gatsby-plugin-gatsby-cloud/build-headers-program.js

A Gatsby plugin which optimizes working with Gatsby Cloud

"use strict";

var _interopRequireDefault = require("@babel/runtime/helpers/interopRequireDefault");
exports.__esModule = true;
exports.default = buildHeadersProgram;
var _flow2 = _interopRequireDefault(require("lodash/flow"));
var _map2 = _interopRequireDefault(require("lodash/map"));
var _mapValues2 = _interopRequireDefault(require("lodash/mapValues"));
var _mergeWith2 = _interopRequireDefault(require("lodash/mergeWith"));
var _union2 = _interopRequireDefault(require("lodash/union"));
var _isArray2 = _interopRequireDefault(require("lodash/isArray"));
var _fsExtra = require("fs-extra");
var _constants = require("./constants");
var _ipc = require("./ipc");
function getHeaderName(header) {
  const matches = header.match(/^([^:]+):/);
  return matches && matches[1];
}
function headersPath(pathPrefix, path) {
  return `${pathPrefix}${path}`;
}
function defaultMerge(...headers) {
  function unionMerge(objValue, srcValue) {
    if ((0, _isArray2.default)(objValue)) {
      return (0, _union2.default)(objValue, srcValue);
    } else {
      return undefined; // opt into default merge behavior
    }
  }

  return (0, _mergeWith2.default)({}, ...headers, unionMerge);
}
function headersMerge(userHeaders, defaultHeaders) {
  const merged = {};
  Object.keys(defaultHeaders).forEach(path => {
    if (!userHeaders[path]) {
      merged[path] = defaultHeaders[path];
      return;
    }
    const headersMap = {};
    defaultHeaders[path].forEach(header => {
      headersMap[getHeaderName(header)] = header;
    });
    userHeaders[path].forEach(header => {
      headersMap[getHeaderName(header)] = header; // override if exists
    });

    merged[path] = Object.values(headersMap);
  });
  Object.keys(userHeaders).forEach(path => {
    if (!merged[path]) {
      merged[path] = userHeaders[path];
    }
  });
  return merged;
}
function transformLink(manifest, publicFolder, pathPrefix) {
  return header => header.replace(_constants.LINK_REGEX, (__, prefix, file, suffix) => {
    const hashed = manifest[file];
    if (hashed) {
      return `${prefix}${pathPrefix}${hashed}${suffix}`;
    } else if ((0, _fsExtra.existsSync)(publicFolder(file))) {
      return `${prefix}${pathPrefix}${file}${suffix}`;
    } else {
      throw new Error(`Could not find the file specified in the Link header \`${header}\`.` + `The gatsby-plugin-gatsby-cloud is looking for a matching file (with or without a ` + `webpack hash). Check the public folder and your gatsby-config.js to ensure you are ` + `pointing to a public file.`);
    }
  });
}

// program methods

const mapUserLinkHeaders = ({
  manifest,
  pathPrefix,
  publicFolder
}) => headers => (0, _mapValues2.default)(headers, headerList => (0, _map2.default)(headerList, transformLink(manifest, publicFolder, pathPrefix)));
const mapUserLinkAllPageHeaders = (pluginData, {
  allPageHeaders
}) => headers => {
  if (!allPageHeaders) {
    return headers;
  }
  const {
    pages,
    manifest,
    publicFolder,
    pathPrefix
  } = pluginData;
  const headersList = (0, _map2.default)(allPageHeaders, transformLink(manifest, publicFolder, pathPrefix));
  const duplicateHeadersByPage = {};
  pages.forEach(page => {
    const pathKey = headersPath(pathPrefix, page.path);
    duplicateHeadersByPage[pathKey] = headersList;
  });
  return defaultMerge(headers, duplicateHeadersByPage);
};
const applySecurityHeaders = ({
  mergeSecurityHeaders
}) => headers => {
  if (!mergeSecurityHeaders) {
    return headers;
  }

  // It is a common use case to want to iframe preview
  if (process.env.GATSBY_IS_PREVIEW === `true`) {
    _constants.SECURITY_HEADERS[`/*`] = _constants.SECURITY_HEADERS[`/*`].filter(headers => headers !== `X-Frame-Options: DENY`);
  }
  return headersMerge(headers, _constants.SECURITY_HEADERS);
};
const applyCachingHeaders = (pluginData, {
  mergeCachingHeaders
}) => headers => {
  if (!mergeCachingHeaders) {
    return headers;
  }
  const files = new Set();
  for (const [_assetOrChunkName, fileNameOrArrayOfFileNames] of Object.entries(pluginData.manifest)) {
    if (Array.isArray(fileNameOrArrayOfFileNames)) {
      for (const filename of fileNameOrArrayOfFileNames) {
        files.add(filename);
      }
    } else if (typeof fileNameOrArrayOfFileNames === `string`) {
      files.add(fileNameOrArrayOfFileNames);
    }
  }
  const cachingHeaders = {};
  files.forEach(file => {
    if (typeof file === `string`) {
      cachingHeaders[`/` + file] = [_constants.IMMUTABLE_CACHING_HEADER];
    }
  });
  return defaultMerge(headers, cachingHeaders, _constants.CACHING_HEADERS);
};
const applyTransfromHeaders = ({
  transformHeaders
}) => headers => (0, _mapValues2.default)(headers, transformHeaders);
const sendHeadersViaIPC = async headers => {
  /**
   * Emit Headers via IPC
   */
  let lastMessage;
  Object.entries(headers).forEach(([k, val]) => {
    lastMessage = (0, _ipc.emitHeaders)({
      url: k,
      headers: val
    });
  });
  await lastMessage;
};
const writeHeadersFile = async (publicFolder, contents) => new Promise((resolve, reject) => {
  const contentsStr = JSON.stringify(contents);
  const writeStream = (0, _fsExtra.createWriteStream)(publicFolder(_constants.HEADERS_FILENAME));
  const chunkSize = 10000;
  const numChunks = Math.ceil(contentsStr.length / chunkSize);
  for (let i = 0; i < numChunks; i++) {
    writeStream.write(contentsStr.slice(i * chunkSize, Math.min((i + 1) * chunkSize, contentsStr.length)));
  }
  writeStream.end();
  writeStream.on(`finish`, () => {
    resolve();
  });
  writeStream.on(`error`, reject);
});
const saveHeaders = ({
  publicFolder
}) => contents => Promise.all([sendHeadersViaIPC(contents), writeHeadersFile(publicFolder, contents)]);
function buildHeadersProgram(pluginData, pluginOptions) {
  return (0, _flow2.default)(mapUserLinkHeaders(pluginData), applySecurityHeaders(pluginOptions), applyCachingHeaders(pluginData, pluginOptions), mapUserLinkAllPageHeaders(pluginData, pluginOptions), applyTransfromHeaders(pluginOptions), saveHeaders(pluginData))(pluginOptions.headers);
}