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- // Copyright 2015 Google Inc. All rights reserved.
- //
- // 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 header
-
- import (
- "encoding/json"
- "net/http"
-
- "github.com/google/martian"
- "github.com/google/martian/parse"
- )
-
- const idHeaderName string = "X-Martian-ID"
-
- func init() {
- parse.Register("header.Id", idModifierFromJSON)
- }
-
- type idModifier struct{}
-
- type idModifierJSON struct {
- Scope []parse.ModifierType `json:"scope"`
- }
-
- // NewIDModifier returns a request modifier that will set a header with the name
- // X-Martian-ID with a value that is a unique identifier for the request. In the case
- // that the X-Martian-ID header is already set, the header is unmodified.
- func NewIDModifier() martian.RequestModifier {
- return &idModifier{}
- }
-
- // ModifyRequest sets the X-Martian-ID header with a unique identifier. In the case
- // that the X-Martian-ID header is already set, the header is unmodified.
- func (im *idModifier) ModifyRequest(req *http.Request) error {
- // Do not rewrite an ID if req already has one
- if req.Header.Get(idHeaderName) != "" {
- return nil
- }
-
- ctx := martian.NewContext(req)
- req.Header.Set(idHeaderName, ctx.ID())
-
- return nil
- }
-
- func idModifierFromJSON(b []byte) (*parse.Result, error) {
- msg := &idModifierJSON{}
- if err := json.Unmarshal(b, msg); err != nil {
- return nil, err
- }
-
- modifier := NewIDModifier()
-
- return parse.NewResult(modifier, msg.Scope)
- }
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