facepp python接入工具

旷视官方系统的webapi调用的封装文件地址：https://github.com/FacePlusPlus/python-sdk.git这个api接口文件的编写应该需要满足以下几点要求：1、在python中调用方式应该是api.function(param1,param2)2、这个SDK应该在API实现更新升级后，尽量不需要改动。3、官方提供的webapi的格式是url加post参数POST "https://api-cn.faceplusplus.com/facepp/v3/detect" -F "api_key=<api_key>" -F "api_secret=<api_secret>" \-F "image_file=@image_file.jpg" \-F "return_landmark=1" \-F "return_attributes=gender,age"接下来区分下变的部分和不变的部分webapi的形式是不变的，webapi的方法是随着版本更新而变化的，其post部分的参数也是变化的我们（SDK）希望，提供给调用放的调用方式是不变的，但提供给调用方的方法是随着版本变化能够动态调整的简单的说，facepp这个文件充当webapi和以对象方式调用之间的一个动态适配器，其输出能够根据webapi的动态调整而能够动态调整，单SDK部分的编码应当最小的变化。本着这几点来看下面的这个文件，我们的SDK应该暴露给用户的应该是要使用的方法，以及参数的辅助类。

# -*- coding: utf-8 -*-"""a simple facepp sdkexample:api = API(key, secret)api.detect(img = File('/tmp/test.jpg'))"""__all__ = ['File', 'APIError', 'API']#所有暴露给调用方的类DEBUG_LEVEL = 1import sysimport socketimport urllib2import jsonimport os.pathimport itertoolsimport mimetoolsimport mimetypesimport timeimport tempfilefrom collections import Iterableclass File(object):#暴露给用户的发送图片文件的的支持类    """an object representing a local file"""    path = None    content = None    def __init__(self, path):        self.path = path        self._get_content()    def _get_content(self):        """read image content"""        if os.path.getsize(self.path) > 2 * 1024 * 1024:            raise APIError(-1, None, 'image file size too large')        else:            with open(self.path, 'rb') as f:                self.content = f.read()    def get_filename(self):        return os.path.basename(self.path)class APIError(Exception):#定义的报错类    code = None    """HTTP status code"""    url = None    """request URL"""    body = None    """server response body; or detailed error information"""    def __init__(self, code, url, body):        self.code = code        self.url = url        self.body = body    def __str__(self):        return 'code={s.code}\nurl={s.url}\n{s.body}'.format(s=self)    __repr__ = __str__class API(object):#暴露给用户的接口类，其应当实现webapi到API对应方法的动态转换。    key = None    secret = None    server = 'https://api-cn.faceplusplus.com/facepp/v3/'    decode_result = True    timeout = None    max_retries = None    retry_delay = None    def __init__(self, key, secret, srv=None,                 decode_result=True, timeout=30, max_retries=10,                 retry_delay=5):        """:param srv: The API server address        :param decode_result: whether to json_decode the result        :param timeout: HTTP request timeout in seconds        :param max_retries: maximal number of retries after catching URL error            or socket error        :param retry_delay: time to sleep before retrying"""        self.key = key        self.secret = secret        if srv:            self.server = srv        self.decode_result = decode_result        assert timeout >= 0 or timeout is None        assert max_retries >= 0        self.timeout = timeout        self.max_retries = max_retries        self.retry_delay = retry_delay        _setup_apiobj(self, self, [])#生成API类对应的方法    def update_request(self, request):        """overwrite this function to update the request before sending it to        server"""        passdef _setup_apiobj(self, api, path):#根据_APIS列表生成API类对应的方法    if self is not api:        self._api = api        self._urlbase = api.server + '/'.join(path)    lvl = len(path)    done = set()    for i in _APIS:        if len(i) <= lvl:            continue        cur = i[lvl]        if i[:lvl] == path and cur not in done:            done.add(cur)            setattr(self, cur, _APIProxy(api, i[:lvl + 1]))class _APIProxy(object):    _api = None    """underlying :class:`API`object"""    _urlbase = None    def __init__(self, api, path):        _setup_apiobj(self, api, path)    def __call__(self, *args, **kargs):#将此类实现成方法调用        if len(args):#通过生成异常，来实现只支持keyword的方法调用。如果存在非keyword参数，则args的长度非零            raise TypeError('Only keyword arguments are allowed')        form = _MultiPartForm()#将键值对形式的参数，转换为webapi需要的格式        for (k, v) in kargs.iteritems():#文件参数的处理            if isinstance(v, File):                form.add_file(k, v.get_filename(), v.content)        url = self._urlbase        for k, v in self._mkarg(kargs).iteritems():#普通参数的处理            form.add_field(k, v)        request = urllib2.Request(url)        body = str(form)        request.add_header('Content-type', form.get_content_type())        request.add_header('Content-length', str(len(body)))        request.add_data(body)        self._api.update_request(request)        retry = self._api.max_retries        while True:            retry -= 1            try:                ret = urllib2.urlopen(request, timeout=self._api.timeout).read()                break            except urllib2.HTTPError as e:                raise APIError(e.code, url, e.read())            except (socket.error, urllib2.URLError) as e:                if retry < 0:                    raise e                _print_debug('caught error: {}; retrying'.format(e))                time.sleep(self._api.retry_delay)        if self._api.decode_result:            try:                ret = json.loads(ret)            except:                raise APIError(-1, url, 'json decode error, value={0!r}'.format(ret))        return ret    def _mkarg(self, kargs):        """change the argument list (encode value, add api key/secret)        :return: the new argument list"""        def enc(x):            if isinstance(x, unicode):                return x.encode('utf-8')            return str(x)        kargs = kargs.copy()        kargs['api_key'] = self._api.key        kargs['api_secret'] = self._api.secret        for (k, v) in kargs.items():            if isinstance(v, Iterable) and not isinstance(v, basestring):                kargs[k] = ','.join([enc(i) for i in v])            elif isinstance(v, File) or v is None:                del kargs[k]            else:                kargs[k] = enc(v)        return kargs# ref: http://www.doughellmann.com/PyMOTW/urllib2/class _MultiPartForm(object):#将键值对形式的参数，转换为webapi需要的格式

    """Accumulate the data to be used when posting a form."""    def __init__(self):        self.form_fields = []        self.files = []        self.boundary = mimetools.choose_boundary()        return    def get_content_type(self):        return 'multipart/form-data; boundary=%s' % self.boundary    def add_field(self, name, value):#提供了键值对格式的参数到webapi格式参数的转换方法        """Add a simple field to the form data."""        self.form_fields.append((name, value))        return    def add_file(self, fieldname, filename, content, mimetype=None):#提供了文件类型键值对参数到webapi格式参数的转换方法        """Add a file to be uploaded."""        if mimetype is None:            mimetype = mimetypes.guess_type(filename)[0] or 'application/octet-stream'        self.files.append((fieldname, filename, mimetype, content))        return    def __str__(self):        """Return a string representing the form data, including attached files."""        # Build a list of lists, each containing "lines" of the        # request.  Each part is separated by a boundary string.        # Once the list is built, return a string where each        # line is separated by '\r\n'.        parts = []        part_boundary = '--' + self.boundary        # Add the form fields        parts.extend(            [part_boundary,             'Content-Disposition: form-data; name="%s"' % name,'',value, ]            for name, value in self.form_fields        )        # Add the files to upload        parts.extend(            [part_boundary,             'Content-Disposition: file; name="%s"; filename="%s"' %             (field_name, filename),             'Content-Type: %s' % content_type,             '',             body,             ]            for field_name, filename, content_type, body in self.files        )        # Flatten the list and add closing boundary marker,        # then return CR+LF separated data        flattened = list(itertools.chain(*parts))        flattened.append('--' + self.boundary + '--')        flattened.append('')        return '\r\n'.join(flattened)def _print_debug(msg):    if DEBUG_LEVEL:        sys.stderr.write(str(msg) + '\n')_APIS = [    '/detect',    '/compare',    '/search',    '/faceset/create',    '/faceset/addface',    '/faceset/removeface',    '/faceset/update',    '/faceset/getdetail',    '/faceset/delete',    '/faceset/getfacesets',    '/face/analyze',    '/face/getdetail',    '/face/setuserid']_APIS = [i.split('/')[1:] for i in _APIS]

总结：这段代码是学习灵活适应api变化SDK开发很好的例子，有助于自己软件开发代码的设计。