-Control-Allow-Credentials", "true")
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}
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if len(s.headers.AccessControlExposeHeaders) > 0 {
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exposeHeaders := strings.Join(s.headers.AccessControlExposeHeaders, ",")
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rw.Header().Set("Access-Control-Expose-Headers", exposeHeaders)
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}
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}
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// PostRequestModifyResponseHeaders set or delete response headers.
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// This method is called AFTER the response is generated from the backend
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// and can merge/override headers from the backend response.
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func (s *Header) PostRequestModifyResponseHeaders(res *http.Response) error {
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// Loop through Custom response headers
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for header, value := range s.headers.CustomResponseHeaders {
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if value == "" {
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res.Header.Del(header)
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} else {
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res.Header.Set(header, value)
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}
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}
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if !s.headers.AddVaryHeader {
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return nil
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}
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varyHeader := res.Header.Get("Vary")
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if varyHeader == "Origin" {
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return nil
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}
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if varyHeader != "" {
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varyHeader += ","
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}
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varyHeader += "Origin"
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res.Header.Set("Vary", varyHeader)
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return nil
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}
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// processCorsHeaders processes the incoming request,
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// and returns if it is a preflight request.
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// If not a preflight, it handles the preRequestModifyCorsResponseHeaders.
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func (s *Header) processCorsHeaders(rw http.ResponseWriter, req *http.Request) bool {
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if !s.hasCorsHeaders {
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return false
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}
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reqAcMethod := req.Header.Get("Access-Control-Request-Method")
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originHeader := req.Header.Get("Origin")
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if reqAcMethod != "" && originHeader != "" && req.Method == http.MethodOptions {
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// If the request is an OPTIONS request with an Access-Control-Request-Method header,
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// and Origin headers, then it is a CORS preflight request,
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// and we need to build a custom response: https://www.w3.org/TR/cors/#preflight-request
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if s.headers.AccessControlAllowCredentials {
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rw.Header().Set("Access-Control-Allow-Credentials", "true")
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}
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allowHeaders := strings.Join(s.headers.AccessControlAllowHeaders, ",")
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if allowHeaders != "" {
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rw.Header().Set("Access-Control-Allow-Headers", allowHeaders)
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}
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allowMethods := strings.Join(s.headers.AccessControlAllowMethods, ",")
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if allowMethods != "" {
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rw.Header().Set("Access-Control-Allow-Methods", allowMethods)
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}
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allowOrigin := s.getAllowOrigin(originHeader)
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if allowOrigin != "" {
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rw.Header().Set("Access-Control-Allow-Origin", allowOrigin)
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}
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rw.Header().Set("Access-Control-Max-Age", strconv.Itoa(int(s.headers.AccessControlMaxAge)))
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return true
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}
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s.preRequestModifyCorsResponseHeaders(rw, req)
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return false
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}
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func (s *Header) getAllowOrigin(header string) string {
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switch s.headers.AccessControlAllowOrigin {
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case "origin-list-or-null":
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if len(header) == 0 {
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return "null"
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}
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return header
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case "*":
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return "*"
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default:
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return ""
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}
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}
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