"Disabling the promise manager in selenium-webdriver: A step-by-step guide

Question

"Disabling the promise manager in selenium-webdriver: A step-by-step guide

According to the information provided on https://code.google.com/p/selenium/wiki/WebDriverJs#Promises, the selenium-webdriver library utilizes an automatic promise manager to streamline promise chaining and avoid repetitive tasks.

However, there are situations where the assumption made by the promise manager about chaining successive calls may be inaccurate and need to be turned off.

Consider the following scenario:

var isLoaded = function (browser) {
    var waitForJS = waitForElement(browser, By.css('body.js'));
    var waitForMobile = waitForElement(browser, By.css('#mobile_landing_page'));

    return Promise.any([waitForJS, waitForMobile]);
};

In this case, I aim to develop a universal function that will wait for either of the two conditions to be met, regardless of whether it's a mobile landing page or desktop site.

Unfortunately, the promise manager interprets it differently

var isLoaded = function (browser) {
    var waitForMobile = waitForElement(browser, By.css('#mobile_landing_page'));
    var waitForJS = waitForElement(browser, By.css('body.js')).then(function () {
        return waitForMobile;
    });

    return Promise.any([waitForJS, waitForMobile]);
};

This implementation can never resolve for the non-mobile situation, as only one of the conditions can be true at any given time.

Is there a way to disable the promise manager entirely and manually schedule all calls?

Below is the definition of waitForElement

var waitForElement = function (browser, element, timeout) {
    return browser.wait(until.elementLocated(element), timeout);
};

javascript selenium selenium-webdriver

Answer 1

Answer №1

If you want to achieve your desired outcome easily, consider using a CSS selector that searches for either one id or the other. For instance, in this demonstration of delayed loading, we are seeking an element with either #foo or #bar. Therefore, we utilize the selector #foo, #bar. In your situation, it could be body.js, #mobile_landing_page. This approach is efficient as it minimizes the back-and-forth communication between your Selenium script and the browser.

var webdriver = require('selenium-webdriver');
var By = webdriver.By;
var until = webdriver.until;
var firefox = require('selenium-webdriver/firefox');
var Promise = require('bluebird').Promise;

var browser = new firefox.Driver();

browser.get("http://www.example.com");

// Randomly determine the element we will search for
var flip = Math.round(Math.random(0, 1));
var id = flip ? "foo": "bar";
console.log("We'll simulate the delayed loading of an element with id", id);

var waitForElement = function (browser, element, timeout) {
    return browser.wait(until.elementLocated(element), timeout);
};

var isLoaded = function (browser) {
    return waitForElement(browser, By.css("#foo, #bar"));
};

// Simulate the delayed loading of the element we are searching for
browser.executeScript('\
var id = arguments[0];\
setTimeout(function () {\
  var el = document.createElement("div");\
  el.id = id;\
  document.body.appendChild(el);\
}, 1000);\
', id);

isLoaded(browser);
browser.quit();

Answer 2

If you want to achieve your desired outcome easily, consider using a CSS selector that searches for either one id or the other. For instance, in this demonstration of delayed loading, we are seeking an element with either #foo or #bar. Therefore, we utilize the selector #foo, #bar. In your situation, it could be body.js, #mobile_landing_page. This approach is efficient as it minimizes the back-and-forth communication between your Selenium script and the browser.

var webdriver = require('selenium-webdriver');
var By = webdriver.By;
var until = webdriver.until;
var firefox = require('selenium-webdriver/firefox');
var Promise = require('bluebird').Promise;

var browser = new firefox.Driver();

browser.get("http://www.example.com");

// Randomly determine the element we will search for
var flip = Math.round(Math.random(0, 1));
var id = flip ? "foo": "bar";
console.log("We'll simulate the delayed loading of an element with id", id);

var waitForElement = function (browser, element, timeout) {
    return browser.wait(until.elementLocated(element), timeout);
};

var isLoaded = function (browser) {
    return waitForElement(browser, By.css("#foo, #bar"));
};

// Simulate the delayed loading of the element we are searching for
browser.executeScript('\
var id = arguments[0];\
setTimeout(function () {\
  var el = document.createElement("div");\
  el.id = id;\
  document.body.appendChild(el);\
}, 1000);\
', id);

isLoaded(browser);
browser.quit();

Answer 3

Answer №2

While this information may be considered outdated, for those who stumble upon this post during or after 2017, here's a helpful suggestion:

Promise.any is actually a bluebird feature that returns the first resolved item.

If you're looking to wait for both items to resolve, the appropriate approach is to use Promise.all.

You can implement it like so:

var checkLoadingStatus = function (browser) {
    var waitForJS = waitForElement(browser, By.css('body.js'));
    var waitForMobile = waitForElement(browser, By.css('#mobile_landing_page'));

    return Promise.all([waitForJS, waitForMobile]);
};

// Utilize it in this manner:
checkLoadingStatus(browser)
.then((elementCheck) => {
  const hasBodyJsTag = elementCheck[0]
  const hasMobileTag = elementCheck[1]
  console.log('Element Status:', elementCheck)
})

Answer 4

While this information may be considered outdated, for those who stumble upon this post during or after 2017, here's a helpful suggestion:

Promise.any is actually a bluebird feature that returns the first resolved item.

If you're looking to wait for both items to resolve, the appropriate approach is to use Promise.all.

You can implement it like so:

var checkLoadingStatus = function (browser) {
    var waitForJS = waitForElement(browser, By.css('body.js'));
    var waitForMobile = waitForElement(browser, By.css('#mobile_landing_page'));

    return Promise.all([waitForJS, waitForMobile]);
};

// Utilize it in this manner:
checkLoadingStatus(browser)
.then((elementCheck) => {
  const hasBodyJsTag = elementCheck[0]
  const hasMobileTag = elementCheck[1]
  console.log('Element Status:', elementCheck)
})

"Disabling the promise manager in selenium-webdriver: A step-by-step guide

Answer №1

Answer №2

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