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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"
- "regexp"
-
- "github.com/google/martian"
- "github.com/google/martian/parse"
- )
-
- // ValueRegexFilter executes resmod and reqmod when the header
- // value matches regex.
- type ValueRegexFilter struct {
- regex *regexp.Regexp
- header string
- reqmod martian.RequestModifier
- resmod martian.ResponseModifier
- }
-
- type headerValueRegexFilterJSON struct {
- Regex string `json:"regex"`
- HeaderName string `json:"header"`
- Modifier json.RawMessage `json:"modifier"`
- Scope []parse.ModifierType `json:"scope"`
- }
-
- func init() {
- parse.Register("header.RegexFilter", headerValueRegexFilterFromJSON)
- }
-
- // NewValueRegexFilter builds a new header value regex filter.
- func NewValueRegexFilter(regex *regexp.Regexp, header string) *ValueRegexFilter {
- return &ValueRegexFilter{
- regex: regex,
- header: header,
- reqmod: noop,
- resmod: noop,
- }
- }
-
- func headerValueRegexFilterFromJSON(b []byte) (*parse.Result, error) {
- msg := &headerValueRegexFilterJSON{}
- if err := json.Unmarshal(b, msg); err != nil {
- return nil, err
- }
-
- cr, err := regexp.Compile(msg.Regex)
- if err != nil {
- return nil, err
- }
- filter := NewValueRegexFilter(cr, msg.HeaderName)
-
- r, err := parse.FromJSON(msg.Modifier)
- if err != nil {
- return nil, err
- }
-
- reqmod := r.RequestModifier()
- filter.SetRequestModifier(reqmod)
-
- resmod := r.ResponseModifier()
- filter.SetResponseModifier(resmod)
-
- return parse.NewResult(filter, msg.Scope)
- }
-
- // ModifyRequest runs reqmod iff the value of header matches regex.
- func (f *ValueRegexFilter) ModifyRequest(req *http.Request) error {
- hvalue := req.Header.Get(f.header)
- if hvalue == "" {
- return nil
- }
-
- if f.regex.MatchString(hvalue) {
- return f.reqmod.ModifyRequest(req)
- }
-
- return nil
- }
-
- // ModifyResponse runs resmod iff the value of request header matches regex.
- func (f *ValueRegexFilter) ModifyResponse(res *http.Response) error {
- hvalue := res.Request.Header.Get(f.header)
- if hvalue == "" {
- return nil
- }
-
- if f.regex.MatchString(hvalue) {
- return f.resmod.ModifyResponse(res)
- }
-
- return nil
- }
-
- // SetRequestModifier sets the request modifier of HeaderValueRegexFilter.
- func (f *ValueRegexFilter) SetRequestModifier(reqmod martian.RequestModifier) {
- if reqmod == nil {
- f.reqmod = noop
- return
- }
-
- f.reqmod = reqmod
- }
-
- // SetResponseModifier sets the response modifier of HeaderValueRegexFilter.
- func (f *ValueRegexFilter) SetResponseModifier(resmod martian.ResponseModifier) {
- if resmod == nil {
- f.resmod = noop
- return
- }
-
- f.resmod = resmod
- }
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