Flask Restplus返回损坏的PNG文件

Question

Developing a rest API using flask with flask_restplus. It successfully returns an image file, generated by the PIL library, but the file is corrupted and cannot be viewed.

@api.route('/annotate')
class Annotate(Resource):
        @api.representation('image/png')
        def post(self):
                file = io.BytesIO()
                img = Image.new('RGBA', (50, 50), (70, 0, 0, 255))
                img.save(file, 'png')
                file.seek(0)
                return send_file(file,
                                 as_attachment=True,
                                 attachment_filename='annotated.png',
                                 mimetype='image/png')

Answer 1

It seems to be working just fine. I jus tried the following and it works as expected. Here is the resulting image as well.

from flask import Flask, render_template, jsonify, send_file
from PIL import Image
import io
app = Flask(__name__)


@app.route('/image')
def image():
    file = io.BytesIO()
    img = Image.new('RGBA', (50, 50), (70, 0, 0, 255))
    img.save(file, 'png')
    file.seek(0)
    return send_file(
        file,
        as_attachment=True,
        attachment_filename='annotated.png',
        mimetype='image/png')

Start it like so FLASK_APP=f1.py flask run .

Answer 2

Please reference to this github issue .

Swagger basically messes up the encoding. If you make the call though another client it should work properly.