flask wtf upload image file to aws s3 - python-3.x

Question

I want to upload image to aws s3 using presigned url and the image is selected by users only.
So I make file input field using flask-wtf filefield.
After user submit the form(PostForm), I want to get the image's data and send to presigned-url.
But I don't know how to get image file's information from the Form.
Please help me!!!
I used example code from below tutorials. But the difference is that I use flask-wtf not local image file.
https://boto3.amazonaws.com/v1/documentation/api/latest/guide/s3-presigned-urls.html
In following code, the problem line is here.
files = {'file': (save_objectname, image.read())}
http_response = requests.post(response['url'], data=response['fields'], files=files)
when I print(image.read())
it shows
b'' <--- nothing...
How can I fix it???
def create_post():
form = PostForm()
save_post_foldername = 'post_images'
if form.validate_on_submit():
if form.post_image.data:
image_file = form.post_image.data
save_post_objectname = generate_filename(image_file)
# Generate a presigned S3 POST URL
post_to_aws_s3(image_file, save_post_foldername, save_post_objectname)
def post_to_aws_s3(image, save_foldername, save_objectname):
fields = {
"acl": "public-read",
"Content-Type": image.content_type
}
conditions = [
{"acl": "public-read"},
{"Content-Type": image.content_type}
]
try:
response = s3_client.generate_presigned_post(
Bucket=S3_BUCKET,
Key=save_foldername+'/'+save_objectname,
Fields=fields,
Conditions=conditions,
ExpiresIn=600
)
print(response)
print(response['url'])
print(image.content_type)
#with open(image, 'rb') as f:
#files = {'file': ('abc.png', f)}
#files = {'file': (image, f)}
files = {'file': (save_objectname, image.read())}
http_response = requests.post(response['url'], data=response['fields'], files=files)
print(image.read())
except ClientError as e:
print("error")

Answer 1

Access_ID and secret ID refer to your aws user access id and secret key, because boto3 will use that to access your aws s3 using the user you assign to it.
s3 = boto3.resource("s3", aws_access_key_id=os.getenv("ACCESS_ID"), aws_secret_access_key=os.getenv("ACCESS_SECRET_ID"))
s3.Bucket("[NAME OF BUCKET]").put_object(Key="images/"+request.files["image"].filename, Body=request.files["image"] )
make sure you you include "enctype" under forms, under jinja, e.g.
<form method="POST" action="" enctype="multipart/form-data">