RCurl：在Rgui中显示进度表 [英] RCurl: Display progress meter in Rgui

问题描述

使用 R.exe 或 Rterm.exe ，这将是一个很好的进度表。

Using R.exe or Rterm.exe, this gives an excellent progress meter.

page=getURL(url="ftp.wcc.nrcs.usda.gov", noprogress=FALSE) 

在Rgui中，我限制为：

In Rgui I am limited to:

page=getURL(url="ftp.wcc.nrcs.usda.gov", 
            noprogress=FALSE, progressfunction=function(down,up) print(down))

它提供了非常有限的一组下载信息。

which gives a very limited set of download information.

有办法改善吗？

推荐答案

我开始怀疑使用标准R命令可以重写覆盖当前行，这是RCurl在非GUI模式下所做的。

I start doubting that with standard R commands it is possible to reprint overwriting the current line, which is what RCurl does in non-GUI mode.

我很高兴告诉我我错了。至少对于单行， \r 可以做的伎俩。事实上：

I am glad to tell that I was wrong. At least for a single line, \r can do the trick. In fact:

conc=function(){
    cat(" abcd")
    cat(" ABCD", '\n')

}
conc()

# abcd ABCD 

但是：

over=function(){
    cat(" abcd")
    cat("\r ABCD", "\n")
}
over()

# ABCD

这样，我写了 progressDown 可以监视下载状态重写始终在同一行：

That given, I wrote this progressDown function, which can monitor download status rewriting always on the same same line:

library(RCurl) # Don't forget

### Callback function for curlPerform
progressDown=function(down, up, pcur, width){
    total=as.numeric(down[1]) # Total size as passed from curlPerform
    cur=as.numeric(down[2])   # Current size as passed from curlPerform
    x=cur/total
    px= round(100 * x)
    ## if(!is.nan(x) &&  px>60) return(pcur) # Just to debug at 60%
    if(!is.nan(x) && px!=pcur){
        x= round(width * x)
        sc=rev(which(total> c(1024^0, 1024^1, 1024^2, 1024^3)))[1]-1
        lb=c('B', 'KB', 'MB', 'GB')[sc+1]
        cat(paste(c(
            "\r  |", rep.int(".", x), rep.int(" ", width - x),
            sprintf("| %g%s of %g%s %3d%%",round(cur/1024^sc, 2), lb, round(total/1024^sc, 2), lb, px)),
                  collapse = ""))
        flush.console() # if the outptut is buffered, it will go immediately to console
        return(px)
    }
    return(pcur)
}

现在我们可以使用 curlPerform

curlProgress=function(url, fname){
    f = CFILE(fname, mode="wb")
    width= getOption("width") - 25   # you can make here your line shorter/longer
    pcur=0
    ret=curlPerform(url=url, writedata=f@ref,  noprogress=FALSE,
        progressfunction=function(down,up) pcur<<-progressDown(down, up, pcur, width),
        followlocation=T)
        close(f)
        cat('\n Download', names(ret), '- Ret', ret, '\n') # is success? 
}

使用小型示例二进制文件运行：

Running it with a small sample binary:

curlProgress("http://www.nirsoft.net/utils/websitesniffer-x64.zip", "test.zip")

中间输出为60％是（无＃保护） / p>

the intermediate output at 60% is (no # protection):

  |.................................                      | 133.74KB of 222.75KB  60%

其中 KB ，将根据总大小调整为<​​code> B，KB，MB，GB 。

where KB, will be adjusted to B, KB, MB, GB, based on total size.

具有成功状态的最终产品是：

Final output with success status, is:

  |.......................................................| 222.61KB of 222.75KB 100%
 Download OK - Ret 0 

width是相对于R width选项（它控制一行上的最大列数），并且可以自定义改变 curlProgress 行：

Note, the output line width is relative to R width option (which controls the maximum number of columns on a line) and can be customised changing the curlProgress line:

width= getOption("width") - 25

$ b b

这足以满足我的需要，并解决我自己的问题。

This is enough for my needs and solves my own question.

这篇关于RCurl：在Rgui中显示进度表的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！