Direct Upload to S3 Using Python/Boto/Django to Construct Policy


I have been through many iterations of this problem so far, searched out many different examples, and have been all through the documentation.

I am trying to combine Plupload ( with the AWS S3 direct post method ( However, I believe there’s something wrong with the way I am constructing my policy and signature for transmission. When I submit the form, I don’t get a response from the server, but rather my connection to the server is reset.

I have attempted using the python code in the example:

I have also tried to use the more up-to-date hashlib library in python. Whatever method I use to construct my policy and signature, I always get different values than those generated here:

I have read through this question:

How do I make Plupload upload directly to Amazon S3?

But I found the examples provided to be overly complicated and wasn’t able to accurately implement them.

My most recent attempts have been to use portions of the boto library:

But using the S3Commection.build_post_form_args method has not worked for me either.

If anyone could provide a proper example of how to create the post form using python, I would very much appreciate it. Even some simple insights on why the connection is always reset would be nice.

Some caveats:

I would like to use hashlib if possible.
I want to get an XML response from Amazon (presumably “success_action_status = ‘201’” does this)
I need to be able to upload largish type files, max size ~2GB.

One final note, when I run this in Chrome, it provides upload progress, and the upload usually fails around 37%.


Nathan’s answer helped get me started. I’ve included two solutions that are currently working for me.

The first solution uses plain Python. The second uses boto.

I tried to get boto working first, but kept getting errors. So I went back to the Amazon ruby documentation and got S3 to accept files using python without boto. (Browser Uploads to S3 using HTML POST)

After understanding what was going on, I was able to fix my errors and use boto, which is a simpler solution.

I’m including solution 1 because it shows explicitly how to setup the policy document and signature using python.

My goal was to create the html upload page as a dynamic page, along with the “success” page the user sees after a successful upload. Solution 1 shows the dynamic creation of the form upload page, while solution 2 shows the creation of both the upload form page and the success page.

Solution 1:

Solution 2:

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