python-Image streaming transfer ideas and examples (url conversion QR code)

1. Scene

Dynamically generate the URL into a QR code front-end display (WeChat Payment, etc.,) -

1. Static file path access
Return URL_name, (a tag, src static route access)

2. Streaming, front-end rendering
The binary stream is returned to the front-end, which displays it according to the binary stream encoding type

3. Front-end js generation
The backend gets the code_url of the wechat payment,the frontend js generates a QR code from the code_url and renders it

Actual code

Using the python_web framework --> tornado

import os
import asyncio

import 
import 
import 
import 

from  import define, options, parse_command_line
from apps import UrlHandler, Url2Handler, Url3Handler


define("port", default=8000, type=int)


def create_app():
  settings = {
    "template_path": ((__file__), "templates"),
    "static_path": ((__file__), "static"),
  }
  application = (
    handlers=[
      (r"/url", UrlHandler),
      (r"/url2", Url2Handler),
      (r"/url3", Url3Handler),
    ],
    debug=True,
    **settings,
  )
  return application


if __name__ == '__main__':
  parse_command_line()
  app = create_app()
  server = (app)
  ()
  asyncio.get_event_loop().run_forever()

import 
from manager_handler import gen_qrcode, gen_qrcode_obj,gen_qrcode_buf


class BaseHandler():
  pass


class UrlHandler(BaseHandler):
  def get(self):
    # Get the link
    ('', title='url', data='URL-Submit', img_stream='')

  async def post(self):
    # Generate QR code
    url = self.get_argument('url_str')

    # URL to QR code conversion
    img_stream = gen_qrcode(url)
    await ('', title='qrcode', data='Sweeping code payment', img_stream=img_stream)


class Url2Handler(BaseHandler):
  def get(self):
    # Get the link
    ('', title='url', data='URL-Submit', img_stream='')

  async def post(self):
    # Generate QR code
    url = self.get_argument('url_str')

    # URL to QR code conversion
    img_stream = gen_qrcode_obj(url=url)
    # await ('', title='qrcode', data='Sweep Payment', img_stream=img_stream)
    self.set_header('Content_Type', 'image/jpg')
    self.set_header('Content_length', len(img_stream))
    (img_stream)


class Url3Handler(BaseHandelr):
  def get(self):
    ('', title='url', data='URL-Submit', img_stream='')

  def post(self):
    url = self.get_argument('url')
    img_stream = gen_qrcode_buf(url)
    self.set_header('Content-Type', 'image/png')
    (img_stream)

manager_handler.py

import qrcode
import io
import base64
import time


def gen_qrcode(url):
  """
  Way 1: URL to convert QR code
  :param url: the URL to convert the QR code to
  :return: base64-encoded binary stream of QR code data
  """
  qr = (url)
  buf = ()
  (buf)
  img_buf = ()
  img_stream = base64.b64encode(img_buf)
  return img_stream


def gen_qrcode_obj(version=1, box_size=10, border=4, url=None):
  """
  Way 2: URL to QR code conversion (image streaming, template needs to specify data:base64 encoding)
  :param version: :param box_size.
  :param box_size.
  :param border.
  :return: :param box_size: :param border.
  """
  qr = (
    version=version,
    error_correction=.ERROR_CORRECT_L,
    box_size=box_size,
    border=border,
  )

  url = "https://" if url is None else url
  save_name = "./" + "qrcode" + str(()) + ".png"

  qr.add_data(url)
  ()
  img = qr.make_image()
  (save_name.encode())
  with open(save_name, 'rb') as img_f:
    img_stream = img_f.read()
    img_stream = base64.b64encode(img_stream)
    print(img_stream)
  return img_stream

def gen_qrcode_buf(words):
  qr = (words)
  buf = ()
  (buf, 'png')
  qr_buf = ()
  # img_stream = base64.b64encode(qr_buf)
  return qr_buf

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <title>{% block title %}{% end %}</title>
  {% block head %}{% end %}
</head>

<body>
  <h1 style="text-align: center">
    {% block h1 %}{{ data }}{% end %}
  </h1>
  {% block content %}{% end %}
</body>
</html>

{% extends "" %}

{% block title %}
  {{ title }}
{% end %}

{% block h1 %}
  {{ data }}
{% end %}


{% block content %}
  <form method="post" action="" >
    <p>
      Input the value to be convertedURL：<input name="url_str"/>
      <br>
{#      {{ img_stream }}#}
      {% if img_stream %}
        <img style="width:180px" src="data:;base64,{{ img_stream }}" alt="">
      {% end %}
    </p>
    <br>
    <input  type="submit" value="Generate QR code">
  </form>
{% end %}

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