ghost/core/core/server/services/url/UrlService.js
const _debug = require('@tryghost/debug')._base;
const debug = _debug('ghost:services:url:service');
const _ = require('lodash');
const errors = require('@tryghost/errors');
const labs = require('../../../shared/labs');
const UrlGenerator = require('./UrlGenerator');
const Queue = require('./Queue');
const Urls = require('./Urls');
const Resources = require('./Resources');
const urlUtils = require('../../../shared/url-utils');
const resourcesConfig = require('./config');
/**
* The url service class holds all instances in a centralized place.
* It's the public API you can talk to.
* It will tell you if the url generation is in progress or not.
*/
class UrlService {
/**
*
* @param {Object} [options]
* @param {Object} [options.cache] - cache handler instance
* @param {Function} [options.cache.read] - read cache by type
* @param {Function} [options.cache.write] - write into cache by type
*/
constructor({cache} = {}) {
this.utils = urlUtils;
this.cache = cache;
this.onFinished = null;
this.finished = false;
this.urlGenerators = [];
// Get urls
this.queue = new Queue();
// NOTE: Urls and Resources should not be initialized here but only in the init method.
// Way too many tests fail if the initialization is removed so leaving it as is for time being
this.urls = new Urls();
this.resources = new Resources({
resourcesConfig: resourcesConfig,
queue: this.queue
});
this._listeners();
}
/**
* @description Helper function to register the listeners for this instance.
* @private
*/
_listeners() {
this._onQueueStartedListener = this._onQueueStarted.bind(this);
this.queue.addListener('started', this._onQueueStartedListener);
this._onQueueEndedListener = this._onQueueEnded.bind(this);
this.queue.addListener('ended', this._onQueueEnded.bind(this));
}
/**
* @description The queue will notify us if the queue has started with an event.
*
* The "init" event is basically the bootstrap event, which is the siganliser if url generation
* is in progress or not.
*
* @param {String} event
* @private
*/
_onQueueStarted(event) {
if (event === 'init') {
this.finished = false;
}
}
/**
* @description The queue will notify us if the queue has ended with an event.
* @param {String} event
* @private
*/
_onQueueEnded(event) {
if (event === 'init') {
this.finished = true;
if (this.onFinished) {
this.onFinished();
}
}
}
/**
* @description Router was created, connect it with a url generator.
* @param {String} identifier frontend router ID reference
* @param {String} filter NQL filter
* @param {String} resourceType
* @param {String} permalink
*/
onRouterAddedType(identifier, filter, resourceType, permalink) {
debug('Registering route: ', filter, resourceType, permalink);
let urlGenerator = new UrlGenerator({
identifier,
filter,
resourceType,
permalink,
queue: this.queue,
resources: this.resources,
urls: this.urls,
position: this.urlGenerators.length
});
this.urlGenerators.push(urlGenerator);
}
/**
* @description Router update handler - regenerates it's resources
* @param {String} identifier router ID linked to the UrlGenerator
*/
onRouterUpdated(identifier) {
const generator = this.urlGenerators.find(g => g.identifier === identifier);
generator.regenerateResources();
}
/**
* @description Get Resource by url.
*
* You have a url and want to know which the url belongs to.
*
* It's in theory possible that multiple resources generate the same url,
* but they both would serve different content.
*
* e.g. if we remove the slug uniqueness and you create a static
* page and a post with the same slug. And both are served under `/` with the permalink `/:slug/`.
*
*
* Each url is unique and it depends on the hierarchy of router registration is configured.
* There is no url collision, everything depends on registration order.
*
* e.g. posts which live in a collection are stronger than a static page.
*
* We only return the resource, which would be served.
*
* @NOTE: only accepts relative urls at the moment.
*
* @param {String} url
* @param {Object} options
* @returns {Object}
*/
getResource(url, options) {
options = options || {};
let objects = this.urls.getByUrl(url);
if (!objects.length) {
if (!this.hasFinished()) {
throw new errors.InternalServerError({
message: 'UrlService is processing.',
code: 'URLSERVICE_NOT_READY'
});
} else {
return null;
}
}
if (objects.length > 1) {
objects = _.reduce(objects, (toReturn, object) => {
if (!toReturn.length) {
toReturn.push(object);
} else {
const i1 = _.findIndex(this.urlGenerators, {uid: toReturn[0].generatorId});
const i2 = _.findIndex(this.urlGenerators, {uid: object.generatorId});
if (i2 < i1) {
toReturn = [];
toReturn.push(object);
}
}
return toReturn;
}, []);
}
if (options.returnEverything) {
return objects[0];
}
return objects[0].resource;
}
/**
* @description Get resource by id.
* @param {String} resourceId
* @returns {Object}
*/
getResourceById(resourceId) {
const object = this.urls.getByResourceId(resourceId);
if (!object) {
throw new errors.NotFoundError({
message: 'Resource not found.',
code: 'URLSERVICE_RESOURCE_NOT_FOUND'
});
}
return object.resource;
}
/**
* @description Figure out if url generation is in progress or not.
* @returns {boolean}
*/
hasFinished() {
return this.finished;
}
/**
* @description Get url by resource id.
*
* If we can't find a url for an id, we have to return a url.
* There are many components in Ghost which call `getUrlByResourceId` and
* based on the return value, they set the resource url somewhere e.g. meta data.
* Or if you define no collections in your yaml file and serve a page.
* You will see a suggestion of posts, but they all don't belong to a collection.
* They would show localhost:2368/null/.
*
* @param {String} id
* @param {Object} [options]
* @param {Object} [options.absolute]
* @param {Object} [options.withSubdirectory]
* @returns {String}
*/
getUrlByResourceId(id, options = {}) {
const obj = this.urls.getByResourceId(id);
if (obj) {
if (options.absolute) {
return this.utils.createUrl(obj.url, options.absolute);
}
if (options.withSubdirectory) {
return this.utils.createUrl(obj.url, false, true);
}
return obj.url;
}
if (options.absolute) {
return this.utils.createUrl('/404/', options.absolute);
}
if (options.withSubdirectory) {
return this.utils.createUrl('/404/', false);
}
return '/404/';
}
/**
* @description Check whether a router owns a resource id.
* @param {String} routerId
* @param {String} id
* @returns {boolean}
*/
owns(routerId, id) {
debug('owns', routerId, id);
let urlGenerator;
this.urlGenerators.every((_urlGenerator) => {
if (_urlGenerator.identifier === routerId) {
urlGenerator = _urlGenerator;
return false;
}
return true;
});
if (!urlGenerator) {
return false;
}
return urlGenerator.hasId(id);
}
/**
* @description Get permlink structure for url.
* @param {String} url
* @param {object} options
* @returns {*}
*/
getPermalinkByUrl(url, options) {
options = options || {};
const object = this.getResource(url, {returnEverything: true});
if (!object) {
return null;
}
const permalink = _.find(this.urlGenerators, {uid: object.generatorId}).permalink;
if (options.withUrlOptions) {
return urlUtils.urlJoin(permalink, '/:options(edit)?/');
}
return permalink;
}
/**
* @description Initializes components needed for the URL Service to function
* @param {Object} options
* @param {Function} [options.onFinished] - callback when url generation is finished
* @param {Boolean} [options.urlCache] - whether to init using url cache or not
*/
async init({onFinished, urlCache} = {}) {
this.onFinished = onFinished;
let persistedUrls;
let persistedResources;
if (this.cache && (labs.isSet('urlCache') || urlCache)) {
persistedUrls = await this.cache.read('urls');
persistedResources = await this.cache.read('resources');
}
if (persistedUrls && persistedResources) {
this.urls.urls = persistedUrls;
this.resources.data = persistedResources;
this.resources.initEventListeners();
this._onQueueEnded('init');
} else {
this.resources.initEventListeners();
await this.resources.fetchResources();
// CASE: all resources are fetched, start the queue
this.queue.start({
event: 'init',
tolerance: 100,
requiredSubscriberCount: 1
});
}
}
async shutdown() {
if (!labs.isSet('urlCache')) {
return null;
}
await this.cache.write('urls', this.urls.urls);
await this.cache.write('resources', this.resources.getAll());
}
/**
* @description Reset this service.
* @param {Object} options
*/
reset(options = {}) {
debug('reset');
this.urlGenerators = [];
this.urls.reset();
this.queue.reset();
this.resources.reset();
if (!options.keepListeners) {
this._onQueueStartedListener && this.queue.removeListener('started', this._onQueueStartedListener);
this._onQueueEndedListener && this.queue.removeListener('ended', this._onQueueEndedListener);
}
}
/**
* @description Reset the generators.
* @param {Object} options
*/
resetGenerators(options = {}) {
debug('resetGenerators');
this.finished = false;
this.urlGenerators = [];
this.urls.reset();
this.queue.reset();
if (options.releaseResourcesOnly) {
this.resources.releaseAll();
} else {
this.resources.softReset();
}
}
/**
* @description Soft reset this service. Only used in test env.
*/
softReset() {
debug('softReset');
this.finished = false;
this.urls.softReset();
this.queue.softReset();
this.resources.softReset();
}
}
module.exports = UrlService;