Add a common way to create HTTP client (#3110)

Ensure User-Agent and originator are always sent.

codex-rs/core/src/default_client.rs

@@ -0,0 +1,106 @@
+pub const DEFAULT_ORIGINATOR: &str = "codex_cli_rs";
+
+pub fn get_codex_user_agent(originator: Option<&str>) -> String {
+    let build_version = env!("CARGO_PKG_VERSION");
+    let os_info = os_info::get();
+    format!(
+        "{}/{build_version} ({} {}; {}) {}",
+        originator.unwrap_or(DEFAULT_ORIGINATOR),
+        os_info.os_type(),
+        os_info.version(),
+        os_info.architecture().unwrap_or("unknown"),
+        crate::terminal::user_agent()
+    )
+}
+
+/// Create a reqwest client with default `originator` and `User-Agent` headers set.
+pub fn create_client(originator: &str) -> reqwest::Client {
+    use reqwest::header::HeaderMap;
+    use reqwest::header::HeaderValue;
+
+    let mut headers = HeaderMap::new();
+    let originator_value = HeaderValue::from_str(originator)
+        .unwrap_or_else(|_| HeaderValue::from_static(DEFAULT_ORIGINATOR));
+    headers.insert("originator", originator_value);
+    let ua = get_codex_user_agent(Some(originator));
+
+    match reqwest::Client::builder()
+        // Set UA via dedicated helper to avoid header validation pitfalls
+        .user_agent(ua)
+        .default_headers(headers)
+        .build()
+    {
+        Ok(client) => client,
+        Err(_) => reqwest::Client::new(),
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_get_codex_user_agent() {
+        let user_agent = get_codex_user_agent(None);
+        assert!(user_agent.starts_with("codex_cli_rs/"));
+    }
+
+    #[tokio::test]
+    async fn test_create_client_sets_default_headers() {
+        use wiremock::Mock;
+        use wiremock::MockServer;
+        use wiremock::ResponseTemplate;
+        use wiremock::matchers::method;
+        use wiremock::matchers::path;
+
+        let originator = "test_originator";
+        let client = create_client(originator);
+
+        // Spin up a local mock server and capture a request.
+        let server = MockServer::start().await;
+        Mock::given(method("GET"))
+            .and(path("/"))
+            .respond_with(ResponseTemplate::new(200))
+            .mount(&server)
+            .await;
+
+        let resp = client
+            .get(server.uri())
+            .send()
+            .await
+            .expect("failed to send request");
+        assert!(resp.status().is_success());
+
+        let requests = server
+            .received_requests()
+            .await
+            .expect("failed to fetch received requests");
+        assert!(!requests.is_empty());
+        let headers = &requests[0].headers;
+
+        // originator header is set to the provided value
+        let originator_header = headers
+            .get("originator")
+            .expect("originator header missing");
+        assert_eq!(originator_header.to_str().unwrap(), originator);
+
+        // User-Agent matches the computed Codex UA for that originator
+        let expected_ua = get_codex_user_agent(Some(originator));
+        let ua_header = headers
+            .get("user-agent")
+            .expect("user-agent header missing");
+        assert_eq!(ua_header.to_str().unwrap(), expected_ua);
+    }
+
+    #[test]
+    #[cfg(target_os = "macos")]
+    fn test_macos() {
+        use regex_lite::Regex;
+        let user_agent = get_codex_user_agent(None);
+        let re = Regex::new(
+            r"^codex_cli_rs/\d+\.\d+\.\d+ \(Mac OS \d+\.\d+\.\d+; (x86_64|arm64)\) (\S+)$",
+        )
+        .unwrap();
+        assert!(re.is_match(&user_agent));
+    }
+}