parse-data-url.js 6.46 KB
"use strict";

Object.defineProperty(exports, "__esModule", {
  value: true
});
exports.default = parseDataUrl;

var _abab = require("abab");

const removeLeadingAndTrailingHTTPWhitespace = string => string.replace(/^[ \t\n\r]+/, "").replace(/[ \t\n\r]+$/, "");

const removeTrailingHTTPWhitespace = string => string.replace(/[ \t\n\r]+$/, "");

const isHTTPWhitespaceChar = char => char === " " || char === "\t" || char === "\n" || char === "\r";

const solelyContainsHTTPTokenCodePoints = string => /^[-!#$%&'*+.^_`|~A-Za-z0-9]*$/.test(string);

const soleyContainsHTTPQuotedStringTokenCodePoints = string => /^[\t\u0020-\u007E\u0080-\u00FF]*$/.test(string);

const asciiLowercase = string => string.replace(/[A-Z]/g, l => l.toLowerCase());

const collectAnHTTPQuotedString = (input, position) => {
  let value = ""; // eslint-disable-next-line no-param-reassign

  position += 1; // eslint-disable-next-line no-constant-condition

  while (true) {
    while (position < input.length && input[position] !== '"' && input[position] !== "\\") {
      value += input[position]; // eslint-disable-next-line no-param-reassign

      position += 1;
    }

    if (position >= input.length) {
      break;
    }

    const quoteOrBackslash = input[position]; // eslint-disable-next-line no-param-reassign

    position += 1;

    if (quoteOrBackslash === "\\") {
      if (position >= input.length) {
        value += "\\";
        break;
      }

      value += input[position]; // eslint-disable-next-line no-param-reassign

      position += 1;
    } else {
      break;
    }
  }

  return [value, position];
};

function isASCIIHex(c) {
  return c >= 0x30 && c <= 0x39 || c >= 0x41 && c <= 0x46 || c >= 0x61 && c <= 0x66;
}

function percentDecodeBytes(input) {
  const output = new Uint8Array(input.byteLength);
  let outputIndex = 0;

  for (let i = 0; i < input.byteLength; ++i) {
    const byte = input[i];

    if (byte !== 0x25) {
      output[outputIndex] = byte;
    } else if (byte === 0x25 && (!isASCIIHex(input[i + 1]) || !isASCIIHex(input[i + 2]))) {
      output[outputIndex] = byte;
    } else {
      output[outputIndex] = parseInt(String.fromCodePoint(input[i + 1], input[i + 2]), 16);
      i += 2;
    }

    outputIndex += 1;
  }

  return output.slice(0, outputIndex);
}

function parseDataUrl(stringInput) {
  let parsedUrl;

  try {
    parsedUrl = new URL(stringInput);
  } catch (error) {
    return null;
  }

  if (parsedUrl.protocol !== "data:") {
    return null;
  }

  parsedUrl.hash = ""; // `5` is value of `'data:'.length`

  const input = parsedUrl.toString().substring(5);
  let position = 0;
  let mediaType = "";

  while (position < input.length && input[position] !== ",") {
    mediaType += input[position];
    position += 1;
  }

  mediaType = mediaType.replace(/^[ \t\n\f\r]+/, "").replace(/[ \t\n\f\r]+$/, "");

  if (position === input.length) {
    return null;
  }

  position += 1;
  const encodedBody = input.substring(position);
  let body = Buffer.from(percentDecodeBytes(Buffer.from(encodedBody, "utf-8"))); // Can't use /i regexp flag because it isn't restricted to ASCII.

  const mimeTypeBase64MatchResult = /(.*); *[Bb][Aa][Ss][Ee]64$/.exec(mediaType);

  if (mimeTypeBase64MatchResult) {
    const stringBody = body.toString("binary");
    const asString = (0, _abab.atob)(stringBody);

    if (asString === null) {
      return null;
    }

    body = Buffer.from(asString, "binary");
    [, mediaType] = mimeTypeBase64MatchResult;
  }

  if (mediaType.startsWith(";")) {
    mediaType = `text/plain ${mediaType}`;
  }

  const result = {
    // eslint-disable-next-line no-undefined
    type: undefined,
    // eslint-disable-next-line no-undefined
    subtype: undefined,
    parameters: new Map(),
    isBase64: Boolean(mimeTypeBase64MatchResult),
    body
  };

  if (!mediaType) {
    return result;
  }

  const inputMediaType = removeLeadingAndTrailingHTTPWhitespace(mediaType);
  let positionMediaType = 0;
  let type = "";

  while (positionMediaType < inputMediaType.length && inputMediaType[positionMediaType] !== "/") {
    type += inputMediaType[positionMediaType];
    positionMediaType += 1;
  }

  if (type.length === 0 || !solelyContainsHTTPTokenCodePoints(type)) {
    return result;
  }

  if (positionMediaType >= inputMediaType.length) {
    return result;
  } // Skips past "/"


  positionMediaType += 1;
  let subtype = "";

  while (positionMediaType < inputMediaType.length && inputMediaType[positionMediaType] !== ";") {
    subtype += inputMediaType[positionMediaType];
    positionMediaType += 1;
  }

  subtype = removeTrailingHTTPWhitespace(subtype);

  if (subtype.length === 0 || !solelyContainsHTTPTokenCodePoints(subtype)) {
    return result;
  }

  result.type = asciiLowercase(type);
  result.subtype = asciiLowercase(subtype);

  while (positionMediaType < inputMediaType.length) {
    // Skip past ";"
    positionMediaType += 1;

    while (isHTTPWhitespaceChar(inputMediaType[positionMediaType])) {
      positionMediaType += 1;
    }

    let parameterName = "";

    while (positionMediaType < inputMediaType.length && inputMediaType[positionMediaType] !== ";" && inputMediaType[positionMediaType] !== "=") {
      parameterName += inputMediaType[positionMediaType];
      positionMediaType += 1;
    }

    parameterName = asciiLowercase(parameterName);

    if (positionMediaType < inputMediaType.length) {
      if (inputMediaType[positionMediaType] === ";") {
        // eslint-disable-next-line no-continue
        continue;
      } // Skip past "="


      positionMediaType += 1;
    }

    let parameterValue = "";

    if (inputMediaType[positionMediaType] === '"') {
      [parameterValue, positionMediaType] = collectAnHTTPQuotedString(inputMediaType, positionMediaType);

      while (positionMediaType < inputMediaType.length && inputMediaType[positionMediaType] !== ";") {
        positionMediaType += 1;
      }
    } else {
      while (positionMediaType < inputMediaType.length && inputMediaType[positionMediaType] !== ";") {
        parameterValue += inputMediaType[positionMediaType];
        positionMediaType += 1;
      }

      parameterValue = removeTrailingHTTPWhitespace(parameterValue);

      if (parameterValue === "") {
        // eslint-disable-next-line no-continue
        continue;
      }
    }

    if (parameterName.length > 0 && solelyContainsHTTPTokenCodePoints(parameterName) && soleyContainsHTTPQuotedStringTokenCodePoints(parameterValue) && !result.parameters.has(parameterName)) {
      result.parameters.set(parameterName, parameterValue);
    }
  }

  return result;
}