從多個URL自動下載，處理反饋對話框/ cookies

Question

我嘗試從this site批量下載CORINE Landcover zip文件，但我認爲Google Analytics的互連反饋調查窗口正在製造麻煩..是否存在某種類型的Curl處理程序對於這些問題？

我在sqlite管理器中查看了cookie，這些條目是：baseDomain =「europa.eu」，name =「clc06_c133.zip」，value =「sectors％3Denvironment」，host =「www.eea.europa。歐盟」，.. 的Cookie路徑爲 「C：\用戶\凱\應用程序數據\漫遊\ Mozilla的\火狐\ Profiles文件\ ckut8fjm.default \ cookies.sqlite」

setwd("D:/GIS DataBase/CorineLC/") 

mylist <- list(
clc06_1 <- "111 - Continuous urban fabric", 
clc06_2 <- "112 - Discontinuous urban fabric", 
clc06_3 <- "121 - Industrial or commercial units", 
clc06_4 <- "122 - Road and rail networks and associated land", 
clc06_5 <- "123 - Port areas", 
clc06_6 <- "124 - Airports", 
clc06_7 <- "131 - Mineral extraction sites", 
clc06_8 <- "132 - Dump sites", 
clc06_9 <- "133 - Construction sites", 
clc06_10 <- "141 - Green urban areas", 
clc06_11 <- "142 - Sport and leisure facilities", 
clc06_12 <- "211 - Non-irrigated arable land", 
clc06_13 <- "212 - Permanently irrigated land", 
clc06_14 <- "213 - Rice fields", 
clc06_15 <- "221 - Vineyards", 
clc06_16 <- "222 - Fruit trees and berry plantations", 
clc06_17 <- "223 - Olive groves", 
clc06_18 <- "231 - Pastures", 
clc06_19 <- "241 - Annual crops associated with permanent crops", 
clc06_20 <- "242 - Complex cultivation patterns", 
clc06_21 <- "243 - Land principally occupied by agriculture, with significant areas of natural vegetation", 
clc06_22 <- "244 - Agro-forestry areas", 
clc06_23 <- "311 - Broad-leaved forest", 
clc06_24 <- "312 - Coniferous forest", 
clc06_25 <- "313 - Mixed forest", 
clc06_26 <- "321 - Natural grasslands", 
clc06_27 <- "322 - Moors and heathland", 
clc06_28 <- "323 - Sclerophyllous vegetation", 
clc06_29 <- "324 - Transitional woodland-shrub", 
clc06_30 <- "331 - Beaches, dunes, sands", 
clc06_31 <- "332 - Bare rocks", 
clc06_32 <- "333 - Sparsely vegetated areas", 
clc06_33 <- "334 - Burnt areas", 
clc06_34 <- "335 - Glaciers and perpetual snow", 
clc06_35 <- "411 - Inland marshes", 
clc06_36 <- "412 - Peat bogs", 
clc06_37 <- "421 - Salt marshes", 
clc06_38 <- "422 - Salines", 
clc06_39 <- "423 - Intertidal flats", 
clc06_40 <- "511 - Water courses", 
clc06_41 <- "512 - Water bodies", 
clc06_42 <- "521 - Coastal lagoons", 
clc06_43 <- "522 - Estuaries", 
clc06_44 <- "523 - Sea and ocean") 

# extract the CLC codes which are the 3-digit number in the string: 
foo1 <- function(x) unlist(strsplit(x, " - "))[[1]] 
# and the names 
foo2 <- function(x) unlist(strsplit(x, " - "))[[2]] 

codes <- sapply(mylist, foo1, simplify = T) 
names <- sapply(mylist, foo2, simplify = T) 

# make urls 
names_url <- gsub(",", "", gsub("\\s", "-", names)) 
dl_url <- paste0("http://www.eea.europa.eu/data-and-maps/data/clc-2006-vector-data-version-2/", 
       codes, "-", names_url, "/clc06_c", codes, ".zip/at_download/file") 

# get zip file names 
get_zip_name <- function(x) unlist(strsplit(x, "/"))[grep(".zip", unlist(strsplit(x, "/")))] 

# function to plug into sapply 
dl_url_to_zip <- function(x) download.file(x, dest = get_zip_name(x)) 

# gives http status 404! 
sapply(dl_url, dl_url_to_zip) 

Answer 1

可以使用httr包：

require(httr) 
require(XML) 

response <- GET("http://www.eea.europa.eu/data-and-maps/data/clc-2006-vector-data-version-2") 
doc <- htmlParse(content(response,as="text")) 
files <- xpathSApply(doc,'//*/a[contains(@href,"http://www.eea.europa.eu/data-and-maps/data/clc-2006-vector-data-version-2/")]/@href') 
files <- files[-c(1,47:50)] 

files[10] 
#href 
#"http://www.eea.europa.eu/data-and-maps/data/clc-2006-vector-data-version-2/141-green-urban-areas/clc06_c141.zip/at_download/file" 
dl_url[10] 
#[1] "http://www.eea.europa.eu/data-and-maps/data/clc-2006-vector-data-version-2/141-Green-urban-areas/clc06_c141.zip/at_download/file" 

請注意，您的首都是Green-urban-areas而不是green-urban-areas

response <- GET(files[10]) 
writeBin(content(response),'test.zip') 

我開始httr包，因爲我認爲我們可能需要的cookies。實際上

download.file(files[10],'test.zip',mode="wb") 

也同樣適用。原始代碼中的錯誤是大寫。