Using Webshot to "Print" Flexdashboards

printing_flexdashboard_with_webshot

This gist holds the files necessary to reproduce a minimal example of "printing" a flexdashboard using a headless browser.

main_application.Rmd

---
title: "Snapshot Example"
runtime: shiny
output:
  flexdashboard::flex_dashboard:
    orientation: rows
    vertical_layout: scroll
---


```{r setup, include=FALSE}
knitr::opts_chunk$set(warning = FALSE, message = FALSE)
library(flexdashboard)

options(digits = 1)
```

```{r libraries, message=FALSE, warning=FALSE}

# Load the required packages... you will need to ensure they are installed first.
library(dplyr); library(knitr); library(ggplot2); library(magrittr); library(shiny); library(data.table); library(DT); library(webshot)

# MAKE SURE PHANTOM JS IS INSTALLED
# webshot::install_phantomjs()

```


```{r import3, message=FALSE, warning=FALSE, include=FALSE}
data(mtcars)
```

Sidebar {.sidebar data-width=270}
=======================================================================

**Feature Selection**
```{r}
gears = mtcars$gear %>% as.factor() %>% levels()
selectizeInput("grs", "GEARS",
               gears, selected = gears[1])
renderUI({
downloadButton("downloadFile", "Download")
})
```


Dashboard
=======================================================================

Row {.tabset .tabset-fade}
-----------------------------------------------------------------------

### MPG Summary
```{r MPG}
mpgg = reactive({
mtcars %>% filter(gear %in% input$grs) %>% group_by(carb) %>% summarize(count = n(), `Avg HP` = mean(hp), `Avg mpg` = mean(mpg))
})
renderTable({
mpgg() 
})
```

### MPG Graph

```{r Graph}
mpgp = reactive({
  mtcars %>% filter(gear %in% input$grs) %>% ggplot(aes(x = hp, y = mpg)) + geom_point() + geom_smooth()
  
})

renderPlot({
  mpgp()
  
})

```

```{r download}
output$downloadFile <- downloadHandler(filename = function() { 
return(paste('Cars', '.png', sep=''))
},
    content = function(file){
    to_save <- list(
    mpgg = mpgg(),
    mpgp = mpgp()
    )
      saveRDS(to_save, "config_data.RDS")
      rmarkdown::render("shadow_page.Rmd")
      # file.remove("config_data.RDS")
      webshot::webshot("shadow_page.html", file = file)
                        })
```

shadow_page.Rmd

---
title: "Snapshot Example"
runtime: shiny
output:
  flexdashboard::flex_dashboard:
    orientation: rows
    vertical_layout: scroll
---


```{r setup, include=FALSE}
knitr::opts_chunk$set(warning = FALSE, message = FALSE)
library(flexdashboard)

options(digits = 1)
```

```{r libraries, message=FALSE, warning=FALSE}

# Load the required packages... you will need to ensure they are installed first.
library(dplyr); library(knitr); library(ggplot2); library(magrittr); library(shiny); library(data.table); library(DT); library(webshot)

# MAKE SURE PHANTOM JS IS INSTALLED
# webshot::install_phantomjs()

```


```{r import3, message=FALSE, warning=FALSE, include=FALSE}
data(mtcars)
```

Sidebar {.sidebar data-width=270}
=======================================================================

**Feature Selection**
```{r}
gears = mtcars$gear %>% as.factor() %>% levels()
selectizeInput("grs", "GEARS",
               gears, selected = gears[1])
renderUI({
downloadButton("downloadFile", "Download")
})
```


Dashboard
=======================================================================

Row {.tabset .tabset-fade}
-----------------------------------------------------------------------

### MPG Summary
```{r MPG}
mpgg = reactive({
mtcars %>% filter(gear %in% input$grs) %>% group_by(carb) %>% summarize(count = n(), `Avg HP` = mean(hp), `Avg mpg` = mean(mpg))
})
renderTable({
mpgg() 
})
```

### MPG Graph

```{r Graph}
mpgp = reactive({
  mtcars %>% filter(gear %in% input$grs) %>% ggplot(aes(x = hp, y = mpg)) + geom_point() + geom_smooth()
  
})

renderPlot({
  mpgp()
  
})

```

```{r download}
output$downloadFile <- downloadHandler(filename = function() { 
return(paste('Cars', '.png', sep=''))
},
    content = function(file){
    to_save <- list(
    mpgg = mpgg(),
    mpgp = mpgp()
    )
      saveRDS(to_save, "config_data.RDS")
      rmarkdown::render("shadow_page.Rmd")
      # file.remove("config_data.RDS")
      webshot::webshot("shadow_page.html", file = file)
                        })
```

Thanks for the code. When I run it I get: "Warning: Error in : path for html_dependency not provided". Do you know what the issue might be?

I get the same issue as erichar1..

The shadow_page.Rmd file appears to be a direct copy of main_application.Rmd without the notable changes mentioned in the blog post.