邮递员：使用 SHA256 和 RSA 的自定义签名请求

Question

我写了一个接口，用 python 向内部音频 api 发出请求。每个 API 请求都需要使用 RSA SHA256 签名。

现在我想用 Postman 测试 API 的端点并使用预请求脚本功能。但我对 javascript 并不坚定。也许有人可以帮助我将以下 python 函数翻译成 Postman 脚本：


def sign_request(
    request: httpx.Request, adp_token: str, private_key: str
) -> httpx.Request:
    """
    Helper function who creates a signed requests for authentication.

    :param request: The request to be signed
    :param adp_token: the token is obtained after register as device
    :param private_key: the rsa key obtained after register as device
    :returns: The signed request
    """
    method = request.method
    path = request.url.path
    query = request.url.query
    body = request.content.decode("utf-8")
    date = datetime.utcnow().isoformat("T") + "Z"

    if query:
        path += f"?{query}"

    data = f"{method}\n{path}\n{date}\n{body}\n{adp_token}"

    key = rsa.PrivateKey.load_pkcs1(private_key.encode())
    cipher = rsa.pkcs1.sign(data.encode(), key, "SHA-256")
    signed_encoded = base64.b64encode(cipher)

    signed_header = {
        "x-adp-token": adp_token,
        "x-adp-alg": "SHA256withRSA:1.0",
        "x-adp-signature": f"{signed_encoded.decode()}:{date}"
    }
    request.headers.update(signed_header)

    return request

我找到了如何获取请求方法和 body。我可以使用 pm.request.url.getPathWithQuery() 获取路径和查询。要将 headers 添加到请求中，我使用 pm.request.headers.add.

但我不知道如何获取等格式的日期时间、连接字符串和签署数据。

Answer 1

在 Postman 中执行此操作的问题是您只能使用 sandbox. So for this, you have crypto-js 中可用的那些包作为加密操作的唯一包助手。

var CryptoJS = require("crypto-js");
var moment = require("moment");

signRequest(pm.request, "yourAdpToken", "yourPrivateKey")

function signRequest(request, adpToken, privateKey) {
    const method = request.method;
    const path = request.url.getPathWithQuery();
    const body = request.body.raw;
    const date = moment.utc().format();
    const data = `${method}\n${path}\n${date}\n${body}\n${adpToken}`
    const hash = CryptoJS.HmacSHA256(data, privateKey);
    const signedEncoded = CryptoJS.enc.Base64.stringify(hash);

    pm.request.headers.add({
        key: 'x-adp-token',
        value: adpToken
    });

    pm.request.headers.add({
        key: 'x-adp-alg',
        value: 'SHA256withRSA:1.0'
    });

    pm.request.headers.add({
        key: 'x-adp-signature',
        value: `${CryptoJS.enc.Base64.parse(signedEncoded)}:${date}`
    });
}

将以上内容添加到 Pre-request 脚本会将您想要的 headers 添加到请求中，如下所示：

您可能需要更改编码部分，检查encode options

Answer 2

我明白了运行 pm lib。感谢您的帮助。

唯一的问题是从 env var 中获取包含换行符的私有证书会出现错误，这些代码 sig.init(privateKey);。我不得不直接在预请求脚本中写入私有证书字符串。

这是我的脚本。

eval( pm.globals.get('pmlib_code') );
var CryptoJS = require("crypto-js");
var moment = require("moment");

const adpToken = pm.environment.get("adp-token")
// private-key loaded from env var doesn't work because of newlines in it; bugfix
const privateKey = pm.environment.get("private-key")
// use private-key in pre request script directly make use of newline correctly
const privateKey2 = "-----BEGIN RSA PRIVATE KEY-----\nMIIE...==\n-----END RSA PRIVATE KEY-----\n"


signRequest(pm.request, adpToken, privateKey);

function signRequest(request, adpToken, privateKey2) {
    const method = request.method;
    const path = request.url.getPathWithQuery();
    const body = request.body || "";
    const date = moment.utc().format();
    const data = `${method}\n${path}\n${date}\n${body}\n${adpToken}`;
    var sig = new pmlib.rs.KJUR.crypto.Signature({"alg": "SHA256withRSA"});
    sig.init(privateKey);
    var hash = sig.signString(data);
    const signedEncoded = CryptoJS.enc.Base64.stringify(CryptoJS.enc.Hex.parse(hash));

    pm.request.headers.add({
        key: 'x-adp-token',
        value: adpToken
    });

    pm.request.headers.add({
        key: 'x-adp-alg',
        value: 'SHA256withRSA:1.0'
    });

    pm.request.headers.add({
        key: 'x-adp-signature',
        value: `${signedEncoded}:${date}`
    });
}

更新：

现在可以从 env var 读取设备证书了。我不得不用 const privateKey = pm.environment.get("private-key").replace(/\n/g, "\n")

替换 const privateKey = pm.environment.get("private-key")

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