Generate Cache Key

generateCacheKey.js

'use strict';

const { generateHeadersKey } = require('./generateHeadersKey');
const { generateQueryParamsKey } = require('./generateQueryParamsKey');

function generateCacheKey(
  ctx,
  keys = {
    useQueryParams: false, // @todo: array or boolean => can be optimized
    useHeaders: [],
  }
) {
  let querySuffix = '';
  let headersSuffix = '';

  if (keys.useQueryParams !== false) {
    querySuffix = generateQueryParamsKey(ctx, keys.useQueryParams);
  }

  if (keys.useHeaders.length > 0) {
    headersSuffix = generateHeadersKey(ctx, keys.useHeaders);
  }

  return `${ctx.request.path}?${querySuffix}&${headersSuffix}`;
}

module.exports = { generateCacheKey };

generateHeadersKey.js

'use strict';

function generateHeadersKey(ctx, useHeaders = []) {
  return useHeaders
    .filter((k) => ctx.request.header[k] !== undefined)
    .map((k) => `${k.toLowerCase()}=${ctx.request.header[k.toLowerCase()]}`) // headers are key insensitive
    .join(',');
}

module.exports = { generateHeadersKey };

generateQueryParamsKey.js

'use strict';

function generateQueryParamsKey(
  ctx,
  useQueryParams = true // @todo: array or boolean => can be optimized
) {
  let keys = [];

  if (useQueryParams === true) {
    keys = Object.keys(ctx.query);
  } else if (useQueryParams.length > 0) {
    keys = Object.keys(ctx.query).filter((key) => useQueryParams.includes(key));
  }

  if (keys.length === 0) {
    return '';
  }

  keys.sort();

  return keys
    .map(
      (k) =>
        `${k}=${
          typeof ctx.query[k] === 'object'
            ? JSON.stringify(ctx.query[k])
            : ctx.query[k]
        }`
    ) // query strings are key sensitive
    .join(',');
}

module.exports = { generateQueryParamsKey };