将图像上传到S3（boto + GAE）

Question

I'm trying to get s3 (using boto) setup with my GAE python app to store images uploaded by users. Currently I get the following error:

File "/Users/phyzikz/project/boto/s3/key.py", line 936, in set_contents_from_file spos = fp.tell()
AttributeError: 'str' object has no attribute 'tell'

I'm at a loss for why this is happening – the file uploaded should be a png. Here's the code that makes the upload:

class Settings(Handler):
    def get(self):
        self.render('settings.html')

    def post(self):
        image = self.request.get('image')

        if image:
            connection = S3Connection('<ak>','<sak>')
            bucket = connection.create_bucket('<s3bucket>')
            k = Key(bucket)
            k.key = '/pictures/users/'+ str(self.user.key().id())
            k.set_contents_from_file(image)

If it helps, while debugging it worked beautifully when substituting set_contents_from_file(image) with set_contents_from_string('some string'). I must be missing something simple. Here's the html:

<form method='post' action='/settings' enctype='multipart/form-data'>
    <input type='file' name='image'>
    <input type='submit'>
</form>

disclaimer: I'm new to both python and SO (this is my first question!) Any edits to improving the phrasing of the question if necessary would be appreciated.

Answer 1

You will need to wrap image in a StringIO instance so it looks like a file object

Python 2.7.2+ (default, Oct  4 2011, 20:03:08) 
[GCC 4.6.1] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> x = "123"
>>> from StringIO import StringIO
>>> y = StringIO(x)
>>> y.tell()
0
>>> 

So in your case you would

k.set_contents_from_file(StringIO(image))

Answer 2

If you can put the code (in the method: set_contents_from_file inside the Key class ) where you have defined or assigned fp , we can help better. But, looking at the error AttributeError: 'str' object has no attribute 'tell' , it is quite clear that fp is not a file object. It is a string object, hence the error. As you are new to SO, first try to correct the code yourself, then, if you ae still not getting it resolved, you can paste the code you are using to change fp to a file object.