Reading RDS files from a select list

[Aurelio García]

Hi,

I am trying to use Shiny to do this:

I have 10 rds files in the /app/data/ directory.

I want to let the user choose one of this files and then read it into R to make some data processing.

I have tried this in ui.R:

       
selectInput("user_file", "Usuario", list.files("data/"), selected = list.files("data/")[1])

Then I am trying to read the file in server.R:

shinyServer(function(input, output, session) { 

  

    data_plot <- reactive({

      readRDS(file.path("data", input$user_file))

    })

}

or 

shinyServer(function(input, output, session) {

  

 data_plot <- reactiveFileReader(1000, session, reactive(input$user_file), readRDS) 

}

None of them seems to work.

Any help please?

Thanks,

Aurelio

[MySchizo Buddy]

print out input$user_file to see if it contains the correct path or not

[Joe Cheng]

That should work--what seems to be the problem?

I'd also be sure that, on the server side, you be very careful to validate `input$user_file %in% list.files("data/")` before you go reading anything, and stop("Access denied") if not. A malicious user could set input$user_file to "../../path-to-sensitive-data" or something, potentially.

On Wed, Feb 24, 2016 at 10:41 AM MySchizo Buddy <myschi...@gmail.com> wrote:

print out input$user_file to see if it contains the correct path or not

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[Aurelio García]

Hi,

Yes, I printed and the path is OK

[Aurelio García]

Hi Joe,

Thanks for your suggestion on validating.

The problem is: when I try to do anything with the dataframe i get an error, as if the file hadn't been read.

For example:

shinyServer(function(input, output, session) { 

  

    data_plot <- reactive({

      readRDS(file.path("data", input$user_file))

    })

    t1 <- min(data_plot$datetime)

}

Gives an error when trying to set t1:

Error in data_plot$datetime : object of type 'closure' is not subsettable

[Sigbert Klinke]

Hi,

did you try:

mydata <- data_plot()
if (mydata$datetime) { ...}

Sigbert

[Aurelio García]

Hi Sigbert,

datetime does exists, but you gave me the clue,

in my previous example I forget to put () to the variable outside a reactive context.

So this works:

shinyServer(function(input, output, session) { 

  

    data_plot <- reactive({

      readRDS(file.path("data", input$user_file))

    })

    t1 <- min(data_plot()$datetime)

}

 

Thanks so much