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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 port provides utilities for modifying and filtering
- // based on the port of request URLs.
- package port
-
- import (
- "encoding/json"
- "net"
- "net/http"
- "strconv"
- "strings"
-
- "github.com/google/martian"
- "github.com/google/martian/parse"
- )
-
- var noop = martian.Noop("port.Filter")
-
- func init() {
- parse.Register("port.Filter", filterFromJSON)
- }
-
- // Filter runs modifiers iff the port in the request URL matches port.
- type Filter struct {
- reqmod martian.RequestModifier
- resmod martian.ResponseModifier
- port int
- }
-
- type filterJSON struct {
- Port int `json:"port"`
- Modifier json.RawMessage `json:"modifier"`
- Scope []parse.ModifierType `json:"scope"`
- }
-
- // NewFilter returns a filter that executes modifiers if the port of
- // request matches port.
- func NewFilter(port int) *Filter {
- return &Filter{
- port: port,
- reqmod: noop,
- resmod: noop,
- }
- }
-
- // SetRequestModifier sets the request modifier.
- func (f *Filter) SetRequestModifier(reqmod martian.RequestModifier) {
- if reqmod == nil {
- reqmod = noop
- }
-
- f.reqmod = reqmod
- }
-
- // SetResponseModifier sets the response modifier.
- func (f *Filter) SetResponseModifier(resmod martian.ResponseModifier) {
- if resmod == nil {
- resmod = noop
- }
-
- f.resmod = resmod
- }
-
- // ModifyRequest runs the modifier if the port matches the provided port.
- func (f *Filter) ModifyRequest(req *http.Request) error {
- var defaultPort int
- if req.URL.Scheme == "http" {
- defaultPort = 80
- }
- if req.URL.Scheme == "https" {
- defaultPort = 443
- }
-
- hasPort := strings.Contains(req.URL.Host, ":")
- if hasPort {
- _, p, err := net.SplitHostPort(req.URL.Host)
- if err != nil {
- return err
- }
-
- pt, err := strconv.Atoi(p)
- if err != nil {
- return err
- }
- if pt == f.port {
- return f.reqmod.ModifyRequest(req)
- }
- return nil
- }
-
- // no port explictly declared - default port
- if f.port == defaultPort {
- return f.reqmod.ModifyRequest(req)
- }
-
- return nil
- }
-
- // ModifyResponse runs the modifier if the request URL matches urlMatcher.
- func (f *Filter) ModifyResponse(res *http.Response) error {
- var defaultPort int
- if res.Request.URL.Scheme == "http" {
- defaultPort = 80
- }
- if res.Request.URL.Scheme == "https" {
- defaultPort = 443
- }
-
- if !strings.Contains(res.Request.URL.Host, ":") && (f.port == defaultPort) {
- return f.resmod.ModifyResponse(res)
- }
-
- _, p, err := net.SplitHostPort(res.Request.URL.Host)
- if err != nil {
- return err
- }
-
- pt, err := strconv.Atoi(p)
- if err != nil {
- return err
- }
- if pt == f.port {
- return f.resmod.ModifyResponse(res)
- }
-
- return nil
- }
-
- func filterFromJSON(b []byte) (*parse.Result, error) {
- msg := &filterJSON{}
- if err := json.Unmarshal(b, msg); err != nil {
- return nil, err
- }
-
- filter := NewFilter(msg.Port)
- r, err := parse.FromJSON(msg.Modifier)
- if err != nil {
- return nil, err
- }
-
- reqmod := r.RequestModifier()
- if err != nil {
- return nil, err
- }
- if reqmod != nil {
- filter.SetRequestModifier(reqmod)
- }
-
- resmod := r.ResponseModifier()
- if resmod != nil {
- filter.SetResponseModifier(resmod)
- }
-
- return parse.NewResult(filter, msg.Scope)
- }
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