乾坤大挪移,如何將同步阻塞(sync)三方庫包轉換為非同步非阻塞(async)模式?Python3.10實現。

劉悅的技術部落格 發表於 2022-12-30
Python

眾所周知,非同步併發程式設計可以幫助程式更好地處理阻塞操作,比如網路 IO 操作或檔案 IO 操作,避免因等待這些操作完成而導致程式卡住的情況。雲端儲存檔案傳輸場景正好包含網路 IO 操作和檔案 IO 操作,比如業內相對著名的七牛雲端儲存,官方sdk的預設阻塞傳輸模式雖然差強人意,但未免有些循規蹈矩,不夠銳意創新。在全球同性交友網站Github上找了一圈,也沒有找到非同步版本,那麼本次我們來自己動手將同步阻塞版本改造為非同步非阻塞版本,並上傳至Python官方庫。

非同步改造

首先參見七牛雲官方介面文件:https://developer.qiniu.com/kodo,新建qiniu_async.py檔案:

# @Author:Liu Yue (v3u.cn)  
# @Software:Vscode  
# @Time:2022/12/30  
  
import base64  
import hmac  
import time  
from hashlib import sha1  
import json  
import httpx  
import aiofiles  
  
  
  
class Qiniu:  
  
    def __init__(self, access_key, secret_key):  
        """初始化"""  
        self.__checkKey(access_key, secret_key)  
        self.__access_key = access_key  
        self.__secret_key = secret_key.encode('utf-8')  
  
    def get_access_key(self):  
        return self.__access_key  
  
    def get_secret_key(self):  
        return self.__secret_key  
  
    def __token(self, data):  
        hashed = hmac.new(self.__secret_key,data.encode('utf-8'), sha1)  
        return self.urlsafe_base64_encode(hashed.digest())  
  
    def token(self, data):  
        return '{0}:{1}'.format(self.__access_key, self.__token(data))  
  
    def token_with_data(self, data):  
        data = self.urlsafe_base64_encode(data)  
        return '{0}:{1}:{2}'.format(  
            self.__access_key, self.__token(data), data)  
  
    def urlsafe_base64_encode(self,data):  
  
        if isinstance(data, str):  
            data = data.encode('utf-8')  
  
        ret = base64.urlsafe_b64encode(data)  
  
        data = ret.decode('utf-8')  
  
        return data  
  
  
    @staticmethod  
    def __checkKey(access_key, secret_key):  
        if not (access_key and secret_key):  
            raise ValueError('invalid key')  
  
  
    def upload_token(  
            self,  
            bucket,  
            key=None,  
            expires=3600,  
            policy=None,  
            strict_policy=True):  
        """生成上傳憑證  
  
        Args:  
            bucket:  上傳的空間名  
            key:     上傳的檔名,預設為空  
            expires: 上傳憑證的過期時間,預設為3600s  
            policy:  上傳策略,預設為空  
  
        Returns:  
            上傳憑證  
        """  
        if bucket is None or bucket == '':  
            raise ValueError('invalid bucket name')  
  
        scope = bucket  
        if key is not None:  
            scope = '{0}:{1}'.format(bucket, key)  
  
        args = dict(  
            scope=scope,  
            deadline=int(time.time()) + expires,  
        )  
  
        return self.__upload_token(args)  
  
    @staticmethod  
    def up_token_decode(up_token):  
        up_token_list = up_token.split(':')  
        ak = up_token_list[0]  
        sign = base64.urlsafe_b64decode(up_token_list[1])  
        decode_policy = base64.urlsafe_b64decode(up_token_list[2])  
        decode_policy = decode_policy.decode('utf-8')  
        dict_policy = json.loads(decode_policy)  
        return ak, sign, dict_policy  
  
    def __upload_token(self, policy):  
        data = json.dumps(policy, separators=(',', ':'))  
        return self.token_with_data(data)  
  
  
    @staticmethod  
    def __copy_policy(policy, to, strict_policy):  
        for k, v in policy.items():  
            if (not strict_policy) or k in _policy_fields:  
                to[k] = v

這裡有兩個很關鍵的非同步非阻塞三方庫,分別是httpx和aiofiles,對應處理網路IO和檔案IO阻塞問題:

pip3 install httpx  
pip3 install aiofiles

隨後按照文件流程透過加密方法獲取檔案上傳token,這裡無須進行非同步改造,因為並不涉及IO操作:

q = Qiniu(access_key,access_secret)  
  
token = q.upload_token("空間名稱")  
  
print(token)

程式返回:

➜  mydemo git:(master) ✗ /opt/homebrew/bin/python3.10 "/Users/liuyue/wodfan/work/mydemo/src/test.py"  
q06bq54Ps5JLfZyP8Ax-qvByMBdu8AoIVJpMco2m:8RjIo9a4CxHM3009DwjbMxDzlU8=:eyJzY29wZSI6ImFkLWgyMTEyIiwiZGVhZGxpbmUiOjE2NzIzNjg2NTd9

接著新增檔案流推送方法,先看官方原版邏輯:

def put_data(  
        up_token, key, data, params=None, mime_type='application/octet-stream', check_crc=False, progress_handler=None,  
        fname=None, hostscache_dir=None, metadata=None):  
    """上傳二進位制流到七牛  
    Args:  
        up_token:         上傳憑證  
        key:              上傳檔名  
        data:             上傳二進位制流  
        params:           自定義變數,規格參考 https://developer.qiniu.com/kodo/manual/vars#xvar  
        mime_type:        上傳資料的mimeType  
        check_crc:        是否校驗crc32  
        progress_handler: 上傳進度  
        hostscache_dir:   host請求 快取檔案儲存位置  
        metadata:         後設資料  
    Returns:  
        一個dict變數,類似 {"hash": "<Hash string>", "key": "<Key string>"}  
        一個ResponseInfo物件  
    """  
    final_data = b''  
    if hasattr(data, 'read'):  
        while True:  
            tmp_data = data.read(config._BLOCK_SIZE)  
            if len(tmp_data) == 0:  
                break  
            else:  
                final_data += tmp_data  
    else:  
        final_data = data  
  
    crc = crc32(final_data)  
    return _form_put(up_token, key, final_data, params, mime_type,  
                     crc, hostscache_dir, progress_handler, fname, metadata=metadata)  
  
def _form_put(up_token, key, data, params, mime_type, crc, hostscache_dir=None, progress_handler=None, file_name=None,  
              modify_time=None, keep_last_modified=False, metadata=None):  
    fields = {}  
    if params:  
        for k, v in params.items():  
            fields[k] = str(v)  
    if crc:  
        fields['crc32'] = crc  
    if key is not None:  
        fields['key'] = key  
  
    fields['token'] = up_token  
    if config.get_default('default_zone').up_host:  
        url = config.get_default('default_zone').up_host  
    else:  
        url = config.get_default('default_zone').get_up_host_by_token(up_token, hostscache_dir)  
    # name = key if key else file_name  
  
    fname = file_name  
    if not fname or not fname.strip():  
        fname = 'file_name'  
  
    # last modify time  
    if modify_time and keep_last_modified:  
        fields['x-qn-meta-!Last-Modified'] = rfc_from_timestamp(modify_time)  
  
    if metadata:  
        for k, v in metadata.items():  
            if k.startswith('x-qn-meta-'):  
                fields[k] = str(v)  
  
    r, info = http._post_file(url, data=fields, files={'file': (fname, data, mime_type)})  
    if r is None and info.need_retry():  
        if info.connect_failed:  
            if config.get_default('default_zone').up_host_backup:  
                url = config.get_default('default_zone').up_host_backup  
            else:  
                url = config.get_default('default_zone').get_up_host_backup_by_token(up_token, hostscache_dir)  
        if hasattr(data, 'read') is False:  
            pass  
        elif hasattr(data, 'seek') and (not hasattr(data, 'seekable') or data.seekable()):  
            data.seek(0)  
        else:  
            return r, info  
        r, info = http._post_file(url, data=fields, files={'file': (fname, data, mime_type)})  
  
    return r, info

這裡官方使用兩個方法,先試用put_data方法將字串轉換為二進位制檔案流,隨後呼叫_form_put進行同步上傳操作,這裡_form_put這個私有方法是可複用的,既相容檔案流也相容檔案實體,寫法上非常值得我們借鑑,弄明白了官方原版的流程後,讓我們撰寫檔案流傳輸的非同步版本:

# 上傳檔案流  
    async def upload_data(self,up_token, key,data,url="http://up-z1.qiniup.com",params=None,mime_type='application/octet-stream',file_name=None,metadata=None):  
  
        data.encode('utf-8')  
          
        fields = {}  
        if params:  
            for k, v in params.items():  
                fields[k] = str(v)  
  
        if key is not None:  
            fields['key'] = key  
        fields['token'] = up_token  
  
        fname = file_name  
        if not fname or not fname.strip():  
            fname = 'file_name'  
  
        async with httpx.AsyncClient() as client:  
  
            # 呼叫非同步使用await關鍵字  
            res = await client.post(url,data=fields,files={'file': (fname,data,mime_type)})  
  
            print(res.text)

這裡我們宣告非同步方法upload_data,透過encode直接轉換檔案流,並使用非同步httpx.AsyncClient()物件將檔案流推送到官網介面地址:up-z1.qiniup.com

隨後進行測試:

import asyncio
q = qiniu_async.Qiniu("accesskey","accesssecret")  
  
token = q.upload_token("空間名稱")  
  
#檔案流上傳  
asyncio.run(q.upload_data(token,"3343.txt","123測試"))

程式返回:

➜  mydemo git:(master) ✗ /opt/homebrew/bin/python3.10 "/Users/liuyue/wodfan/work/mydemo/src/test.py"  
{"hash":"FtnQXAXft5AsOH1mrmXGaRzSt-95","key":"33434.txt"}

介面會返回檔案流的hash編碼,沒有問題。

接著檢視檔案上傳流程:

def put_file(up_token, key, file_path, params=None,  
             mime_type='application/octet-stream', check_crc=False,  
             progress_handler=None, upload_progress_recorder=None, keep_last_modified=False, hostscache_dir=None,  
             part_size=None, version=None, bucket_name=None, metadata=None):  
    """上傳檔案到七牛  
    Args:  
        up_token:                 上傳憑證  
        key:                      上傳檔名  
        file_path:                上傳檔案的路徑  
        params:                   自定義變數,規格參考 https://developer.qiniu.com/kodo/manual/vars#xvar  
        mime_type:                上傳資料的mimeType  
        check_crc:                是否校驗crc32  
        progress_handler:         上傳進度  
        upload_progress_recorder: 記錄上傳進度,用於斷點續傳  
        hostscache_dir:           host請求 快取檔案儲存位置  
        version:                  分片上傳版本 目前支援v1/v2版本 預設v1  
        part_size:                分片上傳v2必傳欄位 預設大小為4MB 分片大小範圍為1 MB - 1 GB  
        bucket_name:              分片上傳v2欄位 空間名稱  
        metadata:                 後設資料資訊  
    Returns:  
        一個dict變數,類似 {"hash": "<Hash string>", "key": "<Key string>"}  
        一個ResponseInfo物件  
    """  
    ret = {}  
    size = os.stat(file_path).st_size  
    with open(file_path, 'rb') as input_stream:  
        file_name = os.path.basename(file_path)  
        modify_time = int(os.path.getmtime(file_path))  
        if size > config.get_default('default_upload_threshold'):  
            ret, info = put_stream(up_token, key, input_stream, file_name, size, hostscache_dir, params,  
                                   mime_type, progress_handler,  
                                   upload_progress_recorder=upload_progress_recorder,  
                                   modify_time=modify_time, keep_last_modified=keep_last_modified,  
                                   part_size=part_size, version=version, bucket_name=bucket_name, metadata=metadata)  
        else:  
            crc = file_crc32(file_path)  
            ret, info = _form_put(up_token, key, input_stream, params, mime_type,  
                                  crc, hostscache_dir, progress_handler, file_name,  
                                  modify_time=modify_time, keep_last_modified=keep_last_modified, metadata=metadata)  
    return ret, info

這裡官方使用的是標準庫上下文管理器同步讀取檔案,改寫為非同步方法:

# 上傳檔案實體  
    async def upload_file(self,up_token,key,path,url="http://up-z1.qiniup.com",params=None,mime_type='application/octet-stream',file_name=None,metadata=None):  
  
  
        async with aiofiles.open(path, mode='rb') as f:  
            contents = await f.read()  
          
        fields = {}  
        if params:  
            for k, v in params.items():  
                fields[k] = str(v)  
  
        if key is not None:  
            fields['key'] = key  
        fields['token'] = up_token  
  
        fname = file_name  
        if not fname or not fname.strip():  
            fname = 'file_name'  
  
        async with httpx.AsyncClient() as client:  
  
            # 呼叫非同步使用await關鍵字  
            res = await client.post(url,data=fields,files={'file': (fname,contents,mime_type)})  
  
            print(res.text)

透過aiofiles非同步讀取檔案後,在透過httpx.AsyncClient()進行非同步傳輸。

需要注意的是,這裡預設傳輸到up-z1.qiniup.com介面,如果是不同區域的雲端儲存伺服器,需要更改url引數的值,具體伺服器介面列表請參照官網文件。

至此,檔案流和檔案非同步傳輸就改造好了。

上傳至Python官方庫

為了方便廣大七牛雲使用者使用非同步傳輸版本庫,可以將qiniu-async上傳到Python官方庫,首先註冊成為Python官方庫的開發者:pypi.org/

隨後在專案根目錄下新建setup.py檔案:

import setuptools  
import pathlib  
  
here = pathlib.Path(__file__).parent.resolve()  
long_description = (here / "README.md").read_text(encoding="utf-8")  
  
setuptools.setup(  
    name="qiniu-async",  
    version="1.0.1",  
    author="LiuYue",  
    author_email="[email protected]",  
    description="qiniu_async python library",  
    long_description=long_description,  
    long_description_content_type="text/markdown",  
    url="https://github.com/qiniu-async",  
    packages=setuptools.find_packages(),  
    license="Apache 2.0",  
    classifiers=[  
        "Development Status :: 3 - Alpha",  
        "Intended Audience :: Developers",  
        "Programming Language :: Python :: 3",  
        "Programming Language :: Python :: 3.7",  
        "Programming Language :: Python :: 3.8",  
        "Programming Language :: Python :: 3.9",  
        "Programming Language :: Python :: 3.10",  
        "Programming Language :: Python :: 3 :: Only",  
        "License :: OSI Approved :: MIT License",  
        "Operating System :: OS Independent",  
  
    ],  
    keywords="qiniu, qiniu_async, async",  
    py_modules=[  
        'qiniu_async'  
    ],  
    install_requires=["aiofiles","httpx"],  
)

這是安裝檔案,主要為了宣告該模組的名稱、作者、版本以及依賴庫。

隨後本地打包檔案:

python3 setup.py sdist

程式會根據setup.py檔案生成壓縮包:

➜  qiniu_async tree  
.  
├── README.md  
├── dist  
│ └── qiniu-async-1.0.1.tar.gz  
├── https:  
│ └── github.com  
│     └── zcxey2911  
│         └── qiniu-async.git  
├── qiniu_async.egg-info  
│ ├── PKG-INFO  
│ ├── SOURCES.txt  
│ ├── dependency_links.txt  
│ ├── requires.txt  
│ └── top_level.txt  
├── qiniu_async.py  
└── setup.py

接著安裝twine庫, 準備提交Python官網:

pip3 install twine

隨後在根目錄執行命令提交:

twine upload dist/*

在官網進行檢視:https://pypi.org/project/qiniu-async/

隨後本地就可以直接透過pip命令句進行安裝了:

pip install qiniu-async -i https://pypi.org/simple

非常方便。

結語

雲端儲存,非同步加持,猛虎添翼,未敢擁缽獨饗,除了透過pip安裝qiniu-async庫,也奉上Github專案地址:https://github.com/zcxey2911/qiniu-async ,與眾鄉親同饗。