/
header_value_regex_filter.go
128 lines (105 loc) · 3.11 KB
/
header_value_regex_filter.go
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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
}