NEO是一個(gè)非盈利的社區(qū)化的區(qū)塊鏈項(xiàng)目，是利用區(qū)塊鏈技術(shù)和數(shù)字身份進(jìn)行資產(chǎn)數(shù)字化，利用智能合約對(duì)數(shù)字資產(chǎn)進(jìn)行自動(dòng)化管理，實(shí)現(xiàn)“智能經(jīng)濟(jì)”的一種分布式網(wǎng)絡(luò)，被稱為“中國(guó)以太坊”。本文將帶領(lǐng)大家學(xué)習(xí)如何使用Python編寫NEO智能合約。
更多介紹移步NEO官網(wǎng)和 NEO 白皮書感謝NEO Workshop Steve 葉凡的分享
環(huán)境搭建
基于macOS或Ubuntu，windows用戶請(qǐng)自備虛擬機(jī)。
安裝Docker及拉取鏡像
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macOS:
1.點(diǎn)我去下載，下載后安裝并啟動(dòng)，啟動(dòng)成功后任務(wù)欄會(huì)有個(gè)Docker的圖標(biāo)，點(diǎn)擊可以查看運(yùn)行狀態(tài)image
2.拉取私鏈鏡像，打開終端執(zhí)行
docker pull cityofzion/neo-privatenet
Tip：由于國(guó)內(nèi)環(huán)境問題，docker鏡像的拉取往往會(huì)非常慢，所以我們可以配置一些國(guó)內(nèi)的鏡像加速，如DaoCloud的Docker 加速器，免費(fèi)注冊(cè)一下，按照說明配置即可，非常簡(jiǎn)單和方便。
image
3.運(yùn)行Docker容器，執(zhí)行
docker run --rm -d --name neo-privatenet -p 20333-20336:20333-20336/tcp -p 30333-30336:30333-30336/tcp cityofzion/neo-privatenet
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Ubuntu:
1.安裝Docker，執(zhí)行
sudo apt install docker.io
2.啟動(dòng)Docker，執(zhí)行(安裝成功后應(yīng)該會(huì)默認(rèn)已啟動(dòng))
sudo service docker start
3.拉取私有鏈網(wǎng)絡(luò)鏡像，執(zhí)行
sudo docker pull cityofzion/neo-privatenet
4.運(yùn)行docker容器，執(zhí)行
sudo docker run --rm -d --name neo-privatenet -p 20333-20336:20333-20336/tcp -p 30333-30336:30333-30336/tcp cityofzion/neo-privatenet
安裝Python3和levelDB
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macOS:
沒有安裝過Homebrew的請(qǐng)先執(zhí)行下面的命令，已安裝的忽略。
/usr/bin/ruby -e "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install)"
1.macOS是自帶Python2的，我們需要安裝Python3
brew install python3
2.安裝levelDB
brew install leveldb
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Ubuntu:
簡(jiǎn)單粗暴的依次執(zhí)行下面命令：
sudo apt install software-properties-common python-software-properties
sudo add-apt-repository ppa:deadsnakes/ppa
sudo apt update
sudo apt install python3.6 python3.6-dev python3.6-venv python3-pip libleveldb-dev libssl-dev g++
Tip：因?yàn)?strong>NEO最低需要Python3.6的環(huán)境，Homebrew是會(huì)安裝最新版本的Python，而apt-get源上直接install python3安裝的是python3.5，所以這里我們指定的python3.6。
neo-python
- 從GitHub克隆neo-python項(xiàng)目
git clone https://github.com/CityOfZion/neo-python.git
- 創(chuàng)建并進(jìn)入虛擬環(huán)境
cd neo-python
python3 -m venv venv # 創(chuàng)建虛擬環(huán)境，Ubuntu這里使用 python3.6 -m venv venv
source venv/bin/activate # 進(jìn)入虛擬環(huán)境，退出虛擬環(huán)境使用命令 deactivate
- 安裝依賴包
pip install -r requirements.txt
pip install -e .
- 啟動(dòng)連接到私有鏈網(wǎng)絡(luò)，進(jìn)入NEO cli命令行
np-prompt -p # 退出命令行 在命令行輸入 quit
出現(xiàn)如下界面進(jìn)入了NEO命令行，那么恭喜你已經(jīng)成功搭建好所有環(huán)境，如果你報(bào)錯(cuò)了，請(qǐng)接著往下看。
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np-prompt -p可能出現(xiàn)的錯(cuò)誤
錯(cuò)誤一
Traceback (most recent call last):
File "/home/parallels/Code/neosc/neo-python/venv/bin/np-prompt", line 11, in <module>
load_entry_point('neo-python', 'console_scripts', 'np-prompt')()
File "/home/parallels/Code/neosc/neo-python/venv/lib/python3.6/site-packages/pkg_resources/__init__.py", line 480, in load_entry_point
return get_distribution(dist).load_entry_point(group, name)
File "/home/parallels/Code/neosc/neo-python/venv/lib/python3.6/site-packages/pkg_resources/__init__.py", line 2693, in load_entry_point
return ep.load()
File "/home/parallels/Code/neosc/neo-python/venv/lib/python3.6/site-packages/pkg_resources/__init__.py", line 2324, in load
return self.resolve()
File "/home/parallels/Code/neosc/neo-python/venv/lib/python3.6/site-packages/pkg_resources/__init__.py", line 2330, in resolve
module = __import__(self.module_name, fromlist=['__name__'], level=0)
File "/home/parallels/Code/neosc/neo-python/neo/bin/prompt.py", line 28, in <module>
from neo.Implementations.Wallets.peewee.UserWallet import UserWallet
File "/home/parallels/Code/neosc/neo-python/neo/Implementations/Wallets/peewee/UserWallet.py", line 8, in <module>
from neo.Wallets.Wallet import Wallet
File "/home/parallels/Code/neosc/neo-python/neo/Wallets/Wallet.py", line 13, in <module>
from Crypto.Cipher import AES
File "/home/parallels/Code/neosc/neo-python/venv/lib/python3.6/site-packages/Crypto/Cipher/__init__.py", line 3, in <module>
from Crypto.Cipher._mode_ecb import _create_ecb_cipher
File "/home/parallels/Code/neosc/neo-python/venv/lib/python3.6/site-packages/Crypto/Cipher/_mode_ecb.py", line 29, in <module>
from Crypto.Util._raw_api import (load_pycryptodome_raw_lib,
File "/home/parallels/Code/neosc/neo-python/venv/lib/python3.6/site-packages/Crypto/Util/_raw_api.py", line 32, in <module>
from Crypto.Util.py3compat import byte_string
ImportError: cannot import name 'byte_string'
這是因?yàn)橐蕾嚢陌姹締栴}，解決方案如下
# 卸載依賴包
pip uninstall pycrypto
pip uninstall pycryptodemo
# 重新安裝依賴包
pip install pycrypto
pip install pycryptodemo
pip install -e .
錯(cuò)誤二
......
Traceback (most recent call last):
File "/home/parallels/Code/neosc/neo-python/venv/bin/np-prompt", line 11, in <module>
load_entry_point('neo-python', 'console_scripts', 'np-prompt')()
File "/home/parallels/Code/neosc/neo-python/neo/bin/prompt.py", line 1061, in main
settings.setup_privnet(args.privnet)
File "/home/parallels/Code/neosc/neo-python/neo/Settings.py", line 228, in setup_privnet
self.check_privatenet()
File "/home/parallels/Code/neosc/neo-python/neo/Settings.py", line 314, in check_privatenet
version = client.get_version()
File "/home/parallels/Code/neosc/neo-python/venv/lib/python3.6/site-packages/neorpc/Client.py", line 283, in get_version
return self._call_endpoint(GET_VERSION, id=id, endpoint=endpoint)
File "/home/parallels/Code/neosc/neo-python/venv/lib/python3.6/site-packages/neorpc/Client.py", line 310, in _call_endpoint
raise NEORPCException("Could not call method %s with endpoint: %s : %s " % (method, endpoint.addr, e))
neorpc.Client.NEORPCException: Could not call method getversion with endpoint: http://127.0.0.1:30333 : HTTPConnectionPool(host='127.0.0.1', port=30333): Max retries exceeded with url: / (Caused by NewConnectionError('<urllib3.connection.HTTPConnection object at 0x7f14dee4b9b0>: Failed to establish a new connection: [Errno 111] Connection refused',))
說明你沒有啟動(dòng)docker容器并進(jìn)行端口映射，請(qǐng)看第一部分安裝Docker及拉取鏡像
