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forward_headers.go
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/
forward_headers.go
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/*
* Copyright 2020 The Compass Authors
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package http
import (
"context"
"net/http"
"github.com/kyma-incubator/compass/components/director/pkg/log"
"github.com/pkg/errors"
)
type key int
const HeadersContextKey key = iota
// HeaderForwarder stores the specified request headers in the context so that they can later be used and forwarded to other backends
func HeaderForwarder(forwardHeaders []string) func(next http.Handler) http.Handler {
return func(next http.Handler) http.Handler {
return http.HandlerFunc(func(rw http.ResponseWriter, r *http.Request) {
ctx := r.Context()
for _, header := range forwardHeaders {
if value := r.Header.Get(header); value != "" {
ctx = SaveToContext(ctx, header, value)
log.C(ctx).Debugf("Forwarding header %s", header)
}
}
r = r.WithContext(ctx)
next.ServeHTTP(rw, r)
})
}
}
func LoadFromContext(ctx context.Context) (map[string]string, error) {
value := ctx.Value(HeadersContextKey)
headers, ok := value.(map[string]string)
if !ok {
return nil, errors.Errorf("headers not found in context")
}
return headers, nil
}
func SaveToContext(ctx context.Context, key, val string) context.Context {
headers := make(map[string]string)
if value := ctx.Value(HeadersContextKey); value != nil {
if currentHeaders, ok := value.(map[string]string); ok {
headers = currentHeaders
}
}
headers[key] = val
return context.WithValue(ctx, HeadersContextKey, headers)
}