乾坤大挪移,如何将同步阻塞(sync)三方库包转换为异步非阻塞(async)模式?Python3.10实现。

众所周知,异步并发编程可以帮助程序更好地处理阻塞操作,比如网络 IO 操作或文件 IO 操作,避免因等待这些操作完成而导致程序卡住的情况。云存储文件传输场景正好包含网络 IO 操作和文件 IO 操作,比如业内相对著名的七牛云存储,官方sdk的默认阻塞传输模式虽然差强人意,但未免有些循规蹈矩,不够锐意创新。在全球同性交友网站Github上找了一圈,也没有找到异步版本,那么本次我们来自己动手将同步阻塞版本改造为异步非阻塞版本,并上传至Python官方库。

异步改造

首先参见七牛云官方接口文档:https://developer.qiniu.com/kodo,新建qiniu_async.py文件:

# @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):           """生成上传凭证              Args:               bucket:  上传的空间名               key:     上传的文件名,默认为空               expires: 上传凭证的过期时间,默认为3600s               policy:  上传策略,默认为空              Returns:               上传凭证           """           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 

这里有两个很关键的异步非阻塞三方库,分别是httpx和aiofiles,对应处理网络IO和文件IO阻塞问题:

pip3 install httpx   pip3 install aiofiles 

随后按照文档流程通过加密方法获取文件上传token,这里无须进行异步改造,因为并不涉及IO操作:

q = Qiniu(access_key,access_secret)      token = q.upload_token("空间名称")      print(token) 

程序返回:

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

接着添加文件流推送方法,先看官方原版逻辑:

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):       """上传二进制流到七牛       Args:           up_token:         上传凭证           key:              上传文件名           data:             上传二进制流           params:           自定义变量,规格参考 https://developer.qiniu.com/kodo/manual/vars#xvar           mime_type:        上传数据的mimeType           check_crc:        是否校验crc32           progress_handler: 上传进度           hostscache_dir:   host请求 缓存文件保存位置           metadata:         元数据       Returns:           一个dict变量,类似 {"hash": "<Hash string>", "key": "<Key string>"}           一个ResponseInfo对象       """       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 

这里官方使用两个方法,先试用put_data方法将字符串转换为二进制文件流,随后调用_form_put进行同步上传操作,这里_form_put这个私有方法是可复用的,既兼容文件流也兼容文件实体,写法上非常值得我们借鉴,弄明白了官方原版的流程后,让我们撰写文件流传输的异步版本:

# 上传文件流       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:                  # 调用异步使用await关键字               res = await client.post(url,data=fields,files={'file': (fname,data,mime_type)})                  print(res.text) 

这里我们声明异步方法upload_data,通过encode直接转换文件流,并使用异步httpx.AsyncClient()对象将文件流推送到官网接口地址:up-z1.qiniup.com

随后进行测试:

import asyncio q = qiniu_async.Qiniu("accesskey","accesssecret")      token = q.upload_token("空间名称")      #文件流上传   asyncio.run(q.upload_data(token,"3343.txt","123测试")) 

程序返回:

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

接口会返回文件流的hash编码,没有问题。

接着查看文件上传流程:

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):       """上传文件到七牛       Args:           up_token:                 上传凭证           key:                      上传文件名           file_path:                上传文件的路径           params:                   自定义变量,规格参考 https://developer.qiniu.com/kodo/manual/vars#xvar           mime_type:                上传数据的mimeType           check_crc:                是否校验crc32           progress_handler:         上传进度           upload_progress_recorder: 记录上传进度,用于断点续传           hostscache_dir:           host请求 缓存文件保存位置           version:                  分片上传版本 目前支持v1/v2版本 默认v1           part_size:                分片上传v2必传字段 默认大小为4MB 分片大小范围为1 MB - 1 GB           bucket_name:              分片上传v2字段 空间名称           metadata:                 元数据信息       Returns:           一个dict变量,类似 {"hash": "<Hash string>", "key": "<Key string>"}           一个ResponseInfo对象       """       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 

这里官方使用的是标准库上下文管理器同步读取文件,改写为异步方法:

# 上传文件实体       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:                  # 调用异步使用await关键字               res = await client.post(url,data=fields,files={'file': (fname,contents,mime_type)})                  print(res.text) 

通过aiofiles异步读取文件后,在通过httpx.AsyncClient()进行异步传输。

需要注意的是,这里默认传输到up-z1.qiniup.com接口,如果是不同区域的云存储服务器,需要更改url参数的值,具体服务器接口列表请参照官网文档。

至此,文件流和文件异步传输就改造好了。

上传至Python官方库

为了方便广大七牛云用户使用异步传输版本库,可以将qiniu-async上传到Python官方库,首先注册成为Python官方库的开发者:pypi.org/

随后在项目根目录下新建setup.py文件:

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="zcxey2911@gmail.com",       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"],   ) 

这是安装文件,主要为了声明该模块的名称、作者、版本以及依赖库。

随后本地打包文件:

python3 setup.py sdist 

程序会根据setup.py文件生成压缩包:

➜  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 

接着安装twine库, 准备提交Python官网:

pip3 install twine 

随后在根目录运行命令提交:

twine upload dist/* 

在官网进行查看:https://pypi.org/project/qiniu-async/

随后本地就可以直接通过pip命令句进行安装了:

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

非常方便。

结语

云端存储,异步加持,猛虎添翼,未敢拥钵独飨,除了通过pip安装qiniu-async库,也奉上Github项目地址:https://github.com/zcxey2911/qiniu-async ,与众乡亲同飨。

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