Unnecessary warning when POST (JSON) body has multiple lines

[jnolis]

If the POST JSON body has newlines in it, plumber creates a warning during the request:

Warning in if (stri_startswith_fixed(body, "{")) { :
  the condition has length > 1 and only the first element will be used

Here is a toy example that creates the warning with a multi-line JSON body:

functions.R:

#' @post /test
function(message){
  "it works!"
}

run.R

library(plumber)
r <- plumb("functions.R")
r$run(port=80)

I think this could be fixed by simply changing the body in this line to body[1]

[schloerke]

I believe the body should be set to a multiline string.

https://github.com/trestletech/plumber/blob/8987a48a590dcab9e918c9d3109308220e6bc1de/R/post-body.R#L4 should be

  body <- paste0(req$rook.input$read_lines(), collapse = "\n")

[robertdj]

Both suggestions fix this issue. I have just tried the collapse approach and it doesn't cause any tests to fail.

Edit: How to decide which of the suggestions is better? @schloerke : Is there a reason why the body should be a multiline string?

[schloerke]

I don't know why it was a multiline string. My belief is that is should be collapsed to a single string as soon as possible. Most body elements do not make sense as individual lines.

Mind making a PR with the collapse change? (and a news item.)

[robertdj]

Sure :-)

[ksens]

Just for reference, noting that this warning still comes up in the version of plumber currently available on CRAN (published 2018-06-05).

I was able to get rid of the issue by installing the latest version from Github:

# in R
devtools::install_github('trestletech/plumber')