## On your app.forms.py
from member.models import UserProfile
from django import forms
import datetime
import base64
import hmac, sha, simplejson
class S3UploadForm(forms.Form):
"""
http://developer.amazonwebservices.com/connect/entry.jspa?externalID=1434
<input type="hidden" name="key" value="uploads/${filename}">
<input type="hidden" name="AWSAccessKeyId" value="YOUR_AWS_ACCESS_KEY">
<input type="hidden" name="acl" value="private">
<input type="hidden" name="success_action_redirect" value="http://localhost/">
<input type="hidden" name="policy" value="YOUR_POLICY_DOCUMENT_BASE64_ENCODED">
<input type="hidden" name="signature" value="YOUR_CALCULATED_SIGNATURE">
<input type="hidden" name="content_type" value="image/jpeg">
"""
key = forms.CharField(widget = forms.HiddenInput)
AWSAccessKeyId = forms.CharField(widget = forms.HiddenInput)
acl = forms.CharField(widget = forms.HiddenInput)
success_action_redirect = forms.CharField(widget = forms.HiddenInput)
policy = forms.CharField(widget = forms.HiddenInput)
signature = forms.CharField(widget = forms.HiddenInput)
content_type = forms.CharField(widget = forms.HiddenInput)
file = forms.FileField()
def __init__(self, aws_access_key, aws_secret_key, bucket, key,
expires_after = datetime.timedelta(days = 30),
acl = 'public-read',
success_action_redirect = None,
content_type = '',
min_size = 0,
max_size = None,
):
self.aws_access_key = aws_access_key
self.aws_secret_key = aws_secret_key
self.bucket = bucket
self.key = key
self.expires_after = expires_after
self.acl = acl
self.success_action_redirect = success_action_redirect
self.content_type = content_type
self.min_size = min_size
self.max_size = max_size
policy = base64.b64encode(self.calculate_policy())
signature = self.sign_policy(policy)
initial = {
'key': self.key,
'AWSAccessKeyId': self.aws_access_key,
'acl': self.acl,
'policy': policy,
'signature': signature,
'content_type': self.content_type,
}
if self.success_action_redirect:
initial['success_action_redirect'] = self.success_action_redirect
super(S3UploadForm, self).__init__(initial = initial)
if self.content_type:
# we change the name of the field to the S3 required
self.fields['content_type'].widget.attrs.update({'name':'Content-Type'})
# We need to manually rename the content_type field to content_type
if self.max_size:
self.fields['MAX_SIZE'] = forms.CharField(widget=forms.HiddenInput)
self.initial['MAX_SIZE'] = self.max_size
# Don't show success_action_redirect if it's not being used
if not self.success_action_redirect:
del self.fields['success_action_redirect']
def add_prefix(self, field_name):
# Hack to use the S3 required field name
if field_name == 'content_type' and self.content_type:
field_name = 'Content-Type'
return super(S3UploadForm, self).add_prefix(field_name)
def as_html(self):
"""
Use this instead of as_table etc, because S3 requires the file field
come AFTER the hidden fields, but Django's normal form display methods
position the visible fields BEFORE the hidden fields.
"""
html = ''.join(map(unicode, self.hidden_fields()))
html += unicode(self['file'])
return html
def as_form_html(self, prefix='', suffix=''):
html = """
<form action="%s" method="post" enctype="multipart/form-data">
<p>%s <input type="submit" value="Upload"></p>
</form>
""".strip() % (self.action(), self.as_html())
return html
def is_multipart(self):
return True
def action(self):
return 'https://%s.s3.amazonaws.com/' % self.bucket
def calculate_policy(self):
conditions = [
{'bucket': self.bucket},
{'acl': self.acl},
['starts-with', '$key', self.key.replace('${filename}', '')],
["starts-with", "$Content-Type", self.content_type],
]
if self.content_type:
conditions.append(
['starts-with','$Content-Type',self.content_type]
)
if self.max_size:
conditions.append(
['content-length-range',self.min_size,self.max_size]
)
if self.success_action_redirect:
conditions.append(
{'success_action_redirect': self.success_action_redirect},
)
policy_document = {
"expiration": (
datetime.datetime.now() + self.expires_after
).isoformat().split('.')[0] + 'Z',
"conditions": conditions,
}
return simplejson.dumps(policy_document, indent=2)
def sign_policy(self, policy):
return base64.b64encode(
hmac.new(self.aws_secret_key, policy, sha).digest()
)
## On a app.view.py
def profile_image(request,template_name=None,user=None):
s3uploadform = S3UploadForm(
settings.AWS_ACCESS_KEY_ID,
settings.AWS_SECRET_ACCESS_KEY,
settings.AWS_STORAGE_BUCKET_NAME,
'uploads/'+user+'_photo.jpg',
content_type='image/',
success_action_redirect = 'http://domain/johnTheUser/upload_success',
max_size=734003, # 700 kbs
expires_after = datetime.timedelta(days=99999) #forever!
)
context = {'form':s3uploadform}
return render_to_response(template_name,context,
context_instance=RequestContext(request))
## On a template.html
<html>
<head>
<script type="text/javascript" src="//ajax.googleapis.com/ajax/libs/jquery/1.7.1/jquery.min.js"></script>
<script>
$(function(){
var max_size = {{form.max_size}};
var allowed_file_extensions = ['png','jpg'];
var $upload_form = $('#image_upload_form');
$('#id_file').change(function(){
if($(this).val()){
file_name = $(this).val();
file_extension = file_name.substring(file_name.length - 3,file_name.length)
if($.inArray(file_extension,allowed_file_extensions) < 0){
alert('Wrong file type');
return false;
}
if($(this)[0].files[0].size > max_size){
alert('The file is too big.')
return false;
}
$upload_form.submit();
}
else{
return false;
}
})
})
</script>
</head>
<form id='upload_form' action="https://{{BUCKET_NAME}}.amazonaws.com/" method="post" enctype="multipart/form-data">
{{form.key}}
{{form.AWSAccessKeyId}}
{{form.acl}}
{{form.success_action_redirect}}
{{form.policy}}
{{form.signature}}
{{form.content_type}}
{{form.file}}
<input type="submit" value="Save" />
</form>
</html>