结合前3节的内容，下面实现一个简易的HTTPS代理。
在第二节了解了一个HTTPS请求的代理过程，在建立链接的第一步是一个HTTP CONNECT请求，在这一步可以获得客户端请求目标网站的域名（这么说不是很准确，具体可看看SNI）。用预先安装好的CA证书和密钥，生成对应域名的子证书。这个过程其实就是一个HTTPS代理的核心步骤。
const http = require('http');
const url = require('url');
const net = require('net');
const createFakeHttpsWebSite = require('./createFakeHttpsWebSite')
let httpTunnel = new http.Server();
// 启动端口
let port = 6789;
httpTunnel.listen(port, () => {
console.log(`简易HTTPS中间人代理启动成功，端口：${port}`);
});
httpTunnel.on('error', (e) => {
if (e.code == 'EADDRINUSE') {
console.error('HTTP中间人代理启动失败！！');
console.error(`端口：${port}，已被占用。`);
} else {
console.error(e);
}
});
// https的请求通过http隧道方式转发
httpTunnel.on('connect', (req, cltSocket, head) => {
// connect to an origin server
var srvUrl = url.parse(`http://${req.url}`);
console.log(`CONNECT ${srvUrl.hostname}:${srvUrl.port}`);
// 根据域名生成对应的https服务
createFakeHttpsWebSite(srvUrl.hostname, (port) => {
var srvSocket = net.connect(port, '127.0.0.1', () => {
cltSocket.write('HTTP/1.1 200 Connection Established\r\n' +
'Proxy-agent: MITM-proxy\r\n' +
'\r\n');
srvSocket.write(head);
srvSocket.pipe(cltSocket);
cltSocket.pipe(srvSocket);
});
srvSocket.on('error', (e) => {
console.error(e);
});
})
});/**
* 根据域名生成一个伪造的https服务
* @param {[type]} domain [description]
* @param {[type]} successFun [description]
* @return {[type]} [description]
*/
function createFakeHttpsWebSite(domain, successFun) {
const fakeCertObj = createFakeCertificateByDomain(caKey, caCert, domain)
var fakeServer = new https.Server({
key: fakeCertObj.key,
cert: fakeCertObj.cert,
SNICallback: (hostname, done) => {
let certObj = createFakeCertificateByDomain(caKey, caCert, hostname)
done(null, tls.createSecureContext({
key: pki.privateKeyToPem(certObj.key),
cert: pki.certificateToPem(certObj.cert)
}))
}
});
fakeServer.listen(0, () => {
var address = fakeServer.address();
successFun(address.port);
});
fakeServer.on('request', (req, res) => {
// 解析客户端请求
var urlObject = url.parse(req.url);
let options = {
protocol: 'https:',
hostname: req.headers.host.split(':')[0],
method: req.method,
port: req.headers.host.split(':')[1] || 80,
path: urlObject.path,
headers: req.headers
};
res.writeHead(200, { 'Content-Type': 'text/html;charset=utf-8'});
res.write(`<html><body>我是伪造的: ${options.protocol}//${options.hostname} 站点</body></html>`)
res.end();
});
fakeServer.on('error', (e) => {
console.error(e);
});
}
/**
* 根据所给域名生成对应证书
* @param {[type]} caKey [description]
* @param {[type]} caCert [description]
* @param {[type]} domain [description]
* @return {[type]} [description]
*/
function createFakeCertificateByDomain(caKey, caCert, domain) {
var keys = pki.rsa.generateKeyPair(2046);
var cert = pki.createCertificate();
cert.publicKey = keys.publicKey;
cert.serialNumber = (new Date()).getTime()+'';
cert.validity.notBefore = new Date();
cert.validity.notBefore.setFullYear(cert.validity.notBefore.getFullYear() - 1);
cert.validity.notAfter = new Date();
cert.validity.notAfter.setFullYear(cert.validity.notAfter.getFullYear() + 1);
var attrs = [{
name: 'commonName',
value: domain
}, {
name: 'countryName',
value: 'CN'
}, {
shortName: 'ST',
value: 'GuangDong'
}, {
name: 'localityName',
value: 'ShengZhen'
}, {
name: 'organizationName',
value: 'https-mitm-proxy-handbook'
}, {
shortName: 'OU',
value: 'https://github.com/wuchangming/https-mitm-proxy-handbook'
}];
cert.setIssuer(caCert.subject.attributes);
cert.setSubject(attrs);
cert.setExtensions([{
name: 'basicConstraints',
critical: true,
cA: false
},
{
name: 'keyUsage',
critical: true,
digitalSignature: true,
contentCommitment: true,
keyEncipherment: true,
dataEncipherment: true,
keyAgreement: true,
keyCertSign: true,
cRLSign: true,
encipherOnly: true,
decipherOnly: true
},
{
name: 'subjectAltName',
altNames: [{
type: 2,
value: domain
}]
},
{
name: 'subjectKeyIdentifier'
},
{
name: 'extKeyUsage',
serverAuth: true,
clientAuth: true,
codeSigning: true,
emailProtection: true,
timeStamping: true
},
{
name:'authorityKeyIdentifier'
}]);
cert.sign(caKey, forge.md.sha256.create());
return {
key: keys.privateKey,
cert: cert
};
}完整源码：../code/chapter4
npm script运行方式
npm run simpleHttpsProxy
这样一个简易的HTTPS代理就完成了。
