7 | 
8 |
9 | ## ℹ️ About
10 | Anyone who wants to understand how blockchain technology works, then BlockShell should be a great start. Because I have created BlockShell keeping blockchain fundamentals in the center of development. With BlockShell you will actually create a tiny blockchain in your system where you can create blocks with data, explore blocks etc.
11 |
12 | So, by using BlockShell anyone can learn following blockchain concepts,
13 | * Block & Chaining
14 | * Hashing
15 | * Mining
16 | * Proof of Work
17 |
18 | ## 🌐 BlockShell Web Explorer
19 | 
67 |
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/_config.yml:
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1 | theme: jekyll-theme-cayman
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/blockchain/__init__.py:
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https://raw.githubusercontent.com/daxeel/blockshell/f23af007d8a65a3a265f8db4430d15c843479aff/blockchain/__init__.py
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/blockchain/chain.py:
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1 | # -*- coding: utf-8 -*-
2 | # ===================================================
3 | # ==================== META DATA ===================
4 | # ==================================================
5 | __author__ = "Daxeel Soni"
6 | __url__ = "https://daxeel.github.io"
7 | __email__ = "daxeelsoni44@gmail.com"
8 | __license__ = "MIT"
9 | __version__ = "0.1"
10 | __maintainer__ = "Daxeel Soni"
11 |
12 | # ==================================================
13 | # ================= IMPORT MODULES =================
14 | # ==================================================
15 | import hashlib
16 | import datetime
17 | import json
18 | from colorama import Fore, Back, Style
19 | import time
20 | import sys
21 |
22 | # ==================================================
23 | # =================== BLOCK CLASS ==================
24 | # ==================================================
25 | class Block:
26 | """
27 | Create a new block in chain with metadata
28 | """
29 | def __init__(self, data, index=0):
30 | self.index = index
31 | self.previousHash = ""
32 | self.data = data
33 | self.timestamp = str(datetime.datetime.now())
34 | self.nonce = 0
35 | self.hash = self.calculateHash()
36 |
37 | def calculateHash(self):
38 | """
39 | Method to calculate hash from metadata
40 | """
41 | hashData = str(self.index) + str(self.data) + self.timestamp + self.previousHash + str(self.nonce)
42 | return hashlib.sha256(hashData).hexdigest()
43 |
44 | def mineBlock(self, difficulty):
45 | """
46 | Method for Proof of Work
47 | """
48 | print Back.RED + "\n[Status] Mining block (" + str(self.index) + ") with PoW ..."
49 | startTime = time.time()
50 |
51 | while self.hash[:difficulty] != "0"*difficulty:
52 | self.nonce += 1
53 | self.hash = self.calculateHash()
54 |
55 | endTime = time.time()
56 | print Back.BLUE + "[ Info ] Time Elapsed : " + str(endTime - startTime) + " seconds."
57 | print Back.BLUE + "[ Info ] Mined Hash : " + self.hash
58 | print Style.RESET_ALL
59 |
60 | # ==================================================
61 | # ================ BLOCKCHAIN CLASS ================
62 | # ==================================================
63 | class Blockchain:
64 | """
65 | Initialize blockchain
66 | """
67 | def __init__(self):
68 | self.chain = [self.createGenesisBlock()]
69 | self.difficulty = 3
70 |
71 | def createGenesisBlock(self):
72 | """
73 | Method create genesis block
74 | """
75 | return Block("Genesis Block")
76 |
77 | def addBlock(self, newBlock):
78 | """
79 | Method to add new block from Block class
80 | """
81 | newBlock.index = len(self.chain)
82 | newBlock.previousHash = self.chain[-1].hash
83 | newBlock.mineBlock(self.difficulty)
84 | self.chain.append(newBlock)
85 | self.writeBlocks()
86 |
87 | def writeBlocks(self):
88 | """
89 | Method to write new mined block to blockchain
90 | """
91 | dataFile = file("chain.txt", "w")
92 | chainData = []
93 | for eachBlock in self.chain:
94 | chainData.append(eachBlock.__dict__)
95 | dataFile.write(json.dumps(chainData, indent=4))
96 | dataFile.close()
97 |
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/bscli.py:
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1 | # -*- coding: utf-8 -*-
2 | # ===================================================
3 | # ==================== META DATA ===================
4 | # ==================================================
5 | __author__ = "Daxeel Soni"
6 | __url__ = "https://daxeel.github.io"
7 | __email__ = "daxeelsoni44@gmail.com"
8 | __license__ = "MIT"
9 | __version__ = "0.1"
10 | __maintainer__ = "Daxeel Soni"
11 |
12 | # ==================================================
13 | # ================= IMPORT MODULES =================
14 | # ==================================================
15 | import click
16 | import urllib
17 | import json
18 | from blockchain.chain import Block, Blockchain
19 |
20 | # ==================================================
21 | # ===== SUPPORTED COMMANDS LIST IN BLOCKSHELL ======
22 | # ==================================================
23 | SUPPORTED_COMMANDS = [
24 | 'dotx',
25 | 'allblocks',
26 | 'getblock',
27 | 'help'
28 | ]
29 |
30 | # Init blockchain
31 | coin = Blockchain()
32 |
33 | # Create group of commands
34 | @click.group()
35 | def cli():
36 | """
37 | Create a group of commands for CLI
38 | """
39 | pass
40 |
41 | # ==================================================
42 | # ============= BLOCKSHELL CLI COMMAND =============
43 | # ==================================================
44 | @cli.command()
45 | @click.option("--difficulty", default=3, help="Define difficulty level of blockchain.")
46 | def init(difficulty):
47 | """Initialize local blockchain"""
48 | print """
49 | ____ _ _ _____ _ _ _
50 | | _ \ | | | | / ____| | | | | | |
51 | | |_) | | | ___ ___ | | __ | (___ | |__ ___ | | | |
52 | | _ < | | / _ \ / __| | |/ / \___ \ | '_ \ / _ \ | | | |
53 | | |_) | | | | (_) | | (__ | < ____) | | | | | | __/ | | | |
54 | |____/ |_| \___/ \___| |_|\_\ |_____/ |_| |_| \___| |_| |_|
55 |
56 | > A command line utility for learning Blockchain concepts.
57 | > Type 'help' to see supported commands.
58 | > Project by Daxeel Soni - https://daxeel.github.io
59 |
60 | """
61 |
62 | # Set difficulty of blockchain
63 | coin.difficulty = difficulty
64 |
65 | # Start blockshell shell
66 | while True:
67 | cmd = raw_input("[BlockShell] $ ")
68 | processInput(cmd)
69 |
70 | # Process input from Blockshell shell
71 | def processInput(cmd):
72 | """
73 | Method to process user input from Blockshell CLI.
74 | """
75 | userCmd = cmd.split(" ")[0]
76 | if len(cmd) > 0:
77 | if userCmd in SUPPORTED_COMMANDS:
78 | globals()[userCmd](cmd)
79 | else:
80 | # error
81 | msg = "Command not found. Try help command for documentation"
82 | throwError(msg)
83 |
84 |
85 | # ==================================================
86 | # =========== BLOCKSHELL COMMAND METHODS ===========
87 | # ==================================================
88 | def dotx(cmd):
89 | """
90 | Do Transaction - Method to perform new transaction on blockchain.
91 | """
92 | txData = cmd.split("dotx ")[-1]
93 | if "{" in txData:
94 | txData = json.loads(txData)
95 | print "Doing transaction..."
96 | coin.addBlock(Block(data=txData))
97 |
98 | def allblocks(cmd):
99 | """
100 | Method to list all mined blocks.
101 | """
102 | print ""
103 | for eachBlock in coin.chain:
104 | print eachBlock.hash
105 | print ""
106 |
107 | def getblock(cmd):
108 | """
109 | Method to fetch the details of block for given hash.
110 | """
111 | blockHash = cmd.split(" ")[-1]
112 | for eachBlock in coin.chain:
113 | if eachBlock.hash == blockHash:
114 | print ""
115 | print eachBlock.__dict__
116 | print ""
117 |
118 | def help(cmd):
119 | """
120 | Method to display supported commands in Blockshell
121 | """
122 | print "Commands:"
123 | print " dotx {{data['hash']}}
58 |59 |
| Height | 62 |{{data['index']}} | 63 |
| Timestamp | 66 |{{data['timestamp']}} | 67 |
| Data | 70 |{{data['data']}} | 71 |
| Hash | 74 |{{data['hash']}} | 75 |
| Previous Block Hash | 78 |{{data['previousHash']}} | 79 |
| Nonce | 82 |{{data['nonce']}} | 83 |
86 |
87 |
91 | About Project
93 |Project BlockShell is created by with a vision to teach blockchain concepts to students and programmers.
94 | Contact Creator 95 |
114 | Latest Blocks
58 | {% for item in data -%} 59 |64 |
65 |
69 | About Project
71 |Project BlockShell is created by with a vision to teach blockchain concepts to students and programmers.
72 | Contact Creator 73 |🏁 Introduction
64 |Blockshell works on blockchain concepts and it creates a tiny blockchain in your local system. So, you will actually learn the concepts like blocks, mining, hashing, proof of work and lot more.
65 |So, with blockshell you will be creating blocks with simple commands and rest of the tasks will be handled by Blockshell. In this wiki I will try to explain how Blockshell works behind every commands and how it is executing blockchain.
66 |Let's get start!
67 |🆕 Initialize New Blockchain
68 |First we will initialize the new blockchain with following command in blockshell CLI.
69 |[BLOCKSHELL] $ blockshell init --difficulty 3
70 |Above command initializes new blockchain and creates chain.txt in your working directory where our blockchain data will be stored. You can compare this chain.txt file as real world blockchain's ledger.
71 |--difficulty number indicates the difficulty level for blockchain's proof of work. More the number, more time will be taken to mine new block in our blockchain.
72 |In our blockchain we have Initial Zeros Proof of Work algorithm. So, when we want to mine new block, our PoW will look for the hash that has the initial 3 characters are zeros(0) as right now our blockchain's difficulty level is set to 3 at the time of initialization.
73 |Eg. hash
74 |0002fdd96ffec46277a753fa983773599c816dcf100c956afae0a4853fd1ce32
75 |⛏️ Mine First Block
76 |Let's store some data and Mine very first block of our blockchain by doing PoW.
77 |[BlockShell] $ dotx hello blockchain
78 |Blockshell comes with build-in command dotx which is used to create a new transaction and this will mine new block with given data (eg. hello blockchain)
79 |Output
80 |[Status] Mining block (1) with PoW ...
81 | [ Info ] Time Elapsed : 0.0164740085602 seconds.
82 | [ Info ] Mined Hash : 000eea381e45c9f6c1c330cf991b5b1e7d15f739da3894b703e412881b2c2edd
83 |
Mining this block will depend on the difficulty level of the blockchain. Right now difficulty is of 3 and thats why our block mined in less than a second. After mining action, we received hash of that block with 3 initials as zero as difficulty is 3.
85 |📦 Genesis Blocks
86 |First block in blockchain is known as Genesis block and which is created manually at the time of blockchain development. In our case, creation of this genesis block is handled by Blockshell. When we initialized the blockchain, it also created genesis block. Lets check this out.
87 |🕸️ Explore Blockchain
88 |Now, we have 2 blocks in our blockchain. First is genesis block and other we created in previous step and that contains data hello blockchain
89 |List all blocks in blockchain with following command
90 |[BlockShell] $ allblocks
91 |This lists hashes of all the blocks. 92 | Output 93 |
94 |338a2d1ac1b8135283ae19a304b2b426b69b9caba7ef462f246fc577a0297230 95 | 000eea381e45c9f6c1c330cf991b5b1e7d15f739da3894b703e412881b2c2edd 96 |
97 |ℹ️ View Block Data
98 |Let's check what's inside each block. For this Blockshell has getblock command.
99 |Here, 338a2d1ac1b8135283ae19a304b2b426b69b9caba7ef462f246fc577a0297230 is genesis block. Let's look inside our genesis block
100 |[BlockShell] $ getblock 338a2d1ac1b8135283ae19a304b2b426b69b9caba7ef462f246fc577a0297230
101 |Output
102 |{
103 | 'nonce': 0,
104 | 'index': 0,
105 | 'hash': '338a2d1ac1b8135283ae19a304b2b426b69b9caba7ef462f246fc577a0297230',
106 | 'previousHash': '',
107 | 'timestamp': '2018-01-27 20:13:44.835930',
108 | 'data': 'Genesis Block'
109 | }
110 |
Similarly, let's check what's inside our own created block.
112 |[BlockShell] $ getblock 000eea381e45c9f6c1c330cf991b5b1e7d15f739da3894b703e412881b2c2edd
113 |Output
114 |
115 | {
116 | 'nonce': 1959,
117 | 'index': 1,
118 | 'hash': '000eea381e45c9f6c1c330cf991b5b1e7d15f739da3894b703e412881b2c2edd',
119 | 'previousHash': '338a2d1ac1b8135283ae19a304b2b426b69b9caba7ef462f246fc577a0297230',
120 | 'timestamp': '2018-01-27 20:15:01.515716',
121 | 'data': 'hello blockchain'
122 | }
123 |
🌐 Launch Blockshell Web
125 |Blockshell comes with built-in Blockchain web explorer. You can search blocks and data in your blockchain from your web browser.
127 |Open new terminal, go to cloned Blockshell directory and run web.py python script.
128 |python web.py
129 |Go to localhost 127.0.0.1:5000/allblocks in browser and give it a shot!
130 |
134 | About Project
136 |Project BlockShell is created by with a vision to teach blockchain concepts to students and programmers.
137 | Contact Creator 138 |