python Idea and Example of Image Stream Transmission of url Converting Two dimensional Code

1. Scenarios

Dynamically generate URL for 2D code front-end display (WeChat payment, etc.)-"

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

2. Streaming, front-end rendering
The binary stream returns to the front end, which is displayed according to the binary stream code type

3. Front-end js generation
The background obtains code_url paid by WeChat, and the front-end js generates code_url into a 2-dimensional code and renders it

Actual code

Using the python_web framework-"tornado
manager.py

import os
import asyncio

import tornado.ioloop
import tornado.httpserver
import tornado.web
import tornado.options

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


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


def create_app():
  settings = {
    "template_path": os.path.join(os.path.dirname(__file__), "templates"),
    "static_path": os.path.join(os.path.dirname(__file__), "static"),
  }
  application = tornado.web.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 = tornado.httpserver.HTTPServer(app)
  server.listen(options.port)
  asyncio.get_event_loop().run_forever()

apps.py

import tornado.web
from manager_handler import gen_qrcode, gen_qrcode_obj,gen_qrcode_buf


class BaseHandler(tornado.web.RequestHandler):
  pass


class UrlHandler(BaseHandler):
  def get(self):
    #  Get a link 
    self.render('qrcode.html', title='url', data='URL- Submit ', img_stream='')

  async def post(self):
    #  Generate 2 Dimension code 
    url = self.get_argument('url_str')

    # URL Conversion 2 Dimension code 
    img_stream = gen_qrcode(url)
    await self.render('qrcode.html', title='qrcode', data=' Scan code payment ', img_stream=img_stream)


class Url2Handler(BaseHandler):
  def get(self):
    #  Get a link 
    self.render('qrcode.html', title='url', data='URL- Submit ', img_stream='')

  async def post(self):
    #  Generate 2 Dimension code 
    url = self.get_argument('url_str')

    # URL Conversion 2 Dimension code 
    img_stream = gen_qrcode_obj(url=url)
    # await self.render('qrcode.html', title='qrcode', data=' Scan code payment ', img_stream=img_stream)
    self.set_header('Content_Type', 'image/jpg')
    self.set_header('Content_length', len(img_stream))
    self.write(img_stream)


class Url3Handler(BaseHandelr):
  def get(self):
    self.render('qrcode.html', 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')
    self.write(img_stream)

manager_handler.py

import qrcode
import io
import base64
import time


def gen_qrcode(url):
  """
   Mode 1 :  URL Conversion 2 Dimension code 
  :param url:  Conversion 2 Dimensional code URL
  :return: base64 Coded  2 Binary flow  2 Dimension code data 
  """
  qr = qrcode.make(url)
  buf = io.BytesIO()
  qr.save(buf)
  img_buf = buf.getvalue()
  img_stream = base64.b64encode(img_buf)
  return img_stream


def gen_qrcode_obj(version=1, box_size=10, border=4, url=None):
  """
   Mode 2 :  URL Conversion 2 Dimension code (picture stream transmission,  template Need to be specified  data:base64 Coding) 
  :param version:
  :param box_size:
  :param border:
  :return:
  """
  qr = qrcode.QRCode(
    version=version,
    error_correction=qrcode.constants.ERROR_CORRECT_L,
    box_size=box_size,
    border=border,
  )

  url = "https://www.12dms.com" if url is None else url
  save_name = "./" + "qrcode" + str(time.time()) + ".png"

  qr.add_data(url)
  qr.make()
  img = qr.make_image()
  img.save(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 = qrcode.make(words)
  buf = io.BytesIO()
  qr.save(buf, 'png')
  qr_buf = buf.getvalue()
  # img_stream = base64.b64encode(qr_buf)
  return qr_buf

base.html

<!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>

qrcode.html

{% extends "base.html" %}

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

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


{% block content %}
  <form method="post" action="" >
    <p>
       Enter the to be converted URL : <input name="url_str"/>
      <br>
{#      {{ img_stream }}#}
      {% if img_stream %}
        <img style="width:180px" src="data:;base64,{{ img_stream }}" alt="">
      {% end %}
    </p>
    <br>
    <input id="submit" type="submit" value=" Generate 2 Dimension code ">
  </form>
{% end %}

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