Rewrite: Support for Regular Expressions.

config/setup/rewrite.go

@@ -60,6 +60,7 @@ func rewriteParse(c *Controller) ([]rewrite.Rule, error) {
 					return nil, c.ArgErr()
 				}
 			}
+			// ensure pattern and to are specified
 			if pattern == "" || to == "" {
 				return nil, c.ArgErr()
 			}

config/setup/rewrite_test.go

@@ -3,7 +3,9 @@ package setup
 import (
 	"testing"
 
+	"fmt"
 	"github.com/mholt/caddy/middleware/rewrite"
+	"regexp"
 )
 
 func TestRewrite(t *testing.T) {
@@ -33,27 +35,27 @@ func TestRewrite(t *testing.T) {
 }
 
 func TestRewriteParse(t *testing.T) {
-	tests := []struct {
+	simpleTests := []struct {
 		input     string
 		shouldErr bool
 		expected  []rewrite.Rule
 	}{
 		{`rewrite /from /to`, false, []rewrite.Rule{
-			{From: "/from", To: "/to"},
+			rewrite.SimpleRule{"/from", "/to"},
 		}},
 		{`rewrite /from /to
 		  rewrite a b`, false, []rewrite.Rule{
-			{From: "/from", To: "/to"},
-			{From: "a", To: "b"},
+			rewrite.SimpleRule{"/from", "/to"},
+			rewrite.SimpleRule{"a", "b"},
 		}},
 		{`rewrite a`, true, []rewrite.Rule{}},
 		{`rewrite`, true, []rewrite.Rule{}},
 		{`rewrite a b c`, true, []rewrite.Rule{
-			{From: "a", To: "b"},
+			rewrite.SimpleRule{"a", "b"},
 		}},
 	}
 
-	for i, test := range tests {
+	for i, test := range simpleTests {
 		c := newTestController(test.input)
 		actual, err := rewriteParse(c)
 
@@ -61,6 +63,8 @@ func TestRewriteParse(t *testing.T) {
 			t.Errorf("Test %d didn't error, but it should have", i)
 		} else if err != nil && !test.shouldErr {
 			t.Errorf("Test %d errored, but it shouldn't have; got '%v'", i, err)
+		} else if err != nil && test.shouldErr {
+			continue
 		}
 
 		if len(actual) != len(test.expected) {
@@ -68,8 +72,9 @@ func TestRewriteParse(t *testing.T) {
 				i, len(test.expected), len(actual))
 		}
 
-		for j, expectedRule := range test.expected {
-			actualRule := actual[j]
+		for j, e := range test.expected {
+			actualRule := actual[j].(rewrite.SimpleRule)
+			expectedRule := e.(rewrite.SimpleRule)
 
 			if actualRule.From != expectedRule.From {
 				t.Errorf("Test %d, rule %d: Expected From=%s, got %s",
@@ -82,4 +87,98 @@ func TestRewriteParse(t *testing.T) {
 			}
 		}
 	}
+
+	regexpTests := []struct {
+		input     string
+		shouldErr bool
+		expected  []rewrite.Rule
+	}{
+		{`rewrite {
+			r	.*
+			to	/to
+		 }`, false, []rewrite.Rule{
+			&rewrite.RegexpRule{"/", "/to", nil, regexp.MustCompile(".*")},
+		}},
+		{`rewrite {
+			regexp	.*
+			to		/to
+			ext		/ html txt
+		 }`, false, []rewrite.Rule{
+			&rewrite.RegexpRule{"/", "/to", []string{"/", "html", "txt"}, regexp.MustCompile(".*")},
+		}},
+		{`rewrite /path {
+			r	rr
+			to	/dest
+		 }
+		 rewrite / {
+		 	regexp	[a-z]+
+		 	to 		/to
+		 }
+		 `, false, []rewrite.Rule{
+			&rewrite.RegexpRule{"/path", "/dest", nil, regexp.MustCompile("rr")},
+			&rewrite.RegexpRule{"/", "/to", nil, regexp.MustCompile("[a-z]+")},
+		}},
+		{`rewrite {
+			to	/to
+		 }`, true, []rewrite.Rule{
+			&rewrite.RegexpRule{},
+		}},
+		{`rewrite {
+			r	.*
+		 }`, true, []rewrite.Rule{
+			&rewrite.RegexpRule{},
+		}},
+		{`rewrite {
+
+		 }`, true, []rewrite.Rule{
+			&rewrite.RegexpRule{},
+		}},
+		{`rewrite /`, true, []rewrite.Rule{
+			&rewrite.RegexpRule{},
+		}},
+	}
+
+	for i, test := range regexpTests {
+		c := newTestController(test.input)
+		actual, err := rewriteParse(c)
+
+		if err == nil && test.shouldErr {
+			t.Errorf("Test %d didn't error, but it should have", i)
+		} else if err != nil && !test.shouldErr {
+			t.Errorf("Test %d errored, but it shouldn't have; got '%v'", i, err)
+		} else if err != nil && test.shouldErr {
+			continue
+		}
+
+		if len(actual) != len(test.expected) {
+			t.Fatalf("Test %d expected %d rules, but got %d",
+				i, len(test.expected), len(actual))
+		}
+
+		for j, e := range test.expected {
+			actualRule := actual[j].(*rewrite.RegexpRule)
+			expectedRule := e.(*rewrite.RegexpRule)
+
+			if actualRule.Base != expectedRule.Base {
+				t.Errorf("Test %d, rule %d: Expected Base=%s, got %s",
+					i, j, expectedRule.Base, actualRule.Base)
+			}
+
+			if actualRule.To != expectedRule.To {
+				t.Errorf("Test %d, rule %d: Expected To=%s, got %s",
+					i, j, expectedRule.To, actualRule.To)
+			}
+
+			if fmt.Sprint(actualRule.Exts) != fmt.Sprint(expectedRule.Exts) {
+				t.Errorf("Test %d, rule %d: Expected Ext=%v, got %v",
+					i, j, expectedRule.To, actualRule.To)
+			}
+
+			if actualRule.String() != expectedRule.String() {
+				t.Errorf("Test %d, rule %d: Expected Pattern=%s, got %s",
+					i, j, expectedRule.String(), actualRule.String())
+			}
+		}
+	}
+
 }

middleware/rewrite/rewrite.go

@@ -30,31 +30,47 @@ func (rw Rewrite) ServeHTTP(w http.ResponseWriter, r *http.Request) (int, error)
 	return rw.Next.ServeHTTP(w, r)
 }
 
-// A Rule describes an internal location rewrite rule.
+// Rule describes an internal location rewrite rule.
 type Rule interface {
+	// Rewrite rewrites the internal location of the current request.
 	Rewrite(*http.Request) bool
 }
 
-type SimpleRule [2]string
+// SimpleRule is a simple rewrite rule.
+type SimpleRule struct {
+	From, To string
+}
 
+// NewSimpleRule creates a new Simple Rule
 func NewSimpleRule(from, to string) SimpleRule {
 	return SimpleRule{from, to}
 }
 
+// Rewrite rewrites the internal location of the current request.
 func (s SimpleRule) Rewrite(r *http.Request) bool {
-	if s[0] == r.URL.Path {
-		r.URL.Path = s[1]
+	if s.From == r.URL.Path {
+		r.URL.Path = s.To
 		return true
 	}
 	return false
 }
 
+// RegexpRule is a rewrite rule based on a regular expression
 type RegexpRule struct {
-	base, to string
-	ext      []string
+	// Path base. Request to this path and subpaths will be rewritten
+	Base string
+
+	// Path to rewrite to
+	To string
+
+	// Extensions to filter by
+	Exts []string
+
 	*regexp.Regexp
 }
 
+// NewRegexpRule creates a new RegexpRule. It returns an error if regexp
+// pattern (pattern) or extensions (ext) are invalid.
 func NewRegexpRule(base, pattern, to string, ext []string) (*RegexpRule, error) {
 	r, err := regexp.Compile(pattern)
 	if err != nil {
@@ -64,7 +80,7 @@ func NewRegexpRule(base, pattern, to string, ext []string) (*RegexpRule, error)
 	// validate extensions
 	for _, v := range ext {
 		if len(v) < 2 || (len(v) < 3 && v[0] == '!') {
-			// check if it is no extension
+			// check if no extension is specified
 			if v != "/" && v != "!/" {
 				return nil, fmt.Errorf("Invalid extension %v", v)
 			}
@@ -79,48 +95,62 @@ func NewRegexpRule(base, pattern, to string, ext []string) (*RegexpRule, error)
 	}, nil
 }
 
+// regexpVars are variables that can be used for To (rewrite destination path).
 var regexpVars []string = []string{
 	"{path}",
 	"{query}",
 }
 
+// Rewrite rewrites the internal location of the current request.
 func (r *RegexpRule) Rewrite(req *http.Request) bool {
 	rPath := req.URL.Path
-	if strings.Index(rPath, r.base) != 0 {
+
+	// validate base
+	if !strings.HasPrefix(rPath, r.Base) {
 		return false
 	}
+
+	// validate extensions
 	if !r.matchExt(rPath) {
 		return false
 	}
-	if !r.MatchString(rPath[len(r.base):]) {
+
+	// validate regexp
+	if !r.MatchString(rPath[len(r.Base):]) {
 		return false
 	}
 
-	to := r.to
+	to := r.To
 
 	// check variables
 	for _, v := range regexpVars {
-		if strings.Contains(r.to, v) {
+		if strings.Contains(r.To, v) {
 			switch v {
-			case regexpVars[0]:
+			case "{path}":
 				to = strings.Replace(to, v, req.URL.Path[1:], -1)
-			case regexpVars[1]:
+			case "{query}":
 				to = strings.Replace(to, v, req.URL.RawQuery, -1)
 			}
 		}
 	}
 
+	// validate resulting path
 	url, err := url.Parse(to)
 	if err != nil {
 		return false
 	}
 
+	// perform rewrite
 	req.URL.Path = url.Path
-	req.URL.RawQuery = url.RawQuery
-
+	if url.RawQuery != "" {
+		// overwrite query string if present
+		req.URL.RawQuery = url.RawQuery
+	}
 	return true
 }
 
+// matchExt matches rPath against registered file extensions.
+// Returns true if a match is found and false otherwise.
 func (r *RegexpRule) matchExt(rPath string) bool {
 	f := filepath.Base(rPath)
 	ext := path.Ext(f)
@@ -129,7 +159,7 @@ func (r *RegexpRule) matchExt(rPath string) bool {
 	}
 
 	mustUse := false
-	for _, v := range r.ext {
+	for _, v := range r.Exts {
 		use := true
 		if v[0] == '!' {
 			use = false

middleware/rewrite/rewrite_test.go

@@ -7,16 +7,38 @@ import (
 	"testing"
 
 	"github.com/mholt/caddy/middleware"
+	"strings"
 )
 
 func TestRewrite(t *testing.T) {
 	rw := Rewrite{
 		Next: middleware.HandlerFunc(urlPrinter),
 		Rules: []Rule{
-			{From: "/from", To: "/to"},
-			{From: "/a", To: "/b"},
+			NewSimpleRule("/from", "/to"),
+			NewSimpleRule("/a", "/b"),
 		},
 	}
+
+	regexpRules := [][]string{
+		[]string{"/reg/", ".*", "/to", ""},
+		[]string{"/r/", "[a-z]+", "/toaz", "!.html|"},
+		[]string{"/url/", "a([a-z0-9]*)s([A-Z]{2})", "/to/{path}", ""},
+		[]string{"/ab/", "ab", "/ab?{query}", ".txt|"},
+		[]string{"/ab/", "ab", "/ab?type=html&{query}", ".html|"},
+	}
+
+	for _, regexpRule := range regexpRules {
+		var ext []string
+		if s := strings.Split(regexpRule[3], "|"); len(s) > 1 {
+			ext = s[:len(s)-1]
+		}
+		rule, err := NewRegexpRule(regexpRule[0], regexpRule[1], regexpRule[2], ext)
+		if err != nil {
+			t.Fatal(err)
+		}
+		rw.Rules = append(rw.Rules, rule)
+	}
+
 	tests := []struct {
 		from       string
 		expectedTo string
@@ -29,6 +51,25 @@ func TestRewrite(t *testing.T) {
 		{"/asdf?foo=bar", "/asdf?foo=bar"},
 		{"/foo#bar", "/foo#bar"},
 		{"/a#foo", "/b#foo"},
+		{"/reg/foo", "/to"},
+		{"/re", "/re"},
+		{"/r/", "/r/"},
+		{"/r/123", "/r/123"},
+		{"/r/a123", "/toaz"},
+		{"/r/abcz", "/toaz"},
+		{"/r/z", "/toaz"},
+		{"/r/z.html", "/r/z.html"},
+		{"/r/z.js", "/toaz"},
+		{"/url/asAB", "/to/url/asAB"},
+		{"/url/aBsAB", "/url/aBsAB"},
+		{"/url/a00sAB", "/to/url/a00sAB"},
+		{"/url/a0z0sAB", "/to/url/a0z0sAB"},
+		{"/ab/aa", "/ab/aa"},
+		{"/ab/ab", "/ab/ab"},
+		{"/ab/ab.txt", "/ab"},
+		{"/ab/ab.txt?name=name", "/ab?name=name"},
+		{"/ab/ab.html?name=name", "/ab?type=html&name=name"},
+		{"/ab/ab.html", "/ab?type=html&"},
 	}
 
 	for i, test := range tests {