My requirements is to upload the assets to s3 bucket. One approach is to upload file to my server and then to amazon s3, but my application deals in big file in that case it blocks my process which i don't want. Second approach i can upload directly to amazon s3 bucket in this case i can save my asset block.
I work on rails so code snippet reflects ruby but its an easy you can do in any language
Variables
AWS-BUCKET-NAME - name of the bucket in which you want to upload.
AWSAccessKeyId - Aws access key of your account.
PATH - where you want to upload file(its your logic to generate dynamic value, i used ruby SecureRandom.uuid).
REDIRECTPATH - where amazon sends the response with uploaded file path and bucket name.
Policy - it is base64 encoded policy i will explain later.
Signature - it is base64 encoded signature
HTML Code for form
.s3.amazonaws.com/" method="post" enctype="multipart/form-data">
PATH">
AWSAccessKeyId">
REDIRECTPATH">
Policy">
Signature">
File to upload to S3:
I work on rails so code snippet reflects ruby but its an easy you can do in any language
Variables
AWS-BUCKET-NAME - name of the bucket in which you want to upload.
AWSAccessKeyId - Aws access key of your account.
PATH - where you want to upload file(its your logic to generate dynamic value, i used ruby SecureRandom.uuid).
REDIRECTPATH - where amazon sends the response with uploaded file path and bucket name.
Policy - it is base64 encoded policy i will explain later.
Signature - it is base64 encoded signature
HTML Code for form
.s3.amazonaws.com/" method="post" enctype="multipart/form-data">
PATH">
AWSAccessKeyId">
REDIRECTPATH">
Policy">
Signature">
File to upload to S3:
Policy - it a base64 encoded string which contain the policy. Policy just nothing but the cross verification of the form field value(other than AWSAccessKeyId, policy and signature fields). you 3 options starts_with, exact match and range
sample policy is
example(Its ruby code but you can easy understand it) :-
def generate_encoded_policy
policy_document = {expiration: "2029-01-01T00:00:00Z",
conditions: [
{bucket: AWS-BUCKET-NAME},
["starts-with", "$key", key_base_name],
{acl: "private"},
{success_action_redirect: REDIRECTPATH},
["starts-with", "$Content-Type", "application/pdf"],
["content-length-range", 0, 104857600]
]
}.to_json
Base64.encode64(policy_document).gsub("\n","")
end
it is a ruby function which return me the BASE64 encoded string
Signature - It is also the base64 encoded signature
example:-
def generate_signature
Base64.encode64(
OpenSSL::HMAC.digest(
OpenSSL::Digest::Digest.new('sha1'),
AWSSECRETKEY, generate_encoded_policy)
).gsub("\n","")
end
for more detail refer http://aws.amazon.com/articles/1434
