fix(drive): write files.download --output contents

crates/google-workspace-cli/src/executor.rs

@@ -187,10 +187,7 @@ async fn build_http_request(
         }
     }
 
-    // Set quota project from ADC for billing/quota attribution
-    if let Some(quota_project) = crate::auth::get_quota_project() {
-        request = request.header("x-goog-user-project", quota_project);
-    }
+    request = add_quota_project_header(request);
 
     let mut all_query_params = input.query_params.clone();
     if let Some(pt) = page_token {
@@ -384,6 +381,50 @@ async fn handle_binary_response(
     Ok(None)
 }
 
+fn extract_download_uri(json_val: &Value) -> Option<&str> {
+    [
+        "/response/downloadUri",
+        "/response/downloadUrl",
+        "/metadata/downloadUri",
+        "/metadata/downloadUrl",
+        "/downloadUri",
+        "/downloadUrl",
+    ]
+    .into_iter()
+    .find_map(|path| json_val.pointer(path).and_then(|v| v.as_str()))
+}
+
+fn is_google_download_uri(uri: &str) -> bool {
+    let Ok(url) = reqwest::Url::parse(uri) else {
+        return false;
+    };
+    if url.scheme() != "https" || !url.username().is_empty() || url.password().is_some() {
+        return false;
+    }
+    let Some(host) = url.host_str() else {
+        return false;
+    };
+
+    host == "storage.googleapis.com"
+        || host.ends_with(".googleapis.com")
+        || host.ends_with(".googleusercontent.com")
+}
+
+fn extract_google_download_uri(body_text: &str) -> Result<Option<String>, GwsError> {
+    let Ok(json_val) = serde_json::from_str::<Value>(body_text) else {
+        return Ok(None);
+    };
+    let Some(uri) = extract_download_uri(&json_val) else {
+        return Ok(None);
+    };
+    if !is_google_download_uri(uri) {
+        return Err(GwsError::Validation(
+            "Refusing to follow non-Google downloadUri from API response".to_string(),
+        ));
+    }
+    Ok(Some(uri.to_string()))
+}
+
 /// Executes an API method call.
 ///
 /// This is the core function of the CLI that handles:
@@ -464,7 +505,10 @@ pub async fn execute_method(
             .to_string();
 
         if !status.is_success() {
-            let error_body = response.text().await.unwrap_or_default();
+            let error_body = response
+                .text()
+                .await
+                .context("Failed to read API error response body")?;
             tracing::warn!(
                 api_method = method_id,
                 http_method = %method.http_method,
@@ -495,6 +539,45 @@ pub async fn execute_method(
                 .await
                 .context("Failed to read response body")?;
 
+            if output_path.is_some() && method.id.as_deref() == Some("drive.files.download") {
+                if let Some(download_uri) = extract_google_download_uri(&body_text)? {
+                    let download_request =
+                        build_download_request(&client, &download_uri, token, &auth_method);
+                    let download_response = download_request
+                        .send()
+                        .await
+                        .context("HTTP download request failed")?;
+                    let download_status = download_response.status();
+                    let download_content_type = download_response
+                        .headers()
+                        .get("content-type")
+                        .and_then(|v| v.to_str().ok())
+                        .unwrap_or("application/octet-stream")
+                        .to_string();
+
+                    if !download_status.is_success() {
+                        let error_body = download_response
+                            .text()
+                            .await
+                            .context("Failed to read Drive download error response body")?;
+                        return handle_error_response(download_status, &error_body, &auth_method);
+                    }
+
+                    if let Some(res) = handle_binary_response(
+                        download_response,
+                        &download_content_type,
+                        output_path,
+                        output_format,
+                        capture_output,
+                    )
+                    .await?
+                    {
+                        captured_values.push(res);
+                    }
+                    break;
+                }
+            }
+
             let should_continue = handle_json_response(
                 &body_text,
                 pagination,
@@ -537,6 +620,31 @@ pub async fn execute_method(
     Ok(None)
 }
 
+fn add_quota_project_header(request: reqwest::RequestBuilder) -> reqwest::RequestBuilder {
+    if let Some(quota_project) = crate::auth::get_quota_project() {
+        request.header("x-goog-user-project", quota_project)
+    } else {
+        request
+    }
+}
+
+fn build_download_request(
+    client: &reqwest::Client,
+    download_uri: &str,
+    token: Option<&str>,
+    auth_method: &AuthMethod,
+) -> reqwest::RequestBuilder {
+    // Keep secondary Drive downloads on the same reqwest client so they use
+    // the same client-level configuration as API requests.
+    let mut request = add_quota_project_header(client.get(download_uri));
+    if let Some(token) = token {
+        if *auth_method == AuthMethod::OAuth {
+            request = request.bearer_auth(token);
+        }
+    }
+    request
+}
+
 fn build_url(
     doc: &RestDescription,
     method: &RestMethod,
@@ -1209,6 +1317,97 @@ mod tests {
         assert_ne!(AuthMethod::OAuth, AuthMethod::None);
     }
 
+    #[test]
+    fn test_extract_download_uri_from_drive_operation_response() {
+        let operation = json!({
+            "done": true,
+            "response": {
+                "downloadUri": "https://www.googleapis.com/download/drive/v3/files/abc?alt=media"
+            }
+        });
+
+        assert_eq!(
+            extract_download_uri(&operation),
+            Some("https://www.googleapis.com/download/drive/v3/files/abc?alt=media")
+        );
+    }
+
+    #[test]
+    fn test_extract_google_download_uri_rejects_non_google_url() {
+        let operation = json!({
+            "done": true,
+            "response": {
+                "downloadUri": "https://example.com/file.csv"
+            }
+        })
+        .to_string();
+
+        let err = extract_google_download_uri(&operation).unwrap_err();
+        assert!(err.to_string().contains("non-Google downloadUri"));
+    }
+
+    #[test]
+    #[serial_test::serial]
+    fn test_add_quota_project_header_uses_configured_project() {
+        unsafe {
+            std::env::set_var("GOOGLE_WORKSPACE_PROJECT_ID", "quota-project");
+        }
+
+        let request = add_quota_project_header(reqwest::Client::new().get("https://example.com"))
+            .build()
+            .unwrap();
+
+        unsafe {
+            std::env::remove_var("GOOGLE_WORKSPACE_PROJECT_ID");
+        }
+
+        assert_eq!(
+            request
+                .headers()
+                .get("x-goog-user-project")
+                .and_then(|value| value.to_str().ok()),
+            Some("quota-project")
+        );
+    }
+
+    #[test]
+    #[serial_test::serial]
+    fn test_build_download_request_keeps_client_auth_and_quota_headers() {
+        let client = reqwest::Client::new();
+
+        unsafe {
+            std::env::set_var("GOOGLE_WORKSPACE_PROJECT_ID", "quota-project");
+        }
+
+        let request = build_download_request(
+            &client,
+            "https://www.googleapis.com/download/drive/v3/files/abc?alt=media",
+            Some("access-token"),
+            &AuthMethod::OAuth,
+        )
+        .build()
+        .unwrap();
+
+        unsafe {
+            std::env::remove_var("GOOGLE_WORKSPACE_PROJECT_ID");
+        }
+
+        assert_eq!(
+            request
+                .headers()
+                .get("x-goog-user-project")
+                .and_then(|value| value.to_str().ok()),
+            Some("quota-project")
+        );
+        assert_eq!(
+            request
+                .headers()
+                .get(reqwest::header::AUTHORIZATION)
+                .and_then(|value| value.to_str().ok()),
+            Some("Bearer access-token")
+        );
+    }
+
     #[test]
     fn test_mime_to_extension_more_types() {
         assert_eq!(mime_to_extension("text/plain"), "txt");