How to fake local time in pyppeteer?

Question

Python

How to fake local time in pyppeteer? In order for sites to see the time corresponding to the time zone of the proxy.

Answer 1

As someone who has just encountered a problem, I help those who will be here after me.
The essence of the solution is to run a JS script that changes the time / time zone using evaluateOnNewDocument.
Working code example: (includes TimeShift script )

import asyncio
from pyppeteer import launch

time_shift_js = '''/*!
 * TimeShift.js
 *
 * Copyright 2013 Mobile Wellness Solutions MWS Ltd, Sampo Juustila
 * Released under the MIT license
 */

() =>{ 

(function() {

    var root = this;
    var OriginalDate = root.Date;

    var TimeShift;
    if (typeof exports !== 'undefined') {
        TimeShift = exports;
    } else {
        TimeShift = root.TimeShift = {};
    }


    var currentTime = undefined;
    var timezoneOffset = new OriginalDate().getTimezoneOffset();

    function currentDate() {
        if (currentTime) {
            return new OriginalDate(currentTime);
        } else {
            return new OriginalDate();
        }
    }


    function realLocalToUtc(realLocal) {
        return new OriginalDate(realLocal.getTime() - realLocal.getTimezoneOffset()*60*1000 + timezoneOffset*60*1000);
    }
    function utcToLocal(utc) {
        return new OriginalDate(utc.getTime() - timezoneOffset*60*1000);
    }
    function localToUtc(local) {
        return new OriginalDate(local.getTime() + timezoneOffset*60*1000);
    }
    function twoDigit(n) {
        if (n < 10) {
            return "0" + n;
        } else {
            return "" + n;
        }
    }
    function timezoneName() {
        var zone = "GMT";
        var offset = Math.abs(timezoneOffset);
        if (timezoneOffset < 0) {
            zone = zone + "+";
        } else if (timezoneOffset > 0) {
            zone = zone + "-";
        } else {
            return zone;
        }
        return zone + twoDigit(Math.floor(offset/60)) + twoDigit(offset%60);
    }
    TimeShift.getTimezoneOffset = function() {
        return timezoneOffset;
    }
    TimeShift.setTimezoneOffset = function(offset) {
        timezoneOffset = offset;
    }
    TimeShift.getTime = function() {
        return currentTime;
    }
    TimeShift.setTime = function(time) {
        currentTime = time;
    }
    TimeShift.OriginalDate = OriginalDate;
    TimeShift.Date = function() {
        var isConstructor = false;
        if (this instanceof TimeShift.Date && !this.__previouslyConstructedByTimeShift) {
            isConstructor = true;
            this.__previouslyConstructedByTimeShift = true;
        }
        if (!isConstructor) {
            return (new TimeShift.Date()).toString();
        }

        switch (arguments.length) {
        case 0:
            this.utc = currentDate();
            break;
        case 1:
            this.utc = new OriginalDate(arguments[0]);
            break;
        }
    }

    TimeShift.Date.prototype.getDate = function() { return utcToLocal(this.utc).getUTCDate(); }
    TimeShift.Date.prototype.getDay = function() { return utcToLocal(this.utc).getUTCDay(); }
    TimeShift.Date.prototype.getFullYear = function() { return utcToLocal(this.utc).getUTCFullYear(); }
    TimeShift.Date.prototype.getHours = function() { return utcToLocal(this.utc).getUTCHours(); }
    TimeShift.Date.prototype.getMilliseconds = function() { return utcToLocal(this.utc).getUTCMilliseconds(); }
    TimeShift.Date.prototype.getMinutes = function() { return utcToLocal(this.utc).getUTCMinutes(); }
    TimeShift.Date.prototype.getMonth = function() { return utcToLocal(this.utc).getUTCMonth(); }
    TimeShift.Date.prototype.getSeconds = function() { return utcToLocal(this.utc).getUTCSeconds(); }

    TimeShift.Date.prototype.getUTCDate = function() { return this.utc.getUTCDate(); }
    TimeShift.Date.prototype.getUTCDay = function() { return this.utc.getUTCDay(); }
    TimeShift.Date.prototype.getUTCFullYear = function() { return this.utc.getUTCFullYear(); }
    TimeShift.Date.prototype.getUTCHours = function() { return this.utc.getUTCHours(); }
    TimeShift.Date.prototype.getUTCMilliseconds = function() { return this.utc.getUTCMilliseconds(); }
    TimeShift.Date.prototype.getUTCMinutes = function() { return this.utc.getUTCMinutes(); }
    TimeShift.Date.prototype.getUTCMonth = function() { return this.utc.getUTCMonth(); }
    TimeShift.Date.prototype.getUTCSeconds = function() { return this.utc.getUTCSeconds(); }

    TimeShift.Date.prototype.setDate = function() { var d = utcToLocal(this.utc); d.setUTCDate.apply(d, Array.prototype.slice.call(arguments, 0)); this.utc = localToUtc(d); }
    TimeShift.Date.prototype.setFullYear = function() { var d = utcToLocal(this.utc); d.setUTCFullYear.apply(d, Array.prototype.slice.call(arguments, 0)); this.utc = localToUtc(d); }
    TimeShift.Date.prototype.setHours = function() { var d = utcToLocal(this.utc); d.setUTCHours.apply(d, Array.prototype.slice.call(arguments, 0)); this.utc = localToUtc(d); }
    TimeShift.Date.prototype.setMilliseconds = function() { var d = utcToLocal(this.utc); d.setUTCMilliseconds.apply(d, Array.prototype.slice.call(arguments, 0)); this.utc = localToUtc(d); }
    TimeShift.Date.prototype.setMinutes = function() { var d = utcToLocal(this.utc); d.setUTCMinutes.apply(d, Array.prototype.slice.call(arguments, 0)); this.utc = localToUtc(d); }
    TimeShift.Date.prototype.setMonth = function() { var d = utcToLocal(this.utc); d.setUTCMonth.apply(d, Array.prototype.slice.call(arguments, 0)); this.utc = localToUtc(d); }
    TimeShift.Date.prototype.setSeconds = function() { var d = utcToLocal(this.utc); d.setUTCSeconds.apply(d, Array.prototype.slice.call(arguments, 0)); this.utc = localToUtc(d); }

    TimeShift.Date.prototype.setUTCDate = function() { this.utc.setUTCDate.apply(this.utc, Array.prototype.slice.call(arguments, 0)); }
    TimeShift.Date.prototype.setUTCFullYear = function() { this.utc.setUTCFullYear.apply(this.utc, Array.prototype.slice.call(arguments, 0)); }
    TimeShift.Date.prototype.setUTCHours = function() { this.utc.setUTCHours.apply(this.utc, Array.prototype.slice.call(arguments, 0)); }
    TimeShift.Date.prototype.setUTCMilliseconds = function() { this.utc.setUTCMilliseconds.apply(this.utc, Array.prototype.slice.call(arguments, 0)); }
    TimeShift.Date.prototype.setUTCMinutes = function() { this.utc.setUTCMinutes.apply(this.utc, Array.prototype.slice.call(arguments, 0)); }
    TimeShift.Date.prototype.setUTCMonth = function() { this.utc.setUTCMonth.apply(this.utc, Array.prototype.slice.call(arguments, 0)); }
    TimeShift.Date.prototype.setUTCSeconds = function() { this.utc.setUTCSeconds.apply(this.utc, Array.prototype.slice.call(arguments, 0)); }


    TimeShift.Date.prototype.getYear = function() { return this.getFullYear() - 1900; }
    TimeShift.Date.prototype.setYear = function(v) { this.setFullYear(v + 1900); }

    TimeShift.Date.prototype.getTime = function() { return this.utc.getTime(); }
    TimeShift.Date.prototype.setTime = function(v) { this.utc.setTime(v); }

    TimeShift.Date.prototype.getTimezoneOffset = function() { return timezoneOffset; }

    TimeShift.Date.prototype.toDateString = function() { return utcToLocal(this.utc).toDateString(); }  // Wrong
    TimeShift.Date.prototype.toLocaleDateString = function() { return utcToLocal(this.utc).toLocaleDateString(); }  // Wrong

    TimeShift.Date.prototype.toISOString = function() { return this.utc.toISOString(); }
    TimeShift.Date.prototype.toGMTString = function() { return this.utc.toGMTString(); }
    TimeShift.Date.prototype.toUTCString = function() { return this.utc.toUTCString(); }

    TimeShift.Date.prototype.toString = function() {
        var wkdays = ["Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat"];
        var months = ["Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"];
        var d = utcToLocal(this.utc);
        return wkdays[d.getUTCDay()] + " " + months[d.getUTCMonth()] + " " + twoDigit(d.getUTCDate()) + " " + d.getUTCFullYear() +
            " " + twoDigit(d.getUTCHours()) + ":" + twoDigit(d.getUTCMinutes()) + ":" + twoDigit(d.getUTCSeconds()) + " " + timezoneName();
    }
    TimeShift.Date.prototype.toLocaleString = function() { return this.toString(); }  // Wrong
    TimeShift.Date.prototype.toLocaleTimeString = function() { return this.toString(); }  // Wrong
    TimeShift.Date.prototype.toTimeString = function() { return this.toString(); }  // Wrong

    TimeShift.Date.prototype.toJSON = function() { return this.utc.toJSON(); }
    TimeShift.Date.prototype.valueOf = function() { return this.utc.getTime(); }


    TimeShift.Date.now = function() { return currentDate().getTime(); }
    TimeShift.Date.parse = OriginalDate.parse;  // Wrong
    TimeShift.Date.UTC = OriginalDate.UTC;


    /**
     * Helper method that describes a Date object contents.
     */
    TimeShift.Date.prototype.desc = function() {
        return "utc=" + this.utc.toUTCString() + "   local=" + utcToLocal(this.utc).toUTCString() + "   offset=" + timezoneOffset;
    }

}).call(typeof global !== 'undefined' ? global : this);

Date = TimeShift.Date; 
TimeShift.setTimezoneOffset(0);
}'''

async def main():
    browser = await launch(headless=False)
    page = await browser.newPage()

    await page.setExtraHTTPHeaders({'Accept-Language': 'en-US,en;q=0.9'})
    await page.setUserAgent('Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/88.0.4324.150 Safari/537.36')

    await page.evaluateOnNewDocument(time_shift_js)
    await page.goto("https://amiunique.org/fp")

    input()

    await browser.close()
asyncio.get_event_loop().run_until_complete(main())