在访问一些网站如GitHub时，经常会发生加载缓慢的情况出现，我们可以借助workers来加速访问这些网站。

Workers类似于腾讯云的云函数SCF，都是无服务器运算，不同的是Workers基于全球服务器，且个人限制很宽松，每天10W次次数限制。

点此进入Cloudflare控制台：https://dash.cloudflare.com/

注册的步骤省略。

点击左侧Workers进入设置。

点击创建服务。

设置好名字，箭头处为设置好后要访问的网址，建议设置成方便记忆的字符串。

点击快速编辑。

在左侧填入以下代码（以Github为例）

// 你要镜像的网站.
const upstream = 'www.github.com'

// 镜像网站的目录，比如你想镜像某个网站的二级目录则填写二级目录的目录名，镜像 google 用不到，默认即可.
const upstream_path = '/'

// 镜像站是否有手机访问专用网址，没有则填一样的.
const upstream_mobile = 'www.github.com'

// 屏蔽国家和地区.
const blocked_region = ['KP', 'SY', 'PK', 'CU']

// 屏蔽 IP 地址.
const blocked_ip_address = ['0.0.0.0', '127.0.0.1']

// 镜像站是否开启 HTTPS.
const https = true

// 文本替换.
const replace_dict = {
    '$upstream': '$custom_domain',
    '//github.com': ''
}

// 以下保持默认，不要动
addEventListener('fetch', event => {
    event.respondWith(fetchAndApply(event.request));
})

async function fetchAndApply(request) {

    const region = request.headers.get('cf-ipcountry').toUpperCase();
    const ip_address = request.headers.get('cf-connecting-ip');
    const user_agent = request.headers.get('user-agent');

    let response = null;
    let url = new URL(request.url);
    let url_hostname = url.hostname;

    if (https == true) {
        url.protocol = 'https:';
    } else {
        url.protocol = 'http:';
    }

    if (await device_status(user_agent)) {
        var upstream_domain = upstream;
    } else {
        var upstream_domain = upstream_mobile;
    }

    url.host = upstream_domain;
    if (url.pathname == '/') {
        url.pathname = upstream_path;
    } else {
        url.pathname = upstream_path + url.pathname;
    }

    if (blocked_region.includes(region)) {
        response = new Response('Access denied: WorkersProxy is not available in your region yet.', {
            status: 403
        });
    } else if (blocked_ip_address.includes(ip_address)) {
        response = new Response('Access denied: Your IP address is blocked by WorkersProxy.', {
            status: 403
        });
    } else {
        let method = request.method;
        let request_headers = request.headers;
        let new_request_headers = new Headers(request_headers);

        new_request_headers.set('Host', url.hostname);
        new_request_headers.set('Referer', url.hostname);

        let original_response = await fetch(url.href, {
            method: method,
            headers: new_request_headers
        })

        let original_response_clone = original_response.clone();
        let original_text = null;
        let response_headers = original_response.headers;
        let new_response_headers = new Headers(response_headers);
        let status = original_response.status;

        new_response_headers.set('access-control-allow-origin', '*');
        new_response_headers.set('access-control-allow-credentials', true);
        new_response_headers.delete('content-security-policy');
        new_response_headers.delete('content-security-policy-report-only');
        new_response_headers.delete('clear-site-data');

        const content_type = new_response_headers.get('content-type');
        if (content_type.includes('text/html') && content_type.includes('UTF-8')) {
            original_text = await replace_response_text(original_response_clone, upstream_domain, url_hostname);
        } else {
            original_text = original_response_clone.body
        }

        response = new Response(original_text, {
            status,
            headers: new_response_headers
        })
    }
    return response;
}

async function replace_response_text(response, upstream_domain, host_name) {
    let text = await response.text()

    var i, j;
    for (i in replace_dict) {
        j = replace_dict[i]
        if (i == '$upstream') {
            i = upstream_domain
        } else if (i == '$custom_domain') {
            i = host_name
        }

        if (j == '$upstream') {
            j = upstream_domain
        } else if (j == '$custom_domain') {
            j = host_name
        }

        let re = new RegExp(i, 'g')
        text = text.replace(re, j);
    }
    return text;
}


async function device_status(user_agent_info) {
    var agents = ["Android", "iPhone", "SymbianOS", "Windows Phone", "iPad", "iPod"];
    var flag = true;
    for (var v = 0; v < agents.length; v++) {
        if (user_agent_info.indexOf(agents[v]) > 0) {
            flag = false;
            break;
        }
    }
    return flag;
}

以Google为例（已经不可用，Google已经把Cloudflare给ban了）：

// 你要镜像的网站.
const upstream = 'www.google.com'

// 镜像网站的目录，比如你想镜像某个网站的二级目录则填写二级目录的目录名，镜像 google 用不到，默认即可.
const upstream_path = '/'

// 镜像站是否有手机访问专用网址，没有则填一样的.
const upstream_mobile = 'www.google.com'

// 屏蔽国家和地区.
const blocked_region = ['KP', 'SY', 'PK', 'CU']

// 屏蔽 IP 地址.
const blocked_ip_address = ['0.0.0.0', '127.0.0.1']

// 镜像站是否开启 HTTPS.
const https = true

// 文本替换.
const replace_dict = {
    '$upstream': '$custom_domain',
    '//google.com': ''
}

// 以下保持默认，不要动
addEventListener('fetch', event => {
    event.respondWith(fetchAndApply(event.request));
})

async function fetchAndApply(request) {

    const region = request.headers.get('cf-ipcountry').toUpperCase();
    const ip_address = request.headers.get('cf-connecting-ip');
    const user_agent = request.headers.get('user-agent');

    let response = null;
    let url = new URL(request.url);
    let url_hostname = url.hostname;

    if (https == true) {
        url.protocol = 'https:';
    } else {
        url.protocol = 'http:';
    }

    if (await device_status(user_agent)) {
        var upstream_domain = upstream;
    } else {
        var upstream_domain = upstream_mobile;
    }

    url.host = upstream_domain;
    if (url.pathname == '/') {
        url.pathname = upstream_path;
    } else {
        url.pathname = upstream_path + url.pathname;
    }

    if (blocked_region.includes(region)) {
        response = new Response('Access denied: WorkersProxy is not available in your region yet.', {
            status: 403
        });
    } else if (blocked_ip_address.includes(ip_address)) {
        response = new Response('Access denied: Your IP address is blocked by WorkersProxy.', {
            status: 403
        });
    } else {
        let method = request.method;
        let request_headers = request.headers;
        let new_request_headers = new Headers(request_headers);

        new_request_headers.set('Host', url.hostname);
        new_request_headers.set('Referer', url.hostname);

        let original_response = await fetch(url.href, {
            method: method,
            headers: new_request_headers
        })

        let original_response_clone = original_response.clone();
        let original_text = null;
        let response_headers = original_response.headers;
        let new_response_headers = new Headers(response_headers);
        let status = original_response.status;

        new_response_headers.set('access-control-allow-origin', '*');
        new_response_headers.set('access-control-allow-credentials', true);
        new_response_headers.delete('content-security-policy');
        new_response_headers.delete('content-security-policy-report-only');
        new_response_headers.delete('clear-site-data');

        const content_type = new_response_headers.get('content-type');
        if (content_type.includes('text/html') && content_type.includes('UTF-8')) {
            original_text = await replace_response_text(original_response_clone, upstream_domain, url_hostname);
        } else {
            original_text = original_response_clone.body
        }

        response = new Response(original_text, {
            status,
            headers: new_response_headers
        })
    }
    return response;
}

async function replace_response_text(response, upstream_domain, host_name) {
    let text = await response.text()

    var i, j;
    for (i in replace_dict) {
        j = replace_dict[i]
        if (i == '$upstream') {
            i = upstream_domain
        } else if (i == '$custom_domain') {
            i = host_name
        }

        if (j == '$upstream') {
            j = upstream_domain
        } else if (j == '$custom_domain') {
            j = host_name
        }

        let re = new RegExp(i, 'g')
        text = text.replace(re, j);
    }
    return text;
}


async function device_status(user_agent_info) {
    var agents = ["Android", "iPhone", "SymbianOS", "Windows Phone", "iPad", "iPod"];
    var flag = true;
    for (var v = 0; v < agents.length; v++) {
        if (user_agent_info.indexOf(agents[v]) > 0) {
            flag = false;
            break;
        }
    }
    return flag;
}

点击保存并部署。

现在，就可以通过右侧的链接访问自己搭建的镜像站了。

附上DEMO，也是我自己在使用的：

GitHub: Where the world builds software · GitHub (yqs.workers.dev)