coredns/core/setup/rewrite.go

109 lines
2.5 KiB
Go

package setup
import (
"strconv"
"strings"
"github.com/miekg/coredns/middleware"
"github.com/miekg/coredns/middleware/rewrite"
)
// Rewrite configures a new Rewrite middleware instance.
func Rewrite(c *Controller) (middleware.Middleware, error) {
rewrites, err := rewriteParse(c)
if err != nil {
return nil, err
}
return func(next middleware.Handler) middleware.Handler {
return rewrite.Rewrite{
Next: next,
Rules: rewrites,
}
}, nil
}
func rewriteParse(c *Controller) ([]rewrite.Rule, error) {
var simpleRules []rewrite.Rule
var regexpRules []rewrite.Rule
for c.Next() {
var rule rewrite.Rule
var err error
var base = "."
var pattern, to string
var status int
var ext []string
args := c.RemainingArgs()
var ifs []rewrite.If
switch len(args) {
case 1:
base = args[0]
fallthrough
case 0:
for c.NextBlock() {
switch c.Val() {
case "r", "regexp":
if !c.NextArg() {
return nil, c.ArgErr()
}
pattern = c.Val()
case "to":
args1 := c.RemainingArgs()
if len(args1) == 0 {
return nil, c.ArgErr()
}
to = strings.Join(args1, " ")
case "ext": // TODO(miek): fix or remove
args1 := c.RemainingArgs()
if len(args1) == 0 {
return nil, c.ArgErr()
}
ext = args1
case "if":
args1 := c.RemainingArgs()
if len(args1) != 3 {
return nil, c.ArgErr()
}
ifCond, err := rewrite.NewIf(args1[0], args1[1], args1[2])
if err != nil {
return nil, err
}
ifs = append(ifs, ifCond)
case "status": // TODO(miek): fix or remove
if !c.NextArg() {
return nil, c.ArgErr()
}
status, _ = strconv.Atoi(c.Val())
if status < 200 || (status > 299 && status < 400) || status > 499 {
return nil, c.Err("status must be 2xx or 4xx")
}
default:
return nil, c.ArgErr()
}
}
// ensure to or status is specified
if to == "" && status == 0 {
return nil, c.ArgErr()
}
// TODO(miek): complex rules
base, pattern, to, status, ext, ifs = base, pattern, to, status, ext, ifs
err = err
// if rule, err = rewrite.NewComplexRule(base, pattern, to, status, ext, ifs); err != nil {
// return nil, err
// }
regexpRules = append(regexpRules, rule)
// the only unhandled case is 2 and above
default:
rule = rewrite.NewSimpleRule(args[0], strings.Join(args[1:], " "))
simpleRules = append(simpleRules, rule)
}
}
// put simple rules in front to avoid regexp computation for them
return append(simpleRules, regexpRules...), nil
}