First commit

core/setup/rewrite.go

@@ -0,0 +1,109 @@
+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":
+					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":
+					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
+}