How to return a bytes value in a cherry py request body

Question

I have a postgres table that contains a bytea column. This column contains an image.

The SqlAlchemy model has this column defined as a LargeBinary. I've also tried to using BLOB, but It didn't change a thing.

I can easily retrieve a value from the database and what I get is a variable of type bytes.

How can I jsonify that bytes array? I need the json value so I can return it in the cherrypy request body like so :

data = { 'id_image': image.id_image, 'image': image.value }

Answer 1

I'm assuming you need to show that image in a browser or similar software.

Normally you can use Data URI when embedding image as a string into a web page. Modern browsers know how to decode it back.

Also I'm assuming you have a PNG image. If your case is different, feel free to change image/png to something, which matches your needs.

Here's how you can generate data URI using Python.

This example uses Python 3.6 syntax:

import base64

img_id = image.id_image
img_base64_encoded = base64.b64encode(image.value).decode('ascii')
img_type = 'image/png'  # Use some smart image type guessing if applicable

img_data_uri = f'data:{img_type};base64,{img_base64_encoded}'

img_data = {
    'id': image.id_image,
    'data_uri': img_data_uri
}