How to authorize access to Azure storage using Shared Key Authorization in Postman

const crypto = require("crypto-js");

// Set Date header value for authorization
// Should be UTC GMT string
pm.environment.set("header_date", new Date().toUTCString());
console.log("header date", new Date().toUTCString());
// Sadness: https://github.com/postmanlabs/postman-app-support/issues/2922
var substituteEnvVars = function (varStr) {
    let match;
    let replacedVar = varStr;
    
    while ((match = /\{\{([^{}]*?)}}/g.exec(replacedVar)) !== null ) {
        if (!pm.variables.get(match[1])) {
            continue;
        }
        var envVar = new RegExp(RegExp.escape(match[0]), 'g');
        replacedVar = replacedVar.replace(envVar, pm.variables.get(match[1]));
    }
    
    return replacedVar;
};

// Get hash of all header-name:value
const headers = pm.request.getHeaders({ ignoreCase: true, enabled: true });

// Construct Signature value for Authorization header
var signatureParts = [
    pm.request.method.toUpperCase(),
    headers["content-encoding"] || "",
    headers["content-language"] || "",
    pm.request.body.toString().length || "",
    headers["content-md5"] || "",
    headers["content-type"] || "",
    headers["x-ms-date"] ? "" : (pm.variables.get("header_date") || ""),
    headers["if-modified-since"] || "",
    headers["if-match"] || "",
    headers["if-none-match"] || "",
    headers["if-unmodified-since"] || "",
    headers["range"] || ""
];

// Construct CanonicalizedHeaders
const canonicalHeaderNames = [];
Object.keys(headers).forEach(key => {
    if (key.startsWith("x-ms-")) {
        canonicalHeaderNames.push(key);
        console.log("key: ", canonicalHeaderNames);
    }
});
// Sort headers lexographically by name
canonicalHeaderNames.sort();

const canonicalHeaderParts = [];
canonicalHeaderNames.forEach(key => {
    let value = pm.request.getHeaders({ ignoreCase: true, enabled: true })[key];
    console.log("value: ",value);
    // Populate variables
    value = substituteEnvVars(value);
    console.log("value: ",value);
    // Replace whitespace in value but not if its within quotes
    if (!value.startsWith("\"")) {
        value = value.replace(/\s+/, " ");
        console.log("value: ",value);
    }
    
    canonicalHeaderParts.push(`${key}:${value}`);
    console.log("canonicalHeaderParts: ",canonicalHeaderParts);
});

// Add headers to signature
signatureParts.push.apply(signatureParts, canonicalHeaderParts);

// Construct CanonicalizedResource
const canonicalResourceParts = [
    `/${pm.environment.get("azure_storage_account")}${pm.request.url.getPath()}`
];
console.log("canonicalResourceParts: ",canonicalResourceParts);
const canonicalQueryNames = [];
pm.request.url.query.each(query => {
    canonicalQueryNames.push(query.key.toLowerCase());
    console.log("canonicalQueryNames: ",query.key.toLowerCase());
});
canonicalQueryNames.sort();
canonicalQueryNames.forEach(queryName => {
    const value = pm.request.url.query.get(queryName);
    console.log("canonicalQueryNames: ",value);
    // NOTE: This does not properly explode multiple same query params' values
    // and turn them into comma-separated list
    canonicalResourceParts.push(`${queryName}:${value}`);
    console.log("canonicalResourcePartss: ",canonicalResourceParts);
});
// Add resource to signature
signatureParts.push.apply(signatureParts, canonicalResourceParts);

console.log("Signature Parts", signatureParts);

// Now, construct signature raw string
const signatureRaw = signatureParts.join("\n");

console.log("Signature String", JSON.stringify(signatureRaw));

// Hash it using HMAC-SHA256 and then encode using base64
const storageKey = pm.environment.get("azure_storage_key");
const signatureBytes = crypto.HmacSHA256(signatureRaw, crypto.enc.Base64.parse(storageKey));
const signatureEncoded = signatureBytes.toString(crypto.enc.Base64);

console.log("Storage Account", pm.environment.get("azure_storage_account"));
console.log("Storage Key", storageKey);

// Finally, make it available for headers
pm.variables.set("header_authorization", 
    `SharedKey ${pm.environment.get("azure_storage_account")}:${signatureEncoded}`);