feat: add proxy support to ClobClient initialization

[zyaiire]

Summary

Fixes #309

Adds optional proxy parameter to ClobClient initialization, allowing users in regions with restricted access to configure an HTTP/HTTPS proxy for all CLOB API requests.

Changes

• Added set_proxy(proxy) function to py_clob_client/http_helpers/helpers.py that reconfigures the shared httpx.Client with the given proxy URL
• Added optional proxy: Optional[str] = None parameter to ClobClient.__init__ — when provided, calls set_proxy() during initialization
• Added unit tests for set_proxy() in tests/http_helpers/test_proxy.py

Usage

from py_clob_client.client import ClobClient

# With proxy
client = ClobClient(
    host="https://clob.polymarket.com",
    chain_id=137,
    key="0x...",
    proxy="http://user:pass@proxy-host:8080",
)

# Without proxy (default, backward-compatible)
client = ClobClient(
    host="https://clob.polymarket.com",
    chain_id=137,
    key="0x...",
)

Testing

• Added tests/http_helpers/test_proxy.py with 3 test cases covering proxy set, proxy=None, and proxy="" (empty string)
• No new dependencies required — httpx natively supports the proxy parameter
• Fully backward-compatible: proxy defaults to None, preserving existing behavior

---

Note

Medium Risk
Introduces a new global httpx.Client reconfiguration path and closes/replaces the shared client, which could affect connection reuse or concurrent callers if used in multi-client scenarios.

Overview
Adds optional proxy configuration for all API requests by introducing set_proxy() in http_helpers/helpers.py, which rebuilds the shared httpx.Client with (or without) a proxy setting.

ClobClient.__init__ now accepts proxy and applies it during client construction, and new unit tests validate proxy/non-proxy behavior and that the old client is closed.

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Cursor Bugbot has reviewed your changes and found 2 potential issues.

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[cursor]

Unconditional set_proxy call destroys shared HTTP client

High Severity

set_proxy(proxy) is called unconditionally in __init__, even when proxy is None (the default). Since set_proxy always closes the existing module-level _http_client and creates a new one, every ClobClient instantiation — even without a proxy — destroys the shared HTTP client, dropping all keep-alive connections and HTTP/2 state. This is a regression for all existing users and can break in-flight requests if multiple ClobClient instances coexist.

Additional Locations (1)

• py_clob_client/http_helpers/helpers.py#L21-L35

 

[cursor]

Tests assert on wrong mock object for close

Medium Severity

The module-level _http_client is a real httpx.Client created at import time, before the mock is applied. When set_proxy runs, the mocked httpx.Client() call returns side_effect[0] (the test's old_client MagicMock) as the new _http_client. Then .close() is called on the real original client, not the MagicMock. The assertion old_client.close.assert_called_once() checks the wrong object, so these tests would fail when run.

Additional Locations (2)

• tests/http_helpers/test_proxy.py#L21-L28
• tests/http_helpers/test_proxy.py#L32-L39