How to react on components inserted via the eval() function

[Johnny Baillargeaux]

Hi,

Using uiOutput (ui.r) and renderUI (server.r) I insert components dynamically but for some reason, the components are extracted from a text variable and displayed using eval(parse()). 

How can i react on components inserted this way because they are not known in advance in UI.R

pseudo code:

ui.r

uiOutput("criteriaList")

server.r

output$criteriaList <- renderUI({

x <- 'textInput("ID", "LABEL", "")'   

eval(parse(text=x))

})

Of course, i have reduced the real source code to pay attention to my real problem because the real source is more complexe and the variable is not so simple.

Cdts,

[Vincent]

Try to avoid eval/parse where possible in Shiny apps. If ID and LABEL are not know you could take a look at Winston's code. 

https://github.com/wch/testapp/blob/master/dynamic_in_out/server.r

If you give some more information we might be able to help you find a more convenient way to achieve the effect you are looking for.

[Winston Chang]

I would very, very strongly recommend NOT using eval() on any code that the user types. A user could easily run any command just by typing in some text with a call to system().

Here's a way to access an input with a name. If the text input is ID, then you can use this:

  input[[input$ID]]

-Winston

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[Stéphane Laurent]

x <- 'textInput("ID", "LABEL", "")'   

eval(parse(text=x))

generates the same output as 

x <- '<label for="ID">LABEL</label><input id="ID" type="text" value=""/>'

HTML(x)

and the second option is safe.