Fix Content-Length set prior to SendUrl injection

changelogs/unreleased/fix-content-length-missing.yml

+---
+title: Fix Content-Length set prior to SendUrl injection
+merge_request: 496
+author: Georges-Etienne Legendre
+type: fixed

internal/sendurl/sendurl.go

@@ -148,6 +148,9 @@ func (e *entry) Inject(w http.ResponseWriter, r *http.Request, sendData string)
 		return
 	}
 
+	// fix issue #267, where Content-Length was set prior to injection
+	w.Header().Del("Content-Length")
+
 	// copy response headers and body, except the headers from preserveHeaderKeys
 	for key, value := range resp.Header {
 		if !preserveHeaderKeys[key] {