Use a default user agent

cmd/csaf_aggregator/config.go

@@ -301,6 +301,11 @@ func (c *config) httpClient(p *provider) util.Client {
 			Client: client,
 			Header: c.ExtraHeader,
 		}
+	default:
+		client = &util.HeaderClient{
+			Client: client,
+			Header: http.Header{},
+		}
 	}
 
 	if c.Verbose {

cmd/csaf_checker/processor.go

@@ -435,11 +435,9 @@ func (p *processor) fullClient() util.Client {
 	client := util.Client(&hClient)
 
 	// Add extra headers.
-	if len(p.cfg.ExtraHeader) > 0 {
-		client = &util.HeaderClient{
-			Client: client,
-			Header: p.cfg.ExtraHeader,
-		}
+	client = &util.HeaderClient{
+		Client: client,
+		Header: p.cfg.ExtraHeader,
 	}
 
 	// Add optional URL logging.

cmd/csaf_downloader/downloader.go

@@ -126,11 +126,9 @@ func (d *downloader) httpClient() util.Client {
 	client := util.Client(&hClient)
 
 	// Add extra headers.
-	if len(d.cfg.ExtraHeader) > 0 {
-		client = &util.HeaderClient{
-			Client: client,
-			Header: d.cfg.ExtraHeader,
-		}
+	client = &util.HeaderClient{
+		Client: client,
+		Header: d.cfg.ExtraHeader,
 	}
 
 	// Add optional URL logging.

cmd/csaf_downloader/forwarder.go

@@ -111,11 +111,9 @@ func (f *forwarder) httpClient() util.Client {
 	client := util.Client(&hClient)
 
 	// Add extra headers.
-	if len(f.cfg.ForwardHeader) > 0 {
-		client = &util.HeaderClient{
-			Client: client,
-			Header: f.cfg.ForwardHeader,
-		}
+	client = &util.HeaderClient{
+		Client: client,
+		Header: f.cfg.ForwardHeader,
 	}
 
 	// Add optional URL logging.

util/client.go

@@ -61,6 +61,11 @@ func (hc *HeaderClient) Do(req *http.Request) (*http.Response, error) {
 			req.Header.Add(key, v)
 		}
 	}
+
+	// Use default user agent if none is set
+	if userAgent := hc.Header.Get("User-Agent"); userAgent == "" {
+		req.Header.Add("User-Agent", "csaf-distribution/"+SemVersion)
+	}
 	return hc.Client.Do(req)
 }