use different registry when in china, fixes #3700 (#3702)

reflex/constants/installer.py

@@ -51,6 +51,8 @@ class Bun(SimpleNamespace):
     WINDOWS_INSTALL_URL = (
         "https://raw.githubusercontent.com/reflex-dev/reflex/main/scripts/install.ps1"
     )
+    # Path of the bunfig file
+    CONFIG_PATH = "bunfig.toml"
 
 
 # FNM config.

reflex/utils/prerequisites.py

@@ -38,6 +38,7 @@ from reflex.compiler import templates
 from reflex.config import Config, get_config
 from reflex.utils import console, path_ops, processes
 from reflex.utils.format import format_library_name
+from reflex.utils.registry import _get_best_registry
 
 CURRENTLY_INSTALLING_NODE = False
 
@@ -577,6 +578,15 @@ def initialize_package_json():
     code = _compile_package_json()
     output_path.write_text(code)
 
+    best_registry = _get_best_registry()
+    bun_config_path = get_web_dir() / constants.Bun.CONFIG_PATH
+    bun_config_path.write_text(
+        f"""
+[install]
+registry = "{best_registry}"
+"""
+    )
+
 
 def init_reflex_json(project_hash: int | None):
     """Write the hash of the Reflex project to a REFLEX_JSON.

reflex/utils/registry.py

@@ -0,0 +1,48 @@
+"""Utilities for working with registries."""
+
+import httpx
+
+from reflex.utils import console
+
+
+def latency(registry: str) -> int:
+    """Get the latency of a registry.
+
+    Args:
+        registry (str): The URL of the registry.
+
+    Returns:
+        int: The latency of the registry in microseconds.
+    """
+    try:
+        return httpx.get(registry).elapsed.microseconds
+    except httpx.HTTPError:
+        console.info(f"Failed to connect to {registry}.")
+        return 10_000_000
+
+
+def average_latency(registry, attempts: int = 3) -> int:
+    """Get the average latency of a registry.
+
+    Args:
+        registry (str): The URL of the registry.
+        attempts (int): The number of attempts to make. Defaults to 10.
+
+    Returns:
+        int: The average latency of the registry in microseconds.
+    """
+    return sum(latency(registry) for _ in range(attempts)) // attempts
+
+
+def _get_best_registry() -> str:
+    """Get the best registry based on latency.
+
+    Returns:
+        str: The best registry.
+    """
+    registries = [
+        "https://registry.npmjs.org",
+        "https://r.cnpmjs.org",
+    ]
+
+    return min(registries, key=average_latency)