munro/selenium_wait_for_images_loaded.py

## selenium_wait_for_images_loaded.py
from textwrap import dedent


def wait_until_images_loaded(driver, timeout=30):
    """Waits for all images & background images to load."""
    driver.set_script_timeout(timeout)
    driver.execute_async_script(dedent('''
        // Function to extract URL from CSS 'url()' function
        function extractCSSURL(text) {
            var url_str = text.replace(/.*url\((.*)\).*/, '$1');
            // If the URL is enclosed with double quotes
            if (url_str[0] === '"') {
                return JSON.parse(url_str);
            }
            // If the URL is enclosed with single quotes
            if (url_str[0] === "'") {
                return JSON.parse(
                    url_str
                        .replace(/'/g, '__DOUBLE__QUOTE__HERE__')
                        .replace(/"/g, "'")
                        .replace(/__DOUBLE__QUOTE__HERE__/g, '"')
                );
            }
            // Return the URL as is
            return url_str;
        }

        // Function to create a promise that resolves when the image is loaded
        function imageResolved(url) {
            return new Promise(function (resolve) {
                var img = new Image();
                img.onload = function () {
                    resolve(url);
                };
                img.src = url;
                // If the image is already loaded, resolve the promise immediately
                if (img.complete) {
                    resolve(url);
                }
            });
        }

        // The last argument is expected to be a callback function
        var callback = arguments[arguments.length - 1];

        Promise.all([
            // Get all img tags, create a promise for each one
            ...Array.from(document.querySelectorAll('img[src]'), img => imageResolved(img.src)),
            // Get all inline styles with 'url()' and create a promise for each one
            ...Array.from(document.querySelectorAll('[style*="url("]'), elem => imageResolved(extractCSSURL(elem.style.cssText)))
        ])
        .then(function () {
            // After all images are loaded, wait for all fonts to load
            return document.fonts.ready;
        })
        .then(function() {
            // After all fonts are loaded, check for images in CSS stylesheets
            let cssImagesPromises = [];
            for(let i = 0; i < document.styleSheets.length; i++) {
                let rules = document.styleSheets[i].cssRules;
                for (let j = 0; j < rules.length; j++) {
                    let style = rules[j].style;
                    // Check if a background image is found and if it's a URL
                    if (style && String(style.backgroundImage).startsWith('url(')) {
                        let url = extractCSSURL(style.backgroundImage);
                        cssImagesPromises.push(imageResolved(url));
                    }
                }
            }
            return Promise.all(cssImagesPromises);
        })
        .then(function () {
            // Call the callback function when all promises are resolved
            callback(arguments);
        });

        return undefined;
    '''))
	from textwrap import dedent


	def wait_until_images_loaded(driver, timeout=30):
	"""Waits for all images & background images to load."""
	driver.set_script_timeout(timeout)
	driver.execute_async_script(dedent('''
	// Function to extract URL from CSS 'url()' function
	function extractCSSURL(text) {
	var url_str = text.replace(/.url\((.)\).*/, '$1');
	// If the URL is enclosed with double quotes
	if (url_str[0] === '"') {
	return JSON.parse(url_str);
	}
	// If the URL is enclosed with single quotes
	if (url_str[0] === "'") {
	return JSON.parse(
	url_str
	.replace(/'/g, '__DOUBLE__QUOTE__HERE__')
	.replace(/"/g, "'")
	.replace(/__DOUBLE__QUOTE__HERE__/g, '"')
	);
	}
	// Return the URL as is
	return url_str;
	}

	// Function to create a promise that resolves when the image is loaded
	function imageResolved(url) {
	return new Promise(function (resolve) {
	var img = new Image();
	img.onload = function () {
	resolve(url);
	};
	img.src = url;
	// If the image is already loaded, resolve the promise immediately
	if (img.complete) {
	resolve(url);
	}
	});
	}

	// The last argument is expected to be a callback function
	var callback = arguments[arguments.length - 1];

	Promise.all([
	// Get all img tags, create a promise for each one
	...Array.from(document.querySelectorAll('img[src]'), img => imageResolved(img.src)),
	// Get all inline styles with 'url()' and create a promise for each one
	...Array.from(document.querySelectorAll('[style*="url("]'), elem => imageResolved(extractCSSURL(elem.style.cssText)))
	])
	.then(function () {
	// After all images are loaded, wait for all fonts to load
	return document.fonts.ready;
	})
	.then(function() {
	// After all fonts are loaded, check for images in CSS stylesheets
	let cssImagesPromises = [];
	for(let i = 0; i < document.styleSheets.length; i++) {
	let rules = document.styleSheets[i].cssRules;
	for (let j = 0; j < rules.length; j++) {
	let style = rules[j].style;
	// Check if a background image is found and if it's a URL
	if (style && String(style.backgroundImage).startsWith('url(')) {
	let url = extractCSSURL(style.backgroundImage);
	cssImagesPromises.push(imageResolved(url));
	}
	}
	}
	return Promise.all(cssImagesPromises);
	})
	.then(function () {
	// Call the callback function when all promises are resolved
	callback(arguments);
	});

	return undefined;
	'''))