在R中重新创建python机械化脚本

Question

我想重新创建下面的python脚本，该脚本在R中使用mechanize和http.cookiejar。我认为使用rvest是直截了当但我无法这样做。有关使用和应用哪些软件包的任何见解都非常有用。我意识到网状可能是一种可能性，但我认为必须有一种方法可以在R中直接做到这一点。

import mechanize
import http.cookiejar

b = mechanize.Browser()
b.set_handle_refresh(True)
b.set_debug_redirects(True)
b.set_handle_redirect(True)
b.set_debug_http(True)
cj = http.cookiejar.CookieJar()
b.set_cookiejar(cj)

b.addheaders = [
    ('User-agent', 'Mozilla/5.0 (Macintosh; Intel Mac OS X 10_9_4) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/37.0.2062.94 Safari/537.36'),
    ('Accept', 'text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8'),
    ('Host', 'www.fangraphs.com'),
    ('Referer', 'https://www.fangraphs.com/auctiontool.aspx?type=pit&proj=atc&pos=1,1,1,1,5,1,1,0,0,1,5,5,0,18,0&dollars=400&teams=12&mp=5&msp=5&mrp=5&mb=1&split=&points=c|0,1,2,3,4,5|0,1,2,3,4,5&lg=MLB&rep=0&drp=0&pp=C,SS,2B,3B,OF,1B&players=')
]
b.open("https://www.fangraphs.com/auctiontool.aspx?type=pit&proj=atc&pos=1,1,1,1,5,1,1,0,0,1,5,5,0,18,0&dollars=400&teams=12&mp=5&msp=5&mrp=5&mb=1&split=&points=c|0,1,2,3,4,5|0,1,2,3,4,5&lg=MLB&rep=0&drp=0&pp=C,SS,2B,3B,OF,1B&players=")

def is_form1_form(form):
    return "id" in form.attrs and form.attrs['id'] == "form1"

b.select_form(predicate=is_form1_form)
b.form.find_control(name='__EVENTTARGET').readonly = False
b.form.find_control(name='__EVENTARGUMENT').readonly = False
b.form['__EVENTTARGET'] = 'AuctionBoard1$cmdCSV'
b.form['__EVENTARGUMENT'] = ''

print(b.submit().read())

我用来尝试用rvest重新创建的R代码如下。评论表明了我困惑的主要原因。特别是当我用rvest抓取表单时，python代码抓取的所需字段没有出现，当我尝试手动插入它们时，我在提交时拒绝连接。

    library(rvest)

    atc.pitcher.link = "https://www.fangraphs.com/auctiontool.aspx?type=pit&proj=atc&pos=1,1,1,1,5,1,1,0,0,1,5,5,0,18,0&dollars=400&teams=12&mp=5&msp=5&mrp=5&mb=1&split=&points=c|0,1,2,3,4,5|0,1,2,3,4,5&lg=MLB&rep=0&drp=0&pp=C,SS,2B,3B,OF,1B&players="

    proj.data = html_session(atc.pitcher.link) 
    form.unfilled = proj.data %>% html_node("form") %>% html_form()

    # note: I am suprised "__EVENTTARGET" and "__EVENTARGUMENT" are not included as attributes of the unfilled form. I can select them in the posted python script.

    # If I try and create them with the appropriate values I get a Connection Refused Error. 

    form.unfilled[[5]]$`__EVENTTARGET` = form.unfilled[[5]]$`__VIEWSTATE` 
    form.unfilled[[5]]$`__EVENTARGUMENT`= form.unfilled[[5]]$`__VIEWSTATE`

    form.unfilled[[5]]$`__EVENTTARGET`$readonly = FALSE
    form.unfilled[[5]]$`__EVENTTARGET`$value = "AuctionBoard1$cmdCSV"

    form.unfilled[[5]]$`__EVENTARGUMENT`$value = ""
    form.unfilled[[5]]$`__EVENTARGUMENT`$readonly = FALSE

    form.filled = form.unfilled 
    session = submit_form(proj.data, form.filled)

Answer 1

这是一种使用RSelenium并将chrome设置为无头的方法，可以远程下载到您的工作目录。它会自动启动无头浏览器，然后让代码驱动它。

我相信在rvest中你需要写一些本地幻像。

library(RSelenium)
library(wdman)

eCaps <- list(
  chromeOptions = list(
    args = c('--headless','--disable-gpu', '--window-size=1280,800'),
    prefs = list(
      "profile.default_content_settings.popups" = 0L,
      "download.prompt_for_download" = FALSE,
      "download.default_directory" = getwd()
    )
  )
)  

cDrv <- wdman::chrome()

rD <- RSelenium::rsDriver(extraCapabilities = eCaps)
remDr <- rD$client

remDr$queryRD(
  ipAddr = paste0(remDr$serverURL, "/session/", remDr$sessionInfo[["id"]], "/chromium/send_command"),
  method = "POST",
  qdata = list(
    cmd = "Page.setDownloadBehavior",
    params = list(
      behavior = "allow",
      downloadPath = getwd()
    )
  )
)

atc.pitcher.link= "http://www.fangraphs.com/auctiontool.aspx?type=pit&proj=atc&pos=1,1,1,1,5,1,1,0,0,1,5,5,0,18,0&dollars=400&teams=12&mp=5&msp=5&mrp=5&mb=1&split=&points=c|0,1,2,3,4,5|0,1,2,3,4,5&lg=MLB&rep=0&drp=0&pp=C,SS,2B,3B,OF,1B&players="

remDr$navigate(atc.pitcher.link)

# sleep to be nice and give things time to load
Sys.sleep(8)

# find the button the page we want to click
option <- remDr$findElement('id', 'AuctionBoard1_cmdCSV')

#click it
option$clickElement()

list.files(getwd(),pattern = 'sysdata')

remDr$closeall()

cDrv$stop()