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changedetection.io/changedetectionio/content_fetcher.py

307 lines
11 KiB

from abc import ABC, abstractmethod
import chardet
import os
import requests
import time
import urllib3.exceptions
import sys
class EmptyReply(Exception):
def __init__(self, status_code, url):
# Set this so we can use it in other parts of the app
self.status_code = status_code
self.url = url
return
pass
class Fetcher():
error = None
status_code = None
content = None
headers = None
# Will be needed in the future by the VisualSelector, always get this where possible.
screenshot = False
fetcher_description = "No description"
system_http_proxy = os.getenv('HTTP_PROXY')
system_https_proxy = os.getenv('HTTPS_PROXY')
@abstractmethod
def get_error(self):
return self.error
@abstractmethod
def run(self,
url,
timeout,
request_headers,
request_body,
request_method,
ignore_status_codes=False):
# Should set self.error, self.status_code and self.content
pass
@abstractmethod
def quit(self):
return
@abstractmethod
def get_last_status_code(self):
return self.status_code
@abstractmethod
# Return true/false if this checker is ready to run, in the case it needs todo some special config check etc
def is_ready(self):
return True
# Maybe for the future, each fetcher provides its own diff output, could be used for text, image
# the current one would return javascript output (as we use JS to generate the diff)
#
def available_fetchers():
# See the if statement at the bottom of this file for how we switch between playwright and webdriver
import inspect
p = []
for name, obj in inspect.getmembers(sys.modules[__name__], inspect.isclass):
if inspect.isclass(obj):
# @todo html_ is maybe better as fetcher_ or something
# In this case, make sure to edit the default one in store.py and fetch_site_status.py
if name.startswith('html_'):
t = tuple([name, obj.fetcher_description])
p.append(t)
return p
class base_html_playwright(Fetcher):
fetcher_description = "Playwright {}/Javascript".format(
os.getenv("PLAYWRIGHT_BROWSER_TYPE", 'chromium').capitalize()
)
if os.getenv("PLAYWRIGHT_DRIVER_URL"):
fetcher_description += " via '{}'".format(os.getenv("PLAYWRIGHT_DRIVER_URL"))
browser_type = ''
command_executor = ''
# Configs for Proxy setup
# In the ENV vars, is prefixed with "playwright_proxy_", so it is for example "playwright_proxy_server"
playwright_proxy_settings_mappings = ['bypass', 'server', 'username', 'password']
proxy = None
def __init__(self):
# .strip('"') is going to save someone a lot of time when they accidently wrap the env value
self.browser_type = os.getenv("PLAYWRIGHT_BROWSER_TYPE", 'chromium').strip('"')
self.command_executor = os.getenv(
"PLAYWRIGHT_DRIVER_URL",
'ws://playwright-chrome:3000/playwright'
).strip('"')
# If any proxy settings are enabled, then we should setup the proxy object
proxy_args = {}
for k in self.playwright_proxy_settings_mappings:
v = os.getenv('playwright_proxy_' + k, False)
if v:
proxy_args[k] = v.strip('"')
if proxy_args:
self.proxy = proxy_args
def run(self,
url,
timeout,
request_headers,
request_body,
request_method,
ignore_status_codes=False):
from playwright.sync_api import sync_playwright
with sync_playwright() as p:
browser_type = getattr(p, self.browser_type)
# Seemed to cause a connection Exception even tho I can see it connect
# self.browser = browser_type.connect(self.command_executor, timeout=timeout*1000)
browser = browser_type.connect_over_cdp(self.command_executor, timeout=timeout * 1000)
# Set user agent to prevent Cloudflare from blocking the browser
# Use the default one configured in the App.py model that's passed from fetch_site_status.py
context = browser.new_context(
user_agent=request_headers['User-Agent'] if request_headers.get('User-Agent') else 'Mozilla/5.0',
proxy=self.proxy
)
page = context.new_page()
page.set_viewport_size({"width": 1280, "height": 1024})
response = page.goto(url, timeout=timeout * 1000)
extra_wait = int(os.getenv("WEBDRIVER_DELAY_BEFORE_CONTENT_READY", 5))
page.wait_for_timeout(extra_wait * 1000)
if response is None:
raise EmptyReply(url=url, status_code=None)
self.status_code = response.status
self.content = page.content()
self.headers = response.all_headers()
# Some bug where it gives the wrong screenshot size, but making a request with the clip set first seems to solve it
# JPEG is better here because the screenshots can be very very large
page.screenshot(type='jpeg', clip={'x': 1.0, 'y': 1.0, 'width': 1280, 'height': 1024})
self.screenshot = page.screenshot(type='jpeg', full_page=True, quality=90)
context.close()
browser.close()
class base_html_webdriver(Fetcher):
if os.getenv("WEBDRIVER_URL"):
fetcher_description = "WebDriver Chrome/Javascript via '{}'".format(os.getenv("WEBDRIVER_URL"))
else:
fetcher_description = "WebDriver Chrome/Javascript"
command_executor = ''
# Configs for Proxy setup
# In the ENV vars, is prefixed with "webdriver_", so it is for example "webdriver_sslProxy"
selenium_proxy_settings_mappings = ['proxyType', 'ftpProxy', 'httpProxy', 'noProxy',
'proxyAutoconfigUrl', 'sslProxy', 'autodetect',
'socksProxy', 'socksVersion', 'socksUsername', 'socksPassword']
proxy = None
def __init__(self):
from selenium.webdriver.common.proxy import Proxy as SeleniumProxy
# .strip('"') is going to save someone a lot of time when they accidently wrap the env value
self.command_executor = os.getenv("WEBDRIVER_URL", 'http://browser-chrome:4444/wd/hub').strip('"')
# If any proxy settings are enabled, then we should setup the proxy object
proxy_args = {}
for k in self.selenium_proxy_settings_mappings:
v = os.getenv('webdriver_' + k, False)
if v:
proxy_args[k] = v.strip('"')
# Map back standard HTTP_ and HTTPS_PROXY to webDriver httpProxy/sslProxy
if not proxy_args.get('webdriver_httpProxy') and self.system_http_proxy:
proxy_args['httpProxy'] = self.system_http_proxy
if not proxy_args.get('webdriver_sslProxy') and self.system_https_proxy:
proxy_args['httpsProxy'] = self.system_https_proxy
if proxy_args:
self.proxy = SeleniumProxy(raw=proxy_args)
def run(self,
url,
timeout,
request_headers,
request_body,
request_method,
ignore_status_codes=False):
from selenium import webdriver
from selenium.webdriver.common.desired_capabilities import DesiredCapabilities
from selenium.common.exceptions import WebDriverException
# request_body, request_method unused for now, until some magic in the future happens.
# check env for WEBDRIVER_URL
self.driver = webdriver.Remote(
command_executor=self.command_executor,
desired_capabilities=DesiredCapabilities.CHROME,
proxy=self.proxy)
try:
self.driver.get(url)
except WebDriverException as e:
# Be sure we close the session window
self.quit()
raise
# @todo - how to check this? is it possible?
self.status_code = 200
# @todo somehow we should try to get this working for WebDriver
# raise EmptyReply(url=url, status_code=r.status_code)
# @todo - dom wait loaded?
time.sleep(int(os.getenv("WEBDRIVER_DELAY_BEFORE_CONTENT_READY", 5)))
self.content = self.driver.page_source
self.headers = {}
self.screenshot = self.driver.get_screenshot_as_png()
self.quit()
# Does the connection to the webdriver work? run a test connection.
def is_ready(self):
from selenium import webdriver
from selenium.webdriver.common.desired_capabilities import DesiredCapabilities
from selenium.common.exceptions import WebDriverException
self.driver = webdriver.Remote(
command_executor=self.command_executor,
desired_capabilities=DesiredCapabilities.CHROME)
# driver.quit() seems to cause better exceptions
self.quit()
return True
def quit(self):
if self.driver:
try:
self.driver.quit()
except Exception as e:
print("Exception in chrome shutdown/quit" + str(e))
# "html_requests" is listed as the default fetcher in store.py!
class html_requests(Fetcher):
fetcher_description = "Basic fast Plaintext/HTTP Client"
def run(self,
url,
timeout,
request_headers,
request_body,
request_method,
ignore_status_codes=False):
# Map back standard HTTP_ and HTTPS_PROXY to requests http/https proxy
proxies={}
if self.system_http_proxy:
proxies['http'] = self.system_http_proxy
if self.system_https_proxy:
proxies['https'] = self.system_https_proxy
r = requests.request(method=request_method,
data=request_body,
url=url,
headers=request_headers,
timeout=timeout,
proxies=proxies,
verify=False)
# If the response did not tell us what encoding format to expect, Then use chardet to override what `requests` thinks.
# For example - some sites don't tell us it's utf-8, but return utf-8 content
# This seems to not occur when using webdriver/selenium, it seems to detect the text encoding more reliably.
# https://github.com/psf/requests/issues/1604 good info about requests encoding detection
if not r.headers.get('content-type') or not 'charset=' in r.headers.get('content-type'):
encoding = chardet.detect(r.content)['encoding']
if encoding:
r.encoding = encoding
# @todo test this
# @todo maybe you really want to test zero-byte return pages?
if (not ignore_status_codes and not r) or not r.content or not len(r.content):
raise EmptyReply(url=url, status_code=r.status_code)
self.status_code = r.status_code
self.content = r.text
self.headers = r.headers
# Decide which is the 'real' HTML webdriver, this is more a system wide config
# rather than site-specific.
use_playwright_as_chrome_fetcher = os.getenv('PLAYWRIGHT_DRIVER_URL', False)
if use_playwright_as_chrome_fetcher:
html_webdriver = base_html_playwright
else:
html_webdriver = base_html_webdriver