@browser-network/database
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A type of distributed database built on top of the distributed browser-network
395 lines (394 loc) • 18.4 kB
JavaScript
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if (v !== undefined) module.exports = v;
}
else if (typeof define === "function" && define.amd) {
define(["require", "exports", "@browser-network/crypto", "./LocalDB", "./util"], factory);
}
})(function (require, exports) {
"use strict";
exports.__esModule = true;
var bnc = __importStar(require("@browser-network/crypto"));
var LocalDB_1 = require("./LocalDB");
var util_1 = require("./util");
var debug = (0, util_1.debugFactory)('Db');
// convenience
var wrapState = function (state, address, pub, priv) { return __awaiter(void 0, void 0, void 0, function () {
var wrapp, signature, wrapped;
return __generator(this, function (_a) {
switch (_a.label) {
case 0:
wrapp = {
id: address,
timestamp: Date.now(),
state: state,
publicKey: pub
};
return [4 /*yield*/, bnc.sign(priv, wrapp)];
case 1:
signature = _a.sent();
wrapped = Object.assign(wrapp, { signature: signature });
return [2 /*return*/, wrapped];
}
});
}); };
// convenience
var verifySignature = function (update) {
var signature = update.signature, wrapp = __rest(update, ["signature"]);
return bnc.verifySignature(wrapp, signature, update.publicKey);
};
// TODO I've seen a loop before, where state-offering messages are being spammed.
// I don't know how this would have happened as it seems to be hard coded to send only
// once per 5 seconds.
var Db = /** @class */ (function () {
function Db(_a) {
var secret = _a.secret, appId = _a.appId, network = _a.network;
var _this = this;
this._denyList = {};
this._allowList = {};
this._onChangeHandlers = [];
/**
* @description Get all entries from our local DB, wrapped in the DB's
* WrappedState type.
*
* @TODO: Does it need to be wrapped? Does the user ever care about this
* wrapping or should they just be able to go straight to their state?
*/
this.getAll = function () { return _this.localDB.getAll(); };
/**
* @description Clear the local storage of everyone's items. Essentially resets the machine
* to as if it's never seen the network before. If it is connected still, it will
* rapidly start to repopulate.
*/
this.clear = function () {
_this.localDB.clear();
_this.runChangeHandlers();
};
/**
* @description Effectively blocks a user. Adds them to our deny list, which means we'll no longer
* accept updates from them, which means we will no longer forward their updates as well. Also
* removes their state from our storage.
*
* It's up to the developer to keep track of these (probably
* within the state object that they store in this db), and repopulate this list on startup.
* Calling deny with an address that's already blocked is a noop and O(1) time so don't worry about
* spamming this call.
*/
this.deny = function (address) {
if (_this._denyList[address]) {
return;
}
_this._denyList[address] = true;
_this.localDB.remove(address);
};
/**
* @description Unblock a user. Removes them from our deny list, at which point the DB will naturally
* start to repopulate that user's state.
*/
this.undeny = function (address) {
delete _this._denyList[address];
};
/**
* @description Add a user to our allow list. Once a single user is on this list, _only users on the
* allow list will be recorded in the database_. All other users will automatically be ignored.
*
* It's up to the developer to keep track of these (probably
* within the state object that they store in this db), and repopulate this list on startup.
* Calling allow with an address that's already on the list is a noop and O(1) time so don't worry about
* spamming this call.
*/
this.allow = function (address) {
if (_this._allowList[address]) {
return;
}
_this._allowList[address] = true;
};
/**
* @description Remove a user from the allow list. Calling this will remove the user's state from
* our storage, and that user's state will no longer be forwarded either.
*/
this.unallow = function (address) {
delete _this._allowList[address];
_this.localDB.remove(address);
};
this.onMessage = function (message) {
switch (message.type) {
case 'state-offering': {
debug(5, 'received state-offering:', message);
return _this.onStateOffering(message.data, message.address);
}
case 'state-request': {
debug(5, 'received state-request:', message);
return _this.broadcastStateUpdateByStateId(message.data);
}
case 'state-update': {
debug(5, 'received state-update:', message);
return _this.onStateUpdate(message.data);
}
}
};
/**
* We will periodically inform the network of what states we have
* and how old they are. If someone else hears that we have a state
* newer than what they have on record, they can send us a request for
* what we have.
*/
this.broadcastStateOfferings = function () {
var offerings = {};
for (var _i = 0, _a = _this.localDB.getAll(); _i < _a.length; _i++) {
var state = _a[_i];
offerings[state.id] = state.timestamp;
}
_this.network.broadcast({
type: 'state-offering',
appId: _this.appId,
data: offerings
});
};
this.runChangeHandlers = function () {
_this._onChangeHandlers.forEach(function (handler) { return handler(); });
};
this.networkId = network.networkId;
this.appId = appId;
this.localDB = new LocalDB_1.LocalDB(appId);
this.address = network.address;
this.secret = secret;
this.network = network;
this.network.on('message', function (message) {
if (message.appId !== _this.appId)
return;
_this.onMessage(message);
});
// Here we derive the pub key from the private
this.publicKey = bnc.derivePubKey(secret);
setInterval(this.broadcastStateOfferings, 5000);
}
/**
* @description This is how you write data to the network. This will put whatever
* state you give it into a DB specific wrapper with your state in the `state` key.
*/
Db.prototype.set = function (state) {
return __awaiter(this, void 0, void 0, function () {
var data;
return __generator(this, function (_a) {
switch (_a.label) {
case 0: return [4 /*yield*/, wrapState(state, this.address, this.publicKey, this.secret)];
case 1:
data = _a.sent();
this.setLocal(data);
// send update into the network
this.broadcastStateUpdate(data);
return [2 /*return*/];
}
});
});
};
/**
* @description Get the state of the user whose address is passed in.
*/
Db.prototype.get = function (address) {
return this.localDB.get(address);
};
/**
* @description This will fire every time we update our state. This way reactive
* UIs can listen for changes and update based on the new state of the world
*/
Db.prototype.onChange = function (handler) {
this._onChangeHandlers.push(handler);
};
/**
* @description clear the DB of all listeners.
*/
Db.prototype.removeChangeHandlers = function () {
this._onChangeHandlers = [];
};
/**
* @description clear the DB of a specific listener.
*/
Db.prototype.removeChangeHandler = function (func) {
var _this = this;
var handlers = Array.from(this._onChangeHandlers);
handlers.forEach(function (handler, i) {
if (handler === func) {
_this._onChangeHandlers.splice(i, 1);
}
});
};
Db.prototype.onStateOffering = function (offerings, sender) {
var _this = this;
var requestState = function (address) {
_this.network.broadcast({
type: 'state-request',
appId: _this.appId,
destination: sender,
data: address
});
};
for (var remoteId in offerings) {
var remoteStateTimestamp = offerings[remoteId];
var localState = this.localDB.get(remoteId);
if (this.isForbidden(remoteId)) {
continue;
}
if (!localState) {
// we don't even have this state yet
requestState(remoteId);
}
else if (localState.timestamp < remoteStateTimestamp) {
// This means they have a newer offering, for which we will now ask
requestState(remoteId);
} // Otherwise we have a newer or equal version
}
};
Db.prototype.onStateUpdate = function (update) {
return __awaiter(this, void 0, void 0, function () {
return __generator(this, function (_a) {
switch (_a.label) {
case 0:
if (this.isForbidden(update.publicKey)) {
return [2 /*return*/, debug(5, 'state update from pubKey not allowed:', update.publicKey)];
}
debug(5, 'received update from another node:', update);
return [4 /*yield*/, this.verify(update)];
case 1:
if (!(_a.sent())) {
return [2 /*return*/];
}
this.setLocal(update);
return [2 /*return*/];
}
});
});
};
// We won't accept state if:
// * The sender is on our deny list, or
// * We have an allow list going and the sender is not on it
Db.prototype.isForbidden = function (address) {
var isForbidden = this._denyList[address] ||
(Object.keys(this._allowList).length > 0 && !this._allowList[address]);
return isForbidden;
};
// Broadcast an update for a specific state id
Db.prototype.broadcastStateUpdate = function (data) {
this.network.broadcast({
type: 'state-update',
appId: this.appId,
data: data
});
};
Db.prototype.broadcastStateUpdateByStateId = function (stateId) {
var data = this.localDB.get(stateId);
if (!data) {
return;
}
this.broadcastStateUpdate(data);
};
Db.prototype.setLocal = function (wrapped) {
this.localDB.set(wrapped, wrapped.id);
// Every time we set local, we've updated our storage, and we
// want to inform the user as such
this.runChangeHandlers();
};
Db.prototype.verify = function (update) {
return __awaiter(this, void 0, void 0, function () {
return __generator(this, function (_a) {
switch (_a.label) {
case 0:
// 1. verify timestamp is newer than last
if (!this.isNew(update)) {
return [2 /*return*/, false];
}
return [4 /*yield*/, verifySignature(update)];
case 1:
// 2. check veracity of signature
if (!(_a.sent())) {
debug(1, 'update does not pass verification! update, local version:', update, this.localDB.get(update.id));
// TODO add motrucka to rude list
return [2 /*return*/, false];
}
return [2 /*return*/, true];
}
});
});
};
Db.prototype.isNew = function (update) {
var local = this.get(update.id);
if (!local)
return true;
return update.timestamp > local.timestamp;
};
return Db;
}());
exports["default"] = Db;
});