RSelenium：在另一个 link 中单击 link

Question

我有这个 RSelenium 脚本：

library(tidyverse)
library(RSelenium) # running through docker
library(rvest)
library(httr)

remDr <- remoteDriver(port = 4445L, browserName = "chrome")
remDr$open()


remDr$navigate("https://books.google.com/")
books <- remDr$findElement(using = "css", "[name = 'q']")

books$sendKeysToElement(list("NHL teams", key = "enter"))

bookElem <- remDr$findElements(using = "xpath",
                               "//h3[@class = 'LC20lb']//parent::a")

links <- sapply(bookElem, function(bookElem){
  bookElem$getElementAttribute("href")
})

以上在 Google 搜索 return 中每 link 次点击（每页有 10 次）。单击进入后，我搜索的大部分书籍都有预览。如果有预览，可以单击一个小的 About this book link 将您带到发布信息。

我想单击第一个 link，如果有预览，请单击 "About this book." 我有以下内容，但我只收到 Error: object of type 'closure' is not subsettable 错误：

for(link in links) {

  # Navigate to each link
  remDr$navigate(link)

  # If statement to get past book previews
  if (str_detect(link, "frontcover")) {

   link2 <- remDr$findElement(using = 'xpath', 
                               '//*[@id="sidebar-atblink"]//parent::a')
   link2 <- as.list(link2)
   print(class(link2))
   link2_about <- sapply(link2, function(ugh){
      ugh$getElementAttribute('href')
    })

  } else {
    print("nice going, dumbass")
  }
}

或者我尝试 for 循环而不是 sapply，我得到 Error: $ operator is invalid for atomic vectors:

for(link in links) {

  # Navigate to each link
  remDr$navigate(link)

  # If statement to get past book previews
  if (str_detect(link, "frontcover")) {

    link2 <- remDr$findElement(using = 'xpath',
       '//a[@id="sidebar-atb-link" and span[.="About this book"]]')

     for(i in length(link2)){
      i$getElementAttribute('href')
     }

    } else {
     print("dumbass")
   }
}

如何才能成功点击到那一秒 link，具体取决于是否有预览？谢谢！

Answer 1

只需更新以下行。

aboutLinks <- remDr$findElements(using = 'xpath', 
                           '//a[@id="sidebar-atb-link" and span[.="About this book"]]')
links2 <- sapply(aboutLinks, function(about_link){
  about_link$getElementAttribute('href')
})

RSelenium：在另一个 link 中单击 link

RSelenium: clicking a link within another link

selenium

r

web-scraping

dplyr

rselenium