How to pass a plot (renderPlot) from shiny app as parameter to R Markdown? - variables

Question

I'm trying to download report form shiny app using R Markdown, but I'm lost! I need to pass a plot from shiny as parameter to R Markdown, and then, include this plot in my report.
I searched a lot about this, but I couldn't find anything. How can I plot this in my report?
Server.R
lm_dif_filter <- reactive({
lm_dif_corn[(lm_dif_corn$farmer == input$farmer) & (lm_dif_corn$Treat_X == 'Farmer'),]
})
output$difPlot <- renderPlotly({
dif <- ggplot(data=lm_dif_filter(), aes(x=Treat_Y, y=dif)) +
geom_bar(stat="identity",color = 'black', position=position_dodge(), width = 0.7)+
geom_hline(yintercept = 0) +
#annotate("text", min(Treat_Y), 0, vjust = -1, label = "Farmer")+
theme(legend.position = "none") +
labs(x = "Treats", y = "Diff")
ggplotly(dif)
To download:
output$report <- downloadHandler(
filename = "report.pdf",
content = function(file) {
tempReport <- file.path(tempdir(), "report.Rmd")
file.copy("report.Rmd", tempReport, overwrite = TRUE)
# Set up parameters to pass to Rmd document
params <- list(set_subtitle = input$farmer, plot = output$difPlot)
rmarkdown::render(tempReport, output_file = file,
params = params,
envir = new.env(parent = globalenv())
)
}
)
My report.rmd
---
title: "Some title"
params:
set_subtitle: test
plot: NA
subtitle: "`r params$set_subtitle`"
date: '`r format(Sys.Date(), "%B %d, %Y")`'
output:
pdf_document:
toc: yes
header-includes:
- \usepackage{fancyhdr}
always_allow_html: yes
---
\addtolength{\headheight}{1.0cm}
\pagestyle{fancyplain}
\lhead{\includegraphics[height=1.2cm]{bg.png}}
\renewcommand{\headrulewidth}{0pt}
```{r, include=FALSE}
options(tinytex.verbose = TRUE)
knitr::opts_chunk$set(echo = FALSE)
cat(params$plot)

Answer 1

One easy option is to not pass the plot, and instead pass the parameter, and refer to a shared plot function used by the shiny app and Rmd doc. For example,
Shiny app,
note the source("util.R") and report_hist(params$n)
source("util.R")
library(shiny)
shinyApp(
ui = fluidPage(
sliderInput("slider", "Slider", 1, 100, 50),
downloadButton("report", "Generate report"),
plotOutput("report_hist")
),
server = function(input, output) {
output$report_hist <- renderPlot({
report_hist(n = input$slider)
})
output$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$slider)
# Knit the document, passing in the `params` list, and eval it in a
# child of the global environment (this isolates the code in the document
# from the code in this app).
rmarkdown::render(tempReport, output_file = file,
params = params,
envir = new.env(parent = globalenv())
)
}
)
}
)
Rmd report,
note the report_hist(params$n)
---
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}
report_hist(params$n) #note this function was created in util.R and loaded by the shiny app.
```
Shared function in util.R
report_hist <- function(n){
hist(rnorm(n))
}
Here's a demo shiny app you can test it out with, https://rstudio.cloud/project/295626