@ -1,5 +1,15 @@
/* jshint esversion: 6 */
/* global Buffer */
var HK = module . exports ; var HK = module . exports ;
const nThen = require ( 'nthen' ) ;
const Once = require ( "./once" ) ;
const Meta = require ( "./metadata" ) ;
const Nacl = require ( 'tweetnacl/nacl-fast' ) ;
const now = function ( ) { return ( new Date ( ) ) . getTime ( ) ; } ;
const ONE _DAY = 1000 * 60 * 60 * 24 ; // one day in milliseconds
/ * g e t H a s h / * g e t H a s h
* this function slices off the leading portion of a message which is
* this function slices off the leading portion of a message which is
most likely unique
most likely unique
@ -12,7 +22,7 @@ var HK = module.exports;
* can ' t be easily migrated
* can ' t be easily migrated
* don ' t break it !
* don ' t break it !
* / * /
HK . getHash = function ( msg , Log ) { const getHash = HK . getHash = function ( msg , Log ) {
if ( typeof ( msg ) !== 'string' ) {
if ( typeof ( msg ) !== 'string' ) {
if ( Log ) {
if ( Log ) {
Log . warn ( 'HK_GET_HASH' , 'getHash() called on ' + typeof ( msg ) + ': ' + msg ) ;
Log . warn ( 'HK_GET_HASH' , 'getHash() called on ' + typeof ( msg ) + ': ' + msg ) ;
@ -24,10 +34,896 @@ HK.getHash = function (msg, Log) {
// historyKeeper should explicitly store any channel
// historyKeeper should explicitly store any channel
// with a 32 character id
// with a 32 character id
HK . STANDARD _CHANNEL _LENGTH = 32 ; const STANDARD _CHANNEL _LENGTH = HK . STANDARD _CHANNEL _LENGTH = 32 ;
// historyKeeper should not store messages sent to any channel
// historyKeeper should not store messages sent to any channel
// with a 34 character id
// with a 34 character id
HK . EPHEMERAL _CHANNEL _LENGTH = 34 ; const EPHEMERAL _CHANNEL _LENGTH = HK . EPHEMERAL _CHANNEL _LENGTH = 34 ;
const tryParse = function ( Env , str ) {
try {
return JSON . parse ( str ) ;
} catch ( err ) {
Env . Log . error ( 'HK_PARSE_ERROR' , err ) ; // XXX
}
} ;
/ * s l i c e C p I n d e x
returns a list of all checkpoints which might be relevant for a client connecting to a session
* if there are two or fewer checkpoints , return everything you have
* if there are more than two
* return at least two
* plus any more which were received within the last 100 messages
This is important because the additional history is what prevents
clients from forking on checkpoints and dropping forked history .
* /
const sliceCpIndex = function ( cpIndex , line ) {
// Remove "old" checkpoints (cp sent before 100 messages ago)
const minLine = Math . max ( 0 , ( line - 100 ) ) ;
let start = cpIndex . slice ( 0 , - 2 ) ;
const end = cpIndex . slice ( - 2 ) ;
start = start . filter ( function ( obj ) {
return obj . line > minLine ;
} ) ;
return start . concat ( end ) ;
} ;
const isMetadataMessage = function ( parsed ) {
return Boolean ( parsed && parsed . channel ) ;
} ;
// validateKeyStrings supplied by clients must decode to 32-byte Uint8Arrays
const isValidValidateKeyString = function ( key ) {
try {
return typeof ( key ) === 'string' &&
Nacl . util . decodeBase64 ( key ) . length === Nacl . sign . publicKeyLength ;
} catch ( e ) {
return false ;
}
} ;
var CHECKPOINT _PATTERN = /^cp\|(([A-Za-z0-9+\/=]+)\|)?/ ;
/ * e x p i r e C h a n n e l i s h e r e t o c l e a n u p c h a n n e l s t h a t s h o u l d h a v e b e e n r e m o v e d
but for some reason are still present
* /
const expireChannel = function ( Env , channel ) {
return void Env . store . archiveChannel ( channel , function ( err ) {
Env . Log . info ( "ARCHIVAL_CHANNEL_BY_HISTORY_KEEPER_EXPIRATION" , {
channelId : channel ,
status : err ? String ( err ) : "SUCCESS" ,
} ) ;
} ) ;
} ;
/ * d r o p C h a n n e l
* cleans up memory structures which are managed entirely by the historyKeeper
* /
const dropChannel = HK . dropChannel = function ( Env , chanName ) {
delete Env . metadata _cache [ chanName ] ;
delete Env . channel _cache [ chanName ] ;
} ;
/ * c h e c k E x p i r e d
* synchronously returns true or undefined to indicate whether the channel is expired
* according to its metadata
* has some side effects :
* closes the channel via the store . closeChannel API
* and then broadcasts to all channel members that the channel has expired
* removes the channel from the netflux - server ' s in - memory cache
* removes the channel metadata from history keeper ' s in - memory cache
FIXME the boolean nature of this API should be separated from its side effects
* /
const checkExpired = function ( Env , Server , channel ) {
const store = Env . store ;
const metadata _cache = Env . metadata _cache ;
if ( ! ( channel && channel . length === STANDARD _CHANNEL _LENGTH ) ) { return false ; }
let metadata = metadata _cache [ channel ] ;
if ( ! ( metadata && typeof ( metadata . expire ) === 'number' ) ) { return false ; }
// the number of milliseconds ago the channel should have expired
let pastDue = ( + new Date ( ) ) - metadata . expire ;
// less than zero means that it hasn't expired yet
if ( pastDue < 0 ) { return false ; }
// if it should have expired more than a day ago...
// there may have been a problem with scheduling tasks
// or the scheduled tasks may not be running
// so trigger a removal from here
if ( pastDue >= ONE _DAY ) { expireChannel ( Env , channel ) ; }
// close the channel
store . closeChannel ( channel , function ( ) {
Server . channelBroadcast ( channel , {
error : 'EEXPIRED' ,
channel : channel
} , Env . id ) ;
dropChannel ( channel ) ;
} ) ;
// return true to indicate that it has expired
return true ;
} ;
/ * c o m p u t e I n d e x
can call back with an error or a computed index which includes :
* cpIndex :
* array including any checkpoints pushed within the last 100 messages
* processed by 'sliceCpIndex(cpIndex, line)'
* offsetByHash :
* a map containing message offsets by their hash
* this is for every message in history , so it could be very large ...
* except we remove offsets from the map if they occur before the oldest relevant checkpoint
* size : in bytes
* metadata :
* validationKey
* expiration time
* owners
* ? ? ? ( anything else we might add in the future )
* line
* the number of messages in history
* including the initial metadata line , if it exists
* /
const computeIndex = function ( Env , channelName , cb ) {
const store = Env . store ;
const Log = Env . Log ;
const cpIndex = [ ] ;
let messageBuf = [ ] ;
let metadata ;
let i = 0 ;
const ref = { } ;
const CB = Once ( cb ) ;
const offsetByHash = { } ;
let size = 0 ;
nThen ( function ( w ) {
// iterate over all messages in the channel log
// old channels can contain metadata as the first message of the log
// remember metadata the first time you encounter it
// otherwise index important messages in the log
store . readMessagesBin ( channelName , 0 , ( msgObj , readMore ) => {
let msg ;
// keep an eye out for the metadata line if you haven't already seen it
// but only check for metadata on the first line
if ( ! i && ! metadata && msgObj . buff . indexOf ( '{' ) === 0 ) {
i ++ ; // always increment the message counter
msg = tryParse ( Env , msgObj . buff . toString ( 'utf8' ) ) ;
if ( typeof msg === "undefined" ) { return readMore ( ) ; }
// validate that the current line really is metadata before storing it as such
if ( isMetadataMessage ( msg ) ) {
metadata = msg ;
return readMore ( ) ;
}
}
i ++ ;
if ( msgObj . buff . indexOf ( 'cp|' ) > - 1 ) {
msg = msg || tryParse ( Env , msgObj . buff . toString ( 'utf8' ) ) ;
if ( typeof msg === "undefined" ) { return readMore ( ) ; }
// cache the offsets of checkpoints if they can be parsed
if ( msg [ 2 ] === 'MSG' && msg [ 4 ] . indexOf ( 'cp|' ) === 0 ) {
cpIndex . push ( {
offset : msgObj . offset ,
line : i
} ) ;
// we only want to store messages since the latest checkpoint
// so clear the buffer every time you see a new one
messageBuf = [ ] ;
}
}
// if it's not metadata or a checkpoint then it should be a regular message
// store it in the buffer
messageBuf . push ( msgObj ) ;
return readMore ( ) ;
} , w ( ( err ) => {
if ( err && err . code !== 'ENOENT' ) {
w . abort ( ) ;
return void CB ( err ) ;
}
// once indexing is complete you should have a buffer of messages since the latest checkpoint
// map the 'hash' of each message to its byte offset in the log, to be used for reconnecting clients
messageBuf . forEach ( ( msgObj ) => {
const msg = tryParse ( Env , msgObj . buff . toString ( 'utf8' ) ) ;
if ( typeof msg === "undefined" ) { return ; }
if ( msg [ 0 ] === 0 && msg [ 2 ] === 'MSG' && typeof ( msg [ 4 ] ) === 'string' ) {
// msgObj.offset is API guaranteed by our storage module
// it should always be a valid positive integer
offsetByHash [ getHash ( msg [ 4 ] , Log ) ] = msgObj . offset ;
}
// There is a trailing \n at the end of the file
size = msgObj . offset + msgObj . buff . length + 1 ;
} ) ;
} ) ) ;
} ) . nThen ( function ( w ) {
// create a function which will iterate over amendments to the metadata
const handler = Meta . createLineHandler ( ref , Log . error ) ;
// initialize the accumulator in case there was a foundational metadata line in the log content
if ( metadata ) { handler ( void 0 , metadata ) ; }
// iterate over the dedicated metadata log (if it exists)
// proceed even in the event of a stream error on the metadata log
store . readDedicatedMetadata ( channelName , handler , w ( function ( err ) {
if ( err ) {
return void Log . error ( "DEDICATED_METADATA_ERROR" , err ) ;
}
} ) ) ;
} ) . nThen ( function ( ) {
// when all is done, cache the metadata in memory
if ( ref . index ) { // but don't bother if no metadata was found...
metadata = Env . metadata _cache [ channelName ] = ref . meta ;
}
// and return the computed index
CB ( null , {
// Only keep the checkpoints included in the last 100 messages
cpIndex : sliceCpIndex ( cpIndex , i ) ,
offsetByHash : offsetByHash ,
size : size ,
metadata : metadata ,
line : i
} ) ;
} ) ;
} ;
/ * g e t I n d e x
calls back with an error if anything goes wrong
or with a cached index for a channel if it exists
( along with metadata )
otherwise it calls back with the index computed by 'computeIndex'
as an added bonus :
if the channel exists but its index does not then it caches the index
* /
const getIndex = ( Env , channelName , cb ) => {
const channel _cache = Env . channel _cache ;
const chan = channel _cache [ channelName ] ;
// if there is a channel in memory and it has an index cached, return it
if ( chan && chan . index ) {
// enforce async behaviour
return void setTimeout ( function ( ) {
cb ( undefined , chan . index ) ;
} ) ;
}
Env . batchIndexReads ( channelName , cb , function ( done ) {
computeIndex ( Env , channelName , ( err , ret ) => {
// this is most likely an unrecoverable filesystem error
if ( err ) { return void done ( err ) ; }
// cache the computed result if possible
if ( chan ) { chan . index = ret ; }
// return
done ( void 0 , ret ) ;
} ) ;
} ) ;
} ;
/ * s t o r e M e s s a g e
* channel id
* the message to store
* whether the message is a checkpoint
* optionally the hash of the message
* it ' s not always used , but we guard against it
* async but doesn ' t have a callback
* source of a race condition whereby :
* two messaages can be inserted
* two offsets can be computed using the total size of all the messages
* but the offsets don ' t correspond to the actual location of the newlines
* because the two actions were performed like ABba ...
* the fix is to use callbacks and implement queueing for writes
* to guarantee that offset computation is always atomic with writes
* /
const storeMessage = function ( Env , channel , msg , isCp , optionalMessageHash ) {
const id = channel . id ;
const Log = Env . Log ;
Env . queueStorage ( id , function ( next ) {
const msgBin = Buffer . from ( msg + '\n' , 'utf8' ) ;
// Store the message first, and update the index only once it's stored.
// store.messageBin can be async so updating the index first may
// result in a wrong cpIndex
nThen ( ( waitFor ) => {
Env . store . messageBin ( id , msgBin , waitFor ( function ( err ) {
if ( err ) {
waitFor . abort ( ) ;
Log . error ( "HK_STORE_MESSAGE_ERROR" , err . message ) ;
// this error is critical, but there's not much we can do at the moment
// proceed with more messages, but they'll probably fail too
// at least you won't have a memory leak
// TODO make it possible to respond to clients with errors so they know
// their message wasn't stored
return void next ( ) ;
}
} ) ) ;
} ) . nThen ( ( waitFor ) => {
getIndex ( Env , id , waitFor ( ( err , index ) => {
if ( err ) {
Log . warn ( "HK_STORE_MESSAGE_INDEX" , err . stack ) ;
// non-critical, we'll be able to get the channel index later
return void next ( ) ;
}
if ( typeof ( index . line ) === "number" ) { index . line ++ ; }
if ( isCp ) {
index . cpIndex = sliceCpIndex ( index . cpIndex , index . line || 0 ) ;
for ( let k in index . offsetByHash ) {
if ( index . offsetByHash [ k ] < index . cpIndex [ 0 ] ) {
delete index . offsetByHash [ k ] ;
}
}
index . cpIndex . push ( {
offset : index . size ,
line : ( ( index . line || 0 ) + 1 )
} ) ;
}
if ( optionalMessageHash ) { index . offsetByHash [ optionalMessageHash ] = index . size ; }
index . size += msgBin . length ;
// handle the next element in the queue
next ( ) ;
} ) ) ;
} ) ;
} ) ;
} ;
/ * g e t H i s t o r y O f f s e t
returns a number representing the byte offset from the start of the log
for whatever history you ' re seeking .
query by providing a 'lastKnownHash' ,
which is really just a string of the first 64 characters of an encrypted message .
OR by - 1 which indicates that we want the full history ( byte offset 0 )
OR nothing , which indicates that you want whatever messages the historyKeeper deems relevant
( typically the last few checkpoints )
this function embeds a lot of the history keeper ' s logic :
0. if you passed - 1 as the lastKnownHash it means you want the complete history
* I 'm not sure why you' d need to call this function if you know it will return 0 in this case ...
* it has a side - effect of filling the index cache if it ' s empty
1. if you provided a lastKnownHash and that message does not exist in the history :
* either the client has made a mistake or the history they knew about no longer exists
* call back with EINVAL
2. if you did not provide a lastKnownHash
* and there are fewer than two checkpoints :
* return 0 ( read from the start of the file )
* and there are two or more checkpoints :
* return the offset of the earliest checkpoint which 'sliceCpIndex' considers relevant
3. if you did provide a lastKnownHash
* read through the log until you find the hash that you ' re looking for
* call back with either the byte offset of the message that you found OR
* - 1 if you didn ' t find it
* /
const getHistoryOffset = ( Env , channelName , lastKnownHash , cb ) => {
const store = Env . store ;
const Log = Env . Log ;
// lastKnownhash === -1 means we want the complete history
if ( lastKnownHash === - 1 ) { return void cb ( null , 0 ) ; }
let offset = - 1 ;
nThen ( ( waitFor ) => {
getIndex ( Env , channelName , waitFor ( ( err , index ) => {
if ( err ) { waitFor . abort ( ) ; return void cb ( err ) ; }
// check if the "hash" the client is requesting exists in the index
const lkh = index . offsetByHash [ lastKnownHash ] ;
// we evict old hashes from the index as new checkpoints are discovered.
// if someone connects and asks for a hash that is no longer relevant,
// we tell them it's an invalid request. This is because of the semantics of "GET_HISTORY"
// which is only ever used when connecting or reconnecting in typical uses of history...
// this assumption should hold for uses by chainpad, but perhaps not for other uses cases.
// EXCEPT: other cases don't use checkpoints!
// clients that are told that their request is invalid should just make another request
// without specifying the hash, and just trust the server to give them the relevant data.
// QUESTION: does this mean mailboxes are causing the server to store too much stuff in memory?
if ( lastKnownHash && typeof ( lkh ) !== "number" ) {
waitFor . abort ( ) ;
return void cb ( new Error ( 'EINVAL' ) ) ;
}
// Since last 2 checkpoints
if ( ! lastKnownHash ) {
waitFor . abort ( ) ;
// Less than 2 checkpoints in the history: return everything
if ( index . cpIndex . length < 2 ) { return void cb ( null , 0 ) ; }
// Otherwise return the second last checkpoint's index
return void cb ( null , index . cpIndex [ 0 ] . offset ) ;
/ * L A T E R . . .
in practice , two checkpoints can be very close together
we have measures to avoid duplicate checkpoints , but editors
can produce nearby checkpoints which are slightly different ,
and slip past these protections . To be really careful , we can
seek past nearby checkpoints by some number of patches so as
to ensure that all editors have sufficient knowledge of history
to reconcile their differences . * /
}
offset = lkh ;
} ) ) ;
} ) . nThen ( ( waitFor ) => {
// if offset is less than zero then presumably the channel has no messages
// returning falls through to the next block and therefore returns -1
if ( offset !== - 1 ) { return ; }
// do a lookup from the index
// FIXME maybe we don't need this anymore?
// otherwise we have a non-negative offset and we can start to read from there
store . readMessagesBin ( channelName , 0 , ( msgObj , readMore , abort ) => {
// tryParse return a parsed message or undefined
const msg = tryParse ( Env , msgObj . buff . toString ( 'utf8' ) ) ;
// if it was undefined then go onto the next message
if ( typeof msg === "undefined" ) { return readMore ( ) ; }
if ( typeof ( msg [ 4 ] ) !== 'string' || lastKnownHash !== getHash ( msg [ 4 ] , Log ) ) {
return void readMore ( ) ;
}
offset = msgObj . offset ;
abort ( ) ;
} , waitFor ( function ( err ) {
if ( err ) { waitFor . abort ( ) ; return void cb ( err ) ; }
} ) ) ;
} ) . nThen ( ( ) => {
cb ( null , offset ) ;
} ) ;
} ;
/ * g e t H i s t o r y A s y n c
* finds the appropriate byte offset from which to begin reading using 'getHistoryOffset'
* streams through the rest of the messages , safely parsing them and returning the parsed content to the handler
* calls back when it has reached the end of the log
Used by :
* GET _HISTORY
* /
const getHistoryAsync = ( Env , channelName , lastKnownHash , beforeHash , handler , cb ) => {
const store = Env . store ;
let offset = - 1 ;
nThen ( ( waitFor ) => {
getHistoryOffset ( Env , channelName , lastKnownHash , waitFor ( ( err , os ) => {
if ( err ) {
waitFor . abort ( ) ;
return void cb ( err ) ;
}
offset = os ;
} ) ) ;
} ) . nThen ( ( waitFor ) => {
if ( offset === - 1 ) { return void cb ( new Error ( "could not find offset" ) ) ; }
const start = ( beforeHash ) ? 0 : offset ;
store . readMessagesBin ( channelName , start , ( msgObj , readMore , abort ) => {
if ( beforeHash && msgObj . offset >= offset ) { return void abort ( ) ; }
var parsed = tryParse ( Env , msgObj . buff . toString ( 'utf8' ) ) ;
if ( ! parsed ) { return void readMore ( ) ; }
handler ( parsed , readMore ) ;
} , waitFor ( function ( err ) {
return void cb ( err ) ;
} ) ) ;
} ) ;
} ;
/ * g e t O l d e r H i s t o r y
* allows clients to query for all messages until a known hash is read
* stores all messages in history as they are read
* can therefore be very expensive for memory
* should probably be converted to a streaming interface
Used by :
* GET _HISTORY _RANGE
* /
const getOlderHistory = function ( Env , channelName , oldestKnownHash , cb ) {
const store = Env . store ;
const Log = Env . Log ;
var messageBuffer = [ ] ;
var found = false ;
store . getMessages ( channelName , function ( msgStr ) {
if ( found ) { return ; }
let parsed = tryParse ( Env , msgStr ) ;
if ( typeof parsed === "undefined" ) { return ; }
// identify classic metadata messages by their inclusion of a channel.
// and don't send metadata, since:
// 1. the user won't be interested in it
// 2. this metadata is potentially incomplete/incorrect
if ( isMetadataMessage ( parsed ) ) { return ; }
var content = parsed [ 4 ] ;
if ( typeof ( content ) !== 'string' ) { return ; }
var hash = getHash ( content , Log ) ;
if ( hash === oldestKnownHash ) {
found = true ;
}
messageBuffer . push ( parsed ) ;
} , function ( err ) {
if ( err ) {
Log . error ( "HK_GET_OLDER_HISTORY" , err ) ;
}
cb ( messageBuffer ) ;
} ) ;
} ;
const handleRPC = function ( Env , Server , seq , userId , parsed ) {
const HISTORY _KEEPER _ID = Env . id ;
/* RPC Calls... */
var rpc _call = parsed . slice ( 1 ) ;
Server . send ( userId , [ seq , 'ACK' ] ) ;
try {
// slice off the sequence number and pass in the rest of the message
Env . rpc ( Server , rpc _call , function ( err , output ) {
if ( err ) {
Server . send ( userId , [ 0 , HISTORY _KEEPER _ID , 'MSG' , userId , JSON . stringify ( [ parsed [ 0 ] , 'ERROR' , err ] ) ] ) ;
return ;
}
Server . send ( userId , [ 0 , HISTORY _KEEPER _ID , 'MSG' , userId , JSON . stringify ( [ parsed [ 0 ] ] . concat ( output ) ) ] ) ;
} ) ;
} catch ( e ) {
// if anything throws in the middle, send an error
Server . send ( userId , [ 0 , HISTORY _KEEPER _ID , 'MSG' , userId , JSON . stringify ( [ parsed [ 0 ] , 'ERROR' , 'SERVER_ERROR' ] ) ] ) ;
}
} ;
const handleGetHistory = function ( Env , Server , seq , userId , parsed ) {
const store = Env . store ;
const tasks = Env . tasks ;
const metadata _cache = Env . metadata _cache ;
const channel _cache = Env . channel _cache ;
const HISTORY _KEEPER _ID = Env . id ;
const Log = Env . Log ;
// parsed[1] is the channel id
// parsed[2] is a validation key or an object containing metadata (optionnal)
// parsed[3] is the last known hash (optionnal)
Server . send ( userId , [ seq , 'ACK' ] ) ;
var channelName = parsed [ 1 ] ;
var config = parsed [ 2 ] ;
var metadata = { } ;
var lastKnownHash ;
// clients can optionally pass a map of attributes
// if the channel already exists this map will be ignored
// otherwise it will be stored as the initial metadata state for the channel
if ( config && typeof config === "object" && ! Array . isArray ( parsed [ 2 ] ) ) {
lastKnownHash = config . lastKnownHash ;
metadata = config . metadata || { } ;
if ( metadata . expire ) {
metadata . expire = + metadata . expire * 1000 + ( + new Date ( ) ) ;
}
}
metadata . channel = channelName ;
metadata . created = + new Date ( ) ;
// if the user sends us an invalid key, we won't be able to validate their messages
// so they'll never get written to the log anyway. Let's just drop their message
// on the floor instead of doing a bunch of extra work
// TODO send them an error message so they know something is wrong
if ( metadata . validateKey && ! isValidValidateKeyString ( metadata . validateKey ) ) {
return void Log . error ( 'HK_INVALID_KEY' , metadata . validateKey ) ;
}
nThen ( function ( waitFor ) {
var w = waitFor ( ) ;
/ * u n l e s s t h i s i s a y o u n g c h a n n e l , w e w i l l s e r v e a l l m e s s a g e s f r o m a n o f f s e t
this will not include the channel metadata , so we need to explicitly fetch that .
unfortunately , we can ' t just serve it blindly , since then young channels will
send the metadata twice , so let 's do a quick check of what we' re going to serve ...
* /
getIndex ( Env , channelName , waitFor ( ( err , index ) => {
/ * i f t h e r e ' s a n e r r o r h e r e , i t s h o u l d b e e n c o u n t e r e d
and handled by the next nThen block .
so , let ' s just fall through ...
* /
if ( err ) { return w ( ) ; }
// it's possible that the channel doesn't have metadata
// but in that case there's no point in checking if the channel expired
// or in trying to send metadata, so just skip this block
if ( ! index || ! index . metadata ) { return void w ( ) ; }
// And then check if the channel is expired. If it is, send the error and abort
// FIXME this is hard to read because 'checkExpired' has side effects
if ( checkExpired ( Env , Server , channelName ) ) { return void waitFor . abort ( ) ; }
// always send metadata with GET_HISTORY requests
Server . send ( userId , [ 0 , HISTORY _KEEPER _ID , 'MSG' , userId , JSON . stringify ( index . metadata ) ] , w ) ;
} ) ) ;
} ) . nThen ( ( ) => {
let msgCount = 0 ;
// TODO compute lastKnownHash in a manner such that it will always skip past the metadata line?
getHistoryAsync ( Env , channelName , lastKnownHash , false , ( msg , readMore ) => {
msgCount ++ ;
// avoid sending the metadata message a second time
if ( isMetadataMessage ( msg ) && metadata _cache [ channelName ] ) { return readMore ( ) ; }
Server . send ( userId , [ 0 , HISTORY _KEEPER _ID , 'MSG' , userId , JSON . stringify ( msg ) ] , readMore ) ;
} , ( err ) => {
if ( err && err . code !== 'ENOENT' ) {
if ( err . message !== 'EINVAL' ) { Log . error ( "HK_GET_HISTORY" , err ) ; }
const parsedMsg = { error : err . message , channel : channelName } ;
Server . send ( userId , [ 0 , HISTORY _KEEPER _ID , 'MSG' , userId , JSON . stringify ( parsedMsg ) ] ) ;
return ;
}
const chan = channel _cache [ channelName ] ;
if ( msgCount === 0 && ! metadata _cache [ channelName ] && Server . channelContainsUser ( channelName , userId ) ) {
metadata _cache [ channelName ] = metadata ;
// the index will have already been constructed and cached at this point
// but it will not have detected any metadata because it hasn't been written yet
// this means that the cache starts off as invalid, so we have to correct it
if ( chan && chan . index ) { chan . index . metadata = metadata ; }
// new channels will always have their metadata written to a dedicated metadata log
// but any lines after the first which are not amendments in a particular format will be ignored.
// Thus we should be safe from race conditions here if just write metadata to the log as below...
// TODO validate this logic
// otherwise maybe we need to check that the metadata log is empty as well
store . writeMetadata ( channelName , JSON . stringify ( metadata ) , function ( err ) {
if ( err ) {
// FIXME tell the user that there was a channel error?
return void Log . error ( 'HK_WRITE_METADATA' , {
channel : channelName ,
error : err ,
} ) ;
}
} ) ;
// write tasks
if ( metadata . expire && typeof ( metadata . expire ) === 'number' ) {
// the fun part...
// the user has said they want this pad to expire at some point
tasks . write ( metadata . expire , "EXPIRE" , [ channelName ] , function ( err ) {
if ( err ) {
// if there is an error, we don't want to crash the whole server...
// just log it, and if there's a problem you'll be able to fix it
// at a later date with the provided information
Log . error ( 'HK_CREATE_EXPIRE_TASK' , err ) ;
Log . info ( 'HK_INVALID_EXPIRE_TASK' , JSON . stringify ( [ metadata . expire , 'EXPIRE' , channelName ] ) ) ;
}
} ) ;
}
Server . send ( userId , [ 0 , HISTORY _KEEPER _ID , 'MSG' , userId , JSON . stringify ( metadata ) ] ) ;
}
// End of history message:
let parsedMsg = { state : 1 , channel : channelName } ;
Server . send ( userId , [ 0 , HISTORY _KEEPER _ID , 'MSG' , userId , JSON . stringify ( parsedMsg ) ] ) ;
} ) ;
} ) ;
} ;
const handleGetHistoryRange = function ( Env , Server , seq , userId , parsed ) {
var channelName = parsed [ 1 ] ;
var map = parsed [ 2 ] ;
const HISTORY _KEEPER _ID = Env . id ;
if ( ! ( map && typeof ( map ) === 'object' ) ) {
return void Server . send ( userId , [ seq , 'ERROR' , 'INVALID_ARGS' , HISTORY _KEEPER _ID ] ) ;
}
var oldestKnownHash = map . from ;
var desiredMessages = map . count ;
var desiredCheckpoint = map . cpCount ;
var txid = map . txid ;
if ( typeof ( desiredMessages ) !== 'number' && typeof ( desiredCheckpoint ) !== 'number' ) {
return void Server . send ( userId , [ seq , 'ERROR' , 'UNSPECIFIED_COUNT' , HISTORY _KEEPER _ID ] ) ;
}
if ( ! txid ) {
return void Server . send ( userId , [ seq , 'ERROR' , 'NO_TXID' , HISTORY _KEEPER _ID ] ) ;
}
Server . send ( userId , [ seq , 'ACK' ] ) ;
return void getOlderHistory ( Env , channelName , oldestKnownHash , function ( messages ) {
var toSend = [ ] ;
if ( typeof ( desiredMessages ) === "number" ) {
toSend = messages . slice ( - desiredMessages ) ;
} else {
let cpCount = 0 ;
for ( var i = messages . length - 1 ; i >= 0 ; i -- ) {
if ( /^cp\|/ . test ( messages [ i ] [ 4 ] ) && i !== ( messages . length - 1 ) ) {
cpCount ++ ;
}
toSend . unshift ( messages [ i ] ) ;
if ( cpCount >= desiredCheckpoint ) { break ; }
}
}
toSend . forEach ( function ( msg ) {
Server . send ( userId , [ 0 , HISTORY _KEEPER _ID , 'MSG' , userId ,
JSON . stringify ( [ 'HISTORY_RANGE' , txid , msg ] ) ] ) ;
} ) ;
Server . send ( userId , [ 0 , HISTORY _KEEPER _ID , 'MSG' , userId ,
JSON . stringify ( [ 'HISTORY_RANGE_END' , txid , channelName ] )
] ) ;
} ) ;
} ;
const handleGetFullHistory = function ( Env , Server , seq , userId , parsed ) {
const HISTORY _KEEPER _ID = Env . id ;
const Log = Env . Log ;
// parsed[1] is the channel id
// parsed[2] is a validation key (optionnal)
// parsed[3] is the last known hash (optionnal)
Server . send ( userId , [ seq , 'ACK' ] ) ;
// FIXME should we send metadata here too?
// none of the clientside code which uses this API needs metadata, but it won't hurt to send it (2019-08-22)
return void getHistoryAsync ( Env , parsed [ 1 ] , - 1 , false , ( msg , readMore ) => {
Server . send ( userId , [ 0 , HISTORY _KEEPER _ID , 'MSG' , userId , JSON . stringify ( [ 'FULL_HISTORY' , msg ] ) ] , readMore ) ;
} , ( err ) => {
let parsedMsg = [ 'FULL_HISTORY_END' , parsed [ 1 ] ] ;
if ( err ) {
Log . error ( 'HK_GET_FULL_HISTORY' , err . stack ) ;
parsedMsg = [ 'ERROR' , parsed [ 1 ] , err . message ] ;
}
Server . send ( userId , [ 0 , HISTORY _KEEPER _ID , 'MSG' , userId , JSON . stringify ( parsedMsg ) ] ) ;
} ) ;
} ;
const directMessageCommands = {
GET _HISTORY : handleGetHistory ,
GET _HISTORY _RANGE : handleGetHistoryRange ,
GET _FULL _HISTORY : handleGetFullHistory ,
} ;
/ * o n D i r e c t M e s s a g e
* exported for use by the netflux - server
* parses and handles all direct messages directed to the history keeper
* check if it ' s expired and execute all the associated side - effects
* routes queries to the appropriate handlers
* /
HK . onDirectMessage = function ( Env , Server , seq , userId , json ) {
const Log = Env . Log ;
Log . silly ( 'HK_MESSAGE' , json ) ;
let parsed ;
try {
parsed = JSON . parse ( json [ 2 ] ) ;
} catch ( err ) {
Log . error ( "HK_PARSE_CLIENT_MESSAGE" , json ) ;
return ;
}
// If the requested history is for an expired channel, abort
// Note the if we don't have the keys for that channel in metadata_cache, we'll
// have to abort later (once we know the expiration time)
if ( checkExpired ( Env , Server , parsed [ 1 ] ) ) { return ; }
// look up the appropriate command in the map of commands or fall back to RPC
var command = directMessageCommands [ parsed [ 0 ] ] || handleRPC ;
// run the command with the standard function signature
command ( Env , Server , seq , userId , parsed ) ;
} ;
/ * o n C h a n n e l M e s s a g e
Determine what we should store when a message a broadcasted to a channel "
* ignores ephemeral channels
* ignores messages sent to expired channels
* rejects duplicated checkpoints
* validates messages to channels that have validation keys
* caches the id of the last saved checkpoint
* adds timestamps to incoming messages
* writes messages to the store
* /
HK . onChannelMessage = function ( Env , Server , channel , msgStruct ) {
const Log = Env . Log ;
// TODO our usage of 'channel' here looks prone to errors
// we only use it for its 'id', but it can contain other stuff
// also, we're using this RPC from both the RPC and Netflux-server
// we should probably just change this to expect a channel id directly
// don't store messages if the channel id indicates that it's an ephemeral message
if ( ! channel . id || channel . id . length === EPHEMERAL _CHANNEL _LENGTH ) { return ; }
const isCp = /^cp\|/ . test ( msgStruct [ 4 ] ) ;
let id ;
if ( isCp ) {
// id becomes either null or an array or results...
id = CHECKPOINT _PATTERN . exec ( msgStruct [ 4 ] ) ;
if ( Array . isArray ( id ) && id [ 2 ] && id [ 2 ] === channel . lastSavedCp ) {
// Reject duplicate checkpoints
return ;
}
}
let metadata ;
nThen ( function ( w ) {
// getIndex (and therefore the latest metadata)
getIndex ( Env , channel . id , w ( function ( err , index ) {
if ( err ) {
w . abort ( ) ;
return void Log . error ( 'CHANNEL_MESSAGE_ERROR' , err ) ;
}
if ( ! index . metadata ) {
// if there's no channel metadata then it can't be an expiring channel
// nor can we possibly validate it
return ;
}
metadata = index . metadata ;
// don't write messages to expired channels
if ( checkExpired ( Env , Server , channel ) ) { return void w . abort ( ) ; }
// if there's no validateKey present skip to the next block
if ( ! metadata . validateKey ) { return ; }
// trim the checkpoint indicator off the message if it's present
let signedMsg = ( isCp ) ? msgStruct [ 4 ] . replace ( CHECKPOINT _PATTERN , '' ) : msgStruct [ 4 ] ;
// convert the message from a base64 string into a Uint8Array
// FIXME this can fail and the client won't notice
signedMsg = Nacl . util . decodeBase64 ( signedMsg ) ;
// FIXME this can blow up
// TODO check that that won't cause any problems other than not being able to append...
const validateKey = Nacl . util . decodeBase64 ( metadata . validateKey ) ;
// validate the message
const validated = Nacl . sign . open ( signedMsg , validateKey ) ;
if ( ! validated ) {
// don't go any further if the message fails validation
w . abort ( ) ;
Log . info ( "HK_SIGNED_MESSAGE_REJECTED" , 'Channel ' + channel . id ) ;
return ;
}
} ) ) ;
} ) . nThen ( function ( ) {
// do checkpoint stuff...
// 1. get the checkpoint id
// 2. reject duplicate checkpoints
if ( isCp ) {
// if the message is a checkpoint we will have already validated
// that it isn't a duplicate. remember its id so that we can
// repeat this process for the next incoming checkpoint
// WARNING: the fact that we only check the most recent checkpoints
// is a potential source of bugs if one editor has high latency and
// pushes a duplicate of an earlier checkpoint than the latest which
// has been pushed by editors with low latency
// FIXME
if ( Array . isArray ( id ) && id [ 2 ] ) {
// Store new checkpoint hash
channel . lastSavedCp = id [ 2 ] ;
}
}
// add the time to the message
msgStruct . push ( now ( ) ) ;
// storeMessage
storeMessage ( Env , channel , JSON . stringify ( msgStruct ) , isCp , getHash ( msgStruct [ 4 ] , Log ) ) ;
} ) ;
} ;
yflory
5 years ago