Google app engine with python

Question

I'm new to Google app engine with python ,please help me!

Here is my html code:

<form action="" method="POST">      
    <div class="form-group">
        <label for="uploaded_file">Attached file:</label>
        <input type="file" id="uploaded_file" name="uploaded_file">
    </div>
    <div class="form-group">
        <button class="btn-primary" type="submit">Save note</button>
    </div>
</form>

Here is my python code:

def post(self):
    uploaded_file = self.request.POST.get('uploaded_file')     
    file_name = getattr(uploaded_file, 'filename', None)
    file_content = getattr(uploaded_file, 'file', None)
    if uploaded_file:
        self.response.out.write(uploaded_file)
        self.response.out.write(file_name)
        self.response.out.write(file_content)

I deploy my project to Google app engine and visit the website. I choose a picture and click the submit button, it can show uploaded_file(file's name). But, file_name and file_content show None.

If I modify my code :

def post(self):
    uploaded_file = self.request.POST.get('uploaded_file')     
    file_name = getattr(uploaded_file, 'filename')
    file_content = getattr(uploaded_file, 'file')

It will show:

File "C:\Users\pc2\Desktop\test\main.py", line 98, in post
    file_name = getattr(uploaded_file, 'filename')
AttributeError: 'unicode' object has no attribute 'filename'

Someone help me to get file or picture ,please!

Have you checked the samples here? : https://cloud.google.com/appengine/docs/python/blobstore/#Python_Uploading_a_blob — Paul Lernmark, Mar 15 '16 at 07:00
I forgot to tell something : I want to upload my file to Google Cloud Storage , not Blobstore. I'm so soory... — 趙偉丞, Mar 15 '16 at 07:25

score 1 · Accepted Answer · edited May 23 '17 at 11:45

In your form, you need to an 'enctype' attribute so that uploaded files are handled properly - see this answer for more details on enctype. Your form tag should look like this:

 <form action="" method="POST" enctype="multipart/form-data">

Change your post method to this:

def post(self):
    uploaded_file = self.request.POST.get('uploaded_file')     
    file_name = getattr(uploaded_file, 'filename', None)
    file_content = getattr(uploaded_file, 'file', None)
    if uploaded_file is not None:
        self.response.out.write(uploaded_file)
        self.response.out.write(file_name)
        self.response.out.write(file_content)

The change here is changing if uploaded_file: to if uploaded_file is not None:. This is because a successfully uploaded file will not be None, but would still fail your original if test. I would leave the 'None' arguments to getattr in place - these will prevent exceptions if the user clicks on submit but has not uploaded a file.

Finally, uploaded files do not have a file_content attribute, so this will always be None. If you want to access the file's raw bytes you will need to do

file_content = uploaded_file.file.read()

Note that the file content could be very large, and will not render as an image if you just write it out to the response - you'll just see the raw bytes.

Google app engine with python

1 Answers1