我尝试了python请求库文档中提供的示例。
使用async.map(rs),我获得了响应代码,但我想获得所请求的每个页面的内容。例如,这是行不通的:
out = async.map(rs)
print out[0].content
我尝试了python请求库文档中提供的示例。
使用async.map(rs),我获得了响应代码,但我想获得所请求的每个页面的内容。例如,这是行不通的:
out = async.map(rs)
print out[0].content
当前回答
我已经使用python请求异步调用github的gist API有一段时间了。
举个例子,请看下面的代码:
https://github.com/davidthewatson/flasgist/blob/master/views.py#L60-72
这种风格的python可能不是最清晰的例子,但我可以向您保证代码是有效的。如果这让你感到困惑,请告诉我,我会记录下来。
其他回答
from threading import Thread
threads=list()
for requestURI in requests:
t = Thread(target=self.openURL, args=(requestURI,))
t.start()
threads.append(t)
for thread in threads:
thread.join()
...
def openURL(self, requestURI):
o = urllib2.urlopen(requestURI, timeout = 600)
o...
如果您想使用asyncio,则requests-async为请求提供async/await功能- https://github.com/encode/requests-async
我也尝试过使用python中的异步方法做一些事情,然而我使用twisted进行异步编程的运气要好得多。它的问题较少,并且有良好的文档记录。这里有一个类似于你在twisted中尝试的东西的链接。
http://pythonquirks.blogspot.com/2011/04/twisted-asynchronous-http-request.html
声明:下面的代码为每个函数创建了不同的线程。
这对于某些情况可能是有用的,因为它使用起来更简单。但要知道,它不是异步的,但使用多线程会给人一种异步的错觉,尽管decorator建议这样做。
可以使用以下装饰器在函数执行完成后给出回调,回调必须处理函数返回的数据。
请注意,在函数被修饰后,它将返回一个Future对象。
import asyncio
## Decorator implementation of async runner !!
def run_async(callback, loop=None):
if loop is None:
loop = asyncio.get_event_loop()
def inner(func):
def wrapper(*args, **kwargs):
def __exec():
out = func(*args, **kwargs)
callback(out)
return out
return loop.run_in_executor(None, __exec)
return wrapper
return inner
实现示例:
urls = ["https://google.com", "https://facebook.com", "https://apple.com", "https://netflix.com"]
loaded_urls = [] # OPTIONAL, used for showing realtime, which urls are loaded !!
def _callback(resp):
print(resp.url)
print(resp)
loaded_urls.append((resp.url, resp)) # OPTIONAL, used for showing realtime, which urls are loaded !!
# Must provide a callback function, callback func will be executed after the func completes execution
# Callback function will accept the value returned by the function.
@run_async(_callback)
def get(url):
return requests.get(url)
for url in urls:
get(url)
如果你想看到实时加载的url,你可以在最后添加以下代码:
while True:
print(loaded_urls)
if len(loaded_urls) == len(urls):
break
也许请求-期货是另一种选择。
from requests_futures.sessions import FuturesSession
session = FuturesSession()
# first request is started in background
future_one = session.get('http://httpbin.org/get')
# second requests is started immediately
future_two = session.get('http://httpbin.org/get?foo=bar')
# wait for the first request to complete, if it hasn't already
response_one = future_one.result()
print('response one status: {0}'.format(response_one.status_code))
print(response_one.content)
# wait for the second request to complete, if it hasn't already
response_two = future_two.result()
print('response two status: {0}'.format(response_two.status_code))
print(response_two.content)
办公文档中也有建议。如果你不想卷入gevent,这是一个不错的选择。