[python] asyncio support (#6245)

* trying an approach with providing asyncio as a framework.

* adding example of asyncio.

* removing sample client to help PR look more manageable.

* possibly fixing a unit test

* getting unit test to pass again.

* addressing comments.

.gitignore

@@ -166,6 +166,6 @@ samples/client/petstore/typescript-angular/tsd-debug.log
 # aspnetcore
 samples/server/petstore/aspnetcore/.vs/
 effective.pom
-
 # kotlin
 samples/client/petstore/kotlin/src/main/kotlin/test/
+\?

bin/python-asyncio-petstore.sh

@@ -0,0 +1,31 @@
+#!/bin/sh
+
+SCRIPT="$0"
+
+while [ -h "$SCRIPT" ] ; do
+  ls=`ls -ld "$SCRIPT"`
+  link=`expr "$ls" : '.*-> \(.*\)$'`
+  if expr "$link" : '/.*' > /dev/null; then
+    SCRIPT="$link"
+  else
+    SCRIPT=`dirname "$SCRIPT"`/"$link"
+  fi
+done
+
+if [ ! -d "${APP_DIR}" ]; then
+  APP_DIR=`dirname "$SCRIPT"`/..
+  APP_DIR=`cd "${APP_DIR}"; pwd`
+fi
+
+executable="./modules/swagger-codegen-cli/target/swagger-codegen-cli.jar"
+
+if [ ! -f "$executable" ]
+then
+  mvn clean package
+fi
+
+# if you've executed sbt assembly previously it will use that instead.
+export JAVA_OPTS="${JAVA_OPTS} -XX:MaxPermSize=256M -Xmx1024M -DloggerPath=conf/log4j.properties"
+ags="generate -t modules/swagger-codegen/src/main/resources/python -i modules/swagger-codegen/src/test/resources/2_0/petstore-with-fake-endpoints-models-for-testing.yaml -l python -o samples/client/petstore/python-asyncio -DpackageName=petstore_api --library asyncio $@"
+
+java $JAVA_OPTS -jar $executable $ags

modules/swagger-codegen/src/main/java/io/swagger/codegen/languages/PythonClientCodegen.java

@@ -21,8 +21,11 @@ import java.util.regex.Pattern;
 
 import org.apache.commons.lang3.StringUtils;
 
+import javax.xml.bind.annotation.adapters.XmlJavaTypeAdapter;
+
 public class PythonClientCodegen extends DefaultCodegen implements CodegenConfig {
     public static final String PACKAGE_URL = "packageUrl";
+    public static final String DEFAULT_LIBRARY = "urllib3";
 
     protected String packageName; // e.g. petstore_api
     protected String packageVersion;
@@ -124,6 +127,13 @@ public class PythonClientCodegen extends DefaultCodegen implements CodegenConfig
                 CodegenConstants.SORT_PARAMS_BY_REQUIRED_FLAG_DESC).defaultValue(Boolean.TRUE.toString()));
         cliOptions.add(new CliOption(CodegenConstants.HIDE_GENERATION_TIMESTAMP, "hides the timestamp when files were generated")
                 .defaultValue(Boolean.TRUE.toString()));
+
+        supportedLibraries.put("urllib3", "urllib3-based client");
+        supportedLibraries.put("asyncio", "Asyncio-based client (python 3.5+)");
+        CliOption libraryOption = new CliOption(CodegenConstants.LIBRARY, "library template (sub-template) to use");
+        libraryOption.setDefault(DEFAULT_LIBRARY);
+        cliOptions.add(libraryOption);
+        setLibrary(DEFAULT_LIBRARY);
     }
 
     @Override
@@ -185,13 +195,10 @@ public class PythonClientCodegen extends DefaultCodegen implements CodegenConfig
 
         supportingFiles.add(new SupportingFile("README.mustache", "", "README.md"));
 
-        supportingFiles.add(new SupportingFile("setup.mustache", "", "setup.py"));
         supportingFiles.add(new SupportingFile("tox.mustache", "", "tox.ini"));
         supportingFiles.add(new SupportingFile("test-requirements.mustache", "", "test-requirements.txt"));
         supportingFiles.add(new SupportingFile("requirements.mustache", "", "requirements.txt"));
 
-        supportingFiles.add(new SupportingFile("api_client.mustache", swaggerFolder, "api_client.py"));
-        supportingFiles.add(new SupportingFile("rest.mustache", swaggerFolder, "rest.py"));
         supportingFiles.add(new SupportingFile("configuration.mustache", swaggerFolder, "configuration.py"));
         supportingFiles.add(new SupportingFile("__init__package.mustache", swaggerFolder, "__init__.py"));
         supportingFiles.add(new SupportingFile("__init__model.mustache", modelPackage, "__init__.py"));
@@ -203,6 +210,15 @@ public class PythonClientCodegen extends DefaultCodegen implements CodegenConfig
         supportingFiles.add(new SupportingFile("git_push.sh.mustache", "", "git_push.sh"));
         supportingFiles.add(new SupportingFile("gitignore.mustache", "", ".gitignore"));
         supportingFiles.add(new SupportingFile("travis.mustache", "", ".travis.yml"));
+        supportingFiles.add(new SupportingFile("setup.mustache", "", "setup.py"));
+        supportingFiles.add(new SupportingFile("api_client.mustache", swaggerFolder, "api_client.py"));
+
+        if ("asyncio".equals(getLibrary())) {
+            supportingFiles.add(new SupportingFile("asyncio/rest.mustache", swaggerFolder, "rest.py"));
+            additionalProperties.put("asyncio", "true");
+        } else {
+            supportingFiles.add(new SupportingFile("rest.mustache", swaggerFolder, "rest.py"));
+        }
     }
 
     private static String dropDots(String str) {

modules/swagger-codegen/src/main/resources/python/api_client.mustache

@@ -81,7 +81,7 @@ class ApiClient(object):
     def set_default_header(self, header_name, header_value):
         self.default_headers[header_name] = header_value
 
-    def __call_api(self, resource_path, method,
+    {{#asyncio}}async {{/asyncio}}def __call_api(self, resource_path, method,
                    path_params=None, query_params=None, header_params=None,
                    body=None, post_params=None, files=None,
                    response_type=None, auth_settings=None,
@@ -134,7 +134,7 @@ class ApiClient(object):
         url = self.configuration.host + resource_path
 
         # perform request and return response
-        response_data = self.request(method, url,
+        response_data = {{#asyncio}}await {{/asyncio}}self.request(method, url,
                                      query_params=query_params,
                                      headers=header_params,
                                      post_params=post_params, body=body,

modules/swagger-codegen/src/main/resources/python/asyncio/rest.mustache

@@ -0,0 +1,242 @@
+# coding: utf-8
+
+{{>partial_header}}
+
+import aiohttp
+import io
+import json
+import ssl
+import certifi
+import logging
+import re
+
+# python 2 and python 3 compatibility library
+from six import PY3
+from six.moves.urllib.parse import urlencode
+
+logger = logging.getLogger(__name__)
+
+
+class RESTResponse(io.IOBase):
+
+    def __init__(self, resp, data):
+        self.aiohttp_response = resp
+        self.status = resp.status
+        self.reason = resp.reason
+        self.data = data
+
+    def getheaders(self):
+        """
+        Returns a CIMultiDictProxy of the response headers.
+        """
+        return self.aiohttp_response.headers
+
+    def getheader(self, name, default=None):
+        """
+        Returns a given response header.
+        """
+        return self.aiohttp_response.headers.get(name, default)
+
+
+class RESTClientObject:
+
+    def __init__(self, configuration, pools_size=4, maxsize=4):
+        # maxsize is the number of requests to host that are allowed in parallel
+        # ca_certs vs cert_file vs key_file
+        # http://stackoverflow.com/a/23957365/2985775
+
+        # ca_certs
+        if configuration.ssl_ca_cert:
+            ca_certs = configuration.ssl_ca_cert
+        else:
+            # if not set certificate file, use Mozilla's root certificates.
+            ca_certs = certifi.where()
+
+        ssl_context = ssl.SSLContext()
+        if configuration.cert_file:
+            ssl_context.load_cert_chain(
+                configuration.cert_file, keyfile=configuration.key_file
+            )
+
+        connector = aiohttp.TCPConnector(
+            limit=maxsize,
+            verify_ssl=configuration.verify_ssl
+        )
+
+        # https pool manager
+        if configuration.proxy:
+            self.pool_manager = aiohttp.ClientSession(
+                connector=connector,
+                proxy=configuration.proxy
+            )
+        else:
+            self.pool_manager = aiohttp.ClientSession(
+                connector=connector
+            )
+
+    async def request(self, method, url, query_params=None, headers=None,
+                      body=None, post_params=None, _preload_content=True, _request_timeout=None):
+        """
+        :param method: http request method
+        :param url: http request url
+        :param query_params: query parameters in the url
+        :param headers: http request headers
+        :param body: request json body, for `application/json`
+        :param post_params: request post parameters,
+                            `application/x-www-form-urlencoded`
+                            and `multipart/form-data`
+        :param _preload_content: this is a non-applicable field for the AiohttpClient.
+        :param _request_timeout: timeout setting for this request. If one number provided, it will be total request
+                                 timeout. It can also be a pair (tuple) of (connection, read) timeouts.
+        """
+        method = method.upper()
+        assert method in ['GET', 'HEAD', 'DELETE', 'POST', 'PUT', 'PATCH', 'OPTIONS']
+
+        if post_params and body:
+            raise ValueError(
+                "body parameter cannot be used with post_params parameter."
+            )
+
+        post_params = post_params or {}
+        headers = headers or {}
+        timeout = _request_timeout or 5 * 60
+
+        if 'Content-Type' not in headers:
+            headers['Content-Type'] = 'application/json'
+
+        args = {
+            "method": method,
+            "url": url,
+            "timeout": timeout,
+            "headers": headers
+        }
+        # For `POST`, `PUT`, `PATCH`, `OPTIONS`, `DELETE`
+        if method in ['POST', 'PUT', 'PATCH', 'OPTIONS', 'DELETE']:
+            if query_params:
+                url += '?' + urlencode(query_params)
+            if re.search('json', headers['Content-Type'], re.IGNORECASE):
+                if body:
+                    body = json.dumps(body)
+                args["data"] = body
+            elif headers['Content-Type'] == 'application/x-www-form-urlencoded':
+                data = aiohttp.FormData()
+                for k, v in post_params.items():
+                    data.add_field(k, v)
+                args["data"] = data
+            elif headers['Content-Type'] == 'multipart/form-data':
+                args["data"] = post_params
+            # Pass a `bytes` parameter directly in the body to support
+            # other content types than Json when `body` argument is provided
+            # in serialized form
+            elif isinstance(body, bytes):
+                args["data"] = body
+            else:
+                # Cannot generate the request from given parameters
+                msg = """Cannot prepare a request message for provided arguments.
+                Please check that your arguments match declared content type."""
+                raise ApiException(status=0, reason=msg)
+        else:
+            args["data"] = query_params
+
+        async with self.pool_manager.request(**args) as r:
+            data = await r.text()
+            r = RESTResponse(r, data)
+
+        # log response body
+        logger.debug("response body: %s", r.data)
+
+        if not 200 <= r.status <= 299:
+            raise ApiException(http_resp=r)
+
+        return r
+
+    async def GET(self, url, headers=None, query_params=None, _preload_content=True, _request_timeout=None):
+        return (await self.request("GET", url,
+                                  headers=headers,
+                                  _preload_content=_preload_content,
+                                  _request_timeout=_request_timeout,
+                                  query_params=query_params))
+
+    async def HEAD(self, url, headers=None, query_params=None, _preload_content=True, _request_timeout=None):
+        return (await self.request("HEAD", url,
+                                   headers=headers,
+                                   _preload_content=_preload_content,
+                                   _request_timeout=_request_timeout,
+                                   query_params=query_params))
+
+    async def OPTIONS(self, url, headers=None, query_params=None, post_params=None, body=None, _preload_content=True,
+                _request_timeout=None):
+        return (await self.request("OPTIONS", url,
+                                   headers=headers,
+                                   query_params=query_params,
+                                   post_params=post_params,
+                                   _preload_content=_preload_content,
+                                   _request_timeout=_request_timeout,
+                                   body=body))
+
+    async def DELETE(self, url, headers=None, query_params=None, body=None, _preload_content=True, _request_timeout=None):
+        return (await self.request("DELETE", url,
+                                   headers=headers,
+                                   query_params=query_params,
+                                   _preload_content=_preload_content,
+                                   _request_timeout=_request_timeout,
+                                   body=body))
+
+    async def POST(self, url, headers=None, query_params=None, post_params=None, body=None, _preload_content=True,
+             _request_timeout=None):
+        return (await self.request("POST", url,
+                                   headers=headers,
+                                   query_params=query_params,
+                                   post_params=post_params,
+                                   _preload_content=_preload_content,
+                                   _request_timeout=_request_timeout,
+                                   body=body))
+
+    async def PUT(self, url, headers=None, query_params=None, post_params=None, body=None, _preload_content=True,
+            _request_timeout=None):
+        return (await self.request("PUT", url,
+                                   headers=headers,
+                                   query_params=query_params,
+                                   post_params=post_params,
+                                   _preload_content=_preload_content,
+                                   _request_timeout=_request_timeout,
+                                   body=body))
+
+    async def PATCH(self, url, headers=None, query_params=None, post_params=None, body=None, _preload_content=True,
+              _request_timeout=None):
+        return (await self.request("PATCH", url,
+                                   headers=headers,
+                                   query_params=query_params,
+                                   post_params=post_params,
+                                   _preload_content=_preload_content,
+                                   _request_timeout=_request_timeout,
+                                   body=body))
+
+
+class ApiException(Exception):
+
+    def __init__(self, status=None, reason=None, http_resp=None):
+        if http_resp:
+            self.status = http_resp.status
+            self.reason = http_resp.reason
+            self.body = http_resp.data
+            self.headers = http_resp.getheaders()
+        else:
+            self.status = status
+            self.reason = reason
+            self.body = None
+            self.headers = None
+
+    def __str__(self):
+        """
+        Custom error messages for exception
+        """
+        error_message = "({0})\n"\
+                        "Reason: {1}\n".format(self.status, self.reason)
+        if self.headers:
+            error_message += "HTTP response headers: {0}\n".format(self.headers)
+
+        if self.body:
+            error_message += "HTTP response body: {0}\n".format(self.body)
+
+        return error_message

modules/swagger-codegen/src/main/resources/python/setup.mustache

@@ -18,6 +18,9 @@ VERSION = "{{packageVersion}}"
 # http://pypi.python.org/pypi/setuptools
 
 REQUIRES = ["urllib3 >= 1.15", "six >= 1.10", "certifi", "python-dateutil"]
+{{#asyncio}}
+REQUIRES.append("aiohttp")
+{{/asyncio}}
 
 setup(
     name=NAME,

modules/swagger-codegen/src/test/java/io/swagger/codegen/options/PythonClientOptionsProvider.java

@@ -27,6 +27,7 @@ public class PythonClientOptionsProvider implements OptionsProvider {
                 .put(CodegenConstants.PACKAGE_VERSION, PACKAGE_VERSION_VALUE)
                 .put(CodegenConstants.SORT_PARAMS_BY_REQUIRED_FLAG, "true")
                 .put(CodegenConstants.HIDE_GENERATION_TIMESTAMP, "true")
+                .put(CodegenConstants.LIBRARY, "urllib3")
                 .build();
     }
 

modules/swagger-codegen/src/test/java/io/swagger/codegen/python/PythonClientOptionsTest.java

@@ -27,12 +27,10 @@ public class PythonClientOptionsTest extends AbstractOptionsTest {
     protected void setExpectations() {
         new Expectations(clientCodegen) {{
             clientCodegen.setPackageName(PythonClientOptionsProvider.PACKAGE_NAME_VALUE);
-            times = 1;
             clientCodegen.setProjectName(PythonClientOptionsProvider.PROJECT_NAME_VALUE);
-            times = 1;
             clientCodegen.setPackageVersion(PythonClientOptionsProvider.PACKAGE_VERSION_VALUE);
-            times = 1;
             clientCodegen.setPackageUrl(PythonClientOptionsProvider.PACKAGE_URL_VALUE);
+            // clientCodegen.setLibrary(PythonClientCodegen.DEFAULT_LIBRARY);
             times = 1;
         }};
     }