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// Copyright 2015 Light Code Labs, LLC
//
// 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 requestid
import (
"context"
"log"
"net/http"
"github.com/google/uuid"
"github.com/mholt/caddy/caddyhttp/httpserver"
)
// Handler is a middleware handler
type Handler struct {
Next httpserver.Handler
HeaderName string // (optional) header from which to read an existing ID
}
func (h Handler) ServeHTTP(w http.ResponseWriter, r *http.Request) (int, error) {
var reqid uuid.UUID
uuidFromHeader := r.Header.Get(h.HeaderName)
if h.HeaderName != "" && uuidFromHeader != "" {
// use the ID in the header field if it exists
var err error
reqid, err = uuid.Parse(uuidFromHeader)
if err != nil {
log.Printf("[NOTICE] Parsing request ID from %s header: %v", h.HeaderName, err)
reqid = uuid.New()
}
} else {
// otherwise, create a new one
reqid = uuid.New()
}
// set the request ID on the context
c := context.WithValue(r.Context(), httpserver.RequestIDCtxKey, reqid.String())
r = r.WithContext(c)
return h.Next.ServeHTTP(w, r)
}
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