aiohttp模块1 client

Make a Request

import aiohttp
async with aiohttp.ClientSession() as session:
    async with session.get('https://api.github.com/events') as resp:
        print(resp.status)
        print(await resp.text())
session.post('http://httpbin.org/post', data=b'data')
session.put('http://httpbin.org/put', data=b'data')
session.delete('http://httpbin.org/delete')
session.head('http://httpbin.org/get')
session.options('http://httpbin.org/get')
session.patch('http://httpbin.org/patch', data=b'data')

aiohttp.ClientSession.get(self, url, allow_redirects=True, **kwargs)
aiohttp.ClientSession.post(self, url, data=None, **kwargs)
aiohttp.ClientSession.put(self, url, data=None, **kwargs)
aiohttp.ClientSession.delete(self, url, **kwargs)
aiohttp.ClientSession.head(self, url, allow_redirects=False, **kwargs)
aiohttp.ClientSession.options(self, url, allow_redirects=True, **kwargs)
aiohttp.ClientSession.patch(self, url, data=None, **kwargs)
# 无须为每个request建立session. 仅需要为每个application建立session供所有request使用. session内部包含连接池，connection复用与长连接加速总性能。

Passing Parameters In URLs

# 字典
params = {'key1': 'value1', 'key2': 'value2'}
async with session.get('http://httpbin.org/get', params=params) as resp:
    assert str(resp.url) == 'http://httpbin.org/get?key2=value2&key1=value1'
# 数组
params = [('key', 'value1'), ('key', 'value2')]
async with session.get('http://httpbin.org/get', params=params) as r:
    assert str(r.url) == 'http://httpbin.org/get?key=value2&key=value1'
# 字符串
async with session.get('http://httpbin.org/get', params='key=value+1') as r:
    assert str(r.url) == 'http://httpbin.org/get?key=value+1'
# aiohttp在发送请求前在内部自动对url进行转码，如URL('http://example.com/путь%30?a=%31') -> URL('http://example.com/%D0%BF%D1%83%D1%82%D1%8C/0?a=1')
# 使用encoded=True开关禁用， 如await session.get(URL('http://example.com/%30', encoded=True))

Response Content and Status Code

async with session.get('https://api.github.com/events') as resp:
    print(resp.status)
    print(await resp.text())

# out
200
'[{"created_at":"2015-06-12T14:06:22Z","public":true,"actor":{... '
# aiohttp自动对服务端返回的内容进行decode.可以使用text()方法自定义encode，如 await resp.text(encoding='windows-1251')

Binary Response Content

async with session.get('https://api.github.com/events') as resp:
    print(await resp.read())

# out
b'[{"created_at":"2015-06-12T14:06:22Z","public":true,"actor":{... ]'
# gzip和deflate压缩算法，自动解码。brotli压缩算法需要安装 brotlipy 模块

JSON Request

async with aiohttp.ClientSession() as session:
    async with session.post(url, json={'test': 'object'})

默认使用标准库json进行序列化，如果想快一点的话，可以使用第三方库ujson，但小小的不兼容

import ujson
async with aiohttp.ClientSession(json_serialize=ujson.dumps) as session:
    async with session.post(url, json={'test': 'object'})

JSON Response Content

async with session.get('https://api.github.com/events') as resp:
    print(await resp.json())
# 如果json解析失败，会抛出异常

Streaming Response Content

async with aiohttp.StreamReader() as session:
    async with session.get('https://api.github.com/events') as resp:
        await resp.content.read(10)
# read(), json()，text()将内容放在内存中，如果文件内容比较大，1G以上，需要使用 aiohttp.StreamReader 替代，它会对gzip和deflate压缩算法自动解码

with open(filename, 'wb') as fd:
    while True:
        chunk = await resp.content.read(chunk_size)
        if not chunk:
            break
        fd.write(chunk)
# 写入文件

More complicated POST requests

payload = {'key1': 'value1', 'key2': 'value2'}
async with session.post('http://httpbin.org/post',
                        data=payload) as resp:
    print(await resp.text())

# form-encoded data (HTML form), 使用字典，字典数据自动编码为form-encoded
{
  ...
  "form": {
    "key2": "value2",
    "key1": "value1"
  },
  ...
}

async with session.post(url, data=b'\x00Binary-data\x00') as resp:
    ...
# 非 form-encoded数据使用bytes类型，数据发送默认使用content-type ‘application/octet-stream’

async with session.post(url, json={'example': 'test'}) as resp:
    ...
# josn类型

async with session.post(url, text='Тест') as resp:
    ...
# content-type text类型

POST a Multipart-Encoded File

url = 'http://httpbin.org/post'
files = {'file': open('report.xls', 'rb')}
await session.post(url, data=files)

url = 'http://httpbin.org/post'
data = FormData()
data.add_field('file',
               open('report.xls', 'rb'),
               filename='report.xls',
               content_type='application/vnd.ms-excel')
await session.post(url, data=data)
# 上传文件对象，aiohttp使用stream

Streaming uploads

with open('massive-body', 'rb') as f:
   await session.post('http://httpbin.org/post', data=f)
# 文件类型过大，使用Stream方式

@aiohttp.streamer
def file_sender(writer, file_name=None):
    with open(file_name, 'rb') as f:
        chunk = f.read(2**16)
        while chunk:
            yield from writer.write(chunk)
            chunk = f.read(2**16)
# Then you can use file_sender as a data provider:
async with session.post('http://httpbin.org/post',
                        data=file_sender(file_name='huge_file')) as resp:
    print(await resp.text())

async def feed_stream(resp, stream):
    h = hashlib.sha256()
    while True:
        chunk = await resp.content.readany()
        if not chunk:
            break
        h.update(chunk)
        stream.feed_data(chunk)
    return h.hexdigest()
resp = session.get('http://httpbin.org/post')
stream = StreamReader()
loop.create_task(session.post('http://httpbin.org/post', data=stream))
file_hash = await feed_stream(resp, stream)

r = await session.get('http://python.org')
await session.post('http://httpbin.org/post', data=r.content)

WebSockets

session = aiohttp.ClientSession()
async with session.ws_connect('http://example.org/websocket') as ws:
    async for msg in ws:
        if msg.type == aiohttp.WSMsgType.TEXT:
            if msg.data == 'close cmd':
                await ws.close()
                break
            else:
                await ws.send_str(msg.data + '/answer')
        elif msg.type == aiohttp.WSMsgType.CLOSED:
            break
        elif msg.type == aiohttp.WSMsgType.ERROR:
            break

Timeouts

async with session.get('https://github.com', timeout=60) as r:
    ...
# 默认IO操作延时5分钟，None 或者 0 禁用延时

# 使用async_timeout模块
import async_timeout
with async_timeout.timeout(0.001):
    async with session.get('https://github.com') as r:
        await r.text()