修了 cf workers 反代脚本的一个小问题

用一个泛滥的脚本在 workers 反代了某 404 网站, 但是今天突然发现这个脚本反代出来的站点如果重复访问同一个链接, 总是隔一次就报错 1101, 遂查文档, 发现是 js 的问题, 打了下 log , 报错 Cannot read properties of null (reading 'includes'), 尝试修了下发现问题是获取上游响应头 content_type 的代码有问题, 遂简单粗暴的修复了, 因为已经找不到这脚本原始的作者了, 遂记录在这里

其实就是给 line83 的判断加了个 content_type 以防止把空值拿来做判断导致出错

我也看不出来具体是什么原因导致的隔一次就获取不到 content-type

在用这个脚本的可以修改下, 防止潜在的错误 完整代码如下

// 替换成你想镜像的站点
const upstream = 'www.nodeseek.com'
 
// 如果那个站点有专门的移动适配站点，否则保持和上面一致
const upstream_mobile = 'www.nodeseek.com'
 
// 你希望禁止哪些国家访问
// const blocked_region = ['RU']
const blocked_region = []
 
// 禁止自访问
const blocked_ip_address = ['0.0.0.0', '127.0.0.1']
 
// 替换成你想镜像的站点
const replace_dict = {
    '$upstream': '$custom_domain',
    '//www.nodeseek.com': ''
}
 
//以下内容都不用动
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_host = url.host;
 
    if (url.protocol == 'http:') {
        url.protocol = 'https:'
        response = Response.redirect(url.href);
        return response;
    }
 
    if (await device_status(user_agent)) {
        upstream_domain = upstream
    } else {
        upstream_domain = upstream_mobile
    }
 
    url.host = upstream_domain;
 
    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', upstream_domain);
        new_request_headers.set('Referer', url.href);
 
        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 && content_type.includes('text/html') && content_type.includes('UTF-8')) {
            original_text = await replace_response_text(original_response_clone, upstream_domain, url_host);
        } 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;
}