Add support for setting a global default User-Agent

http/client/client.go

@@ -72,9 +72,13 @@ func New(url string) *Client {
 
 // NewClientWithConfig initializes a new HTTP client with application config options.
 func NewClientWithConfig(url string, opts *config.Options) *Client {
+	userAgent := opts.UserAgent()
+	if userAgent == "" {
+		userAgent = DefaultUserAgent
+	}
 	return &Client{
 		inputURL:          url,
-		requestUserAgent:  DefaultUserAgent,
+		requestUserAgent:  userAgent,
 		ClientTimeout:     opts.HTTPClientTimeout(),
 		ClientMaxBodySize: opts.HTTPClientMaxBodySize(),
 		ClientProxyURL:    opts.HTTPClientProxy(),

http/client/client_test.go

@@ -4,7 +4,12 @@
 
 package client // import "miniflux.app/http/client"
 
-import "testing"
+import (
+	"os"
+	"testing"
+
+	"miniflux.app/config"
+)
 
 func TestClientWithDelay(t *testing.T) {
 	clt := New("http://httpbin.org/delay/5")
@@ -49,3 +54,21 @@ func TestClientWithBasicAuth(t *testing.T) {
 		t.Fatalf(`The client should be authenticated successfully: %v`, err)
 	}
 }
+
+func TestClientRequestUserAgent(t *testing.T) {
+	clt := New("http://httpbin.org")
+	if clt.requestUserAgent != DefaultUserAgent {
+		t.Errorf(`The client had default User-Agent %q, wanted %q`, clt.requestUserAgent, DefaultUserAgent)
+	}
+
+	userAgent := "Custom User Agent"
+	os.Setenv("USER_AGENT", userAgent)
+	opts, err := config.NewParser().ParseEnvironmentVariables()
+	if err != nil {
+		t.Fatalf(`Parsing config failed: %v`, err)
+	}
+	clt = NewClientWithConfig("http://httpbin.org", opts)
+	if clt.requestUserAgent != userAgent {
+		t.Errorf(`The client had User-Agent %q, wanted %q`, clt.requestUserAgent, userAgent)
+	}
+}