restructure onChannelMessage
parent
8af7308da4
commit
338f967149
118
historyKeeper.js
118
historyKeeper.js
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@ -220,6 +220,10 @@ module.exports.create = function (cfg) {
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if the channel exists but its index does not then it caches the index
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*/
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const getIndex = (ctx, channelName, cb) => {
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// FIXME don't allow more than one index to be computed at a time
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// if one is in progress, the callback to a queue
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// whenever you completed, empty the queue in order
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const chan = ctx.channels[channelName];
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if (chan && chan.index) {
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// enforce async behaviour
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@ -262,6 +266,8 @@ module.exports.create = function (cfg) {
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TODO rename maybeMsgHash to optionalMsgHash
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*/
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const storeMessage = function (ctx, channel, msg, isCp, maybeMsgHash) {
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// TODO implement a queue so that we know messages are written in order
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const msgBin = new Buffer(msg + '\n', 'utf8');
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// Store the message first, and update the index only once it's stored.
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// store.messageBin can be async so updating the index first may
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@ -312,55 +318,96 @@ module.exports.create = function (cfg) {
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* caches the id of the last saved checkpoint
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* adds timestamps to incoming messages
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* writes messages to the store
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*/
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const onChannelMessage = function (ctx, channel, msgStruct) {
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// don't store messages if the channel id indicates that it's an ephemeral message
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if (!channel.id || channel.id.length === EPHEMERAL_CHANNEL_LENGTH) { return; }
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const isCp = /^cp\|/.test(msgStruct[4]);
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if (metadata_cache[channel.id] && metadata_cache[channel.id].expire &&
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metadata_cache[channel.id].expire < +new Date()) {
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return; // Don't store messages on expired channel
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// TODO if a channel expired a long time ago but it's still here, remove it
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}
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let id;
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if (isCp) {
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/*::if (typeof(msgStruct[4]) !== 'string') { throw new Error(); }*/
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// id becomes either null or an array or results...
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id = CHECKPOINT_PATTERN.exec(msgStruct[4]);
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if (Array.isArray(id) && id[2] && id[2] === channel.lastSavedCp) {
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// Reject duplicate checkpoints
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return;
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}
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}
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var metadata = metadata_cache[channel.id];
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if (metadata && metadata.validateKey) {
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/*::if (typeof(msgStruct[4]) !== 'string') { throw new Error(); }*/
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let signedMsg = (isCp) ? msgStruct[4].replace(CHECKPOINT_PATTERN, '') : msgStruct[4];
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signedMsg = Nacl.util.decodeBase64(signedMsg);
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// FIXME PERFORMANCE: cache the decoded key instead of decoding it every time
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// CPU/Memory tradeoff
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const validateKey = Nacl.util.decodeBase64(metadata.validateKey);
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const validated = Nacl.sign.open(signedMsg, validateKey);
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if (!validated) {
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Log.info("HK_SIGNED_MESSAGE_REJECTED", 'Channel '+channel.id);
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return;
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let metadata;
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nThen(function (w) {
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// getIndex (and therefore the latest metadata)
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getIndex(ctx, channel.id, w(function (err, index) {
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if (err) {
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w.abort();
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return void Log.error('CHANNEL_MESSAGE_ERROR', err);
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}
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if (!index.metadata) {
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// if there's no channel metadata then it can't be an expiring channel
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// nor can we possibly validate it
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return;
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}
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metadata = index.metadata;
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if (metadata.expire && metadata.expire < +new Date()) {
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// don't store message sent to expired channels
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w.abort();
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return;
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// TODO if a channel expired a long time ago but it's still here, remove it
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}
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// if there's no validateKey present skip to the next block
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if (!metadata.validateKey) { return; }
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// trim the checkpoint indicator off the message if it's present
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let signedMsg = (isCp) ? msgStruct[4].replace(CHECKPOINT_PATTERN, '') : msgStruct[4];
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// convert the message from a base64 string into a Uint8Array
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// FIXME this can fail and the client won't notice
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signedMsg = Nacl.util.decodeBase64(signedMsg);
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// FIXME this can blow up
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// TODO check that that won't cause any problems other than not being able to append...
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const validateKey = Nacl.util.decodeBase64(metadata.validateKey);
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// validate the message
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const validated = Nacl.sign.open(signedMsg, validateKey);
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if (!validated) {
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// don't go any further if the message fails validation
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w.abort();
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Log.info("HK_SIGNED_MESSAGE_REJECTED", 'Channel '+channel.id);
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return;
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}
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}));
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}).nThen(function () {
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// do checkpoint stuff...
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// 1. get the checkpoint id
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// 2. reject duplicate checkpoints
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if (isCp) {
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// if the message is a checkpoint we will have already validated
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// that it isn't a duplicate. remember its id so that we can
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// repeat this process for the next incoming checkpoint
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// WARNING: the fact that we only check the most recent checkpoints
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// is a potential source of bugs if one editor has high latency and
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// pushes a duplicate of an earlier checkpoint than the latest which
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// has been pushed by editors with low latency
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// FIXME
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if (Array.isArray(id) && id[2]) {
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// Store new checkpoint hash
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channel.lastSavedCp = id[2];
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}
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}
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}
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if (isCp) {
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// WARNING: the fact that we only check the most recent checkpoints
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// is a potential source of bugs if one editor has high latency and
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// pushes a duplicate of an earlier checkpoint than the latest which
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// has been pushed by editors with low latency
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// FIXME
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if (Array.isArray(id) && id[2]) {
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// Store new checkpoint hash
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channel.lastSavedCp = id[2];
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}
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}
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msgStruct.push(now());
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storeMessage(ctx, channel, JSON.stringify(msgStruct), isCp, getHash(msgStruct[4]));
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// add the time to the message
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msgStruct.push(now());
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// storeMessage
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storeMessage(ctx, channel, JSON.stringify(msgStruct), isCp, getHash(msgStruct[4]));
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});
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};
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/* dropChannel
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@ -673,6 +720,9 @@ module.exports.create = function (cfg) {
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}
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metadata.channel = channelName;
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// XXX check that the validateKey is valid, otherwise send an error?
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// don't bother putting it into storage
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nThen(function (waitFor) {
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var w = waitFor();
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