set content_length as len(body) if response ContentLength is -1 (#2407)

* set content_length as len(body) if response ContentLength is -1

* move content-length calculation to utils

* adding basic tests

Co-authored-by: Mzack9999 <mzack9999@protonmail.com>

v2/pkg/protocols/http/operators.go

@@ -12,6 +12,7 @@ import (
 	"github.com/projectdiscovery/nuclei/v2/pkg/output"
 	"github.com/projectdiscovery/nuclei/v2/pkg/protocols"
 	"github.com/projectdiscovery/nuclei/v2/pkg/protocols/common/helpers/responsehighlighter"
+	"github.com/projectdiscovery/nuclei/v2/pkg/protocols/utils"
 	"github.com/projectdiscovery/nuclei/v2/pkg/types"
 )
 
@@ -121,7 +122,6 @@ func (request *Request) responseToDSLMap(resp *http.Response, host, matched, raw
 	data["response"] = rawResp
 	data["status_code"] = resp.StatusCode
 	data["body"] = body
-	data["content_length"] = resp.ContentLength
 	data["all_headers"] = headers
 	data["header"] = headers
 	data["duration"] = duration.Seconds()
@@ -129,6 +129,8 @@ func (request *Request) responseToDSLMap(resp *http.Response, host, matched, raw
 	data["template-info"] = request.options.TemplateInfo
 	data["template-path"] = request.options.TemplatePath
 
+	data["content_length"] = utils.CalculateContentLength(resp.ContentLength, int64(len(body)))
+
 	if request.StopAtFirstMatch || request.options.StopAtFirstMatch {
 		data["stop-at-first-match"] = true
 	}

v2/pkg/protocols/offlinehttp/operators.go

@@ -12,6 +12,7 @@ import (
 	"github.com/projectdiscovery/nuclei/v2/pkg/output"
 	"github.com/projectdiscovery/nuclei/v2/pkg/protocols"
 	"github.com/projectdiscovery/nuclei/v2/pkg/protocols/common/helpers/responsehighlighter"
+	"github.com/projectdiscovery/nuclei/v2/pkg/protocols/utils"
 	"github.com/projectdiscovery/nuclei/v2/pkg/types"
 )
 
@@ -112,7 +113,6 @@ func (request *Request) responseToDSLMap(resp *http.Response, host, matched, raw
 	data["matched"] = matched
 	data["request"] = rawReq
 	data["response"] = rawResp
-	data["content_length"] = resp.ContentLength
 	data["status_code"] = resp.StatusCode
 	data["body"] = body
 	data["type"] = request.Type().String()
@@ -121,6 +121,8 @@ func (request *Request) responseToDSLMap(resp *http.Response, host, matched, raw
 	data["template-id"] = request.options.TemplateID
 	data["template-info"] = request.options.TemplateInfo
 	data["template-path"] = request.options.TemplatePath
+	data["content_length"] = utils.CalculateContentLength(resp.ContentLength, int64(len(body)))
+
 	return data
 }
 

v2/pkg/protocols/utils/utils.go

@@ -38,3 +38,11 @@ func AddConfiguredClientCertToRequest(tlsConfig *tls.Config, options *types.Opti
 	}
 	return tlsConfig, nil
 }
+
+// CalculateContentLength calculates content-length of the http response
+func CalculateContentLength(contentLength, bodyLength int64) int64 {
+	if contentLength > -1 {
+		return contentLength
+	}
+	return bodyLength
+}

v2/pkg/protocols/utils/utils_test.go

@@ -0,0 +1,27 @@
+package utils
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+func TestCalculateContentLength(t *testing.T) {
+	tests := []struct {
+		name                string
+		expected            int64
+		contentLengthHeader int64
+		bodyLength          int64
+	}{
+		{"content-length-header", 10, 10, 10},
+		{"content-length-header-with-body-length", 10, 10, 1000},
+		{"no-content-length-header-with-body-length", 1000, -1, 1000},
+		{"content-length-header-without-body-length", 10, 10, -1},
+	}
+	for _, test := range tests {
+		t.Run(test.name, func(t *testing.T) {
+			got := CalculateContentLength(test.contentLengthHeader, test.bodyLength)
+			require.Equal(t, test.expected, got)
+		})
+	}
+}