RSelenium 编码示例
这是一个独立的代码示例，使用问题中引用的网站。
观察：请不要运行此代码。
为什么？ 有 1k Stack 用户访问网站是 DDOS 攻击。
##介绍先决条件
下面的代码将安装RSelenium，在运行代码之前你需要：
- 安装火狐
- 添加 Selenium IDE 插件
- 安装 RStudio [推荐]
- 创建项目并打开下面的代码文件
下面的代码将带您从第二页 [http://appscvs.supercias.gob.ec/portaldeinformacion/consulta_cia_param.zul] 到您感兴趣的信息的最后一页......
有用的参考资料：
如果您对使用 RSelenium 感兴趣，我强烈建议您阅读以下参考资料，感谢 John Harrison 开发 RSelenium 包。
http://rpubs.com/johndharrison/12843
http://rpubs.com/johndharrison/RSelenium-headless
https://cran.r-project.org/web/packages/RSelenium/vignettes/basics.html
代码示例
# We want to make this as easy as possible to use
# So we need to install required packages for the user...
#
if (!require(RSelenium)) install.packages("RSelenium")
if (!require(XML)) install.packages("XML")
if (!require(RJSONIO)) install.packages("RSJONIO")
if (!require(stringr)) install.packages("stringr")
# Data
#
mainPage <- "http://appscvs.supercias.gob.ec/portalInformacion/sector_societario.zul"
businessPage <- "http://appscvs.supercias.gob.ec/portaldeinformacion/consulta_cia_param.zul"
# StartServer
# We assume RSelenium is not setup, so we check if the RSelenium
# server is available, if not we install RSelenium server.
checkForServer()
# OK. now we start the server
RSelenium::startServer()
remDr <- RSelenium::remoteDriver$new()
# We assume the user has installed Firefox and the Selenium IDE
# https://addons.mozilla.org/en-US/firefox/addon/selenium-ide/
#
# Ok we open firefix
remDr$open(silent = T) # Open up a firefox window...
# Now we open the browser and required URL...
# This is the page that matters...
remDr$navigate(businessPage)
# First things first on the first page, lets get the id's for the radio_button,
# name Element, and button. We need all three.
#
radioButton <- remDr$findElements(using = 'css selector', ".z-radio-cnt")
nameElement <- remDr$findElements(using = 'css selector', ".z-combobox-inp")
searchButton <- remDr$findElements(using = 'css selector', ".z-button-cm")
# Optional: we can highlight the radio elements returned
# lapply(radioButton, function(x){x$highlightElement()})
# Optional: we can highlight the nameElement returned
# lapply(nameElement, function(x){x$highlightElement()})
# Optional: we can highlight the searchButton returned
# lapply(searchButton, function(x){x$highlightElement()})
# Now we can select and press the third radio button
radioButton[[3]]$clickElement()
# We fill in the required name...
nameElement[[1]]$sendKeysToElement(list("PROAÑO & ASOCIADOS CIA. LTDA."))
# This is subtle but required the page triggers a drop down list, so rather than
# hitting the searchButton, we first select, and hit enter in the drop down menu...
selectElement <- remDr$findElements(using = 'css selector', ".z-comboitem-text")
selectElement[[1]]$clickElement()
# OK, now we can click the search button, which will cause the next page to open
searchButton[[1]]$clickElement()
# New Page opens...
#
# Ok, so now we first pull the list of buttons...
finPageButton <- remDr$findElements(using = 'class name', "m_iconos")
# Now we can press the required button to open the page we want to get too...
finPageButton[[9]]$clickElement()
# We are now on the required page.
我们现在在目标页面[查看图片]
正在提取表值...
下一步是提取表值。为此，我们提取 .z-listitem css-selector 数据。现在我们可以检查以确认是否看到数据行。我们这样做了，所以我们现在可以提取返回的值并填充列表或数据框。
# Ok, now we need to extract the table, we identify and pull out the
# '.z-listitem' and assign to modalWindow
modalWindow <- remDr$findElements(using = 'css selector', ".z-listitem")
# Now we can extract the lines from modalWindow... Now that each line is
# returned as a single line of text, so we split into three based on the
# line marker "/n'
lineText <- str_split(modalWindow[[1]]$getElementText()[1], '\n')
lineText
这里是结果：
> lineText <- stringr::str_split(modalWindow[[1]]$getElementText()[1], '\n')
> lineText
[[1]]
[1] "10"
[2] "OPERACIONES DE INGRESO CON PARTES RELACIONADAS EN PARAÍSOS FISCALES, JURISDICCIONES DE MENOR IMPOSICIÓN Y REGÍMENES FISCALES PREFERENTES"
[3] "0.00"
处理隐藏数据。
Selenium WebDriver 和 RSelenium 只与网页的可见元素交互。如果我们尝试读取整个表格，我们将只返回可见（未隐藏）的表格项。
我们可以通过滚动到表格底部来解决这个问题。由于滚动动作，我们强制表格填充。然后我们可以提取完整的表格。
# Select the .z-listbox-body
modalWindow <- remDr$findElements(using = 'css selector', ".z-listbox-body")
# Now we tell the window we want to scroll to the bottom of the table
# This triggers the table to populate all the rows
modalWindow[[1]]$executeScript("window.scrollTo(0, document.body.scrollHeight)")
# Now we can extract the complete table
modalWindow <- remDr$findElements(using = 'css selector', ".z-listitem")
lineText <- stringr::str_split(modalWindow[[9]]$getElementText(), '\n')
lineText
###代码的作用。
上面的代码示例是独立的。我的意思是它应该安装你需要的一切，包括所需的包。安装依赖的 R 包后，R 代码将调用checkForServer()，如果未安装 Selenium，则调用将安装它。 这可能需要一些时间
我的建议是您逐步完成代码，因为我没有包含任何延迟（在生产中您想要），还请注意，我没有针对速度进行优化，而是为了稍微清晰 [从我的角度]...
该代码已显示可用于：
- Mac OS X 10.11.5
- RStudio 0.99.893
- R 版本 3.2.4 (2016-03-10) -- “非常安全的菜肴”