XLSX data upload with RestRserve

Question

I would like to work with RestRServe to have a .xlsx file uploaded for processing. I have tried the below using a .csv with success, but some slight modifications for .xlsx with get_file was not fruitful.

ps <- r_bg(function(){

  library(RestRserve)
  library(readr)
  library(xlsx)

  app = Application$new(content_type = "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet")
  app$add_post(
    path = "/echo",
    FUN = function(request, response) {
      cnt <- request$get_file("xls")
      dt <- xlsx::read.xlsx(cnt, sheetIndex = 1, header = TRUE)
      response$set_body("some function")
    }
  )

  backend = BackendRserve$new()
  backend$start(app, http_port = 65080)
})

Answer 1

What have you tried? According to the documentation request$get_file() method returns a raw vector - a binary representation of the file. I'm not aware of R packages/functions which allow to read xls/xlsx file directly from the raw vector (probably such functions exist, I just don't know).

Here you can write body to a file and then read it normal way then:

library(RestRserve)
library(readxl)

app = Application$new()
app$add_post(
  path = "/xls",
  FUN = function(request, response) {
    fl = tempfile(fileext = '.xlsx')
    xls = request$get_file("xls")

    # need to drop attributes as writeBin() 
    # can't write object with attributes
    attributes(xls) = NULL
    writeBin(xls, fl)
    xls = readxl::read_excel(fl, sheet = 1)
    response$set_body("done")
  }
)

backend = BackendRserve$new()
backend$start(app, http_port = 65080)

Also mind that content_type argument is for response encoding, not for request decoding.