Develop Reference

Async check of several hundred proxies

I need to check several hundred proxy servers and get the number of not working. Script for this
import urllib.request
import socket
net = ['http://192.168.1.1:8080',
'http://192.168.1.2:8080',
'http://192.168.1.3:8080',
'http://192.168.1.4:8080',
'http://192.168.1.5:8080',
'http://192.168.1.6:8080',
'http://192.168.1.7:8080',
'http://192.168.1.8:8080',
'http://192.168.1.9:8080',
'http://192.168.1.10:8080']
fail = 0
socket.setdefaulttimeout(3)
for x in net:
try:
print(x)
proxy = urllib.request.ProxyHandler({'http': (x)})
opener = urllib.request.build_opener(proxy)
urllib.request.install_opener(opener)
urllib.request.urlretrieve('http://google.com')
except IOError:
print ("Connection error")
fail+=1
print(fail)
Proxies in the list, I have given a simple version.
It takes 55 seconds to check 250 working proxies. I can't wait that long, need to increase the execution speed.
How can this be done using async?

This should give you an idea of how to approach it. You have to wrap the various connection blocks in try, except yourself.
NOTE: This code is not tested as I do not have any way of doing so.
import asyncio, aiohttp
def returnPartionedList(inputlist, x=100):
return([inputlist[i:i + x] for i in range(0, len(inputlist), x)])
# Returns: Original list split into segments of x.
async def TestProxy(url, proxy, session):
async with session.get(url, proxy=proxy, timeout=3) as response:
if response.status == 200:
_ = await response.text()
return(proxy)
async def TestProxies(listofproxies):
returnResults = []
url = "https://google.com" # Test proxy with this url
ProxyPartitions = returnPartionedList(listofproxies, 20) # Rate limit 20 per second
for partition in ProxyPartitions:
ProxyTasks = []
async with aiohttp.ClientSession() as session:
for proxy in partition:
ProxyTasks.append(asyncio.create_task(TestProxy(url, proxy, session)))
results = await asyncio.gather(*ProxyTasks, return_exceptions=False)
if results:
for result in results:
if result:
returnResults.append(result)
await asyncio.sleep(1)
return(returnResults)
async def main():
listofproxies = [
'http://10.10.1.1:8080',
'http://10.10.1.2:8080',
'http://10.10.1.3:8080',
'http://10.10.1.4:8080',
'http://10.10.1.5:8080',
'http://10.10.1.6:8080',
'http://10.10.1.7:8080',
'http://10.10.1.8:8080',
'http://10.10.1.9:8080',
'http://10.10.1.10:8080'
]
test_proxies = await TestProxies(listofproxies)
print(test_proxies)
if __name__ == "__main__":
asyncio.run(main())

Different result between urllib and aiohttp

So basically i'm trying to get the currently playing track from online radio direct link (Example -
http://air.radiorecord.ru:8101/rr_320).
Firstly i found something in the internet, written with urllib, my application is asynchronous so i needed to use aiohttp. With urllib it worked perfectly, while aiohttp sometimes just can't find anything. Pls help :(
before:
def get_now(self, session):
request = urllib.Request(self.data.get('url'),headers={'Icy-MetaData': 1} ) # request metadata
response = urllib.urlopen(request)
metadata = response.headers
metaint = int(response.headers['icy-metaint'])
for _ in range(10): # title may be empty initially, try several times
response.read(metaint) # skip to metadata
metadata_length = struct.unpack('B', response.read(1))[0] * 16 # length byte
metadata = response.read(metadata_length).rstrip(b'\0')
# extract title from the metadata
m = re.search(br"StreamTitle='([^']*)';", metadata)
if m:
title = m.group(1)
if title:
break
else:
return "No title found"
return title.decode('utf8', errors='replace')
except:
return "No title found"
after:
async def get_now(self, session):
async with session.get(self.stream_url, headers={'Icy-MetaData': "1"}) as resp:
content = resp.content
metadata = resp.headers
metaint = int(metadata['icy-metaint'])
for _ in range(30):
await content.read(metaint)
metadata_length = struct.unpack('B', await content.read(1))[0] * 16 # length byte
metadata = (await content.read(metadata_length)).rstrip(b'\0')
m = re.search(br"StreamTitle='([^']*)';", metadata)
if m:
title = m.group(1)
if title:
return title.decode('utf8', errors='replace')
else:
return "No title found"
return "Nothing found"

The snippet below is always able to detect the current track (in around 400ms) but instead of processing only part of the chunk it checks the whole chunk as it's read:
import aiohttp
import asyncio
import re
async def get_now(stream_url, session):
headers={"Icy-MetaData": "1"}
async with session.get(stream_url, headers=headers) as resp:
for _ in range(10):
data = await resp.content.read(8192)
m = re.search(br"StreamTitle='([^']*)';", data.rstrip(b"\0"))
if m:
title = m.group(1)
if title:
return title.decode("utf8", errors="replace")
else:
return "No title found"
return "Nothing found"
async def get_track():
session = aiohttp.ClientSession()
stream_url = "http://air.radiorecord.ru:8101/rr_320"
result = await get_now(stream_url, session)
print(f"result: {result}")
await session.close()
asyncio.run(get_track())
Result on my computer (CPU usage is very low on a quite old CPU: i7-3517U):
[ionut#ionut-pc ~]$ time python test.py
result: Record Club - Nejtrino & Baur
real 0m0.401s
user 0m0.198s
sys 0m0.031s

How to avoid error 429 (Too Many Requests) python with Asyncio

I am using the following code to make requests with aiohttp client. The server that I am trying to send request has a 30k request limit per hour per IP. So I am getting 429 too many request error. I want to put the job on sleep whenever it hits the limit.
I can extract the x_rateLimit_reset from the header so I thought I could use it to put the job on sleep but I observed very strange behavior. Sometimes the job the sleep time becomes negative and sometimes it gets stuck in sleeping mode.
For example, the last time that I ran the job, it first slept for 2000 seconds and then after the time passed, it again tried to sleep for another 2500 seconds and got stuck in sleeping mode. I think maybe the other parallel processes caused the issue so was wondering how to deal with too many request error msg when using Asyncio.
#backoff.on_exception(backoff.expo, (asyncio.TimeoutError, aiohttp.client_exceptions.ServerDisconnectedError,TooManyRequests),
max_time=300)
async def fetch(self, url, session, params):
try:
async with session.get(url, params=params) as response:
now = int(time.time())
print(response)
output = await response.read()
output = json.loads(output)
if 'X-RateLimit-Remaining' in response.headers:
rate = response.headers['X-RateLimit-Remaining']
if 'status' in output and output['status'] == 429:
x_rateLimit_reset = int(response.headers['X-RateLimit-Reset'])
print("sleep mode")
seconds = x_rateLimit_reset - now
LOGGER.info("The job will sleep for {} seconds".format(seconds))
time.sleep(max(seconds,0))
raise TooManyRequests()
return output
except (asyncio.TimeoutError, TypeError, json.decoder.JSONDecodeError,
aiohttp.client_exceptions.ServerDisconnectedError) as e:
print(str(e))
async def bound_fetch(self, sem, url, session, params):
# Getter function with semaphore.
async with sem:
output = await self.fetch(url, session, params)
return {"url": url, "output": output}
Edited:
This is how I initiate bound_fetch and define the URLs:
def get_responses(self, urls, office_token, params=None):
loop = asyncio.get_event_loop()
future = asyncio.ensure_future(self.run(office_token, urls, params))
responses = loop.run_until_complete(future)
return responses
async def run(self, office_token, urls, params):
tasks = []
# create instance of Semaphore
sem = asyncio.BoundedSemaphore(200)
timeout = ClientTimeout(total=1000)
async with ClientSession(auth=BasicAuth(office_token, password=' '), timeout=timeout,
connector=TCPConnector(ssl=False)) as session:
for url in urls:
# pass Semaphore and session to every GET request
task = asyncio.ensure_future(self.bound_fetch(sem, url, session, params))
tasks.append(task)
responses = await asyncio.gather(*tasks)
return responses
urls = [
"{}/{}".format(self.base_url, "{}?page={}&api_key={}".format(object_name, page_number, self.api_keys))
for page_number in range(batch * chunk_size + 1, chunk_size * (1 + batch) + 1)]

Main reason you are using time.sleep() instead await asyncio.sleep().
UPDATE
Here is minimal working solution and some comment how it works.
Please use it to adopt your solution.
Take a look on asyncio-throttle
import aiohttp
import asyncio
from datetime import datetime
async def fetch(session, task): # fetching urls and mark result of execution
async with session.get(task['url']) as response:
if response.status != 200:
# response.raise_for_status()
# Here you need to somehow handle 429 code if it acquired
# In my example I just skip it.
task['result'] = response.status
task['status'] = 'done'
await response.text() # just to be sure we acquire data
print(f"{str(datetime.now())}: Got result of {task['url']}") # logging
task['result'] = response.status
task['status'] = 'done'
async def fetch_all(session, urls, persecond):
# convert to list of dicts
url_tasks = [{'url': i, 'result': None, 'status': 'new'} for i in urls]
n = 0 # counter
while True:
# calc how many tasks are fetching right now
running_tasks = len([i for i in url_tasks if i['status'] in ['fetch']])
# calc how many tasks are still need to be executed
is_tasks_to_wait = len([i for i in url_tasks if i['status'] != 'done'])
# check we are not in the end of list n < len()
# check we have room for one more task
if n < len(url_tasks) and running_tasks < persecond:
url_tasks[n]['status'] = 'fetch'
#
# Here is main trick
# If you schedule task inside running loop
# it will start to execute sync code until find some await
#
asyncio.create_task(fetch(session, url_tasks[n]))
n += 1
print(f'Schedule tasks {n}. '
f'Running {running_tasks} '
f'Remain {is_tasks_to_wait}')
# Check persecond constrain and wait a sec (or period)
if running_tasks >= persecond:
print('Throttling')
await asyncio.sleep(1)
#
# Here is another main trick
# To keep asyncio.run (or loop.run_until_complete) executing
# we need to wait a little than check that all tasks are done and
# wait and so on
if is_tasks_to_wait != 0:
await asyncio.sleep(0.1) # wait all tasks done
else:
# All tasks done
break
return url_tasks
async def main():
urls = ['http://google.com/?1',
'http://google.com/?2',
'http://google.com/?3']*3
async with aiohttp.ClientSession() as session:
res = await fetch_all(session, urls, 3)
print(res)
if __name__ == '__main__':
asyncio.run(main())
# (asyncio.run) do cancel all pending tasks (we do not have them,
# because we check all task done)
# (asyncio.run) do await canceling all tasks
# (asyncio.run) do stop loop
# exit program

Asyncio exception handling, possible to not gather exceptions?

I have some code, which makes some API calls with asyncio and aiohttp. For some urls, asyncio will raise an exception, so I allow it to return it (with asyncio.gather(return_exceptions = True)), so it doesn't break the event loop. Is it possible to no gather the returned exceptions, so it returns only the results which worked? Or do I need to clean up the list manually afterwards?
This is the code:
import asyncio
import aiohttp
import ssl
import datetime as dt
limit = 30
start_epoch = int(dt.datetime(2018,7,1).timestamp())
end_epoch = int(dt.datetime.now().timestamp())
epoch_step = 40000
url_list = []
while True:
url = "https://api.pushshift.io/reddit/search/comment/?q=" + "Nestle" + "&size=" + str(limit) + "&after=" + str(start_epoch) + "&before=" + str(start_epoch + epoch_step)
url_list.append(url)
start_epoch += epoch_step
if start_epoch > end_epoch:
break
async def fetch(session, url):
async with session.get(url, ssl=ssl.SSLContext()) as response:
return await response.json()
async def fetch_all(urls, loop):
async with aiohttp.ClientSession(loop=loop) as session:
results = await asyncio.gather(*[fetch(session, url) for url in urls], return_exceptions=True)
return results
if __name__ == '__main__':
loop = asyncio.get_event_loop()
urls = url_list
htmls = loop.run_until_complete(fetch_all(urls, loop))
print(htmls)
and it returns a list which looks something like this:
[ContentTypeError("0, message='Attempt to decode JSON with unexpected mimetype: text/html'",), {'data': [{'author':...]

aiohttp: rate limiting requests-per-second by domain

I am writing a web crawler that is running parallel fetches for many different domains. I want to limit the number of requests-per-second that are made to each individual domain, but I do not care about the total number of connections that are open, or the total requests per second that are made across all domains. I want to maximize the number of open connections and requests-per-second overall, while limiting the number of requests-per-second made to individual domains.
All of the currently existing examples I can find either (1) limit the number of open connections or (2) limit the total number of requests-per-second made in the fetch loop. Examples include:
aiohttp: rate limiting parallel requests
aiohttp: set maximum number of requests per second
Neither of them do what I am requesting which is to limit requests-per-second on a per domain basis. The first question only answers how to limit requests-per-second overall. The second one doesn't even have answers to the actual question (the OP asks about requests per second and the answers all talk about limiting # of connections).
Here is the code that I tried, using a simple rate limiter I made for a synchronous version, which doesn't work when the DomainTimer code is run in an async event loop:
from collections import defaultdict
from datetime import datetime, timedelta
import asyncio
import async_timeout
import aiohttp
from urllib.parse import urlparse
from queue import Queue, Empty
from HTMLProcessing import processHTML
import URLFilters
SEED_URLS = ['http://www.bbc.co.uk', 'http://www.news.google.com']
url_queue = Queue()
for u in SEED_URLS:
url_queue.put(u)
# number of pages to download per run of crawlConcurrent()
BATCH_SIZE = 100
DELAY = timedelta(seconds = 1.0) # delay between requests from single domain, in seconds
HTTP_HEADERS = {'Referer': 'http://www.google.com',
'User-Agent': 'Mozilla/5.0 (X11; Linux x86_64; rv:59.0) Gecko/20100101 Firefox/59.0'}
class DomainTimer():
def __init__(self):
self.timer = None
def resetTimer(self):
self.timer = datetime.now()
def delayExceeded(self, delay):
if not self.timer: #We haven't fetched this before
return True
if (datetime.now() - self.timer) >= delay:
return True
else:
return False
crawl_history = defaultdict(dict) # given a URL, when is last time crawled?
domain_timers = defaultdict(DomainTimer)
async def fetch(session, url):
domain = urlparse(url).netloc
print('here fetching ' + url + "\n")
dt = domain_timers[domain]
if dt.delayExceeded(DELAY) or not dt:
with async_timeout.timeout(10):
try:
dt.resetTimer() # reset domain timer
async with session.get(url, headers=HTTP_HEADERS) as response:
if response.status == 200:
crawl_history[url] = datetime.now()
html = await response.text()
return {'url': url, 'html': html}
else:
# log HTTP response, put into crawl_history so
# we don't attempt to fetch again
print(url + " failed with response: " + str(response.status) + "\n")
return {'url': url, 'http_status': response.status}
except aiohttp.ClientConnectionError as e:
print("Connection failed " + str(e))
except aiohttp.ClientPayloadError as e:
print("Recieved bad data from server # " + url + "\n")
else: # Delay hasn't passed yet: skip for now & put # end of q
url_queue.put(url);
return None
async def fetch_all(urls):
"""Launch requests for all web pages."""
tasks = []
async with aiohttp.ClientSession() as session:
for url in urls:
task = asyncio.ensure_future(fetch(session, url))
tasks.append(task) # create list of tasks
return await asyncio.gather(*tasks) # gather task responses
def batch_crawl():
"""Launch requests for all web pages."""
start_time = datetime.now()
# Here we build the list of URLs to crawl for this batch
urls = []
for i in range(BATCH_SIZE):
try:
next_url = url_queue.get_nowait() # get next URL from queue
urls.append(next_url)
except Empty:
print("Processed all items in URL queue.\n")
break;
loop = asyncio.get_event_loop()
asyncio.set_event_loop(loop)
pages = loop.run_until_complete(fetch_all(urls))
crawl_time = (datetime.now() - start_time).seconds
print("Crawl completed. Fetched " + str(len(pages)) + " pages in " + str(crawl_time) + " seconds.\n")
return pages
def parse_html(pages):
""" Parse the HTML for each page downloaded in this batch"""
start_time = datetime.now()
results = {}
for p in pages:
if not p or not p['html']:
print("Received empty page")
continue
else:
url, html = p['url'], p['html']
results[url] = processHTML(html)
processing_time = (datetime.now() - start_time).seconds
print("HTML processing finished. Processed " + str(len(results)) + " pages in " + str(processing_time) + " seconds.\n")
return results
def extract_new_links(results):
"""Extract links from """
# later we could track where links were from here, anchor text, etc,
# and weight queue priority based on that
links = []
for k in results.keys():
new_urls = [l['href'] for l in results[k]['links']]
for u in new_urls:
if u not in crawl_history.keys():
links.append(u)
return links
def filterURLs(urls):
urls = URLFilters.filterDuplicates(urls)
urls = URLFilters.filterBlacklistedDomains(urls)
return urls
def run_batch():
pages = batch_crawl()
results = parse_html(pages)
links = extract_new_links(results)
for l in filterURLs(links):
url_queue.put(l)
return results
There are no errors or exceptions thrown, and the rate-limiting code works fine in for synchronous fetches, but the DomainTimer has no apparent effect when run in async loop. The delay of one request-per-second per domain is not upheld...
How would I modify this synchronous rate limiting code to work within the async event loop? Thanks!

It's hard to debug your code since it contains many unrelated stuff, it's easier to show idea on a new simple example.
Main idea:
write your Semaphore-like class using __aenter__, __aexit__
that accepts url (domain)
use domain-specific Lock to prevent multiple requests to the same domain
sleep before allowing next request according to domain's last request and RPS
track time of last request for each domain
Code:
import asyncio
import aiohttp
from urllib.parse import urlparse
from collections import defaultdict
class Limiter:
# domain -> req/sec:
_limits = {
'httpbin.org': 4,
'eu.httpbin.org': 1,
}
# domain -> it's lock:
_locks = defaultdict(lambda: asyncio.Lock())
# domain -> it's last request time
_times = defaultdict(lambda: 0)
def __init__(self, url):
self._host = urlparse(url).hostname
async def __aenter__(self):
await self._lock
to_wait = self._to_wait_before_request()
print(f'Wait {to_wait} sec before next request to {self._host}')
await asyncio.sleep(to_wait)
async def __aexit__(self, *args):
print(f'Request to {self._host} just finished')
self._update_request_time()
self._lock.release()
#property
def _lock(self):
"""Lock that prevents multiple requests to same host."""
return self._locks[self._host]
def _to_wait_before_request(self):
"""What time we need to wait before request to host."""
request_time = self._times[self._host]
request_delay = 1 / self._limits[self._host]
now = asyncio.get_event_loop().time()
to_wait = request_time + request_delay - now
to_wait = max(0, to_wait)
return to_wait
def _update_request_time(self):
now = asyncio.get_event_loop().time()
self._times[self._host] = now
# request that uses Limiter instead of Semaphore:
async def get(url):
async with Limiter(url):
async with aiohttp.ClientSession() as session: # TODO reuse session for different requests.
async with session.get(url) as resp:
return await resp.text()
# main:
async def main():
coros = [
get('http://httpbin.org/get'),
get('http://httpbin.org/get'),
get('http://httpbin.org/get'),
get('http://httpbin.org/get'),
get('http://httpbin.org/get'),
get('http://eu.httpbin.org/get'),
get('http://eu.httpbin.org/get'),
get('http://eu.httpbin.org/get'),
get('http://eu.httpbin.org/get'),
get('http://eu.httpbin.org/get'),
]
await asyncio.gather(*coros)
if __name__ == '__main__':
loop = asyncio.get_event_loop()
try:
loop.run_until_complete(main())
finally:
loop.run_until_complete(loop.shutdown_asyncgens())
loop.close()

I developed a library named octopus-api (https://pypi.org/project/octopus-api/), that enables you to rate limit and set the number of connections to the endpoint using aiohttp under the hood. The goal of it is to simplify all the aiohttp setup needed.
Here is an example of how to use it, where the get_ethereum is the user-defined request function. It could have also been a web crawler function request or what ever fits:
from octopus_api import TentacleSession, OctopusApi
from typing import Dict, List
if __name__ == '__main__':
async def get_ethereum(session: TentacleSession, request: Dict):
async with session.get(url=request["url"], params=request["params"]) as response:
body = await response.json()
return body
client = OctopusApi(rate=50, resolution="sec", connections=6)
result: List = client.execute(requests_list=[{
"url": "https://api.pro.coinbase.com/products/ETH-EUR/candles?granularity=900&start=2021-12-04T00:00:00Z&end=2021-12-04T00:00:00Z",
"params": {}}] * 1000, func=get_ethereum)
print(result)
The TentacleSession works the same as how you write POST, GET, PUT and PATCH for aiohttp.ClientSession.
Let me know if it helps your issue related to rate limits and connection for crawling.