[selenium-users] Experimental flags with Chrome webdriver

[Pascal H]

Hi, I'm trying to enable experimental flags when launching Chrome with web
driver :

I did the following :

from selenium.webdriver.chrome.options import Options
myOptions = Options()
myOptions.add_argument("--enable-quic")
myOptions.add_argument("--enable-tcp-fast-open")
driver = webdriver.Chrome(chrome_options=myOptions)

Now, in chrome://version, I have :

Command Line /usr/bin/google-chrome --disable-background-networking
--disable-client-side-phishing-detection --disable-default-apps
--disable-hang-monitor --disable-popup-blocking --disable-prompt-on-repost
--disable-sync --disable-web-resources --enable-automation --enable-logging *--enable-quic
--enable-tcp-fast-open* --force-fieldtrials=SiteIsolationExtensions/Control
--ignore-certificate-errors
--load-extension=/tmp/.org.chromium.Chromium.8w4LVP/internal --log-level=0
--metrics-recording-only --no-first-run --password-store=basic
--remote-debugging-port=0 --test-type=webdriver --use-mock-keychain
--user-data-dir=/home/woo/myTEmp --flag-switches-begin --flag-switches-end


And in chrome://flags, neither QUIC nor Fast Open is enabled.
If I change manually the QUIC and Fast Open option in chrome://flags and
click on relaunch, I will now have :
Command Line /usr/bin/google-chrome --disable-background-networking
--disable-client-side-phishing-detection --disable-default-apps
--disable-hang-monitor --disable-popup-blocking --disable-prompt-on-repost
--disable-sync --disable-web-resources --disk-cache-size=1
--enable-automation --enable-logging *--enable-quic --enable-tcp-fast-open*
--force-fieldtrials=SiteIsolationExtensions/Control
--ignore-certificate-errors
--load-extension=/tmp/.org.chromium.Chromium.8w4LVP/internal --log-level=0
--media-cache-size=1 --metrics-recording-only --no-first-run
--password-store=basic --remote-debugging-port=0 --test-type=webdriver
--use-mock-keychain --user-data-dir=/home/woo/myTEmp --flag-switches-begin *--enable-quic
--enable-tcp-fastopen* --flag-switches-end

(And in chrome://flags I do have the QUIC and Fast Open Options)
So it appears to me that to enable experimental flags, they need to be
located between the
"--flag-switches-begin" and "--flag-switches-end".

So, is there any way to tell Selenium to set the options within those 2
flags ?

Regards,
Pascal

[Pascal H]

For anyone interested, I found this workaround (pretty complex :p), but
didn't find a way to enable this through Selenium functions.

Regards, Pascal

from selenium import webdriver
from selenium.webdriver.chrome.options import Options
import time

## Browser config javascript commands (need to be launched from
chrome://flags)
enable_quic_command = "chrome.send('enableExperimentalFeature',['enable-quic'
+ '@' + 1, 'true'])"
enable_fastopen_command = "chrome.send('enableExperimentalFeature',
['enable-tcp-fast-open', 'true'])"

def chrome_configure_experimental_flags(myDriver):
myDriver.get('chrome://flags') #Load page where configuration javascript
commands are allowed
myDriver.execute_script(enable_quic_command) #Enable QUIC
myDriver.execute_script(enable_fastopen_command) #Enable TCP
myDriver.get('chrome://flags') #Re-load so that we can check
time.sleep(2) #Give some time to check the flag


myOptions = Options()
#Set disk and media cache size to disable caching
myOptions.add_argument("--disk-cache-size=1")
myOptions.add_argument("--media-cache-size=1")
#Set our own, to be re-used, profile
profile_folder = '/tmp/' + 'profile_chrome_' + time_string
myOptions.add_argument("user-data-dir=" + profile_folder)

#Create driver
driver = webdriver.Chrome(chrome_options=myOptions)
#Set experimental features
chrome_configure_experimental_flags(driver)
#Close and re-build driver with same options (and so same profile, so
experimental flags will be kept)
driver.close()
driver = webdriver.Chrome(chrome_options=myOptions)

[Shawn McCarthy]

what kind of different do you see with these two flags ?

Post by Pascal H
Hi, I'm trying to enable experimental flags when launching Chrome with web
from selenium.webdriver.chrome.options import Options
myOptions = Options()
myOptions.add_argument("--enable-quic")
myOptions.add_argument("--enable-tcp-fast-open")
driver = webdriver.Chrome(chrome_options=myOptions)
Command Line /usr/bin/google-chrome --disable-background-networking
--disable-client-side-phishing-detection --disable-default-apps
--disable-hang-monitor --disable-popup-blocking --disable-prompt-on-repost
--disable-sync --disable-web-resources --enable-automation --enable-logging *--enable-quic
--enable-tcp-fast-open*
--force-fieldtrials=SiteIsolationExtensions/Control
--ignore-certificate-errors
--load-extension=/tmp/.org.chromium.Chromium.8w4LVP/internal --log-level=0
--metrics-recording-only --no-first-run --password-store=basic
--remote-debugging-port=0 --test-type=webdriver --use-mock-keychain
--user-data-dir=/home/woo/myTEmp --flag-switches-begin --flag-switches-end
And in chrome://flags, neither QUIC nor Fast Open is enabled.
If I change manually the QUIC and Fast Open option in chrome://flags and
Command Line /usr/bin/google-chrome --disable-background-networking
--disable-client-side-phishing-detection --disable-default-apps
--disable-hang-monitor --disable-popup-blocking --disable-prompt-on-repost
--disable-sync --disable-web-resources --disk-cache-size=1
--enable-automation --enable-logging *--enable-quic
--enable-tcp-fast-open*
--force-fieldtrials=SiteIsolationExtensions/Control
--ignore-certificate-errors
--load-extension=/tmp/.org.chromium.Chromium.8w4LVP/internal --log-level=0
--media-cache-size=1 --metrics-recording-only --no-first-run
--password-store=basic --remote-debugging-port=0 --test-type=webdriver
--use-mock-keychain --user-data-dir=/home/woo/myTEmp --flag-switches-begin *--enable-quic
--enable-tcp-fastopen* --flag-switches-end
(And in chrome://flags I do have the QUIC and Fast Open Options)
So it appears to me that to enable experimental flags, they need to be
located between the
"--flag-switches-begin" and "--flag-switches-end".
So, is there any way to tell Selenium to set the options within those 2
flags ?
Regards,
Pascal

...

[Pascal H]

Hi Shawn,

I'm studying transport-layer protocols and their performance when accessing
Internet through a satellite.
Thanks to those two flags, Chrome will here use the QUIC protocol and the
TFO option of TCP whenever possible.
And then I use Selenium to register some performance metrics with Chrome
when accessing different type of services on different servers, with
different transport layer protocols.
Regards,
Pascal