Fix wrong Content-Length after ESI parsing

pkg/middleware/writer.go

@@ -3,6 +3,7 @@ package middleware
 import (
 	"bytes"
 	"net/http"
+	"strconv"
 	"sync"
 
 	"github.com/darkweak/go-esi/esi"
@@ -79,13 +80,12 @@ func (r *CustomWriter) Write(b []byte) (int, error) {
 
 // Send delays the response to handle Cache-Status
 func (r *CustomWriter) Send() (int, error) {
-	contentLength := r.Header().Get(rfc.StoredLengthHeader)
-	if contentLength != "" {
-		r.Header().Set("Content-Length", contentLength)
-	}
-
 	defer r.Buf.Reset()
+	r.Header().Set("Content-Length", r.Header().Get(rfc.StoredLengthHeader))
 	b := esi.Parse(r.Buf.Bytes(), r.Req)
+	if len(b) != 0 {
+		r.Header().Set("Content-Length", strconv.Itoa(len(b)))
+	}
 	r.Header().Del(rfc.StoredLengthHeader)
 	r.Header().Del(rfc.StoredTTLHeader)
 

plugins/caddy/httpcache_test.go

@@ -787,3 +787,66 @@ func TestVaryHandler(t *testing.T) {
 		checker(res, 119)
 	}
 }
+
+func TestESITags(t *testing.T) {
+	tester := caddytest.NewTester(t)
+	tester.InitServer(`
+	{
+		admin localhost:2999
+		http_port     9080
+		https_port    9443
+		cache {
+			ttl 1000s
+		}
+	}
+	localhost:9080 {
+		route /esi-include-1 {
+			cache
+			respond "esi-include-1 with some long content to ensure the compute works well. Also add some dummy text with some $pecial characters without recursive esi includes"
+		}
+		route /esi-include-2 {
+			cache
+			respond "esi-include-2"
+		}
+		route /esi-path {
+			cache
+			header Cache-Control "max-age=60"
+			respond "Hello <esi:include src=\"http://localhost:9080/esi-include-1\"/> and <esi:include src=\"http://localhost:9080/esi-include-2\"/>!"
+		}
+	}`, "caddyfile")
+
+	resp1, _ := tester.AssertGetResponse(`http://localhost:9080/esi-path`, 200, "Hello esi-include-1 with some long content to ensure the compute works well. Also add some dummy text with some $pecial characters without recursive esi includes and esi-include-2!")
+	if resp1.Header.Get("Age") != "" {
+		t.Errorf("unexpected Age header %v", resp1.Header.Get("Age"))
+	}
+	if resp1.Header.Get("Cache-Status") != "Souin; fwd=uri-miss; stored; key=GET-http-localhost:9080-/esi-path" {
+		t.Errorf("unexpected Cache-Status header %v", resp1.Header.Get("Cache-Status"))
+	}
+	if resp1.Header.Get("Content-Length") != "180" {
+		t.Errorf("unexpected Content-Length header %v", resp1.Header.Get("Content-Length"))
+	}
+
+	resp2, _ := tester.AssertGetResponse(`http://localhost:9080/esi-path`, 200, "Hello esi-include-1 with some long content to ensure the compute works well. Also add some dummy text with some $pecial characters without recursive esi includes and esi-include-2!")
+	if resp2.Header.Get("Age") == "" {
+		t.Error("Age header should be present")
+	}
+	if resp2.Header.Get("Age") != "1" {
+		t.Error("Age header should be present")
+	}
+
+	resp3, _ := tester.AssertGetResponse(`http://localhost:9080/esi-include-1`, 200, "esi-include-1 with some long content to ensure the compute works well. Also add some dummy text with some $pecial characters without recursive esi includes")
+	if resp3.Header.Get("Age") == "" {
+		t.Error("Age header should be present")
+	}
+	if resp3.Header.Get("Cache-Status") == "Souin; fwd=uri-miss; stored; key=GET-http-localhost:9080-/esi-include-1" {
+		t.Error("Cache-Status should be already stored")
+	}
+
+	resp4, _ := tester.AssertGetResponse(`http://localhost:9080/esi-include-2`, 200, "esi-include-2")
+	if resp4.Header.Get("Age") == "" {
+		t.Error("Age header should be present")
+	}
+	if resp4.Header.Get("Cache-Status") == "Souin; fwd=uri-miss; stored; key=GET-http-localhost:9080-/esi-include-2" {
+		t.Error("Cache-Status should be already stored")
+	}
+}