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=" -F "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 sdk
example:
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 = 1
import sys
import socket
import urllib2
import json
import os.path
import itertools
import mimetools
import mimetypes
import time
import tempfile
from collections import Iterable
class 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"""
pass
def _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。