MultiChain Explorer

MultiChain Explorer is a free blockchain browser for MultiChain blockchains.

https://github.com/MultiChain/multichain-explorer

Copyright(C) Coin Sciences Ltd.
Copyright(C) 2011,2012,2013 by Abe developers.
License: GNU Affero General Public License, see the file LICENSE.txt.
Portions Copyright (c) 2010 Gavin Andresen, see bct-LICENSE.txt.

Welcome to MultiChain Explorer!

This software reads the MultiChain block file, transforms and loads the data into a database, and presents a web interface similar to that popularized by Bitcoin block explorers like http://blockexplorer.com/.

MultiChain Explorer is a fork of the popular Abe project to add support for MultiChain blockchains with permissions, assets, streams, filters and upgrades. MultiChain nodes must be online for all explorer functions to work.

MultiChain Explorer is still under development, so things may break or change!

System Requirements

You must have Python 2.x installed on your system to run MultiChain Explorer.

On Ubuntu, you will need to install the following dependencies:

sudo apt-get install python-mysqldb
sudo apt-get install python-dev
sudo apt-get install python-pip
sudo pip install --upgrade pip
sudo pip install pycrypto
sudo pip install py-ubjson

On CentOS, you will need to install the following dependencies:

sudo yum install epel-release
sudo yum install python-pip
sudo pip install --upgrade pip
sudo yum install sqlite-devel
sudo yum install python-devel
sudo yum groupinstall "Development tools"
sudo pip install pycrypto
sudo pip install py-ubjson

MultiChain Compatibility

MultiChain Explorer currently supports all MultiChain 1.0.x release versions and all MultiChain 2.0 alpha and beta versions.

Installation

To install MultiChain Explorer for the current user (recommended):

cd multichain-explorer
python setup.py install --user

If you have root permission and want to install MultiChain Explorer for all users on the system:

cd multichain-explorer
sudo python setup.py install

The explorer needs to connect to a local MultiChain node using the JSON-RPC API, and it also reads the blockchain's contents from disk. So before configuring the explorer, make sure you have a MultiChain blockchain up and running.

Create and launch a MultiChain blockchain

If you do not yet have a chain you want to explore, Download MultiChain to install MultiChain and create a chain named chain1 as follows:

multichain-util create chain1
multichaind chain1 -daemon

By default the runtime parameter txindex is enabled so that the node keeps track of all transactions across the blockchain, and not just those for the node's wallet. This is required for the explorer to work correctly.

MultiChain Explorer. supports viewing streams which the node has subscribed to. Launch MultiChain with the runtime parameter autosubscribe=streams to automatically subscribe to every stream.

The rest of this document assumes your blockchain is named chain1. If not, please substitute accordingly.

Configure multichain.conf

The explorer needs to communicate with the blockchain using JSON-RPC. When you created the blockchain, the JSON-RPC connection details were automatically created by MultiChain and stored in a file named multichain.conf.

The explorer will read this file. If you examine the file you will see a username and password have been auto-generated.

cd ~/.multichain/chain1/
cat multichain.conf

All you need to do is add the RPC port number. Copy the default-rpc-port value from params.dat and add an entry to multichain.conf as follows:

cd ~/.multichain/chain1/
grep rpc params.dat
# Make a note of the default-rpc-port value, let's say it's 1234, and add it to multichain.conf
echo "rpcport=1234" >> multichain.conf

Configure the Explorer

The bundled example config file chain1.example.conf can be used as a template for your own chain.

cd multichain-explorer
cp chain1.example.conf chain1.conf

You can store the config file chain1.conf anywhere you want. When you launch the explorer you can specify the location of your config file. By default, it will look for a config file in the current directory.

The following changes can be made:

• Change port to the port number for serving web pages (make sure your host's firewall allows traffic through that port).
• Change host to 0.0.0.0 to serve web pages to anybody (make sure there is only a single host entry in the config file).
• Change dirname to match the directory for your blockchain.
• Change chain to set how the chain should be listed in the explorer.
• Change connect-args for the location to store the explorer database.

Note: The explorer will automatically read MultiChain specific parameters such as the magic handshake, address checksum, version and script version bytes from params.dat.

Launch the Explorer

To load existing blockchain data into the explorer:

cd multichain-explorer
python -m Mce.abe --config chain1.conf --commit-bytes 100000 --no-serve

Look for output such as:

block_tx 1 1
block_tx 2 2
...

This step may take several minutes to even days depending on chain size and hardware.

To launch the explorer and serve web pages from your local computer:

cd multichain-explorer
python -m Mce.abe --config chain1.conf

By default, the explorer will be listening for web requests on port 2750, unless you changed it in the Explorer's configuration file. In your browser visit:

http://localhost:2750/

To launch the explorer on a server, make sure the explorer is not accidentally terminated when you close your SSH terminal connection.

cd multichain-explorer
nohup python -m Mce.abe --config chain1.conf &

To check the explorer is runnning, in your browser visit:

http://ip_address_of_server:2750/

Reset the Explorer

To start over with new chain data for a chain of the same name, simply:

1. Stop the explorer.

2. Delete the explorer database file chain1.explorer.sqlite (set in connect-args parameter in chain1.conf).

3. Launch the explorer as above.

Advanced Configuration Options

The following options can be set in the explorer config file chain1.conf or as a command-line option with the format --option=value.

• home_refresh_interval_secs specifies how frequently the home page refreshes itself when open in a browser window. The default is every 60 seconds.
• recent_tx_interval_ms specifies how frequently the home page refreshes the recent transactions table including any mempool transactions. The default is every 5000 milliseconds (5 seconds),
• catch_up_tx_interval_secs specifies how frequently the explorer will load blockchain transactions into the explorer database. The default is every 60 seconds.

Misc Notes

• Currently it is not recommended to configure multiple chains in one config file as the search function does not search across chains for an address

• You can run two instances of the explorer with the same config file, with one being passed the --no-serve argument and the other --no-load, so that one instance only loads data into the database, and the other only serves web pages.