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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 auth provides filtering support for a martian.Proxy based on auth
// ID.
package auth
import (
"fmt"
"net/http"
"sync"
"github.com/google/martian"
)
// Filter filters RequestModifiers and ResponseModifiers by auth ID.
type Filter struct {
authRequired bool
mu sync.RWMutex
reqmods map[string]martian.RequestModifier
resmods map[string]martian.ResponseModifier
}
// NewFilter returns a new auth.Filter.
func NewFilter() *Filter {
return &Filter{
reqmods: make(map[string]martian.RequestModifier),
resmods: make(map[string]martian.ResponseModifier),
}
}
// SetAuthRequired determines whether the auth ID must have an associated
// RequestModifier or ResponseModifier. If true, it will set auth error.
func (f *Filter) SetAuthRequired(required bool) {
f.authRequired = required
}
// SetRequestModifier sets the RequestModifier for the given ID. It will
// overwrite any existing modifier with the same ID.
func (f *Filter) SetRequestModifier(id string, reqmod martian.RequestModifier) error {
f.mu.Lock()
defer f.mu.Unlock()
if reqmod != nil {
f.reqmods[id] = reqmod
} else {
delete(f.reqmods, id)
}
return nil
}
// SetResponseModifier sets the ResponseModifier for the given ID. It will
// overwrite any existing modifier with the same ID.
func (f *Filter) SetResponseModifier(id string, resmod martian.ResponseModifier) error {
f.mu.Lock()
defer f.mu.Unlock()
if resmod != nil {
f.resmods[id] = resmod
} else {
delete(f.resmods, id)
}
return nil
}
// RequestModifier retrieves the RequestModifier for the given ID. Returns nil
// if no modifier exists for the given ID.
func (f *Filter) RequestModifier(id string) martian.RequestModifier {
f.mu.RLock()
defer f.mu.RUnlock()
return f.reqmods[id]
}
// ResponseModifier retrieves the ResponseModifier for the given ID. Returns nil
// if no modifier exists for the given ID.
func (f *Filter) ResponseModifier(id string) martian.ResponseModifier {
f.mu.RLock()
defer f.mu.RUnlock()
return f.resmods[id]
}
// ModifyRequest runs the RequestModifier for the associated auth ID. If no
// modifier is found for auth ID then auth error is set.
func (f *Filter) ModifyRequest(req *http.Request) error {
ctx := martian.NewContext(req)
actx := FromContext(ctx)
if reqmod, ok := f.reqmods[actx.ID()]; ok {
return reqmod.ModifyRequest(req)
}
if err := f.requireKnownAuth(actx.ID()); err != nil {
actx.SetError(err)
}
return nil
}
// ModifyResponse runs the ResponseModifier for the associated auth ID. If no
// modifier is found for the auth ID then the auth error is set.
func (f *Filter) ModifyResponse(res *http.Response) error {
ctx := martian.NewContext(res.Request)
actx := FromContext(ctx)
if resmod, ok := f.resmods[actx.ID()]; ok {
return resmod.ModifyResponse(res)
}
if err := f.requireKnownAuth(actx.ID()); err != nil {
actx.SetError(err)
}
return nil
}
func (f *Filter) requireKnownAuth(id string) error {
_, reqok := f.reqmods[id]
_, resok := f.resmods[id]
if !reqok && !resok && f.authRequired {
return fmt.Errorf("auth: unrecognized credentials: %s", id)
}
return nil
}
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