python: reinstate no_proxy support

Author: bachorp

modules/openapi-generator/src/main/resources/python/configuration.mustache

@@ -413,6 +413,9 @@ conf = {{{packageName}}}.Configuration(
         self.proxy: Optional[str] = None
         """Proxy URL
         """
+        self.no_proxy = None
+        """bypass proxy for host in the no_proxy list.
+        """
         self.proxy_headers = None
         """Proxy headers
         """

modules/openapi-generator/src/main/resources/python/rest.mustache

@@ -3,9 +3,12 @@
 {{>partial_header}}
 
 import io
+import ipaddress
 import json
 import re
 import ssl
+from urllib.parse import urlparse
+from urllib.request import proxy_bypass_environment
 
 import urllib3
 
@@ -89,7 +92,7 @@ class RESTClientObject:
         # https pool manager
         self.pool_manager: urllib3.PoolManager
 
-        if configuration.proxy:
+        if configuration.proxy and not should_bypass_proxies(configuration.host, no_proxy=configuration.no_proxy or ''):
             if is_socks_proxy_url(configuration.proxy):
                 from urllib3.contrib.socks import SOCKSProxyManager
                 pool_args["proxy_url"] = configuration.proxy
@@ -246,3 +249,54 @@ class RESTClientObject:
             raise ApiException(status=0, reason=msg)
 
         return RESTResponse(r)
+
+def is_ipv4(target):
+    """ Test if IPv4 address or not
+    """
+    try:
+       chk = ipaddress.IPv4Address(target)
+       return True
+    except ipaddress.AddressValueError:
+       return False
+
+def in_ipv4net(target, net):
+    """ Test if target belongs to given IPv4 network
+    """
+    try:
+        nw = ipaddress.IPv4Network(net)
+        ip = ipaddress.IPv4Address(target)
+        if ip in nw:
+            return True
+        return False
+    except ipaddress.AddressValueError:
+        return False
+    except ipaddress.NetmaskValueError:
+        return False
+
+def should_bypass_proxies(url, no_proxy=None):
+    """ Yet another requests.should_bypass_proxies
+    Test if proxies should not be used for a particular url.
+    """
+
+    parsed = urlparse(url)
+
+    # special cases
+    if parsed.hostname in [None, '']:
+        return True
+
+    # special cases
+    if no_proxy in [None , '']:
+        return False
+    if no_proxy == '*':
+        return True
+
+    no_proxy = no_proxy.lower().replace(' ','');
+    entries = (
+        host for host in no_proxy.split(',') if host
+    )
+
+    if is_ipv4(parsed.hostname):
+        for item in entries:
+           if in_ipv4net(parsed.hostname, item):
+               return True
+    return proxy_bypass_environment(parsed.hostname, {'no': no_proxy} )

modules/openapi-generator/src/test/java/org/openapitools/codegen/python/PythonClientCodegenTest.java

@@ -25,6 +25,7 @@
 import io.swagger.v3.parser.core.models.ParseOptions;
 import io.swagger.v3.parser.util.SchemaTypeUtil;
 import org.openapitools.codegen.*;
+import org.openapitools.codegen.config.CodegenConfigurator;
 import org.openapitools.codegen.languages.PythonClientCodegen;
 import org.openapitools.codegen.languages.features.CXFServerFeatures;
 import org.testng.Assert;
@@ -611,4 +612,26 @@ public void testInitFileImportsExports() throws IOException {
         assertFileContains(initFilePath, "from openapi_client.models.tag import Tag as Tag");
         assertFileContains(initFilePath, "from openapi_client.models.user import User as User");
     }
+
+    @Test(description = "tests NoProxyPyClient")
+    public void testNoProxyPyClient() throws Exception {
+
+        final String gen = "python";
+        final String spec = "src/test/resources/3_0/petstore.yaml";
+
+        File output = Files.createTempDirectory("test").toFile();
+        final CodegenConfigurator configurator = new CodegenConfigurator()
+                .setGeneratorName(gen)
+                .setInputSpec(spec)
+                .setOutputDir(output.getAbsolutePath().replace("\\", "/"));
+        final ClientOptInput clientOptInput = configurator.toClientOptInput();
+        DefaultGenerator generator = new DefaultGenerator();
+        List<File> files = generator.opts(clientOptInput).generate();
+
+        for (String f : new String[] { "openapi_client/configuration.py", "openapi_client/rest.py" } ) {
+            TestUtils.ensureContainsFile(files, output, f);
+            Path p = output.toPath().resolve(f);
+            TestUtils.assertFileContains(p, "no_proxy");
+        }
+    }
 }