Moved the service logic out of the oembed controller

refs #12537
This commit is contained in:
Thibaut Patel 2021-01-12 17:16:05 +00:00
parent 46574de3c5
commit d8245216ec
2 changed files with 238 additions and 230 deletions

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@ -1,233 +1,4 @@
const errors = require('@tryghost/errors');
const {extract, hasProvider} = require('oembed-parser');
const Promise = require('bluebird');
const cheerio = require('cheerio');
const _ = require('lodash');
const {CookieJar} = require('tough-cookie');
const config = require('../../../shared/config');
const {i18n} = require('../../lib/common');
const externalRequest = require('../../lib/request-external');
async function fetchBookmarkData(url) {
const metascraper = require('metascraper')([
require('metascraper-url')(),
require('metascraper-title')(),
require('metascraper-description')(),
require('metascraper-author')(),
require('metascraper-publisher')(),
require('metascraper-image')(),
require('metascraper-logo-favicon')(),
require('metascraper-logo')()
]);
let scraperResponse;
try {
const cookieJar = new CookieJar();
const response = await externalRequest(url, {cookieJar});
const html = response.body;
scraperResponse = await metascraper({html, url});
} catch (err) {
return Promise.reject(err);
}
const metadata = Object.assign({}, scraperResponse, {
thumbnail: scraperResponse.image,
icon: scraperResponse.logo
});
// We want to use standard naming for image and logo
delete metadata.image;
delete metadata.logo;
if (metadata.title) {
return Promise.resolve({
type: 'bookmark',
url,
metadata
});
}
return Promise.reject(new errors.ValidationError({
message: i18n.t('errors.api.oembed.insufficientMetadata'),
context: url
}));
}
const findUrlWithProvider = (url) => {
let provider;
// build up a list of URL variations to test against because the oembed
// providers list is not always up to date with scheme or www vs non-www
let baseUrl = url.replace(/^\/\/|^https?:\/\/(?:www\.)?/, '');
let testUrls = [
`http://${baseUrl}`,
`https://${baseUrl}`,
`http://www.${baseUrl}`,
`https://www.${baseUrl}`
];
for (let testUrl of testUrls) {
provider = hasProvider(testUrl);
if (provider) {
url = testUrl;
break;
}
}
return {url, provider};
};
function unknownProvider(url) {
return Promise.reject(new errors.ValidationError({
message: i18n.t('errors.api.oembed.unknownProvider'),
context: url
}));
}
function knownProvider(url) {
return extract(url, {maxwidth: 1280}).catch((err) => {
return Promise.reject(new errors.InternalServerError({
message: err.message
}));
});
}
function isIpOrLocalhost(url) {
try {
const IPV4_REGEX = /^(?:(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.){3}(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)$/;
const IPV6_REGEX = /:/; // fqdns will not have colons
const HTTP_REGEX = /^https?:/i;
const siteUrl = new URL(config.get('url'));
const {protocol, hostname, host} = new URL(url);
// allow requests to Ghost's own url through
if (siteUrl.host === host) {
return false;
}
if (!HTTP_REGEX.test(protocol) || hostname === 'localhost' || IPV4_REGEX.test(hostname) || IPV6_REGEX.test(hostname)) {
return true;
}
return false;
} catch (e) {
return true;
}
}
function fetchOembedData(_url, cardType) {
// parse the url then validate the protocol and host to make sure it's
// http(s) and not an IP address or localhost to avoid potential access to
// internal network endpoints
if (isIpOrLocalhost(_url)) {
return unknownProvider();
}
// check against known oembed list
let {url, provider} = findUrlWithProvider(_url);
if (provider) {
return knownProvider(url);
}
// url not in oembed list so fetch it in case it's a redirect or has a
// <link rel="alternate" type="application/json+oembed"> element
const cookieJar = new CookieJar();
return externalRequest(url, {
method: 'GET',
timeout: 2 * 1000,
followRedirect: true,
cookieJar
}).then((pageResponse) => {
// url changed after fetch, see if we were redirected to a known oembed
if (pageResponse.url !== url) {
({url, provider} = findUrlWithProvider(pageResponse.url));
if (provider) {
return knownProvider(url);
}
}
// check for <link rel="alternate" type="application/json+oembed"> element
let oembedUrl;
try {
oembedUrl = cheerio('link[type="application/json+oembed"]', pageResponse.body).attr('href');
} catch (e) {
return unknownProvider(url);
}
if (oembedUrl) {
// make sure the linked url is not an ip address or localhost
if (isIpOrLocalhost(oembedUrl)) {
return unknownProvider(oembedUrl);
}
// for standard WP oembed's we want to insert a bookmark card rather than their blockquote+script
// which breaks in the editor and most Ghost themes. Only fallback if card type was not explicitly chosen
if (!cardType && oembedUrl.match(/wp-json\/oembed/)) {
return;
}
// fetch oembed response from embedded rel="alternate" url
return externalRequest(oembedUrl, {
method: 'GET',
json: true,
timeout: 2 * 1000,
followRedirect: true,
cookieJar
}).then((oembedResponse) => {
// validate the fetched json against the oembed spec to avoid
// leaking non-oembed responses
const body = oembedResponse.body;
const hasRequiredFields = body.type && body.version;
const hasValidType = ['photo', 'video', 'link', 'rich'].includes(body.type);
if (hasRequiredFields && hasValidType) {
// extract known oembed fields from the response to limit leaking of unrecognised data
const knownFields = [
'type',
'version',
'html',
'url',
'title',
'width',
'height',
'author_name',
'author_url',
'provider_name',
'provider_url',
'thumbnail_url',
'thumbnail_width',
'thumbnail_height'
];
const oembed = _.pick(body, knownFields);
// ensure we have required data for certain types
if (oembed.type === 'photo' && !oembed.url) {
return;
}
if ((oembed.type === 'video' || oembed.type === 'rich') && (!oembed.html || !oembed.width || !oembed.height)) {
return;
}
// return the extracted object, don't pass through the response body
return oembed;
}
}).catch(() => {});
}
});
}
function errorHandler(url) {
return function (err) {
// allow specific validation errors through for better error messages
if (errors.utils.isIgnitionError(err) && err.errorType === 'ValidationError') {
return Promise.reject(err);
}
// default to unknown provider to avoid leaking any app specifics
return unknownProvider(url);
};
}
const {fetchBookmarkData, fetchOembedData, errorHandler, unknownProvider} = require('../../services/oembed');
module.exports = {
docName: 'oembed',

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@ -0,0 +1,237 @@
const Promise = require('bluebird');
const errors = require('@tryghost/errors');
const {extract, hasProvider} = require('oembed-parser');
const cheerio = require('cheerio');
const _ = require('lodash');
const {CookieJar} = require('tough-cookie');
const config = require('../../shared/config');
const externalRequest = require('../lib/request-external');
const {i18n} = require('../lib/common');
function unknownProvider(url) {
return Promise.reject(new errors.ValidationError({
message: i18n.t('errors.api.oembed.unknownProvider'),
context: url
}));
}
function knownProvider(url) {
return extract(url, {maxwidth: 1280}).catch((err) => {
return Promise.reject(new errors.InternalServerError({
message: err.message
}));
});
}
function errorHandler(url) {
return function (err) {
// allow specific validation errors through for better error messages
if (errors.utils.isIgnitionError(err) && err.errorType === 'ValidationError') {
return Promise.reject(err);
}
// default to unknown provider to avoid leaking any app specifics
return unknownProvider(url);
};
}
async function fetchBookmarkData(url) {
const metascraper = require('metascraper')([
require('metascraper-url')(),
require('metascraper-title')(),
require('metascraper-description')(),
require('metascraper-author')(),
require('metascraper-publisher')(),
require('metascraper-image')(),
require('metascraper-logo-favicon')(),
require('metascraper-logo')()
]);
let scraperResponse;
try {
const cookieJar = new CookieJar();
const response = await externalRequest(url, {cookieJar});
const html = response.body;
scraperResponse = await metascraper({html, url});
} catch (err) {
return Promise.reject(err);
}
const metadata = Object.assign({}, scraperResponse, {
thumbnail: scraperResponse.image,
icon: scraperResponse.logo
});
// We want to use standard naming for image and logo
delete metadata.image;
delete metadata.logo;
if (metadata.title) {
return Promise.resolve({
type: 'bookmark',
url,
metadata
});
}
return Promise.reject(new errors.ValidationError({
message: i18n.t('errors.api.oembed.insufficientMetadata'),
context: url
}));
}
const findUrlWithProvider = (url) => {
let provider;
// build up a list of URL variations to test against because the oembed
// providers list is not always up to date with scheme or www vs non-www
let baseUrl = url.replace(/^\/\/|^https?:\/\/(?:www\.)?/, '');
let testUrls = [
`http://${baseUrl}`,
`https://${baseUrl}`,
`http://www.${baseUrl}`,
`https://www.${baseUrl}`
];
for (let testUrl of testUrls) {
provider = hasProvider(testUrl);
if (provider) {
url = testUrl;
break;
}
}
return {url, provider};
};
function isIpOrLocalhost(url) {
try {
const IPV4_REGEX = /^(?:(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.){3}(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)$/;
const IPV6_REGEX = /:/; // fqdns will not have colons
const HTTP_REGEX = /^https?:/i;
const siteUrl = new URL(config.get('url'));
const {protocol, hostname, host} = new URL(url);
// allow requests to Ghost's own url through
if (siteUrl.host === host) {
return false;
}
if (!HTTP_REGEX.test(protocol) || hostname === 'localhost' || IPV4_REGEX.test(hostname) || IPV6_REGEX.test(hostname)) {
return true;
}
return false;
} catch (e) {
return true;
}
}
function fetchOembedData(_url, cardType) {
// parse the url then validate the protocol and host to make sure it's
// http(s) and not an IP address or localhost to avoid potential access to
// internal network endpoints
if (isIpOrLocalhost(_url)) {
return unknownProvider();
}
// check against known oembed list
let {url, provider} = findUrlWithProvider(_url);
if (provider) {
return knownProvider(url);
}
// url not in oembed list so fetch it in case it's a redirect or has a
// <link rel="alternate" type="application/json+oembed"> element
const cookieJar = new CookieJar();
return externalRequest(url, {
method: 'GET',
timeout: 2 * 1000,
followRedirect: true,
cookieJar
}).then((pageResponse) => {
// url changed after fetch, see if we were redirected to a known oembed
if (pageResponse.url !== url) {
({url, provider} = findUrlWithProvider(pageResponse.url));
if (provider) {
return knownProvider(url);
}
}
// check for <link rel="alternate" type="application/json+oembed"> element
let oembedUrl;
try {
oembedUrl = cheerio('link[type="application/json+oembed"]', pageResponse.body).attr('href');
} catch (e) {
return unknownProvider(url);
}
if (oembedUrl) {
// make sure the linked url is not an ip address or localhost
if (isIpOrLocalhost(oembedUrl)) {
return unknownProvider(oembedUrl);
}
// for standard WP oembed's we want to insert a bookmark card rather than their blockquote+script
// which breaks in the editor and most Ghost themes. Only fallback if card type was not explicitly chosen
if (!cardType && oembedUrl.match(/wp-json\/oembed/)) {
return;
}
// fetch oembed response from embedded rel="alternate" url
return externalRequest(oembedUrl, {
method: 'GET',
json: true,
timeout: 2 * 1000,
followRedirect: true,
cookieJar
}).then((oembedResponse) => {
// validate the fetched json against the oembed spec to avoid
// leaking non-oembed responses
const body = oembedResponse.body;
const hasRequiredFields = body.type && body.version;
const hasValidType = ['photo', 'video', 'link', 'rich'].includes(body.type);
if (hasRequiredFields && hasValidType) {
// extract known oembed fields from the response to limit leaking of unrecognised data
const knownFields = [
'type',
'version',
'html',
'url',
'title',
'width',
'height',
'author_name',
'author_url',
'provider_name',
'provider_url',
'thumbnail_url',
'thumbnail_width',
'thumbnail_height'
];
const oembed = _.pick(body, knownFields);
// ensure we have required data for certain types
if (oembed.type === 'photo' && !oembed.url) {
return;
}
if ((oembed.type === 'video' || oembed.type === 'rich') && (!oembed.html || !oembed.width || !oembed.height)) {
return;
}
// return the extracted object, don't pass through the response body
return oembed;
}
}).catch(() => {});
}
});
}
module.exports = {
fetchBookmarkData,
fetchOembedData,
errorHandler,
unknownProvider
};