mod_provider_cloudfront.js
/**
## /provider/cloudfront
The cloudfront provider module exports a method to fetch resources from an AWS cloudfront service.
@requires fs
@requires path
@requires module:/utils/logger
@requires @aws-sdk/cloudfront-signer
@module /provider/cloudfront
*/
const { readFileSync } = require('fs')
const { join } = require('path')
const { getSignedUrl } = require('@aws-sdk/cloudfront-signer');
const logger = require('../utils/logger')
/**
@function cloudfront
@async
@description
The method creates a signed URL for a cloudfront resource, fetches the resource and returns the fetched resource.
A buffer is returned with the ref.params.buffer flag.
JSON is returned if the URL path matches the .json file ending to fetch a JSON resource from the cloudfront service.
The fetch response will be parsed as text by default.
@param {Object|string} ref Reference object or URL string.
@property {Object} [ref.params] Optional parameters for the request.
@property {string} [params.url] Cloudfront resource URL.
@property {boolean} [params.signedURL] Return a signedURL only.
@property {boolean} [params.buffer] Return a buffer from the fetch.
@returns {Promise<String|JSON|Buffer|Error>} The method resolves to either JSON, Text, or Buffer dependent ref.params.
*/
module.exports = async function cloudfront(ref) {
try {
// Substitutes {*} with process.env.SRC_* key values.
const url = (ref.params?.url || ref).replace(/{(?!{)(.*?)}/g,
matched => process.env[`SRC_${matched.replace(/(^{)|(}$)/g, '')}`])
const date = new Date(Date.now())
date.setDate(date.getDate() + 1);
const signedURL = getSignedUrl({
url: `https://${url}`,
keyPairId: process.env.KEY_CLOUDFRONT,
dateLessThan: date.toDateString(),
privateKey: String(readFileSync(join(__dirname, `../../${process.env.KEY_CLOUDFRONT}.pem`)))
});
// Return signedURL only from request.
if (ref.params?.signedURL) {
return signedURL;
}
const response = await fetch(signedURL)
logger(`${response.status} - ${url}`, 'cloudfront')
if (response.status >= 300) return new Error(`${response.status} ${ref}`)
if (url.match(/\.json$/i)) return await response.json()
if (ref.params?.buffer) {
const arrayBuffer = await response.arrayBuffer()
return Buffer.from(arrayBuffer)
}
return await response.text()
} catch (err) {
console.error(err)
}
}