Module: UploadHelper

Defined in:
lib/generators/authkit/templates/app/helpers/upload_helper.rb

Overview

Allow direct uploads to Amazon S3. Uploads are segmented by the Everything is uploaded into an separate paths based on the current user so that files are not overwritten when multiple people upload different files with the same name.

In order to use this helper you must have the following environment variables set:

aws_access_key_id
aws_secret_access_key
aws_bucket

Configure the AWS bucket with the following CORS policy

<CORSConfiguration>
  <CORSRule>
    <AllowedOrigin>http://0.0.0.0:3000</AllowedOrigin>
    <AllowedOrigin><%= ENV['domain'] %></AllowedOrigin>
    <AllowedMethod>GET</AllowedMethod>
    <AllowedMethod>POST</AllowedMethod>
    <AllowedMethod>PUT</AllowedMethod>
    <MaxAgeSeconds>3600</MaxAgeSeconds>
    <AllowedHeader>*</AllowedHeader>
  </CORSRule>
</CORSConfiguration>

Class Method Summary collapse

Instance Method Summary collapse

Class Method Details

.aws_bucket_url ⇒ Object 



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# File 'lib/generators/authkit/templates/app/helpers/upload_helper.rb', line 99

def self.aws_bucket_url
  "https://#{ENV['aws_bucket']}.#{ENV['aws_region'] || 's3'}.amazonaws.com"
end

.aws_url_for(path, expires = nil) ⇒ Object 



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# File 'lib/generators/authkit/templates/app/helpers/upload_helper.rb', line 109

def self.aws_url_for(path, expires=nil)
  path = "/#{path}" unless path =~ /\A\//
  path = URI.encode(path)
  expires ||= 1.day.from_now
  string_to_sign = "GET\n\n\n#{expires.to_i}\n/#{ENV['aws_bucket']}#{path}"
  signature = Base64.encode64(OpenSSL::HMAC.digest(OpenSSL::Digest::Digest.new('sha1'), ENV['aws_secret_access_key'], string_to_sign)).gsub("\n","")
  query_string = URI.encode_www_form("AWSAccessKeyId" => ENV['aws_access_key_id'], "Signature" => signature, "Expires" => expires.to_i)
  "#{aws_bucket_url}#{path}?#{query_string}"
end

Instance Method Details

#aws_bucket_url ⇒ Object

The destination host for the upload always uses https even though it can be slower. Safe and sure wins the race



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# File 'lib/generators/authkit/templates/app/helpers/upload_helper.rb', line 95

def aws_bucket_url
  UploadHelper.aws_bucket_url
end

#aws_upload_params(options = {}) ⇒ Object

Use this as part of the XHR data params for the upload form Options include:

expires_at: defaults to 1 hour from now
max_file_size: defaults to 5GB (not currently used)
acl: defaults to authenticated-read
starts_with: defaults to "uploads/#{h(current_user.to_param)}/#{SecureRandom.hex}"



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# File 'lib/generators/authkit/templates/app/helpers/upload_helper.rb', line 37

def aws_upload_params(options={})
  expires_at = options[:expires_at] || 1.hours.from_now
  max_file_size = options[:max_file_size] || 5.gigabyte
  acl = options[:acl] || 'authenticated-read'
  hash = "#{SecureRandom.hex}"
  starts_with = options[:starts_with] || "uploads/#{hash}"
  bucket = ENV['aws_bucket']
  # This used to include , but it threw Server IO errors
  policy = Base64.encode64(
    "{'expiration': '#{expires_at.utc.strftime('%Y-%m-%dT%H:%M:%S.000Z')}',
      'conditions': [
        ['starts-with', '$key', '#{starts_with}'],
        ['starts-with', '$hash', '#{hash}'],
        ['starts-with', '$utf8', ''],
        ['starts-with', '$x-requested-with', ''],
        ['eq', '$success_action_status', '201'],
        ['content-length-range', 0, #{max_file_size}],
        {'bucket': '#{bucket}'},
        {'acl': '#{acl}'},
        {'success_action_status': '201'}
      ]
    }").gsub(/\n|\r/, '')

  signature = Base64.encode64(
                OpenSSL::HMAC.digest(
                  OpenSSL::Digest::Digest.new('sha1'),
                  ENV['aws_secret_access_key'], policy)).gsub("\n","")

  return {
    "key" => "#{starts_with}/${filename}",
    "hash" => "#{hash}",
    "utf8" => "",
    "x-requested-with" => "",
    "AWSAccessKeyId" => "#{ENV['aws_access_key_id']}",
    "acl" => "#{acl}",
    "policy" => "#{policy}",
    "signature" => "#{signature}",
    "success_action_status" => "201"
  }
end

#aws_upload_tags ⇒ Object

Use aws_upload_tags when embedding the upload params in a form. For example:

<form action="<%= aws_upload_url %>" method="post" enctype="multipart/form-data" id="avatar_form">
  <input type="file" name="file" id="avatar_attachment">
  <%= aws_upload_tags %>
</form>



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# File 'lib/generators/authkit/templates/app/helpers/upload_helper.rb', line 86

def aws_upload_tags
  aws_upload_params.each do |name, value|
    concat text_field_tag(name, value)
  end
  nil
end

#aws_url_for(path, expires = nil) ⇒ Object

Authenticated url for S3 objects with expiration. By default the URL will expire in 1 day. The path should not include the bucket name.



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# File 'lib/generators/authkit/templates/app/helpers/upload_helper.rb', line 105

def aws_url_for(path, expires=nil)
  UploadHelper.aws_url_for(path, expires)
end