Automatically redirect R Markdown app to a different link

user_415864 0
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I need to put an automatic redirect to a different link in an R Markdown app with Shiny runtime. I tried several approaches but none works for me. (They work fine in Shiny but not in R Markdown).

How can I make my R Markdown app redirect the user to another page?

Here's a list of things I tried.

This solution: Redirect in Shiny app works in Shiny, but I couldn't get it to work in R Markdown.

This solution, again, works in Shiny but fails in R Markdown:

---
title: "Untitled"
output: 
  flexdashboard::flex_dashboard:
    orientation: columns
    vertical_layout: fill
runtime: shiny
---


```{r redirect}
    singleton(tags$head(tags$script('window.location.replace("https://stackoverflow.com");')))

```

I also tried shinyjs approach, based on How do I redirect to another webpage?, which works fine in Shiny but not in R Markdown:

```{r redirect_lab}
library(shinyjs)
useShinyjs(rmd = TRUE)

##both fail in Rmd
runjs('window.location.replace("https://stackoverflow.com");')
# runjs('window.location.href = "https://stackoverflow.com";')
```

I also tried a hacky approach that creates a link, ties it to a button and then programmatically clicks the button using shinyjs: How to select a specific tab in R Markdown?

```{r redirect_lab}
library(shinyjs)
useShinyjs(rmd = TRUE) 

tags$a(href = "https://stackoverflow.com",
  # set this button to `display: none;` but *not* to `hidden`
  shiny::actionButton("btn2", "redirect"
                      # , style = "display: none"
                      )
)
click("btn2")

```

Strangely when the R Markdown page loads it does not redirect automatically. But if I click the button manually with the mouse, then it will redirect to the link. But I'm stumped why this would not work programmatically.

shiny r-markdown r
2 Answers

We can add <meta> tags to the HTML header and trigger a redirect via

<meta http-equiv="refresh" content="0; url=http://www.stackoverflow.com/"/>'

Note that this is working in the browser, but not in the RStudio Viewer.

---
title: "Untitled"
output: 
  flexdashboard::flex_dashboard:
    orientation: columns
    vertical_layout: fill
    includes:
      in_header: myheader.html
runtime: shiny
---

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

fileConn <- file("myheader.html")
writeLines('<meta http-equiv="refresh" content="0; url=http://www.stackoverflow.com/"/>', fileConn)
close(fileConn)
```
user_93493020

A simple solution I found was to directly include a redirect javascript as an explicit <script> in the markdown, and either trigger is as direct event, or as an explicit js call.

#Option one: direct link to JS event
<script type="text/javascript">
    document.getElementById("myButton").onclick = function () {
        location.href = "http://www.google.com";
    };
</script>

```{r, echo=F}
actionButton("myButton", "Redirect")
```

#Option two: dedicate redirect js, triggered by shinyjs
<script type="text/javascript">
    go_away = function () {
        location.href = "http://www.google.com";
    };
</script> 

```{r, echo=F}
shinyjs::useShinyjs(rmd = TRUE)
actionButton("myButton2", "Redirect!!")

observeEvent(input$myButton2, {
  shinyjs::runjs('go_away()')
})

```

The first option works since r Markdown/Shiny explicitly creates input elements by ID. For less hacky second option, the function can also be called explicitly from the runjs call.

user_167002960
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