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// Copyright 2015 Light Code Labs, LLC
//
// 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 httpserver
import (
"fmt"
"net/http"
"regexp"
"strings"
"github.com/caddyserver/caddy"
)
// SetupIfMatcher parses `if` or `if_op` in the current dispenser block.
// It returns a RequestMatcher and an error if any.
func SetupIfMatcher(controller *caddy.Controller) (RequestMatcher, error) {
var c = controller.Dispenser // copy the dispenser
var matcher IfMatcher
for c.NextBlock() {
switch c.Val() {
case "if":
args1 := c.RemainingArgs()
if len(args1) != 3 {
return matcher, c.ArgErr()
}
ifc, err := newIfCond(args1[0], args1[1], args1[2])
if err != nil {
return matcher, err
}
matcher.ifs = append(matcher.ifs, ifc)
matcher.Enabled = true
case "if_op":
if !c.NextArg() {
return matcher, c.ArgErr()
}
switch c.Val() {
case "and":
matcher.isOr = false
case "or":
matcher.isOr = true
default:
return matcher, c.ArgErr()
}
}
}
return matcher, nil
}
// operators
const (
isOp = "is"
notOp = "not"
hasOp = "has"
startsWithOp = "starts_with"
endsWithOp = "ends_with"
matchOp = "match"
)
// ifCondition is a 'if' condition.
type ifFunc func(a, b string) bool
// ifCond is statement for a IfMatcher condition.
type ifCond struct {
a string
op string
b string
neg bool
rex *regexp.Regexp
f ifFunc
}
// newIfCond creates a new If condition.
func newIfCond(a, op, b string) (ifCond, error) {
i := ifCond{a: a, op: op, b: b}
if strings.HasPrefix(op, "not_") {
i.neg = true
i.op = op[4:]
}
switch i.op {
case isOp:
// It checks for equality.
i.f = i.isFunc
case notOp:
// It checks for inequality.
i.f = i.notFunc
case hasOp:
// It checks if b is a substring of a.
i.f = strings.Contains
case startsWithOp:
// It checks if b is a prefix of a.
i.f = strings.HasPrefix
case endsWithOp:
// It checks if b is a suffix of a.
i.f = strings.HasSuffix
case matchOp:
// It does regexp matching of a against pattern in b and returns if they match.
var err error
if i.rex, err = regexp.Compile(i.b); err != nil {
return ifCond{}, fmt.Errorf("Invalid regular expression: '%s', %v", i.b, err)
}
i.f = i.matchFunc
default:
return ifCond{}, fmt.Errorf("Invalid operator %v", i.op)
}
return i, nil
}
// isFunc is condition for Is operator.
func (i ifCond) isFunc(a, b string) bool {
return a == b
}
// notFunc is condition for Not operator.
func (i ifCond) notFunc(a, b string) bool {
return a != b
}
// matchFunc is condition for Match operator.
func (i ifCond) matchFunc(a, b string) bool {
return i.rex.MatchString(a)
}
// True returns true if the condition is true and false otherwise.
// If r is not nil, it replaces placeholders before comparison.
func (i ifCond) True(r *http.Request) bool {
if i.f != nil {
a, b := i.a, i.b
if r != nil {
replacer := NewReplacer(r, nil, "")
a = replacer.Replace(i.a)
if i.op != matchOp {
b = replacer.Replace(i.b)
}
}
if i.neg {
return !i.f(a, b)
}
return i.f(a, b)
}
return i.neg // false if not negated, true otherwise
}
// IfMatcher is a RequestMatcher for 'if' conditions.
type IfMatcher struct {
Enabled bool // if true, matcher has been configured; otherwise it's no-op
ifs []ifCond // list of If
isOr bool // if true, conditions are 'or' instead of 'and'
}
// Match satisfies RequestMatcher interface.
// It returns true if the conditions in m are true.
func (m IfMatcher) Match(r *http.Request) bool {
if m.isOr {
return m.Or(r)
}
return m.And(r)
}
// And returns true if all conditions in m are true.
func (m IfMatcher) And(r *http.Request) bool {
for _, i := range m.ifs {
if !i.True(r) {
return false
}
}
return true
}
// Or returns true if any of the conditions in m is true.
func (m IfMatcher) Or(r *http.Request) bool {
for _, i := range m.ifs {
if i.True(r) {
return true
}
}
return false
}
// IfMatcherKeyword checks if the next value in the dispenser is a keyword for 'if' config block.
// If true, remaining arguments in the dispenser are cleared to keep the dispenser valid for use.
func IfMatcherKeyword(c *caddy.Controller) bool {
if c.Val() == "if" || c.Val() == "if_op" {
// clear remaining args
c.RemainingArgs()
return true
}
return false
}
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