r - 尽管有弹出窗口，但仍通过 R 从 Internet 下载文件

Question

使用 R 从 Internet 下载文件很容易，而且 has been addressed previously .

我的问题是关于如何绕过似乎阻止我的下载执行的弹出消息。具体来说，

download.file(url = "https://www.chicagofed.org/applications/bhc_data/bhcdata_index.cfm?DYR=2012&DQIR=4", destfile = "data/test.zip")

给我一个小垃圾文件，而不是你去 the website 时会得到的所需的 18 兆字节文件。并进入年份 2012和季度4手动。我怀疑问题在于，正如您手动执行时所看到的那样，一个弹出窗口会中断下载过程，询问是保存文件还是打开文件。有没有办法自动绕过弹出窗口(即，通过 download.file )？

Answer 1

这可以通过 Selenium 来完成，参见 https://github.com/ropensci/RSelenium .

require(wdman)
require(RSelenium)


selPort <- 4444L
fprof <- makeFirefoxProfile(list(browser.download.dir = "C:\\temp"
                                 ,  browser.download.folderList = 2L
                                 , browser.download.manager.showWhenStarting = FALSE
                                 , browser.helperApps.neverAsk.saveToDisk = "application/zip"))
selServ <- selenium(port = selPort)
remDr <- remoteDriver(extraCapabilities = fprof, port = selPort)
remDr$open(silent = TRUE)
remDr$navigate("https://www.chicagofed.org/applications/bhc_data/bhcdata_index.cfm")
# click year 2012
webElem <- remDr$findElement("name", "SelectedYear")
webElems <- webElem$findChildElements("css selector", "option")
webElems[[which(sapply(webElems, function(x){x$getElementText()}) == "2012" )]]$clickElement()

# click required quarter

webElem <- remDr$findElement("name", "SelectedQuarter")
Sys.sleep(1)
webElems <- webElem$findChildElements("css selector", "option")
webElems[[which(sapply(webElems, function(x){x$getElementText()}) == "4th Quarter" )]]$clickElement()

# click button

webElem <- remDr$findElement("id", "downloadDataFile")
webElem$clickElement()