Python's Tornado framework implements image uploading and image size modification-Python Tutorial-php.cn

Python's Tornado framework implements image uploading and image size modification

高洛峰

Release： 2017-03-01 13:46:29

Original

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Uploading pictures

Upload pictures using form submission. The following is the html part. enctype="multipart/form-data" means that the bytes will not be encoded and uploaded. The file type needs to be specified. The type="file" of the input tag specifies the upload type.

<form action="/" enctype="multipart/form-data" method="post">
  <input type="file" name="headimg">
</form>

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The following is the part where tornado accepts files

class UploadHandler(BaseHandler):
  def post(self):
    # 这部分就是上传的文件,想要查看更多可以print self.request看看
    # 该文件返回一个元素为字典的列表
    imgfile = self.request.files.get(&#39;headimg&#39;)
    for img in imgfile:
      # img有三个键值对可以通过img.keys()查看
      # 分别是 &#39;filename&#39;, &#39;body&#39;, &#39;content_type&#39; 很明显对应着文件名,内容(二进制)和文件类型
      with open(&#39;./static/uploads/&#39; + img[&#39;filename&#39;], &#39;wb&#39;) as f:
        # 文件内容保存 到&#39;/static/uploads/{{filename}}&#39;
        f.write(f[&#39;body&#39;])

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This way you can access it through the file name of /static/uploads/

Modify the image size

The following will be written to resize the image

class UploadHandler(BaseHandler):
  @tornado.web.authenticated
  def post(self):
    # 应该写到上面, 为了显示写到了函数内
    import time
    # PIL 是 python中对图片进行操作的模块, 感兴趣可以去看一下
    from PIL import Image
    # 可以想文件一样使用, 只是存放在内存
    from cStringIO import StringIO

    # 判断上传文件大小
    size = int(self.request.headers.get(&#39;Content-Length&#39;))
    if size / 1000.0 > 2000:
      self.write("上传图片不能大于2M.")
    imgfile = self.request.files.get(&#39;headimg&#39;)
    for img in imgfile:
      # 对文件进行重命名
      name = str(time.strftime(&#39;%Y%m%d%&#39;), time.localtime())\
          + &#39;_&#39; + self.current_user + &#39;_headimg.png&#39;

      with open(&#39;./static/uploads/&#39; + name, &#39;wb&#39;) as f:
        # image有多种打开方式，一种是 Image.open(&#39;xx.png&#39;)
        # 另一种就是 Image.open(StringIO(buffer)) 
        im = Image.open(StringIO(img[&#39;body&#39;]))
        # 修改图片大小resize接受两个参数, 第一个是宽高的元组数据,第二个是对图片细节的处理，本文表示抗锯齿
        im = im.resize((72, 72), Image.ANTIALIAS)
        # 打开io 就像文件一样
        im_file = StringIO()
        im.save(im_file, format=&#39;png&#39;)
        # 这是获取io中的内容
        im_data = im_file.getvalue() 
        f.write(im_data)

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so that the file size can be modified when uploading

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