在Tornad上载多个文件

Question

我是一个新的龙卷风和尝试做一个简单的多文件上传表单，以便用户能够上传一个或多个文件。在

这是上传.py在

class UploadHandler(tornado.web.RequestHandler):
    def get(self):
        files_dict = {}
        self.render("upload_form.html", files_dict = files_dict)

    def post(self):

        ofn="" #original file name
        ufn="" #uploaded file name
        files_dict = {} # dict of original:uploaded names

        #file1  
        if self.request.files['file1'][0]: 
                file1 = self.request.files['file1'][0] #infput file
                ofn = file1['filename'] 
                extension = os.path.splitext(ofn)[1]

                if extension in EXT:
                    fname = ''.join(random.choice(string.ascii_lowercase + string.digits) for x in range(8))
                    ufn= fname+extension 
                    output_file = open("uploads/" + ufn, 'w')
                    output_file.write(file1['body'])
                    files_dict[ofn]= ufn
                else:
                    files_dict[ofn]= None

        #file2      
        if self.request.files['file2'][0]: 
            file2 = self.request.files['file2'][0] #infput file
            ofn = file2['filename'] 
            extension = os.path.splitext(ofn)[1]

            if extension in EXT:
                fname = ''.join(random.choice(string.ascii_lowercase + string.digits) for x in range(8))
                ufn= fname+extension 
                output_file = open("uploads/" + ufn, 'w')
                output_file.write(file1['body'])
                files_dict[ofn]= ufn
            else:
                files_dict[ofn]= None         


        self.render("upload_form.html", files_dict= files_dict )

以及上传的表格_表单.html公司名称：

^{pr2}$

当File1和File2都被发布时，这很正常，但是当其中一个为空时，我会得到如下错误：

Traceback (most recent call last):
  File "/usr/local/lib/python2.7/dist-packages/tornado-3.1.1-py2.7.egg/tornado/web.py", line 1141, in _when_complete
    callback()
  File "/usr/local/lib/python2.7/dist-packages/tornado-3.1.1-py2.7.egg/tornado/web.py", line 1162, in _execute_method
    self._when_complete(method(*self.path_args, **self.path_kwargs),
  File "upload.py", line 41, in post
    if self.request.files['file2'][0]:
KeyError: 'file2'

我尝试了不同的技巧，比如把每个文件上传代码放在一个尝试中，除了阻止或添加额外的条件来检查文件的主体是否存在，但都是徒劳的。谢谢你的暗示。在

Answer 1

您有KeyKerror，因为字典中没有这样的键。尝试以下代码：

test_dict = {"a":"a"}

if test_dict['a']:
    print "test_dict[a] - ok"

if test_dict['b']:
    print "test_dict[b] - ok"

输出：

^{pr2}$

使用in测试您是否在字典中给定了密钥：

def post(self):
    ofn="" #original file name
    ufn="" #uploaded file name
    files_dict = {} # dict of original:uploaded names

    #file1  
    if 'file1' in self.request.files: 
        file1 = self.request.files['file1'][0] #infput file
        # ...

    #file2    
    if 'file2' in self.request.files: 
        file2 = self.request.files['file2'][0] #infput file
        # ...    

    # ...