Mike的筆記
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[Python] 應用

發表於 更新於

紀錄開發上常遇到的問題，避免重複踩坑。

各種進制轉換成 10 進制

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# 16轉10
val = bytes.fromhex('00FF')
print(int.from_bytes(val, byteorder='big'))  # 255
print(int.from_bytes(val, byteorder='little'))  # 65280

讀取 yaml 檔

需安裝 pyyaml 套件

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pipenv install pyyaml
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import yaml

with open('config.yml', encoding='UTF-8') as stream:
    configs = yaml.safe_load(stream)

讀取 zip 檔內的文字檔內容

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import zipfile

with zipfile.ZipFile('path/to/zip_file', 'r') as zip_ref:
    linesb = zip_ref.open(zip_ref.namelist()[0]).readlines()  # 開啟zip檔內第一個檔案
    print(''.join([lineb.decode('UTF-8') for lineb in linesb]))

讀取加密 zip 檔內的文字檔內容

需安裝 pyzipper 套件

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pipenv install pyzipper
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import pyzipper
import zlib

with pyzipper.AESZipFile(output_path) as zip_ref:
    try:
        linesb = zip_ref.open(zip_ref.namelist()[0], pwd='your/password'.encode()).readlines()
        print(''.join([lineb.decode('UTF-8') for lineb in linesb]))
    except zlib.error as e:
        print('密碼錯誤', e)

解壓縮 rar 檔

需安裝 unrar 套件，並新增環境變數 UNRAR_LIB_PATH = C:\Program Files (x86)\UnrarDLL\x64\UnRAR64.dll

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pipenv install unrar
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from unrar import rarfile

with rarfile.RarFile('path/to/rar_file') as rar_ref:
    rar_ref.extract(rar_ref.namelist()[0], 'unrar/to/path')  # 解壓縮第一個檔案

開啟資料夾

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import subprocess

def open_folder(path):
    """開啟資料夾"""
    if platform.system() == 'Darwin':
        subprocess.call(['open', path])
    else:
        subprocess.call(['start', path], shell=True)

取得日期

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import time
from datetime import datetime, timedelta

today = time.strftime('%Y%m%d')
print(today)
yesterday = datetime.today() + timedelta(days=-1)
print(yesterday.strftime('%Y%m%d'))
someday = datetime.fromtimestamp(1721095603)
print(someday.strftime('%Y%m%d'))

NAS 連線並取檔

需安裝 pysmb 套件

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pipenv install pysmb
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from smb.SMBConnection import SMBConnection

conn = SMBConnection('user', 'pwd', '', '', domain='your_domain')
if not conn.connect('ip', port=445, timeout=10):
    print('連線失敗')
    return
with open('path/to/output_file', 'wb') as output_file:
    conn.retrieveFile('share_folder', 'path/to/file', output_file)
conn.close()

支援 SMB2/3

需安裝 smbprotocol 套件

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pipenv install smbprotocol

參考 https://github.com/jborean93/smbprotocol/blob/master/examples/high-level/file-management.py

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from smbclient import register_session, open_file

register_session('ip', username='user', password='pwd')

with open('path/to/output_file', 'wb') as output_file:
    with open_file(r"\\ip\path\to\file", mode="rb") as fd:
        output_file.write(fd.read())

AES 加解密

需安裝 pycryptodome 套件

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pipenv install pycryptodome

通常拿到的 key 是用 Hex 表示的字串，要用 bytes.fromhex(key)轉換成 bytes。

加密後的結果為 bytes，無法直接編碼成字串，所以中間會先轉成 Base64。因此解密時，資料已經過 Base64 編碼，需 Base64 解碼後才丟進 AES 解密。

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import base64

from Crypto.Cipher import AES
from Crypto.Util.Padding import pad, unpad


aes_key = 'C6DFE59F58353AEF73549370CD98F0A9547EF16C74974C16520F0C868ECB78EC'
# b'\xc6\xdf\xe5\x9fX5:\xefsT\x93p\xcd\x98\xf0\xa9T~\xf1lt\x97L\x16R\x0f\x0c\x86\x8e\xcbx\xec'
data = 'Hello world'

def aes_encrypt(key, text):
    """AES加密"""
    cipher = AES.new(bytes.fromhex(key), AES.MODE_ECB)
    result = cipher.encrypt(pad(text.encode(), AES.block_size))
    result_b64 = base64.b64encode(result)
    result_str = result_b64.decode()
    return result_str

def aes_decrypt(key, text):
    """AES解密"""
    text_b64 = text.encode()
    text_b = base64.b64decode(text_b64)
    cipher = AES.new(bytes.fromhex(key), AES.MODE_ECB)
    result = unpad(cipher.decrypt(text_b), AES.block_size)
    result_str = result.decode()
    return result_str

if __name__ == '__main__':
    text = aes_encrypt(aes_key, data)
    print(text)
    data = aes_decrypt(aes_key, text)
    print(data)

輸出結果

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LE1WdHzcoXb7ul3S9b5otQ==
Hello world

Requests 紀錄 API 請求和回應

參考https://stackoverflow.com/questions/16337511/log-all-requests-from-the-python-requests-module

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import logging
from http.client import HTTPConnection

def debug_requests_on():
    '''Switches on logging of the requests module.'''
    HTTPConnection.debuglevel = 1

    logging.basicConfig()
    logging.getLogger().setLevel(logging.DEBUG)
    requests_log = logging.getLogger("requests.packages.urllib3")
    requests_log.setLevel(logging.DEBUG)
    requests_log.propagate = True

def debug_requests_off():
    '''Switches off logging of the requests module, might be some side-effects'''
    HTTPConnection.debuglevel = 0

    root_logger = logging.getLogger()
    root_logger.setLevel(logging.WARNING)
    root_logger.handlers = []
    requests_log = logging.getLogger("requests.packages.urllib3")
    requests_log.setLevel(logging.WARNING)
    requests_log.propagate = False

requests_html 出現 SSLCertVerificationError

第一次執行會有 SSLCertVerificationError 問題

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[W:pyppeteer.chromium_downloader] start chromium download.
Download may take a few minutes.
Traceback (most recent call last):
  略...
ssl.SSLCertVerificationError: [SSL: CERTIFICATE_VERIFY_FAILED] certificate verify failed: unable to get local issuer certificate (_ssl.c:1056)

修正如下，參考https://github.com/miyakogi/pyppeteer/issues/219

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pip install -U "urllib3<1.25"

輸出 yaml 換行格式

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def repr_str(dumper: yaml.SafeDumper, data):
    if '\n' in data:
        return dumper.represent_scalar('tag:yaml.org,2002:str', data, style='|')
    return dumper.represent_str(data)

yaml.add_representer(str, repr_str, Dumper=yaml.SafeDumper)
print(yaml.safe_dump(foo))

os.popen()在 Windows 下出現 UnicodeDecodeError: ‘cp950’ codec can’t decode byte

os.popen()是封裝 subprocess.Popen()，並用 io.TextIOWrapper 轉換 bytes 輸出成 str 的結果，而 Windows 下的 cmd 指令預設為 cp950，會造成解析錯誤。

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proc = subprocess.Popen(cmd,
                        shell=True,
                        stdout=subprocess.PIPE,
                        bufsize=buffering)
return _wrap_close(io.TextIOWrapper(proc.stdout), proc)

所以針對 Windows 自行實作 popen()，調整如下

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def popen(command):
    if platform.system() == 'Darwin':
        return os.popen(command)
    proc = subprocess.Popen(command, stdout=subprocess.PIPE)
    return io.TextIOWrapper(proc.stdout, encoding='UTF-8')

如果要讀取的是 bytes 則用 io.BufferedReader

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proc = subprocess.Popen(command, stdout=subprocess.PIPE)
stream = io.BufferedReader(proc.stdout)
print(stream.read())

Flask 保留 json 排序

參考https://stackoverflow.com/questions/54446080/how-to-keep-order-of-sorted-dictionary-passed-to-jsonify-function

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app = Flask(__name__)
app.config['JSON_SORT_KEYS'] = False

依指定長度切割陣列

參考https://www.altcademy.com/blog/how-to-split-a-list-in-python/

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def split_list(lst, chunk_size):
    return [lst[i:i + chunk_size] for i in range(0, len(lst), chunk_size)]

numbers = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
chunk_size = 3
chunks = split_list(numbers, chunk_size)

print("Chunks:", chunks)
# Chunks: [[0, 1, 2], [3, 4, 5], [6, 7, 8], [9]]