cryptpad/www/common/metadata-manager.js

226 lines
9.5 KiB
JavaScript

This file contains invisible Unicode characters!

This file contains invisible Unicode characters that may be processed differently from what appears below. If your use case is intentional and legitimate, you can safely ignore this warning. Use the Escape button to reveal hidden characters.

define(['json.sortify'], function (Sortify) {
var UNINIT = 'uninitialized';
var create = function (sframeChan) {
var meta = UNINIT;
var members = [];
var metadataObj = UNINIT;
// This object reflects the metadata which is in the document at this moment.
// Normally when a person leaves the pad, everybody sees them leave and updates
// their metadata, this causes everyone to fight to change the document and
// operational transform doesn't like it. So this is a lazy object which is
// only updated either:
// 1. On changes to the metadata that come in from someone else
// 2. On changes connects, disconnects or changes to your own metadata
var metadataLazyObj = UNINIT;
var priv = {};
var dirty = true;
var history = false;
var degraded = 1; // truthy value but not true: we don't know yet if we're degraded
var changeHandlers = [];
var lazyChangeHandlers = [];
var titleChangeHandlers = [];
// When someone leaves the document, their metadata is removed from our metadataObj
// but it is not removed instantly from the chainpad document metadata. This is
// the result of the lazy object: if we had to remove the metadata instantly, all
// the remaining members would try to push a patch to do it, and it could create
// conflicts. Their metadata is instead removed from the chainpad doc only when
// someone calls onLocal to make another change.
// The leaving user is not visible in the userlist UI because we filter it using
// the list of "members" (netflux ID currently online).
// Our Problem:
// With the addition of shared workers, a user can leave and join back with the same
// netflux ID (just reload the pad). If nobody has made any change in the mean time,
// their metadata will still be in the document, but they won't be in our metadataObj.
// This causes the presence of a "viewer" instead of an editor, because they don't
// have user data.
// To fix this problem, the metadata manager can request "syncs" from a chainpad app,
// and the app should trigger a "metadataMgr.updateMetadata(data)" in the handler.
// See "metadataMgr.onRequestSync" in sframe-app-framework for an example.
var syncHandlers = [];
var rememberedTitle;
var checkUpdate = function (lazy) {
if (!dirty) { return; }
if (meta === UNINIT) { throw new Error(); }
if (metadataObj === UNINIT) {
metadataObj = {
defaultTitle: meta.doc.defaultTitle,
//title: meta.doc.defaultTitle,
type: meta.doc.type,
users: {},
};
metadataLazyObj = JSON.parse(JSON.stringify(metadataObj));
}
if (!metadataObj.users) { metadataObj.users = {}; }
if (!metadataLazyObj.users) { metadataLazyObj.users = {}; }
if (!metadataObj.type) { metadataObj.type = meta.doc.type; }
if (!metadataLazyObj.type) { metadataLazyObj.type = meta.doc.type; }
var mdo = {};
// We don't want to add our user data to the object multiple times.
Object.keys(metadataObj.users).forEach(function (x) {
if (members.indexOf(x) === -1 && !history) { return; }
mdo[x] = metadataObj.users[x];
});
if (!priv.readOnly && !degraded) {
mdo[meta.user.netfluxId] = meta.user;
}
metadataObj.users = mdo;
// Clean old data
delete metadataObj.authors;
delete metadataLazyObj.authors;
// Always update the userlist in the lazy object, otherwise it may be outdated
// and metadataMgr.updateMetadata() won't do anything, and so we won't push events
// to the userlist UI ==> phantom viewers
var lazyUserStr = Sortify(metadataLazyObj.users[meta.user.netfluxId]);
dirty = false;
if (lazy || lazyUserStr !== Sortify(meta.user)) {
metadataLazyObj = JSON.parse(JSON.stringify(metadataObj));
lazyChangeHandlers.forEach(function (f) { f(); });
} else {
metadataLazyObj.users = JSON.parse(JSON.stringify(mdo));
}
if (metadataObj.title !== rememberedTitle) {
rememberedTitle = metadataObj.title;
titleChangeHandlers.forEach(function (f) {
f(metadataObj.title, metadataObj.defaultTitle);
});
}
changeHandlers.forEach(function (f) { f(); });
};
var change = function (lazy) {
dirty = true;
setTimeout(function () {
checkUpdate(lazy);
});
};
var netfluxId;
var isReady = false;
var readyHandlers = [];
sframeChan.on('EV_METADATA_UPDATE', function (ev) {
meta = ev;
if (ev.priv) {
priv = ev.priv;
}
if (netfluxId) {
meta.user.netfluxId = netfluxId;
}
if (!isReady) {
isReady = true;
readyHandlers.forEach(function (f) { f(); });
}
change(true);
});
sframeChan.on('EV_RT_CONNECT', function (ev) {
netfluxId = ev.myID;
members = ev.members;
if (!meta.user) { return; }
meta.user.netfluxId = netfluxId;
change(true);
});
sframeChan.on('EV_RT_JOIN', function (ev) {
var idx = members.indexOf(ev);
if (idx !== -1) { console.log('Error: ' + ev + ' is already in members'); return; }
members.push(ev);
if (!meta.user) { return; }
change(false);
syncHandlers.forEach(function (f) { f(); });
});
sframeChan.on('EV_RT_LEAVE', function (ev) {
var idx = members.indexOf(ev);
if (idx === -1) { console.log('Error: ' + ev + ' not in members'); return; }
members.splice(idx, 1);
if (!meta.user) { return; }
change(false);
});
sframeChan.on('EV_RT_DISCONNECT', function () {
members = [];
if (!meta.user) { return; }
change(true);
});
sframeChan.on('EV_RT_ERROR', function (err) {
if (err.type !== 'EEXPIRED' && err.type !== 'EDELETED') { return; }
members = [];
if (!meta.user) { return; }
change(true);
});
return Object.freeze({
updateMetadata: function (m) {
// JSON.parse(JSON.stringify()) reorders the json, so we have to use sortify even
// if it's on our own computer
if (!m) { return; }
if (Sortify(metadataLazyObj) === Sortify(m)) { return; }
metadataObj = JSON.parse(JSON.stringify(m));
metadataLazyObj = JSON.parse(JSON.stringify(m));
change(false);
},
refresh : function () {
change(true);
},
updateTitle: function (t) {
metadataObj.title = t;
change(true);
},
getMetadata: function () {
checkUpdate(false);
return Object.freeze(JSON.parse(JSON.stringify(metadataObj)));
},
getMetadataLazy: function () {
return metadataLazyObj;
},
setDegraded: function (bool) {
degraded = bool;
},
isDegraded: function () { return degraded; },
onTitleChange: function (f) { titleChangeHandlers.push(f); },
onChange: function (f) { changeHandlers.push(f); },
onChangeLazy: function (f) { lazyChangeHandlers.push(f); },
onRequestSync: function (f) { syncHandlers.push(f); },
off: function (name, f) {
var h = [];
if (name === 'change') { h = changeHandlers; }
else if (name === 'lazy') { h = lazyChangeHandlers; }
else if (name === 'title') { h = titleChangeHandlers; }
else if (name === 'sync') { h = syncHandlers; }
var idx = h.indexOf(f);
if (idx !== -1) { h.splice(idx, 1); }
},
isConnected : function () {
return members.indexOf(meta.user.netfluxId) !== -1;
},
getViewers : function () {
checkUpdate(false);
var list = members.slice().filter(function (m) { return m.length === 32; });
return list.length - Object.keys(metadataLazyObj.users).length;
},
getChannelMembers: function () { return members.slice(); },
getPrivateData : function () {
return priv;
},
getUserData : function () {
return meta.user;
},
getNetfluxId : function () {
return meta.user.netfluxId;
},
onReady: function (f) {
if (isReady) { return void f(); }
readyHandlers.push(f);
},
setHistory: function (bool) {
history = bool;
}
});
};
return Object.freeze({ create: create });
});