# File lib/aws/s3/presigned_post.rb, line 342 def fields signature = config.signer.sign(policy, "sha1") fields = { "AWSAccessKeyId" => config.signer.access_key_id, "key" => key, "policy" => policy, "signature" => signature }.merge(optional_fields) fields["x-amz-security-token"] = config.signer.session_token if config.signer.session_token fields.merge(optional_fields) end