Read multipart form data from Flask

flask_multipart_form_file_upload.py

from werkzeug.utils import secure_filename
from flask import Flask, render_template, request

@app.route("/my-upload-endpoint", methods=["POST"])
def my_upload_function():
	if request.files.get("my-file-field-name") is None:
		return render_template("my_error_page.html", an_optional_message="Error uploading file")
	# Put here some other checks (security, file length etc...)
	f = request.files["my-file-field-name"]
	f.save(secure_filename(f.filename))
	f.stream.seek(0)
	content = ""
	for line in f.stream.readlines():
		content += line.decode("UTF-8") # Decode here as needed
	print(content)
	
	
# <form action="/my-upload-endpoint" method="POST" enctype="multipart/form-data">
#	<input name="my-file-field-name" type="file" class="form-control"/>
#	<input type="submit" value="Upload">
# </form>

What's the difference between:

request.files.get("field_name") and request.files["field_name"]

Well the main differences lies in the value returned and the error raised.

request.files.get("field_name"), just returns an None value but does not raise an error if the key is not found. We can also put a default value in case the key is not on the dictionary: request.files.get("field_name", -1). So it can be easier to check for inconsistency on the request.