File Uploads

Uploading a file to a website requires multipart form handling, which Ring provides with its wrap-multipart-params middleware.

(use 'ring.middleware.params
     'ring.middleware.multipart-params)

(def app
  (-> your-handler
      wrap-params
      wrap-multipart-params))

By default, uploads are stored in temporary files that are deleted an hour after being uploaded. This is handled by ring.middleware.multipart-params.temp-file/temp-file-store function.

This adds a file key to the :params map of the request where :tempfile is a java.io.File object that contains the uploaded data. You can use this to perform any further processing you want.

{
  ...
  :params {
    "file" {
        :filename "words.txt", 
        :content-type "text/plain", 
        :tempfile #object[java.io.File 0x65b164dc "/var/folders/td/2r7vtzs95pq79jzjprb_yztc0000gp/T/ring-multipart-6757896657065234625.tmp"], 
        :size 51
    }
  }, 
  ...
}