在rmarkdown Rmd中呈现谷歌图表的代码

Question

谷歌有一些漂亮的图表。我知道有一些不错的R包来做我想要的事情，但是我想学习如何自己包含谷歌图表，因为这样可能比包含谷歌图表的R包更加灵活。

下面是一个.Rmd文件，它包含一个donut函数，用于生成Google图表库中的甜甜圈图表。该函数按预期输出代码，但实际上，在编织时会出现以下pandoc转换错误。在Rmarkdown .Rmd文件中如何正确地包括谷歌图表代码？

错误

output file: ttt.knit.md

pandoc.exe: Could not fetch https://www.gstatic.com/charts/loader.js
HttpExceptionRequest Request {
  host                 = "www.gstatic.com"
  port                 = 443
  secure               = True
  requestHeaders       = []
  path                 = "/charts/loader.js"
  queryString          = ""
  method               = "GET"
  proxy                = Nothing
  rawBody              = False
  redirectCount        = 10
  responseTimeout      = ResponseTimeoutDefault
  requestVersion       = HTTP/1.1
}
 (InternalException (HandshakeFailed Error_EOF))
Error: pandoc document conversion failed with error 67
In addition: Warning message:
running command '"C:/Program Files/RStudio/bin/pandoc/pandoc" +RTS -K512m -RTS ttt.utf8.md --to html --from markdown+autolink_bare_uris+ascii_identifiers+tex_math_single_backslash --output ttt.html --smart --email-obfuscation none --self-contained --standalone --section-divs --template "C:\R\R-3.3.2\library\rmarkdown\rmd\h\default.html" --no-highlight --variable highlightjs=1 --variable "theme:bootstrap" --include-in-header "C:\Users\trinker\AppData\Local\Temp\RtmpWI5M7o\rmarkdown-str5910399322d6.html" --mathjax --variable "mathjax-url:https://cdn.mathjax.org/mathjax/latest/MathJax.js?config=TeX-AMS-MML_HTMLorMML"' had status 67 
Execution halted

Rmd MWE

---
title: "Untitled"
output: html_document
---

```{r setup, include=FALSE}
knitr::opts_chunk$set(echo = TRUE)

donut <- function(){

    out <- c("<script type=\"text/javascript\" src=\"https://www.gstatic.com/charts/loader.js\"></script>", 
    "<script type=\"text/javascript\">", "  google.charts.load(\"current\", {packages:[\"corechart\"]});", 
    "  google.charts.setOnLoadCallback(drawChart);", "  function drawChart() {", 
    "var data = google.visualization.arrayToDataTable([", "  ['Task', 'Hours per Day'],", 
    "  ['Work',     11],", "  ['Eat',      2],", "  ['Commute',  2],", 
    "  ['Watch TV', 2],", "  ['Sleep',    7]", "]);", "", "var options = {", 
    "  title: 'My Daily Activities',", "  pieHole: 0.4,", "};", "", 
    "var chart = new google.visualization.PieChart(document.getElementById('donutchart'));", 
    "chart.draw(data, options);", "  }", "</script>", "", "<div id=\"donutchart\" style=\"width: 900px; height: 500px;\"></div>"
    )

    cat(paste(out, collapse = "\n"))

}

```


```{r results='asis'}
donut()
```

donut输出而不使用rmarkdown编织

<script type="text/javascript" src="https://www.gstatic.com/charts/loader.js"></script>
<script type="text/javascript">
  google.charts.load("current", {packages:["corechart"]});
  google.charts.setOnLoadCallback(drawChart);
  function drawChart() {
var data = google.visualization.arrayToDataTable([
  ['Task', 'Hours per Day'],
  ['Work',     11],
  ['Eat',      2],
  ['Commute',  2],
  ['Watch TV', 2],
  ['Sleep',    7]
]);

var options = {
  title: 'My Daily Activities',
  pieHole: 0.4,
};

var chart = new google.visualization.PieChart(document.getElementById('donutchart'));
chart.draw(data, options);
  }
</script>

<div id="donutchart" style="width: 900px; height: 500px;"></div>

- Tyler Rinker

---

我的系统（macOS Sierra，R 3.4.0，rstudio daily）上编织工作正常。 - hrbrmstr

嗯，这一定与连接有关。如果我像这里看到的那样使用 self_contained: no，然后再进行编织...它会编织，但我必须在浏览器中打开 RStudio 窗格。 - Tyler Rinker

我正在开发rmarkdown，因为我已经向其中提交了PR。 pandoc的版本是1.19.2.1。 - hrbrmstr

@hrbrmstr 奇怪，我已经将 pandoc 更新到 1.19.2.1 版本，但仍然遇到了问题，尽管错误看起来略有不同。我会在同一台机器上的另一个网络上进行测试。 - Tyler Rinker

同样的错误(InternalException (HandshakeFailed Error_EOF))在昨天发布的这个问题中也出现了：https://stackoverflow.com/questions/44120395/error-when-knitting-github-document-pandoc-document-conversion-failed-with-erro - scoa

Answer 1

这听起来非常像最近 hs-tls 库出现的 bug，pandoc 依赖该库来通过 https 下载图像等内容。

很可能，使用更新的 pandoc nightly（或从源代码编译）并确保它使用 tls >= 1.3.9 将解决您的问题。

- mb21