Flask Web开发入门之文件上传（八）

本章我们介绍Flask Web开发中涉及的文件上传模块

定义后台接收处理逻辑

# http://flask.pocoo.org/docs/0.12/patterns/fileuploads/
@app.route('/upload', methods=['POST'])
def upload_file():
  if request.method == 'POST':
    # check if the post request has the file part
    if 'file' not in request.files:
      logger.debug('No file part')
      return jsonify({'code': -1, 'filename': '', 'msg': 'No file part'})
    file = request.files['file']
    # if user does not select file, browser also submit a empty part without filename
    if file.filename == '':
      logger.debug('No selected file')
      return jsonify({'code': -1, 'filename': '', 'msg': 'No selected file'})
    else:
      try:
        if file and allowed_file(file.filename):
          origin_file_name = file.filename
          logger.debug('filename is %s' % origin_file_name)
          # filename = secure_filename(file.filename)
          filename = origin_file_name

          if os.path.exists(UPLOAD_PATH):
            logger.debug('%s path exist' % UPLOAD_PATH)
            pass
          else:
            logger.debug('%s path not exist, do make dir' % UPLOAD_PATH)
            os.makedirs(UPLOAD_PATH)

          file.save(os.path.join(UPLOAD_PATH, filename))
          logger.debug('%s save successfully' % filename)
          return jsonify({'code': 0, 'filename': origin_file_name, 'msg': ''})
        else:
          logger.debug('%s not allowed' % file.filename)
          return jsonify({'code': -1, 'filename': '', 'msg': 'File not allowed'})
      except Exception as e:
        logger.debug('upload file exception: %s' % e)
        return jsonify({'code': -1, 'filename': '', 'msg': 'Error occurred'})
  else:
    return jsonify({'code': -1, 'filename': '', 'msg': 'Method not allowed'})

判定文件类型

def allowed_file(filename):
  return '.' in filename and \
      filename.rsplit('.', 1)[1].lower() in ALLOWED_EXTENSIONS

前台页面代码

<div class="layui-inline">
      <label class="layui-form-label">上传文件</label>
 <div class="layui-input-inline">
   <input type="text" name="attach" id="upload_message" lay-verify="required" autocomplete="off"
   class="layui-input" readonly="readonly">
 </div>
</div>
<div class="layui-inline">
   <img id='img_delete' src="{{ url_for('static', filename='images/delete.png')}}" onclick="do_delete()"
     style="display: none;">
   <button type="button" class="layui-btn" id="upload"><i class="layui-icon"></i>上传文件</button>

</div>

上传按钮初始化及回调

layui.use(['upload', 'layer'], function () {
    var upload = layui.upload;
    var layer = layui.layer;
    upload.render({
      elem: '#upload'
      , url: '/upload'
      , accept: 'file'
      , exts: 'txt'
      , size: 2048
      , done: function (res) {
        console.log(res);
        if (res.code === 0) {
          layer.msg(res.filename + '上传成功');
          $("#upload_message").val(res.filename);
          $("#img_delete").show()
        } else {
          layer.alert('上传失败');
          $("#upload_message").val('上传失败！');
        }
      }
    });
})

当然允许上传，同时也应该允许对以删除文件进行删除

@app.route('/delete', methods=['GET'])
def delete_file():
  if request.method == 'GET':
    filename = request.args.get('filename')
    timestamp = request.args.get('timestamp')
    logger.debug('delete file : %s, timestamp is %s' % (filename, timestamp))
    try:
      fullfile = os.path.join(UPLOAD_PATH, filename)

      if os.path.exists(fullfile):
        os.remove(fullfile)
        logger.debug("%s removed successfully" % fullfile)
        return jsonify({'code': 0, 'msg': ''})
      else:
        return jsonify({'code': -1, 'msg': 'File not exist'})

    except Exception as e:
      logger.debug("delete file error %s" % e)
      return jsonify({'code': -1, 'msg': 'File deleted error'})

  else:
    return jsonify({'code': -1, 'msg': 'Method not allowed'})

删除按钮初始化及回调处理

function do_delete() {
    var filename = $("#upload_message").val();
    layui.use(['upload', 'layer'], function () {
      var layer = layui.layer;
      $.ajax({
        url: '/delete?filename=' + filename + "&timestamp=" + new Date().getTime()
        , type: 'GET'
        , success: function (response) {
          console.log(response)
          if (response.code == 0) {
            layer.msg('"' + filename + '"删除成功！');
            $("#upload_message").val('')
            $("img_delete").hide()
          } else {
            layer.msg('"' + filename + '"删除失败！');
          }
        }
      })
    })
  }

实现效果

源码参考：flask-sqlalchemy-web