web: add implicit user agent transport to the default one

1 files changed, 26 insertions, 0 deletions

diff --git a/web/user_agent.go b/web/user_agent.go
new file mode 100644
index 0000000..8e4bd4c
--- /dev/null
+++ b/web/user_agent.go
@@ -0,0 +1,26 @@
+package web
+
+import (
+	"fmt"
+	"net/http"
+	"os"
+	"path/filepath"
+	"runtime"
+)
+
+func init() {
+	http.DefaultTransport = &userAgentTransport{http.DefaultTransport}
+}
+
+func genUserAgent() string {
+	return fmt.Sprintf("github.com-Xe-x (%s/%s/%s; %s/bot; +https://github.com/Xe/x/blob/master/web/x.md)", runtime.Version(), runtime.GOOS, runtime.GOARCH, filepath.Base(os.Args[0]))
+}
+
+type userAgentTransport struct {
+	rt http.RoundTripper
+}
+
+func (uat userAgentTransport) RoundTrip(r *http.Request) (*http.Response, error) {
+	r.Header.Set("User-Agent", genUserAgent())
+	return uat.rt.RoundTrip(r)
+}