Better handling of image upload

js/upload_images_controller.js

 
                 if (isOversized) {
                     this.outputTarget.classList.add('oversized')
-                    this.outputTarget.innerText = `Oversized!`
+                    this.outputTarget.innerText = 'Oversized!'
                     this.inputTarget.value = ''
                     return
                 } else {
                     this.outputTarget.classList.remove('oversized')
+                    this.outputTarget.innerText = ''
                     this.dropzoneTarget.classList.add('hidden')
                 }
 

requirements.txt

+filetype==1.0.5
 roll==0.11.0
+Wand==0.5.8

server.py

+import glob
+import mimetypes
+import random
+import string
 from http import HTTPStatus
 from pathlib import Path
 
+import filetype
 from roll import Roll
 from roll.extensions import simple_server, static
+from wand.exceptions import MissingDelegateError
+from wand.image import Image
 
 app = Roll()
 static(app)
+upload_path = Path("uploaded_images")
+
+
+def _get_random_filename():
+    random_string = "".join(
+        random.choices(
+            string.ascii_lowercase + string.digits + string.ascii_uppercase, k=15
+        )
+    )
+    file_exists = len(glob.glob(f"{upload_path}/{random_string}.*")) > 0
+    if file_exists:
+        return _get_random_filename()
+    return random_string
 
 
 @app.route("/")
 async def upload_images(request, response):
     images = request.files.list("images")
     for image in images:
-        filepath = Path("uploaded_images") / image.filename
-        filepath.write_bytes(image.read())
+        random_string = _get_random_filename()
+        tmp_filepath = Path("/tmp/") / random_string
+        tmp_filepath.write_bytes(image.read())
+        output_type = filetype.guess_extension(str(tmp_filepath))
+        error = None
+
+        try:
+            with Image(filename=tmp_filepath) as img:
+                img.strip()
+                with img.convert(output_type) as converted:
+                    output_filename = f"{random_string}.{output_type}"
+                    output_path = upload_path / output_filename
+                    if output_type not in ["gif"]:
+                        converted.sequence = [converted.sequence[0]]
+                    converted.save(filename=str(output_path))
+        except MissingDelegateError:
+            error = "Invalid Filetype"
+        finally:
+            if tmp_filepath.exists():
+                tmp_filepath.unlink()
+    # TODO: deal with errors!
     response.status = HTTPStatus.FOUND
     response.headers["Location"] = "/"