helpers.ts

export function isValidPort(port: number) {
  // verify if port is a number.
  if (typeof port !== "number" || isNaN(port)) {
    return false;
  }
  // port cannot be negative.
  if (port <= 0) {
    return false;
  }
  const minPort = 1;
  const maxPort = 65535;
  // Verify if port is in range.
  return port >= minPort && port <= maxPort;
}

/**
 * Validate a bucket name.
 * http://docs.aws.amazon.com/AmazonS3/latest/dev/BucketRestrictions.html
 */
export function isValidBucketName(bucket: string) {
  if (typeof bucket !== "string") {
    return false;
  }

  // bucket length should be less than and no more than 63
  // characters long.
  if (bucket.length < 3 || bucket.length > 63) {
    return false;
  }
  // bucket with successive periods is invalid.
  if (bucket.indexOf("..") > -1) {
    return false;
  }
  // bucket cannot have ip address style.
  if (bucket.match(/[0-9]+\.[0-9]+\.[0-9]+\.[0-9]+/)) {
    return false;
  }
  // bucket should begin with alphabet/number and end with alphabet/number,
  // with alphabet/number/.- in the middle.
  if (bucket.match(/^[a-z0-9][a-z0-9.-]+[a-z0-9]$/)) {
    return true;
  }
  return false;
}

/**
 * check if objectName is a valid object name
 * http://docs.aws.amazon.com/AmazonS3/latest/dev/UsingMetadata.html
 */
export function isValidObjectName(objectName: string) {
  if (!isValidPrefix(objectName)) return false;
  if (objectName.length === 0) return false;
  return true;
}

// check if prefix is valid
export function isValidPrefix(prefix: string) {
  if (typeof prefix !== "string") return false;
  if (prefix.length > 1024) return false;
  return true;
}

/**
 * Convert some binary data to a hex string
 */
export function bin2hex(binary: Uint8Array) {
  return Array.from(binary).map((b) => b.toString(16).padStart(2, "0")).join(
    "",
  );
}

export function sanitizeETag(etag = "") {
  const replaceChars: Record<string, string> = {
    '"': "",
    "&quot;": "",
    "&#34;": "",
    "&QUOT;": "",
    "&#x00022": "",
  };
  return etag.replace(
    /^("|&quot;|&#34;)|("|&quot;|&#34;)$/g,
    (m) => replaceChars[m],
  );
}

export function getVersionId(headers: Headers): string | null {
  return headers.get("x-amz-version-id") ?? null;
}

/** Create a Date string with format: 'YYYYMMDDTHHmmss' + Z */
export function makeDateLong(date?: Date) {
  date = date || new Date();

  // Gives format like: '2017-08-07T16:28:59.889Z'
  const dateStr = date.toISOString();

  return dateStr.substr(0, 4) +
    dateStr.substr(5, 2) +
    dateStr.substr(8, 5) +
    dateStr.substr(14, 2) +
    dateStr.substr(17, 2) + "Z";
}

/** Create a Date string with format: 'YYYYMMDD' */
export function makeDateShort(date?: Date) {
  date = date || new Date();

  // Gives format like: '2017-08-07T16:28:59.889Z'
  const dateStr = date.toISOString();

  return dateStr.substr(0, 4) + dateStr.substr(5, 2) + dateStr.substr(8, 2);
}

export function getScope(region: string, date: Date) {
  return `${makeDateShort(date)}/${region}/s3/aws4_request`;
}

export async function sha256digestHex(data: Uint8Array | string) {
  if (!(data instanceof Uint8Array)) {
    data = new TextEncoder().encode(data);
  }
  return bin2hex(new Uint8Array(await crypto.subtle.digest("SHA-256", data)));
}