From 0a449f6ea8f3ac352ba540a0ea21ad060a3cba50 Mon Sep 17 00:00:00 2001
From: Sergey Kvachonok <ravenexp@gmail.com>
Date: Tue, 30 Apr 2024 14:55:32 +0300
Subject: [PATCH] feat: Add HTTP client `User-Agent` header

Identify the download client as a proxy server to the crates.io servers.
---
 src/main.rs | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/src/main.rs b/src/main.rs
index 06906c6..f4af73e 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -96,6 +96,9 @@ const JSON_HTTP_CTYPE: &str = "Content-Type: application/json; charset=utf-8";
 /// Program version tag: `"<major>.<minor>.<patch>"`
 const VERSION: &str = env!("CARGO_PKG_VERSION");
 
+/// HTTP client User Agent string
+const HTTP_USER_AGENT: &str = concat!("crates-io-proxy/", env!("CARGO_PKG_VERSION"));
+
 /// Proxy server configuration
 #[derive(Debug, Clone)]
 struct ProxyConfig {
@@ -135,7 +138,10 @@ struct IndexResponse {
 /// The global agent instance is required to use HTTP request pipelining.
 fn ureq_agent() -> ureq::Agent {
     static AGENT: OnceLock<ureq::Agent> = OnceLock::new();
-    AGENT.get_or_init(ureq::agent).clone()
+
+    AGENT
+        .get_or_init(|| ureq::builder().user_agent(HTTP_USER_AGENT).build())
+        .clone()
 }
 
 /// Downloads the crate file from the upstream download server