fix application bug

vendor/github.com/mholt/caddy/caddyhttp/proxy/upstream.go

@@ -21,10 +21,13 @@ import (
 	"fmt"
 	"io"
 	"io/ioutil"
+	"log"
 	"net"
 	"net/http"
+	"net/textproto"
 	"net/url"
 	"path"
+	"regexp"
 	"strconv"
 	"strings"
 	"sync"
@@ -65,18 +68,39 @@ type staticUpstream struct {
 		Port          string
 		ContentString string
 	}
-	WithoutPathPrefix  string
-	IgnoredSubPaths    []string
-	insecureSkipVerify bool
-	MaxFails           int32
-	resolver           srvResolver
-	CaCertPool         *x509.CertPool
+	WithoutPathPrefix            string
+	IgnoredSubPaths              []string
+	insecureSkipVerify           bool
+	MaxFails                     int32
+	resolver                     srvResolver
+	CaCertPool                   *x509.CertPool
+	upstreamHeaderReplacements   headerReplacements
+	downstreamHeaderReplacements headerReplacements
 }
 
 type srvResolver interface {
 	LookupSRV(context.Context, string, string, string) (string, []*net.SRV, error)
 }
 
+// headerReplacement stores a compiled regex matcher and a string replacer, for replacement rules
+type headerReplacement struct {
+	regexp *regexp.Regexp
+	to     string
+}
+
+// headerReplacements stores a mapping of canonical MIME header to headerReplacement
+// Implements a subset of http.Header functions, to allow convenient addition and deletion of rules
+type headerReplacements map[string][]headerReplacement
+
+func (h headerReplacements) Add(key string, value headerReplacement) {
+	key = textproto.CanonicalMIMEHeaderKey(key)
+	h[key] = append(h[key], value)
+}
+
+func (h headerReplacements) Del(key string) {
+	delete(h, textproto.CanonicalMIMEHeaderKey(key))
+}
+
 // NewStaticUpstreams parses the configuration input and sets up
 // static upstreams for the proxy middleware. The host string parameter,
 // if not empty, is used for setting the upstream Host header for the
@@ -86,18 +110,20 @@ func NewStaticUpstreams(c caddyfile.Dispenser, host string) ([]Upstream, error)
 	for c.Next() {
 
 		upstream := &staticUpstream{
-			from:              "",
-			stop:              make(chan struct{}),
-			upstreamHeaders:   make(http.Header),
-			downstreamHeaders: make(http.Header),
-			Hosts:             nil,
-			Policy:            &Random{},
-			MaxFails:          1,
-			TryInterval:       250 * time.Millisecond,
-			MaxConns:          0,
-			KeepAlive:         http.DefaultMaxIdleConnsPerHost,
-			Timeout:           30 * time.Second,
-			resolver:          net.DefaultResolver,
+			from:                         "",
+			stop:                         make(chan struct{}),
+			upstreamHeaders:              make(http.Header),
+			downstreamHeaders:            make(http.Header),
+			Hosts:                        nil,
+			Policy:                       &Random{},
+			MaxFails:                     1,
+			TryInterval:                  250 * time.Millisecond,
+			MaxConns:                     0,
+			KeepAlive:                    http.DefaultMaxIdleConnsPerHost,
+			Timeout:                      30 * time.Second,
+			resolver:                     net.DefaultResolver,
+			upstreamHeaderReplacements:   make(headerReplacements),
+			downstreamHeaderReplacements: make(headerReplacements),
 		}
 
 		if !c.Args(&upstream.from) {
@@ -220,9 +246,11 @@ func (u *staticUpstream) NewHost(host string) (*UpstreamHost, error) {
 				return false
 			}
 		}(u),
-		WithoutPathPrefix: u.WithoutPathPrefix,
-		MaxConns:          u.MaxConns,
-		HealthCheckResult: atomic.Value{},
+		WithoutPathPrefix:            u.WithoutPathPrefix,
+		MaxConns:                     u.MaxConns,
+		HealthCheckResult:            atomic.Value{},
+		UpstreamHeaderReplacements:   u.upstreamHeaderReplacements,
+		DownstreamHeaderReplacements: u.downstreamHeaderReplacements,
 	}
 
 	baseURL, err := url.Parse(uh.Name)
@@ -302,6 +330,8 @@ func parseUpstream(u string) ([]string, error) {
 }
 
 func parseBlock(c *caddyfile.Dispenser, u *staticUpstream, hasSrv bool) error {
+	var isUpstream bool
+
 	switch c.Val() {
 	case "policy":
 		if !c.NextArg() {
@@ -431,23 +461,37 @@ func parseBlock(c *caddyfile.Dispenser, u *staticUpstream, hasSrv bool) error {
 		}
 		u.HealthCheck.ContentString = c.Val()
 	case "header_upstream":
-		var header, value string
-		if !c.Args(&header, &value) {
-			// When removing a header, the value can be optional.
-			if !strings.HasPrefix(header, "-") {
-				return c.ArgErr()
-			}
-		}
-		u.upstreamHeaders.Add(header, value)
+		isUpstream = true
+		fallthrough
 	case "header_downstream":
-		var header, value string
-		if !c.Args(&header, &value) {
-			// When removing a header, the value can be optional.
-			if !strings.HasPrefix(header, "-") {
+		var header, value, replaced string
+		if c.Args(&header, &value, &replaced) {
+			// Don't allow - or + in replacements
+			if strings.HasPrefix(header, "-") || strings.HasPrefix(header, "+") {
 				return c.ArgErr()
 			}
+			r, err := regexp.Compile(value)
+			if err != nil {
+				return err
+			}
+			if isUpstream {
+				u.upstreamHeaderReplacements.Add(header, headerReplacement{r, replaced})
+			} else {
+				u.downstreamHeaderReplacements.Add(header, headerReplacement{r, replaced})
+			}
+		} else {
+			if len(value) == 0 {
+				// When removing a header, the value can be optional.
+				if !strings.HasPrefix(header, "-") {
+					return c.ArgErr()
+				}
+			}
+			if isUpstream {
+				u.upstreamHeaders.Add(header, value)
+			} else {
+				u.downstreamHeaders.Add(header, value)
+			}
 		}
-		u.downstreamHeaders.Add(header, value)
 	case "transparent":
 		// Note: X-Forwarded-For header is always being appended for proxy connections
 		// See implementation of createUpstreamRequest in proxy.go
@@ -589,8 +633,10 @@ func (u *staticUpstream) healthCheck() {
 					return true
 				}
 				defer func() {
-					io.Copy(ioutil.Discard, r.Body)
-					r.Body.Close()
+					if _, err := io.Copy(ioutil.Discard, r.Body); err != nil {
+						log.Println("[ERROR] failed to copy: ", err)
+					}
+					_ = r.Body.Close()
 				}()
 				if r.StatusCode < 200 || r.StatusCode >= 400 {
 					return true