如何在闪亮的应用程序中下载 pdf 以响应用户输入?

How to make pdf download in shiny app response to user inputs?

我想让 table 和由我闪亮的应用程序生成的条形图可以下载为 pdf 报告。第一次在本地计算机上启动应用程序时,我可以使用选定的输入生成报告,但是当我切换输入时,它不会在 pdf 上生成新输入的报告。

这是我的 ui 代码

require(shiny)
require(shinydashboard)
require(ggplot2)
require(ggthemes)

sample <- read.csv("new_sample2.csv", stringsAsFactors = FALSE)

header <- dashboardHeader(title = "XYZ School Student Dashboard", titleWidth = 370)

body <- dashboardBody(
tags$head(tags$style(HTML('
  .main-header .logo {
                        font-family: "Georgia", Times, "Times New Roman", serif;
                        font-weight: bold;
                        font-size: 20px;
                        }
                        '))),
fluidRow(
column(width = 9,
box(title = "Selected Student", width = NULL, solidHeader = TRUE, status = "info",
           textOutput("summary1"),
           textOutput("summary2"),
           textOutput("summary3")
),

       box(title = "Marks card", status = "info", width = NULL, solidHeader = TRUE, collapsible = TRUE,
           tableOutput("table")),
       box(title = "Marks card bar plot", status = "info", width = NULL, solidHeader = TRUE, collapsible = TRUE,
           plotOutput("plot"))
),

column(width = 3,
       box(title = "Select", background = "blue" ,width = NULL,
           selectInput("class", "Class", unique(sample$class)),
           selectInput("name", "Name", unique(sample$name)),
           selectInput("exams", "Exams", choices = c("1st Periodic Test", "1st Term", "2nd Periodic Test",
                                                     "2nd Term", "3rd Periodic Test", "4th Periodic Test",
                                                     "Final")),

           "Note: In the Bar Plot", 
           br(),
           "1. The black line is the average class mark for that particular subject.",
           br(),
           "2. The red line is the pass mark for that particular subject.",
           hr(),
           downloadButton("downloadReport", "Download report")
           )
       )
  )
)


ui <- dashboardPage(skin = "blue",
    header,
      dashboardSidebar(disable = TRUE),
        body
)  

这是我的服务器代码

server <- function(input, output, session){

output$summary1 <- renderText({
paste("Student Name: ", input$name)
})

output$summary2 <- renderText({
paste("Class: ", input$class)
})
output$summary3 <- renderText({
paste("Examination: ", input$exams)
})


getdataset <- reactive({
dataset <- sample[sample$class == input$class & sample$name == input$name & sample$examination == input$exams, ]
})

observe({
classInput <- input$class
updateSelectInput(session, "name", choices = sample$name[sample$class == classInput])
})

output$table <- renderTable({
dataset <- getdataset()
dataset[, c("date", "subject", "maximum_mark", "pass_mark", "obtain_mark", "class_ave", "pc", "exam_pc")]
})

plotInput <- reactive({
df <- getdataset()
ggplot(df, aes(x = subject, y = obtain_mark)) +
  theme_fivethirtyeight() +
  geom_bar(stat = "identity", fill = "#006699") +
  geom_text(aes(label = obtain_mark),vjust = -0.4) +
  geom_errorbar(data = getdataset(),
                aes(y = class_ave, ymax = class_ave,
                    ymin = class_ave), colour = "#000000") +
  geom_errorbar(data = getdataset(),
                aes(y = pass_mark, ymax = pass_mark,
                    ymin = pass_mark), colour = "red") +
  labs(title = paste(input$name,"'s", input$exams, "marks"), x = "", y = "Marks") +
  theme(axis.text=element_text(size=10, face = "bold")
  )
})

output$plot <- renderPlot({
print(plotInput())
 })

output$downloadReport <- downloadHandler(
filename = "Student-report.pdf",
content = function(file){
  inputEnv <- new.env()
  inputEnv$class <- input$class
  inputEnv$name <- input$name
  inputEnv$exams <- input$exams
  inputEnv$data <- getdataset()
  out = rmarkdown::render("student_report.Rmd", envir = inputEnv)
  file.rename(out, file)
     }
    )
   }

 shinyApp(ui, server)  

这是我放在 app.R 所在文件夹中的 .Rmd 文件。

---
title: "school_report"
author: "Management"
date: "May 4, 2016"
output: pdf_document
---

```{r echo=FALSE}
plotInput()
```  

```{r echo=FALSE}
dataset <- getdataset()
dataset[, c("date", "subject", "maximum_mark", "pass_mark", "obtain_mark", "class_ave", "pc", "exam_pc")]
```  

数据是学生在学校组织的考试中的分数样本。

head(sample)
 class   name       examination       date        subject maximum_mark pass_mark obtain_mark  pc class_ave
1   1 Adison 1st Periodic Test 2015-03-23      English-I        20         8          14     70      15
2   1 Adison 1st Periodic Test 2015-03-24    Mathematics        20         8          19     95      16
3   1 Adison 1st Periodic Test 2015-03-25        Science        20         8          18     90      12
4   1 Adison 1st Periodic Test 2015-03-26          Hindi        20         8          20    100      15
5   1 Adison 1st Periodic Test 2015-03-27 Social Studies        20         8          19     95      11
6   1 Adison 1st Periodic Test 2015-03-28            M.M        20         8          20    100      14
 exam_pc
1 92.86
2 92.86
3 92.86
4 92.86
5 92.86
6 92.86  

tail(sample)
     class   name examination       date       subject maximum_mark pass_mark obtain_mark  pc class_ave
1851   2   Denver       Final 2015-12-10    English-II          100        40          93  93        59
1852   2   Denver       Final 2015-12-02       Drawing           50        20          25  50        34
1853   2   Denver       Final 2015-11-30            GK           50        20          50 100        42
1854   2   Denver       Final 2015-12-01 Moral Science           50        20          50 100        41
1855   2   Denver       Final 2015-12-02     Dictation           25        10          25 100        20
1856   2   Denver       Final 2015-11-30  Hand Writing           25        10          25 100        20
       exam_pc
 1851   87.89
 1852   87.89
 1853   87.89
 1854   87.89
 1855   87.89
 1856   87.89  

非常感谢您的帮助。

很抱歉我花了这么长时间才回到这个问题上。在查看我所做的之后,事实证明它比我记得的要复杂一些。

这是我的示例应用程序代码

library(shiny)
library(ggplot2)
library(magrittr)

ui <- shinyUI(
  fluidPage(
    column(
      width = 2,
      selectInput(
        inputId = "x_var",
        label = "Select the X-variable",
        choices = names(mtcars)
      ),
      selectInput(
        inputId = "y_var",
        label = "Select the Y-variable",
        choices = names(mtcars)
      ),
      selectInput(
        inputId = "plot_type",
        label = "Select the plot type",
        choices = c("scatter plot", "boxplot")
      ),
      downloadButton(
        outputId = "downloader",
        label = "Download PDF"
      )
    ),
    column(
      width = 3,
      tableOutput("table")
    ),
    column(
      width = 7,
      plotOutput("plot")
    )
  )
)

server <- shinyServer(function(input, output, session){

  #****************************************
  #* Reactive Values

  table <- reactive({
    mtcars[, c(input[["x_var"]], input[["y_var"]])]
  })

  plot <- reactive({
    p <- ggplot(data = mtcars,
                mapping = aes_string(x = input[["x_var"]],
                                     y = input[["y_var"]]))
    if (input[["plot_type"]] == "scatter plot")
    {
      p + geom_point()
    }
    else
    {
      p + geom_boxplot()
    }
  })

  #****************************************
  #* Output Components

  output$table <- 
    renderTable({
      table()
    })

  output$plot <- 
    renderPlot({
      plot()
    })

  #****************************************
  #* Download Handlers

  output$downloader <- 
    downloadHandler(
      "results_from_shiny.pdf",
      content = 
        function(file)
        {
          rmarkdown::render(
            input = "report_file.Rmd",
            output_file = "built_report.pdf",
            params = list(table = table(),
                          plot = plot())
          ) 
          readBin(con = "built_report.pdf", 
                  what = "raw",
                  n = file.info("built_report.pdf")[, "size"]) %>%
            writeBin(con = file)
        }
    )
})

shinyApp(ui, server)

这是我的 RMD(标题为 report_file.Rmd

---
title: "Parameterized Report for Shiny"
output: pdf_document
params:
  table: 'NULL'
  plot: 'NULL'
---

```{r}
params[["plot"]]
```

```{r}
params[["table"]]
```

一些要寻找的亮点

  • 注意 params 在 RMarkdown 脚本的 YAML front matter 中的存在。这允许我们在调用 rmarkdown::render(..., params = list(...))
  • 时传入要在脚本中使用的值列表
  • 我总是将 PDF 构建为虚拟文件。这样就很容易找到了。
  • 我总是生成一个虚拟文件的原因是为了让下载处理程序工作,您需要读取 PDF 的 bit-content 并使用 file 将其推送到参数 writeBin。请参阅我的 downloadHandler 构造。
  • 使用参数化报告意味着您不必在 rmarkdown 脚本中重新创建输出。这项工作是在 Shiny 应用程序中完成的,参数化报告只是帮助您正确发送 objects。 它与来回传递文件​​不太一样(尽管如果它能那么简单,我很想知道)。

在此处阅读有关参数化报告的更多信息:http://rmarkdown.rstudio.com/developer_parameterized_reports.html