获取 RSelenium 错误:“无法解码来自牵线木偶的响应" [英] Getting RSelenium Error: "Failed to decode response from marionette"

问题描述

我对 R 比较陌生(并且对使用 R 刮擦也很陌生)，所以如果我在这里忽略了一些明显的东西，请提前道歉！

I'm relatively new to R (and brand spanking new to scraping with R), so apologies in advance if I'm overlooking something obvious here!

我一直在尝试按照本教程学习如何使用 RSelenium 进行抓取:https://rawgit.com/petrkeil/Blog/master/2017_08_15_Web_scraping/web_scraping.html#advanced-scraping-with-rselenium

I've been trying to learn how to scrape with RSelenium by following this tutorial: https://rawgit.com/petrkeil/Blog/master/2017_08_15_Web_scraping/web_scraping.html#advanced-scraping-with-rselenium

在终端 (docker run -d -p 4445:4444 selenium/standalone-firefox) 中运行以下命令后，我尝试运行下面的 R 代码，仅从上面的超链接教程中稍作修改即可:

After running the following in Terminal (docker run -d -p 4445:4444 selenium/standalone-firefox), I tried to run the R code below, pulled with only slight modifications from the tutorial hyperlinked above:

get.tree <- function(genus, species) 
{
  # navigate to the page
  browser <- remoteDriver(port=4445L)
  browser$open(silent = T)

  browser$navigate("http://www.bgci.org/global_tree_search.php?sec=globaltreesearch")
  browser$refresh()

  # create r objects from the web search input and button elements

  genusElem <- browser$findElement(using = 'id', value = "genus-field")
  specElem <- browser$findElement(using = 'id', value = "species-field")
  buttonElem <- browser$fiendElement(using = 'class', value = "btn_ohoDO")

  # tell R to fill in the fields

  genusElem$sendKeysToElement(list(genus))
  specElem$sendKeysToElement(list(species))

  # tell R to click the search button

  buttonElem$clickElement()

  # get output

  out <- browser$findElement(using = "css", value = "td.cell_1O3UaG:nth-child(4)") # the country origin
  out <- out$getElementText()[[1]] # extract actual text string
  out <- strsplit(out, split = "; ")[[1]] # turns into character vector

  # close browser

  browser$close()

    return(out)
}

# Now let's try it:

get.tree("Abies", "alba")

但是在完成所有这些之后，我收到以下错误:

But after doing all that, I get the following error:

Selenium 消息:无法解码来自牵线木偶的响应构建信息:版本:'3.6.0'，修订版:'6fbf3ec767'，时间:'2017-09-27T16:15:40.131Z' 系统信息:主机:'d260fa60d69b'，ip:'172.17.0.2', os.name: 'Linux', os.arch: 'amd64', os.version:'4.9.49-moby', java.version: '1.8.0_131' 驱动信息:driver.version:未知

Selenium message:Failed to decode response from marionette Build info: version: '3.6.0', revision: '6fbf3ec767', time: '2017-09-27T16:15:40.131Z' System info: host: 'd260fa60d69b', ip: '172.17.0.2', os.name: 'Linux', os.arch: 'amd64', os.version: '4.9.49-moby', java.version: '1.8.0_131' Driver info: driver.version: unknown

错误:摘要:未知错误详细信息:未知的服务器端错误处理命令时发生.班级:org.openqa.selenium.WebDriverException 更多细节:运行errorDetails 方法

Error: Summary: UnknownError Detail: An unknown server-side error occurred while processing the command. class: org.openqa.selenium.WebDriverException Further Details: run errorDetails method

有人知道这意味着什么以及我哪里出错了吗?

Anyone have any idea what this means and where I went wrong?

非常感谢您的帮助！

推荐答案

只需利用它发出的 XHR 请求来检索内嵌结果并抛出 RSelenium:

Just take advantage of the XHR request it makes to retrieve the in-line results and toss RSelenium:

library(httr)
library(tidyverse)

get_tree <-  function(genus, species) {

  GET(
    url = sprintf("https://data.bgci.org/treesearch/genus/%s/species/%s", genus, species), 
    add_headers(
      Origin = "http://www.bgci.org", 
      Referer = "http://www.bgci.org/global_tree_search.php?sec=globaltreesearch"
    )
  ) -> res

  stop_for_status(res)

  matches <- content(res, flatten=TRUE)$results[[1]]

  flatten_df(matches[c("id", "taxon", "family", "author", "source", "problems", "distributionDone", "note", "wcsp")]) %>% 
    mutate(geo = list(map_chr(matches$TSGeolinks, "country"))) %>% 
    mutate(taxas = list(map_chr(matches$TSTaxas, "checkTaxon")))

}

xdf <- get_tree("Abies", "alba")

xdf
## # A tibble: 1 x 8
##      id      taxon   family author     source distributionDone        geo      taxas
##   <int>      <chr>    <chr>  <chr>      <chr>            <chr>     <list>     <list>
## 1 58373 Abies alba Pinaceae  Mill. WCSP Phans              yes <chr [21]> <chr [45]>

glimpse(xdf)
## Observations: 1
## Variables: 8
## $ id               <int> 58373
## $ taxon            <chr> "Abies alba"
## $ family           <chr> "Pinaceae"
## $ author           <chr> "Mill."
## $ source           <chr> "WCSP Phans"
## $ distributionDone <chr> "yes"
## $ geo              <list> [<"Albania", "Andorra", "Austria", "Bulgaria", "Croatia", "Czech Republic", "Fr...
## $ taxas            <list> [<"Abies abies", "Abies alba f. columnaris", "Abies alba f. compacta", "Abies a...

您很可能在某个时候需要修改 get_tree()，但这比将 Selenium、Splash、phantomjs 或 Headless Chrome 作为依赖项要好.

It's highly likely you'll need to modify get_tree() at some point but it's better than having Selenium or Splash or phantomjs or Headless Chrome as a dependency.

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