I would like to modify an image (make it black and white) using plumber API. Using this code I keep on getting the error that the input file size is zero:
library(plumber)
library(magick)
#* Receive a JPEG file and convert it to black and white
#* @param file:file
#* @post /convert_to_bw
function(req, res, file) {
# Read the uploaded JPEG file
# Convert file$datapath to a string
img <-image_read(as.character(file$datapath))
# Convert the image to black and white
bw_img <- img %>% image_convert(type = "Grayscale", colorspace = "gray")
# Save the black and white image to a temporary file
tmp_file <- tempfile("bw_image_", tmpdir = ".", fileext = ".png")
image_write(bw_img, path = tmp_file, format = "png")
# Return the black and white image as a response
res$setHeader("Content-Type", "image/png")
res$setHeader("Content-Disposition", paste0('attachment; filename="', "bw_", tools::file_path_sans_ext(file$filename), '.png"'))
readBin(tmp_file, "raw", n = file.size(tmp_file))
}
Any idea how to solve that?
