Interactive use: the JSRE REPL Console¶
$ moac console $ moac attach
The attach node accepts an endpoint in case the moac node is running with a non default ipc endpoint or you would like to connect over the rpc interface.
$ moac attach ipc:/some/custom/path $ moac attach http://127.0.0.1:8545 $ moac attach ws://127.0.0.1:8546
Note that by default the moac node doesn’t start the http and weboscket service and not all functionality is provided over these interfaces due to security reasons. These defaults can be overridden when the –rpcapi and –wsapi arguments when the moac node is started, or with admin.startRPC and admin.startWS.
If you need log information, start with:
$ moac --verbosity 4 console 2>> /tmp/vnode.log
Otherwise mute your logs, so that it does not pollute your console:
$ moac console 2>> /dev/null
$ moac --verbosity 0 console
$ moac --preload "/my/scripts/folder/utils.js,/my/scripts/folder/contracts.js" console
Non-interactive use: JSRE script mode¶
$ moac --exec "mc.blockNumber" attach
This prints the current block number of a running moac instance.
Or execute a local script with more complex statements on a remote node over http:
$ moac --exec 'loadScript("/tmp/checkbalances.js")' attach http://127.0.0.1:8545 $ moac --jspath "/tmp" --exec 'loadScript("checkbalances.js")' attach http://127.0.0.1:8545
Use the –jspath <path/to/my/js/root> to set a libdir for your js scripts. Parameters to loadScript() with no absolute path will be understood relative to this directory.
You can exit the console cleanly by typing exit or simply with CTRL-C.
Just like go-ethereum, MOAC’s JSRE uses the Otto JS VM which has some limitations:
“use strict” will parse, but does nothing. The regular expression engine (re2/regexp) is not fully compatible with the ECMA5 specification. Note that the other known limitation of Otto (namely the lack of timers) is taken care of. Ethereum JSRE implements both setTimeout and setInterval. In addition to this, the console provides admin.sleep(seconds) as well as a “blocktime sleep” method admin.sleepBlocks(number).
Since chain3.js uses the bignumber.js library (MIT Expat Licence), it is also autoloded.
In addition to the full functionality of JS (as per ECMA5), the moac JSRE is augmented with various timers. It implements setInterval, clearInterval, setTimeout, clearTimeout you may be used to using in browser windows. It also provides implementation for admin.sleep(seconds) and a block based timer, admin.sleepBlocks(n) which sleeps till the number of new blocks added is equal to or greater than n, think “wait for n confirmations”.
Beside the official DApp API interface the VNODE has support for additional management API’s. These API’s are offered using JSON-RPC and follow the same conventions as used in the DApp API. The VNODE package comes with a console client which has support for all additional API’s.