Python 搭建 Web 服务器

1. 简单的 Web 服务器
2. 接受请求并返回结果的服务器
   1. 服务端
   2. 客户端

使用 Python 的 Web Server Gateway Interface (WSGI) 搭建 Web 服务器，参考官网：https://docs.python.org/2/library/wsgiref.html

简单的 Web 服务器

保存以下代码为 server.py，运行 python server.py，访问 http://127.0.0.1:8000 就能看到效果了。

其中，

• environ：一个包含所有 HTTP 请求信息的 dict 对象
• start_response：一个发送 HTTP 响应的函数

from wsgiref.simple_server import make_server


# Every WSGI application must have an application object - a callable
# object that accepts two arguments. For that purpose, we're going to
# use a function (note that you're not limited to a function, you can
# use a class for example). The first argument passed to the function
# is a dictionary containing CGI-style environment variables and the
# second variable is the callable object (see PEP 333).
def hello_world_app(environ, start_response):
    status = '200 OK'  # HTTP Status
    headers = [('Content-type', 'text/plain')]  # HTTP Headers
    start_response(status, headers)
    # The returned object is going to be printed
    return ["Hello World"]


httpd = make_server('', 8000, hello_world_app)
print "Serving on port 8000..."

# Serve until process is killed
httpd.serve_forever()

接受请求并返回结果的服务器

服务端

运行 python server.py 即启动服务器。

• 使用 environ['REQUEST_METHOD'] 即可判断请求的类型。
• 使用 environ['wsgi.input'].read(environ[CONTENT_LENGTH]) 即可读请求里的内容。

server.py:

"""Server.
"""
from __future__ import print_function

import os
import json
import time
import base64
import argparse
from wsgiref.simple_server import make_server


def get_args():
    """Get arguments.

    Returns:
        Namespace, arguments.
    """
    parser = argparse.ArgumentParser(description=__doc__)
    parser.add_argument('--server_host',
                        type=str,
                        default='0.0.0.0',
                        help='Server host.')
    parser.add_argument('--server_port',
                        type=int,
                        default=8000,
                        help='Server port.')
    parser.add_argument('--images_dir',
                        type=str,
                        default='upload_images/',
                        help='Images directory.')
    args = parser.parse_args()
    return args


ARGS = get_args()


def application(environ, start_response):
    """Application

    Args:
        environ: dict, environment values.
        start_response: func, start_response function.

    Returns:
        str, response.
    """
    method = environ['REQUEST_METHOD']
    path = environ['PATH_INFO']
    status = '200 OK'
    if method == 'POST' and path == '/upload':
        headers = [('Content-type', 'application/json')]
        content_length = int(environ.get('CONTENT_LENGTH', 0))
        request_body = environ['wsgi.input'].read(content_length)
        request_body = json.loads(request_body)
        image_data = request_body['image']
        image_path = os.path.join(ARGS.images_dir,
                                  '{}.jpg'.format(time.time()))
        image_data = base64.b64decode(image_data)
        open(image_path, 'wb').write(image_data)
        response = {'info': 'Get text: {}'.format(request_body['text'])}
        start_response(status, headers)
        return [json.dumps(response)]
    headers = [('Content-type', 'text/plain')]
    start_response(status, headers)
    return 'Hello World'


def main():
    """main.
    """
    print('-----------  Configuration Arguments -----------')
    for arg, value in sorted(vars(ARGS).items()):
        print('{}: {}'.format(arg, value))
    print('------------------------------------------------')
    if not os.path.exists(ARGS.images_dir):
        os.makedirs(ARGS.images_dir)
    httpd = make_server(ARGS.server_host, ARGS.server_port, application)
    print('[INFO] Serving on port {}...'.format(ARGS.server_port))
    # Serve until process is killed
    httpd.serve_forever()


if __name__ == '__main__':
    main()

客户端

使用 urllib2 对服务进行 GET/POST 请求：运行 python client.py 即可进行简单的请求。

client.py:

"""Request demo.
"""
from __future__ import print_function

import json
import time
import base64
import urllib2
import argparse


def get_args():
    """Get arguments.

    Returns:
        Namespace, arguments.
    """
    parser = argparse.ArgumentParser(description=__doc__)
    parser.add_argument('--server_url',
                        type=str,
                        default='0.0.0.0:8000',
                        help='Server url.')
    parser.add_argument('--image_path',
                        type=str,
                        default='1.jpg',
                        help='Image path.')
    args = parser.parse_args()
    return args


def do_request(args):
    """Request.

    Args:
        args: args.
    """
    # get
    service_url = 'http://{}'.format(args.server_url)
    print('{} GET'.format(time.ctime()))
    request = urllib2.Request(service_url)
    request.add_header('Content-Type', 'text/plain')
    response = urllib2.urlopen(request, timeout=3000).read()
    print(response)
    # post
    service_url = 'http://{}/upload'.format(args.server_url)
    print('{} POST {}'.format(time.ctime(), args.image_path))
    image_data = open(args.image_path, 'rb').read()
    image_data = base64.b64encode(image_data)
    request_json = {
        'text': 'Upload {}'.format(args.image_path),
        'image': image_data
    }
    request_json = json.dumps(request_json)
    request = urllib2.Request(service_url)
    request.add_header('Content-Type', 'application/json')
    response = urllib2.urlopen(request, request_json, 3000).read()
    response = json.loads(response)
    print(response)


def main():
    """main.
    """
    args = get_args()
    print('-----------  Configuration Arguments -----------')
    for arg, value in sorted(vars(args).items()):
        print('{}: {}'.format(arg, value))
    print('------------------------------------------------')
    do_request(args)


if __name__ == '__main__':
    main()