Styjun

I'm using NodeJS selenium within my electron desktop application.

"electron-chromedriver": "^4.0.0-beta.1",
"selenium-webdriver": "^4.0.0-alpha.1",

I followed electron documentation about using selenium inside electron app and I have code like this:

let chromeCapabilities = webdriver.Capabilities.chrome();
let chromeOptions = 'args': ['--disable-infobars'] ;
chromeCapabilities.set('chromeOptions', chromeOptions);
capabilities.setPageLoadStrategy('eager');

this.driver = new webdriver.Builder()
 .withCapabilities(chromeCapabilities)
 .usingServer('http://localhost:9515')
 .forBrowser('chrome')
 .build();

after above code there is chain of promises which are doing many different things.

Except that I'm runing chromedriver command in terminal within ./node_modules/.bin/ directory.

Starting ChromeDriver 69.0.3497.106 (857b284701ddf7bef0f14fa76416cf7ca786b411) on port 9515

Only local connections are allowed.

Now when I run entire code it sometimes works correctly but occasionally it print error in terminal in which I npm run dev electron app:

Error: ECONNREFUSED connect ECONNREFUSED 127.0.0.1:9515

I read several similiar SO questions but none of them was helpful. I don't really understand how it's possible that some piece of code is sometimes working and sometimes causing error.

I also checked ports 9515 (chromedriver) and 9080 (electron nodeJS) after getting error and everything looks fine:

I've done some more debugging and I found out that probably this:

webElement.getAttribute('style')

is sometimes causing my error. When I delete above (and also .then() and .catch after it ofcourse) error stop occuring. However I don't know how geting inline styles of webElement might be relevant to connection refused error.

You have used the following capability:

capabilities.setPageLoadStrategy('eager');

Earlier, in a couple of QAs we have discussed about PageLoadStrategy as eager for ChromeDriver and Chrome:

• Page load strategy for Chrome driver (Updated till Selenium v3.12.0)


• “Eager” Page Load Strategy workaround for Chromedriver Selenium in Python

The conclusion was, as per WebDriver Status you will find the list of all WebDriver commands and their current support in ChromeDriver based on what is in the WebDriver Specification. Once the implementation are completed from all aspects PageLoadStrategy.EAGER is bound to be functionally present within Chrome Driver.

Similar discussions were also active on several threads within bugs.chromium.org and groups.google.com as follows:

• PageLoadStrategy.EAGER doesn't work with chromedriver


• Support eager page load strategy


• Implement page load timeout API

If you look at page_load_strategy.cc PageLoadStrategy as eager is yet to be implemented:

#include "chrome/test/chromedriver/chrome/page_load_strategy.h"
#include "base/logging.h"
#include "chrome/test/chromedriver/chrome/navigation_tracker.h"
#include "chrome/test/chromedriver/chrome/non_blocking_navigation_tracker.h"
const char PageLoadStrategy::kNormal[] = "normal";
const char PageLoadStrategy::kNone[] = "none";
const char PageLoadStrategy::kEager[] = "eager";
PageLoadStrategy* PageLoadStrategy::Create(
 std::string strategy,
 DevToolsClient* client,
 const BrowserInfo* browser_info,
 const JavaScriptDialogManager* dialog_manager) 
 if (strategy == kNone) 
 return new NonBlockingNavigationTracker();
 else if (strategy == kNormal) 
 return new NavigationTracker(client, browser_info, dialog_manager);
 else 
 NOTREACHED() << "invalid strategy '" << strategy << "'";
 return nullptr;
 

This may be root cause of the Error: ECONNREFUSED which you are seeing as the dummy elements/iframes may not have generated/created/rendered completely as per the Chrome Browser startup logs:

[1517231304.270][DEBUG]: DEVTOOLS COMMAND Runtime.evaluate (id=11) {
 "expression": "var isLoaded = document.readyState == 'complete' || document.readyState == 'interactive';if (isLoaded) var frame = document.createElement('iframe'); frame.name = 'chromedriver dummy frame'; ..."

This issue inturn causes the line:

webElement.getAttribute('style')

to cause the actual error.

Solution

For a cleaner test you may need to use PageLoadStrategy as normal instead as:

capabilities.setPageLoadStrategy('normal');

Outro

Some relevant discussions:

• How to fix python-selenium error “connection refused” when initializing a selenium webdriver?


• How to fix “WebDriverException: Message: connection refused”?


• ConnectionResetError: [Errno 104] Connection reset by peer and ERR_NAME_NOT_RESOLVED on heroku with mobile testing through Selenium