从 Shiny 本地保存 rmarkdown 输出

Question

我有一个闪亮的应用程序，它使用rmarkdown 生成可下载的报告，效果很好。每次用户上传数据以生成报告时，我希望将报告的副本保存在闪亮的主机上。理想情况下，我想在 downloadHandler 调用中执行此操作，这样我就不必生成两次报告。

一个最小的例子（改编自this shiny article）：

library(shiny)

shinyApp(
  ui = fluidPage(
    sliderInput("slider", "Slider", 1, 100, 50),
    downloadButton("report", "Generate report")
  ),
  server = function(input, output) {
    output$report <- downloadHandler(
      # For PDF output, change this to "report.pdf"
      filename = "report.html",
      content = function(file) {
        # Copy the report file to a temporary directory before processing it, in
        # case we don't have write permissions to the current working dir (which
        # can happen when deployed).
        tempReport <- file.path(tempdir(), "report.Rmd")
        file.copy("report.Rmd", tempReport, overwrite = TRUE)

        # Set up parameters to pass to Rmd document
        params <- list(n = input$slider)

        # Knit the document, passing in the `params` list, and eval it in a
        # child of the global environment (this isolates the code in the document
        # from the code in this app).
        rmarkdown::render(tempReport, output_file = file,
                          params = params,
                          envir = new.env(parent = globalenv())
        )
      }
    )
  }
)

rmarkdown 文件

---
title: "Dynamic report"
output: html_document
params:
  n: NA
---

  ```{r}
# The `params` object is available in the document.
params$n
```

A plot of `params$n` random points.

```{r}
plot(rnorm(params$n), rnorm(params$n))
```

Answer 1

您基本上只需将生成的报告复制到另一个目录即可。这是基于您提供的代码的示例。

library(shiny)

if(!dir.exists("reportDir"))
   dir.create("reportDir")

shinyApp(
  ui = fluidPage(
    sliderInput("slider", "Slider", 1, 100, 50),
    downloadButton("report", "Generate report")
  ),
  server = function(input, output) {
    output$report <- downloadHandler(
      # For PDF output, change this to "report.pdf"
      filename = "report.html",
      content = function(file) {
        # Copy the report file to a temporary directory before processing it, in
        # case we don't have write permissions to the current working dir (which
        # can happen when deployed).
        tempReport <- file.path(tempdir(), "report.Rmd")
        file.copy("report.Rmd", tempReport, overwrite = TRUE)

        # Set up parameters to pass to Rmd document
        params <- list(n = input$slider)

        # Knit the document, passing in the `params` list, and eval it in a
        # child of the global environment (this isolates the code in the document
        # from the code in this app).
        rmarkdown::render(tempReport, output_file = file,
                          params = params,
                          envir = new.env(parent = globalenv())
        )

        # copy generated report
        file.copy(file, paste("reportDir/", Sys.time(), ".html"))
      }
    )
  }
)