Postman pre-request script for signing requests to Bittrex V3 api

postman_bittrex_v3_pre-request.js

// You can import the Bittrex v3 API collection into Postman: https://github.com/Bittrex/bittrex.github.io/tree/master/src/_data

// To use this script ensure the following is available in Postman:
// A Collection Variable `baseUrl`
// An Environment Variable BITTREX_API_KEY
// An Environment Variable BITTREX_API_SECRET

// set up vars
let timestamp = new Date().getTime()
let url = pm.request['url']
let method = pm.request['method']

function getPath(url) {
    var pathRegex = /(?:.+?\:\/\/.+?)?(\/.+)/;
    var result = url.match(pathRegex);
    return result && result.length > 1 ? result[1] : '';
}

function getContentHash(httpMethod, requestBody) {
    if (httpMethod == 'GET' || !requestBody) {
        requestBody = '';
    } else {
        requestBody = requestBody.toString();
    }

    return CryptoJS.SHA512(requestBody).toString(CryptoJS.enc.Hex);
}


function getHmacDigest(httpMethod, requestUrl, requestBody) {
    var requestPath = getPath(requestUrl.toString());

    let contentHash = getContentHash(httpMethod, requestBody);
    let baseUrl = pm.collectionVariables.get('baseUrl')
    var preSign = [timestamp, baseUrl, requestPath, httpMethod.toUpperCase(), contentHash].join('');
    let secret = postman.getEnvironmentVariable("BITTREX_API_SECRET");
    var hmacDigest = CryptoJS.enc.Hex.stringify(CryptoJS.HmacSHA512(preSign, secret));
    return hmacDigest;
}

var signature = getHmacDigest(pm.request.method, pm.request.url, pm.request.body)

// Api-Key
pm.request.headers.add({
    key: 'Api-Key',
    value: postman.getEnvironmentVariable("BITTREX_API_KEY")
});

// Api-Timestamp
pm.request.headers.add({
    key: 'Api-Timestamp',
    value: timestamp
});

// Api-Content-Hash
pm.request.headers.add({
    key: 'Api-Content-Hash',
    value: getContentHash(pm.request.method, pm.request.body)
});

// Api-Signature
pm.request.headers.add({
    key: 'Api-Signature',
    value: signature
});