caddyhttp: Refactor header matching

This allows response matchers to benefit from the same matching logic
as the request header matchers (mainly prefix/suffix wildcards).

1 files changed, 28 insertions, 45 deletions

diff --git a/modules/caddyhttp/matchers.go b/modules/caddyhttp/matchers.go
index 0860780..5dddb71 100644
--- a/modules/caddyhttp/matchers.go
+++ b/modules/caddyhttp/matchers.go
@@ -17,7 +17,6 @@ package caddyhttp
 import (
 	"encoding/json"
 	"fmt"
-	"log"
 	"net"
 	"net/http"
 	"net/textproto"
@@ -28,6 +27,7 @@ import (
 
 	"github.com/caddyserver/caddy/v2"
 	"github.com/caddyserver/caddy/v2/caddyconfig/caddyfile"
+	"go.uber.org/zap"
 )
 
 type (
@@ -105,7 +105,8 @@ type (
 	MatchRemoteIP struct {
 		Ranges []string `json:"ranges,omitempty"`
 
-		cidrs []*net.IPNet
+		cidrs  []*net.IPNet
+		logger *zap.Logger
 	}
 
 	// MatchNot matches requests by negating the results of its matcher
@@ -410,23 +411,28 @@ func (m *MatchHeader) UnmarshalCaddyfile(d *caddyfile.Dispenser) error {
 	return nil
 }
 
-// Like req.Header.Get(), but that works with Host header.
-// go's http module swallows "Host" header.
-func getHeader(r *http.Request, field string) []string {
-	field = textproto.CanonicalMIMEHeaderKey(field)
+// Match returns true if r matches m.
+func (m MatchHeader) Match(r *http.Request) bool {
+	return matchHeaders(r.Header, http.Header(m), r.Host)
+}
 
-	if field == "Host" {
-		return []string{r.Host}
+// getHeaderFieldVals returns the field values for the given fieldName from input.
+// The host parameter should be obtained from the http.Request.Host field since
+// net/http removes it from the header map.
+func getHeaderFieldVals(input http.Header, fieldName, host string) []string {
+	fieldName = textproto.CanonicalMIMEHeaderKey(fieldName)
+	if fieldName == "Host" && host != "" {
+		return []string{host}
 	}
-
-	return r.Header[field]
+	return input[fieldName]
 }
 
-// Match returns true if r matches m.
-func (m MatchHeader) Match(r *http.Request) bool {
-	for field, allowedFieldVals := range m {
-		actualFieldVals := getHeader(r, field)
-
+// matchHeaders returns true if input matches the criteria in against without regex.
+// The host parameter should be obtained from the http.Request.Host field since
+// net/http removes it from the header map.
+func matchHeaders(input, against http.Header, host string) bool {
+	for field, allowedFieldVals := range against {
+		actualFieldVals := getHeaderFieldVals(input, field, host)
 		if allowedFieldVals != nil && len(allowedFieldVals) == 0 && actualFieldVals != nil {
 			// a non-nil but empty list of allowed values means
 			// match if the header field exists at all
@@ -501,8 +507,7 @@ func (m *MatchHeaderRE) UnmarshalCaddyfile(d *caddyfile.Dispenser) error {
 // Match returns true if r matches m.
 func (m MatchHeaderRE) Match(r *http.Request) bool {
 	for field, rm := range m {
-		actualFieldVals := getHeader(r, field)
-
+		actualFieldVals := getHeaderFieldVals(r.Header, field, r.Host)
 		match := false
 	fieldVal:
 		for _, actualFieldVal := range actualFieldVals {
@@ -700,6 +705,7 @@ func (m *MatchRemoteIP) UnmarshalCaddyfile(d *caddyfile.Dispenser) error {
 
 // Provision parses m's IP ranges, either from IP or CIDR expressions.
 func (m *MatchRemoteIP) Provision(ctx caddy.Context) error {
+	m.logger = ctx.Logger(m)
 	for _, str := range m.Ranges {
 		if strings.Contains(str, "/") {
 			_, ipNet, err := net.ParseCIDR(str)
@@ -748,7 +754,7 @@ func (m MatchRemoteIP) getClientIP(r *http.Request) (net.IP, error) {
 func (m MatchRemoteIP) Match(r *http.Request) bool {
 	clientIP, err := m.getClientIP(r)
 	if err != nil {
-		log.Printf("[ERROR] remote_ip matcher: %v", err)
+		m.logger.Error("getting client IP", zap.Error(err))
 		return false
 	}
 	for _, ipRange := range m.cidrs {
@@ -859,7 +865,9 @@ type ResponseMatcher struct {
 	// in that class (e.g. 3 for all 3xx codes).
 	StatusCode []int `json:"status_code,omitempty"`
 
-	// If set, each header specified must be one of the specified values.
+	// If set, each header specified must be one of the
+	// specified values, with the same logic used by the
+	// request header matcher.
 	Headers http.Header `json:"headers,omitempty"`
 }
 
@@ -868,7 +876,7 @@ func (rm ResponseMatcher) Match(statusCode int, hdr http.Header) bool {
 	if !rm.matchStatusCode(statusCode) {
 		return false
 	}
-	return rm.matchHeaders(hdr)
+	return matchHeaders(hdr, rm.Headers, "")
 }
 
 func (rm ResponseMatcher) matchStatusCode(statusCode int) bool {
@@ -883,31 +891,6 @@ func (rm ResponseMatcher) matchStatusCode(statusCode int) bool {
 	return false
 }
 
-func (rm ResponseMatcher) matchHeaders(hdr http.Header) bool {
-	for field, allowedFieldVals := range rm.Headers {
-		actualFieldVals, fieldExists := hdr[textproto.CanonicalMIMEHeaderKey(field)]
-		if allowedFieldVals != nil && len(allowedFieldVals) == 0 && fieldExists {
-			// a non-nil but empty list of allowed values means
-			// match if the header field exists at all
-			continue
-		}
-		var match bool
-	fieldVals:
-		for _, actualFieldVal := range actualFieldVals {
-			for _, allowedFieldVal := range allowedFieldVals {
-				if actualFieldVal == allowedFieldVal {
-					match = true
-					break fieldVals
-				}
-			}
-		}
-		if !match {
-			return false
-		}
-	}
-	return true
-}
-
 var wordRE = regexp.MustCompile(`\w+`)
 
 const regexpPlaceholderPrefix = "http.regexp"