基于django micro搭建网站如何实现加水印功能

from django_micro import route, run, configure
from django.http import HttpRequest, HttpResponse
from dominate.document import document
import dominate.tags as dom
from wand.drawing import Drawing   # 加水印用
from wand.image import Image  # 加水印用
import base64  # 图片转字符串用
 
 
configure({'DEBUG':True})
 
# 一些元素的cls
CENTERFRAME = "flex flex-col items-center justify-center bg-teal-200 h-screen"
UPLOAD_FORM_ATTRIS ={
  "class":"flex flex-col justify-center",
  "ic-post-to": "/file",
  "ic-target": "#result_item",
  "ic-replace-target": "true",
  "enctype": "multipart/form-data"
}
CARD1 = "flex flex-col bg-green-400 shadow-xl p-1 rounded-lg w-80 h-auto"
TEXT_INPUT = "shadow border rounded m-1 p-1 text-base text-center font-thin"
CARD2 = "flex flex-col bg-white shadow-xl p-2 rounded-lg w-80 h-80"
DASHED_BOX = "flex flex-col items-center justify-center border-dashed border-2 border-gray-200 h-full"
UPLOAD_ICON = "fas fa-file-upload text-gray-300 font-medium text-6xl"
UPLOAD_BUTTON = "flex justify-center bg-green-400 px-3 py-2 mt-4 text-white rounded shadow"
RESULT_CONTAINER = "flex flex-col bg-white items-center"
RESULT_ITEM = "flex flex-col justify-center bg-white p-2 border-t border-gray-200 w-64"
TOGGLE_TEXT_ATTRIS = {   # 这个常量后来没用
  "ic-action":"slideToggle",
  # "ic-target":"#toggle_img", # 以ID定位，只能选择第一个元素
  "ic-target":"figure"   # 以元素类型定位，会对所有同类元素进行操作
}
 
 
# 为了写head部分的引入方便，写个link_函数；下面script_函数类似
def link_(lk):
  return dom.link(rel="stylesheet",type="text/css",href=lk)
 
def script_(s):
  return dom.script(src=s)
 
def page():
  doc = document()
  with doc.head:
    link_("https://unpkg.com/tailwindcss@^1.0/dist/tailwind.min.css") # tailwind
    link_("https://extra-uru1z3cxu.now.sh/css/extra.css") # 额外写的扩展库
    link_("https://cdnjs.cloudflare.com/ajax/libs/font-awesome/5.8.2/css/all.css") # 为了使用font-awesome的图标
    script_("https://cdnjs.cloudflare.com/ajax/libs/jquery/3.4.1/jquery.min.js") # jquery
    script_("http://intercoolerjs.org/release/intercooler-1.2.2.js")  # intercooler
  with doc.body:
    with dom.div(cls=CENTERFRAME) as CenterFrame:
      with dom.form(UPLOAD_FORM_ATTRIS) as UploadForm:
        # 输入水印文字区
        with dom.div(cls=CARD1) as Card1:
          dom.p("Write down your mark here",cls="text-base font-thin text-white" )
          dom.input(cls=TEXT_INPUT,id="wm_text",type="text",name="mark_text",placeholder="your watermark text")
        # 上传图片区
        with dom.div(cls=CARD2) as Card2:
          with dom.div(cls=DASHED_BOX):
            dom.i(cls=UPLOAD_ICON,onclick='''$('#fileupload').click()''')
            dom.p("Find File", id="show_info", cls="text-gray-500 mt-4")
            dom.button("Upload", cls=UPLOAD_BUTTON)
            dom.input(cls="hidden", type="file", id="fileupload",name="ori_img",
                 onchange='''$('#show_info').text(this.value.split("\\\\").pop(-1))''')
 
      # 生成水印图片区
      with dom.div(cls=RESULT_CONTAINER) as ResultContainer:
        dom.span(id="result_item")
 
  return doc.render()
 
 
def item(result_file_path):
  filename = result_file_path.split('/',1)[-1].split('.')[0]
  print('filename:',filename)
  # 处理图片，转成字符串
  with open(result_file_path, "rb") as imageFile:
    img_str = base64.b64encode(imageFile.read())
 
  with dom.div(cls=RESULT_ITEM) as ResultItem:
    with dom.a( {
      "ic-action":"slideToggle",
      "ic-target":f"#{filename}"
    }) as ToggleText:
      dom.p(filename, cls="text-sm font-thin text-center text-gray-800")
    with dom.figure(cls="hidden",id=filename): # id中不能带'.'(点)
      dom.img(title="data src",alt="",
          src = "data:image/jpeg;base64," + str(img_str,'utf-8') ) # 转str时要加'utf-8'，否则不能去掉b'
 
  return dom.span(id="result_item").render() + ResultItem.render()
 
 
@route('')
def index(request: HttpRequest):
  return HttpResponse(page())
 
@route('file')
def filehandler(request:HttpRequest):
  ori_img = request.FILES.get('ori_img')
  mark_text = request.POST.get('mark_text') # 得用request.POST，因为form提交是用POST方式
  print('mark_text:',mark_text)
  result_file_path = 'output/Toggle_'+ori_img.name  # 打水印后的文件保存路径
 
  with Image(file=ori_img) as img:
    # 先保存原始图片
    img.save(filename='userupload/' + ori_img.name)
    # 画图，把字画在原图上
    with Drawing() as ctx:
      ctx.font_family = 'Times New Roman, Nimbus Roman No9'
      # ctx.font_size = 50
      ctx.font_size = int(img.height) * 0.1
      ctx.text_kerning = 20 # 字间距
      ctx.fill_color = 'grey'
      # ctx.opacity = 0.9  # 不透明性
      img.annotate(mark_text, ctx, left=int(img.width) * 0.1, baseline=int(img.height) * 0.45)
    img.save(filename=result_file_path)
 
  return HttpResponse(item(result_file_path))
 
app = run()