Monitoring JSON Wire Protocol Logs

According to the selenium documentation, interactions between the webdriver client and a browser is done via JSON Wire Protocol. Basically the client, written in python, ruby, java

Solution 1:

When you use Chrome you can direct the chromedriver instance that will drive Chrome to log more information than what is available through the logging package. This information includes the commands sent to the browser and the responses it gets. Here's an example:

from selenium import webdriver

driver = webdriver.Chrome(service_log_path="/tmp/log")
driver.get("http://www.google.com")
driver.find_element_by_css_selector("input")
driver.quit()

The code above will output the log to /tmp/log. The part of the log that corresponds to the find_element_... call looks like this:

[2.389][INFO]: COMMAND FindElement {
   "sessionId": "b6707ee92a3261e1dc33a53514490663",
   "using": "css selector",
   "value": "input"
}
[2.389][INFO]: Waiting for pending navigations...
[2.389][INFO]: Done waiting for pending navigations
[2.398][INFO]: Waiting for pending navigations...
[2.398][INFO]: Done waiting for pending navigations
[2.398][INFO]: RESPONSE FindElement {
   "ELEMENT": "0.3367185448296368-1"
}

As far as I know, the commands and responses faithfully represent what is going on between the client and the server. I've submitted bug reports and fixes to the Selenium project on the basis of what I saw in these logs.

Solution 2:

Found one option that almost fits my needs.

Just piping the logger to the stdout allows to see underlying requests being made:

import logging
import sys

from selenium import webdriver


# pipe logs to stdout
logger = logging.getLogger()
logger.addHandler(logging.StreamHandler(sys.stdout))
logger.setLevel(logging.NOTSET)

# selenium specific code
driver = webdriver.Chrome()
driver.get('http://google.com')

driver.close()

It prints:

POST http://127.0.0.1:56668/session {"desiredCapabilities": {"platform": "ANY", "browserName": "chrome", "version": "", "javascriptEnabled": true, "chromeOptions": {"args": [], "extensions": []}}}
Finished Request
POST http://127.0.0.1:56668/session/5b6875595143b0b9993ed4f66f1f19fc/url {"url": "http://google.com", "sessionId": "5b6875595143b0b9993ed4f66f1f19fc"}
Finished Request
DELETE http://127.0.0.1:56668/session/5b6875595143b0b9993ed4f66f1f19fc/window {"sessionId": "5b6875595143b0b9993ed4f66f1f19fc"}
Finished Request

I don't see the responses, but this is already a progress.