4b82

4b82 - Continuity Trustcenter Framework

Based on GIT and Merkle Tree

ps. 4B82 is the first four symbols of the hash value for the GIT empty-tree "tree 0\0" 4b825dc642cb6eb9a060e54bf8d69288fbee4904

4B82 Project Key Technical Details

The goal of this project is to allow a straightforward and robust way to establish abstract, provably immutable sequences of digital events.

Currently existing methods for attaining this rely on highly specialized software, are computationally demanding, or both.

We have decided to use GIT’s architectural framework as the core implementing this functionality because of its versatility, robustness, strong safeguards against corruption, as well as its self-evidential flexibility.

Strict linearity was achieved by leveraging hash functionality typical to all git-like solutions while eschewing branching functionality, and was done in a manner that minimizes unnecessary (for our purposes) overhead of typical git object behaviors (but does not compromise the formal integrity of the git structures involved).

Read more about 4b82 Continuity Trustcenter Framework at 4b82.com

How to Use it?

Initialize an empty git repository:

mkdir git-repo && cd git-repo
git init
cd ..

Create the new node.js project:

mkdir 4b82-server && cd 4b82-server
npm init

Add 4b82 code from npm:

npm install 4b82 --save

Now, you can use 4b82 functions and make your own 4b82 server.

API Functions

Note: all callback functions are function (err, result) or function (err). if an error occurs then err object will be passed to callback function. Otherwise, err object is null and result object will be passed to the callback function (if result is exists).

Initialization

First, it is necessary to initialize the application.

During initialization, it is necessary to pass a configuration object. Currently, this object is simple and includes a git field. This field is an object with the path field which stores the path to the GIT repository. For example:

Configuration Object

{
	git: {
		path: 'path-to-git'
	}
}

Application Initialization

function init (conf)

Arguments	Description
conf	Configuration object (see above)

Exclusive Access

Before you make any changes to the GIT-repository, you must obtain an exclusive access to GIT-repository at the application level.

Important: please, do not forget to call releaseAccess() and to release exclusive access to the repository at the end of the operation.

Important: exclusive access is provided only at the application logic level, not the system level.

Obtain the Exclusive Access

function getAccess (callback)

Arguments	Description
callback (err)	Callback function that calls immediately after receiving the exclusive access to the GIT repository

Release the Exclusive Access

function releaseAccess ()

Arguments	Description
none	Releases the exclusive access to the GIT repository

Adding and Reading Commits

Add a Commit to the Repository

function addCommit (message, author, committer, callback)

Arguments	Description
message	Commit message
author	Commit author
committer	Committer (your system)
callback (err, commit)	Callback function that receives commit object after adding or error

Get the Recently Added Commit

function getRecentCommit (callback)

Arguments	Description
callback (err, commit)	Callback function that receives commit object after adding or error. If there is no commits, null is returned.

Get the Commit With Hash Value

function getCommit (hash, callback)

Arguments	Description
hash	The hash value for the desired commit
callback (err, commit)	Callback function that receives commit object after adding or error. If there is no commits, null is returned.

Display the Commit Data

function prettyPrint (commit) - show information about commit

Arguments	Description
commit	Commit object returned by addCommit, getRecentCommit or getCommit functions

Examples

A simple application that adds commit to our fresh 4b82 git repository:

var _4b82 = require('4b82');

var config = {
	git: { path: '~/git-path/' } // Path to git repository
}

// Initialize 4b82
_4b82.init(config, function (err) {
	if (err) return console.error(err);

	// Get exclusive access to GIT
	_4b82.getAccess(function () {

		// Add commit
		_4b82.addCommit('test commit', 'me <me@localhost>', 'me <me@localhost>',
				function (err, commit) {

			if (err) {
				_4b82.releaseAccess();
				return console.error(err);
			}

			// Print commit data
			_4b82.prettyPrint(commit);

			// Release access
			_4b82.releaseAccess();

		});
	});
});

When you run this application it adds new commit to 4b82 git repository and prints the commit hash, data and deflated bytes.

To get specific commit use getCommit function:

// Initialize 4b82
_4b82.init(config, function (err) {
	if (err) return console.error(err);

	// Get commit data
	_4b82.getCommit(hash, function (err, commit) {
		if (err) return console.error(err);

		// Print commit data
		_4b82.prettyPrint(commit);

	})
});

This function returns commit object (with tag field).

commit contains whole git commit data, you can parse it for author, committer, e.t.c.

tag field uses for backward navigation (read more about backward navigation).

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That's all.