在Python中实现PageFactory模式

例子，http://libin0019.iteye.com/blog/1260090   

Python（Selenium）中没有这个类。 PageFactory 的概念和Page Object应该类似，属于一种设计模式。所以并不局限于语言及场景。于是，好奇，既然Java有，那Python也应该有类似的玩法。还真让我给找到了类似的实现。

原文在此：https://jeremykao.wordpress.com/2015/06/10/pagefactory-pattern-in-python/

于是，就借助谷歌翻译加代码运行，弄懂了这哥们想要利用PageFactory 模式实现个什么东西，为了便于你的理解，我这里搬运过来给下结论。

 

selenium in python中的元素定位是这样的：

 

find_element_by_id("kw")

find_element_by_xpath("//*[@id=kw]")

 

或者是这样的：

from selenium.webdriver.common.by import By

find_element(By.ID,"kw")

find_element(By.XPATH,"//*[@id=kw]")

 

通过PageFactory 模式的实现可以把元素定位变成这样的：

from pageobject_support import callable_find_by as find_by

find_by(id_="kw")

find_by(xpath="//*[@id=kw]")

 别看小小的改动，它其实使代码更容易的阅读和理解。

 

核心实现就是pageobject_support.py文件：

__all__ = [cacheable, callable_find_by, property_find_by]

def cacheable_decorator(lookup):

 def func(self):

 if not hasattr(self, _elements_cache):

 self._elements_cache = {} # {callable_id: element(s)}

 cache = self._elements_cache

 key = id(lookup)

 if key not in cache:

 cache[key] = lookup(self)

 return cache[key]

 return func

cacheable = cacheable_decorator

_strategy_kwargs = [id_, xpath, link_text, partial_link_text,

 name, tag_name, class_name, css_selector]

def _callable_find_by(how, using, multiple, cacheable, context, driver_attr, **kwargs):

 def func(self):

 # context - driver or a certain element

 if context:

 ctx = context() if callable(context) else context.__get__(self) # or property

 else:

 ctx = getattr(self, driver_attr)

 # how AND using take precedence over keyword arguments

 if how and using:

 lookup = ctx.find_elements if multiple else ctx.find_element

 return lookup(how, using)

 if len(kwargs) != 1 or kwargs.keys()[0] not in _strategy_kwargs :

 raise ValueError(

 "If how AND using are not specified, one and only one of the following "

 "valid keyword arguments should be provided: %s." % _strategy_kwargs)

 key = kwargs.keys()[0]; value = kwargs[key]

 suffix = key[:-1] if key.endswith(_) else key # find_element(s)_by_xxx

 prefix = find_elements_by if multiple else find_element_by

 lookup = getattr(ctx, %s_%s % (prefix, suffix))

 return lookup(value)

 return cacheable_decorator(func) if cacheable else func

def callable_find_by(how=None, using=None, multiple=False, cacheable=False, context=None, driver_attr=_driver, **kwargs):

 return _callable_find_by(how, using, multiple, cacheable, context, driver_attr, **kwargs)

def property_find_by(how=None, using=None, multiple=False, cacheable=False, context=None, driver_attr=_driver, **kwargs):

 return property(_callable_find_by(how, using, multiple, cacheable, context, driver_attr, **kwargs))

 

然后，我再帖一下具体的例子：

from pageobject_support import callable_find_by as find_by

from selenium import webdriver

class BaiduSearchPage(object):

 def __init__(self, driver):

 self._driver = driver

 search_box = find_by(id_="kw")

 search_button = find_by(id_=su)

 def search(self, keywords):

 self.search_box().clear()

 self.search_box().send_keys(keywords)

 self.search_button().click()


 driver.close()

 

同样封装了8种定位方法：

id_ (为避免与内置的关键字ID冲突，所以多了个下划线的后缀) class_name css_selector tag_name xpath link_text partial_link_text

  

当然，这只是PageFactory 模式的一种表现形式而已。除此之外，我还找到了另外一个PageFactory模式的例子。

https://github.com/mattfair/SeleniumFactory-for-Python

这哥们是利用PageFactory模式把驱动的创建做了封装，感兴趣可以了解一下。

搬运完了，准备过年。新年快了~！！！