Merge pull request #488 from rstudio/no-proxy

Add NO_PROXY support

Author: mmarchetti

CHANGELOG.md

@@ -3,6 +3,17 @@ All notable changes to this project will be documented in this file.
 
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
+## Unreleased
+
+### Fixed
+- The `https_proxy` environment variable is recognized as a synonym for
+  `HTTPS_PROXY`.
+
+### Added
+- Added support for the `no_proxy` or `NO_PROXY` environment variables to specify
+  hosts that should not be accessed via proxy server. It's a comma-separated list
+  of host or domain suffixes. For example, specifying `example.com` will
+  bypass the proxy for example.com, host.example.com, etc.
 
 ## [1.20.0] - 2023-09-11
 

rsconnect/http_support.py

@@ -37,7 +37,7 @@ def _create_plain_connection(host_name, port, disable_tls_check, ca_data):
 
 
 def _get_proxy():
-    proxyURL = os.getenv("HTTPS_PROXY")
+    proxyURL = os.getenv("https_proxy", os.getenv("HTTPS_PROXY"))
     if not proxyURL:
         return None, None, None, None
     parsed = urlparse(proxyURL)
@@ -75,7 +75,12 @@ def _create_ssl_connection(host_name, port, disable_tls_check, ca_data):
     """
     if ca_data is not None and disable_tls_check:
         raise ValueError("Cannot both disable TLS checking and provide a custom certificate")
-    _, _, proxyHost, proxyPort = _get_proxy()
+
+    no_proxy = os.environ.get("no_proxy", os.environ.get("NO_PROXY", "#"))
+    if any([host_name.endswith(host) for host in no_proxy.split(",")]):
+        proxyHost, proxyPort = None, None
+    else:
+        _, _, proxyHost, proxyPort = _get_proxy()
     headers = _get_proxy_headers()
     timeout = get_request_timeout()
     logger.debug(f"The HTTPSConnection timeout is set to '{timeout}' seconds")