Flask Web开发入门（八）之文件上传

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：https://github.com/ypmc/flask-sqlalchemy-web