lib/display/network_utils.js

/**
 * @licstart The following is the entire license notice for the
 * Javascript code in this page
 *
 * Copyright 2020 Mozilla Foundation
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 * @licend The above is the entire license notice for the
 * Javascript code in this page
 */
"use strict";

Object.defineProperty(exports, "__esModule", {
  value: true
});
exports.createResponseStatusError = createResponseStatusError;
exports.extractFilenameFromHeader = extractFilenameFromHeader;
exports.validateRangeRequestCapabilities = validateRangeRequestCapabilities;
exports.validateResponseStatus = validateResponseStatus;

var _util = require("../shared/util.js");

var _content_disposition = require("./content_disposition.js");

function validateRangeRequestCapabilities({
  getResponseHeader,
  isHttp,
  rangeChunkSize,
  disableRange
}) {
  (0, _util.assert)(rangeChunkSize > 0, "Range chunk size must be larger than zero");
  const returnValues = {
    allowRangeRequests: false,
    suggestedLength: undefined
  };
  const length = parseInt(getResponseHeader("Content-Length"), 10);

  if (!Number.isInteger(length)) {
    return returnValues;
  }

  returnValues.suggestedLength = length;

  if (length <= 2 * rangeChunkSize) {
    return returnValues;
  }

  if (disableRange || !isHttp) {
    return returnValues;
  }

  if (getResponseHeader("Accept-Ranges") !== "bytes") {
    return returnValues;
  }

  const contentEncoding = getResponseHeader("Content-Encoding") || "identity";

  if (contentEncoding !== "identity") {
    return returnValues;
  }

  returnValues.allowRangeRequests = true;
  return returnValues;
}

function extractFilenameFromHeader(getResponseHeader) {
  const contentDisposition = getResponseHeader("Content-Disposition");

  if (contentDisposition) {
    let filename = (0, _content_disposition.getFilenameFromContentDispositionHeader)(contentDisposition);

    if (filename.includes("%")) {
      try {
        filename = decodeURIComponent(filename);
      } catch (ex) {}
    }

    if (/\.pdf$/i.test(filename)) {
      return filename;
    }
  }

  return null;
}

function createResponseStatusError(status, url) {
  if (status === 404 || status === 0 && url.startsWith("file:")) {
    return new _util.MissingPDFException('Missing PDF "' + url + '".');
  }

  return new _util.UnexpectedResponseException("Unexpected server response (" + status + ') while retrieving PDF "' + url + '".', status);
}

function validateResponseStatus(status) {
  return status === 200 || status === 206;
}