Error: shiny app crashes on browser when using qr_scanner

[mkaranja]

I have a minimal app working well on my local but crashes on shiny server pro when I click 'Scan Barcode' button (see attached error log). I think the app can't find camera on browser. Is it possible to have a pop-window on browser requesting access to your camera?

library(shiny)
library(opencv)

UI

ui <- fluidPage(
titlePanel("Read QR code in real-time"),
fluidRow(
actionButton("barcode", "Scan Barcode"),
textOutput("results")
)
)

server logic

server <- function(input, output) {
observeEvent( input$barcode , {
identity <- opencv::qr_scanner(draw = FALSE, decoder = "wechat")
output$results <- renderText({
identity
})
})
}

Run the application

shinyApp(ui = ui, server = server)

Error log:

Thanks

[mkaranja]

I have seen many applications using BisonCam, https://cozmo.github.io/jsQR/. And I think it would be a good addition to the opencv::qr_scanner() function.

[jeroen]

Sadly it is not so easy. The qr_scanner will open a camera on the R session, which is on the server side.

But it seems like you can accomplish what you need with BisonCam without the need for R? Or you can use a library to take a picture in the browser and upload that to R and use opencv:: ocv_qr_detect to read and scan the image.

[mkaranja]

Maybe but I'm not giving up.
We can borrow from this shiny app: https://matthew-j-oldach.shinyapps.io/shiny-filteRs/