oauth2-proxy/pkg/middleware/headers.go

145 lines
4.2 KiB
Go

package middleware
import (
"fmt"
"net/http"
"strings"
"github.com/justinas/alice"
middlewareapi "github.com/oauth2-proxy/oauth2-proxy/v7/pkg/apis/middleware"
"github.com/oauth2-proxy/oauth2-proxy/v7/pkg/apis/options"
"github.com/oauth2-proxy/oauth2-proxy/v7/pkg/header"
)
func NewRequestHeaderInjector(headers []options.Header) (alice.Constructor, error) {
headerInjector, err := newRequestHeaderInjector(headers)
if err != nil {
return nil, fmt.Errorf("error building request header injector: %v", err)
}
strip := newStripHeaders(headers)
if strip != nil {
return alice.New(strip, headerInjector).Then, nil
}
return headerInjector, nil
}
func newStripHeaders(headers []options.Header) alice.Constructor {
headersToStrip := []options.Header{}
for _, header := range headers {
if !header.PreserveRequestValue {
headersToStrip = append(headersToStrip, header)
}
}
if len(headersToStrip) == 0 {
return nil
}
return func(next http.Handler) http.Handler {
return stripHeaders(headersToStrip, next)
}
}
func flattenHeaders(headers http.Header) {
for name, values := range headers {
// Set-Cookie should not be flattened, ref: https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Set-Cookie
if len(values) > 1 && name != "Set-Cookie" {
headers.Set(name, strings.Join(values, ","))
}
}
}
func stripHeaders(headers []options.Header, next http.Handler) http.Handler {
return http.HandlerFunc(func(rw http.ResponseWriter, req *http.Request) {
for _, header := range headers {
stripNormalizedHeader(req, header)
}
next.ServeHTTP(rw, req)
})
}
func newRequestHeaderInjector(headers []options.Header) (alice.Constructor, error) {
injector, err := header.NewInjector(headers)
if err != nil {
return nil, fmt.Errorf("error building request injector: %v", err)
}
return func(next http.Handler) http.Handler {
return injectRequestHeaders(injector, next)
}, nil
}
func injectRequestHeaders(injector header.Injector, next http.Handler) http.Handler {
return http.HandlerFunc(func(rw http.ResponseWriter, req *http.Request) {
scope := middlewareapi.GetRequestScope(req)
// If scope is nil, this will panic.
// A scope should always be injected before this handler is called.
injector.Inject(req.Header, scope.Session)
flattenHeaders(req.Header)
next.ServeHTTP(rw, req)
})
}
func NewResponseHeaderInjector(headers []options.Header) (alice.Constructor, error) {
headerInjector, err := newResponseHeaderInjector(headers)
if err != nil {
return nil, fmt.Errorf("error building response header injector: %v", err)
}
return headerInjector, nil
}
func newResponseHeaderInjector(headers []options.Header) (alice.Constructor, error) {
injector, err := header.NewInjector(headers)
if err != nil {
return nil, fmt.Errorf("error building response injector: %v", err)
}
return func(next http.Handler) http.Handler {
return injectResponseHeaders(injector, next)
}, nil
}
func injectResponseHeaders(injector header.Injector, next http.Handler) http.Handler {
return http.HandlerFunc(func(rw http.ResponseWriter, req *http.Request) {
scope := middlewareapi.GetRequestScope(req)
// If scope is nil, this will panic.
// A scope should always be injected before this handler is called.
injector.Inject(rw.Header(), scope.Session)
flattenHeaders(rw.Header())
next.ServeHTTP(rw, req)
})
}
// normalizeHeaderName normalizes the header name by lowercasing it
// and replacing underscores with hyphens.
func normalizeHeaderName(headerName string) string {
headerName = strings.ToLower(headerName)
headerName = strings.ReplaceAll(headerName, "_", "-")
return headerName
}
// stripNormalizedHeader removes any headers from the request that match
// the normalized version of the provided header's name.
func stripNormalizedHeader(req *http.Request, header options.Header) {
normalizedName := normalizeHeaderName(header.Name)
toBeDeleted := []string{}
for h := range req.Header {
if normalizeHeaderName(h) == normalizedName {
// necessary to avoid modifying the map while iterating
toBeDeleted = append(toBeDeleted, h)
}
}
for _, h := range toBeDeleted {
// necessary because req.Header.Del accesses the map via
// the header's canonicalized name. We need to delete by
// the original name.
delete(req.Header, h)
}
}