Technology

Eleni Chappen

Using Active Storage with Active Model Serializers

Jul. 6, 2018

Attachment is the root of all suffering. If you’re a web developer, attachments are the root of all suffering.

Paperclip, a longtime go-to gem for managing file attachments, has been deprecated in favor of Active Storage, which is now officially part of Ruby on Rails as of version 5.2. So for a recent greenfield app, I took the dive into Active Storage.

Switching out dependable gems for new ones can be anxiety-inducing, but that’s web developer life. While Active Storage ended up being a breath of fresh air for many reasons, it came with a few of it’s own gotchas, particularly when dealing with querying data.

Active Storage and N+1 queries

Let’s say a user has one avatar. While Paperclip would add a few columns to your users table to store the avatar’s file data, file type, etc., Active Storage will create new tables that are solely responsible for keeping track of asset data and associating this data to your records.

These tables are called blobs and attachments. Blobs represent the actual metadata of the files, whereas Attachments are what join blobs (file data) to your application’s records (users). For every file you upload, a blob is created and associated to your record through an attachment.

These relationships are created when you attach a file through Active Storage using the has_one_attached shorthand:

class User < ApplicationRecord  
  has_one_attached :avatar

It’s important to understand these relationships between blobs and attachments when dealing with record queries that may have attachments.

For has_one_attached relationships, you can avoid N+1 queries by adding the with_attached_X method that Active Storage generates for you based on your attachment name:

User.with_attached_avatar.where(active: true)  

This is basically saying:

User.includes(avatar_attachment: :blob).where(active: true)  

I had to take special care of these relationships when using Active Model Serializers. Normally, when dealing with child records in a serializer, you can define a relationship using has_one or has_many:

class GameSerializer < ActiveModel::Serializer

  attributes :title

  has_many :users

If my User Serializer is using the avatar in any way, this would create an N+1 scenario:

class UserSerializer < ActiveModel::Serializer

  attributes :avatar_url

  def avatar_url
    ...object.avatar_url...

In order to avoid N+1 queries here, I had to ditch the built-in has_many and create a custom users method for the Game Serializer:

class GameSerializer < ActiveModel::Serializer

  attributes :title, :users

  def users
    User.with_attached_avatar.where(game_id: object.id)

Finding the right asset URL for serialization

When passing image urls through serializers, I had to search through some Active Storage Github issues and documentation to find the right url to use.

Creating images of smaller sizes is common for real-life use of your assets. Active Storage calls these variants. You’ll most likely use variants rather than the original asset in serializers.

If you want a url of the asset variant, include the Rails.application.routes.url_helpers module in your serializer, then use rails_representation_url in your url method:

class UserSerializer < ActiveModel::Serializer  
  include Rails.application.routes.url_helpers

  attributes :avatar_url

  def avatar_url
    variant = object.avatar.variant(resize: "100x100")
    return rails_representation_url(variant, only_path: true)
  end

If you want to use the original asset, use rails_blob_path instead:

return rails_blob_path(object.avatar, only_path: true)  

So there’s a little extra work when serialization is concerned, but overall I really enjoyed working with Active Storage and appreciate what a great thing this is for the Rails community.

Eleni Chappen

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Operations

8/1/16

Good Founders Make Good Clients - 5 Traits We Look For

“Ideas are easy. Implementation is hard.” – Guy Kawasaki

As a development agency that primarily works with early stage startups, we hear all kinds of business ideas. You could even say that we're in the business of building business ideas; but only one's we believe will succeed, and not on our own. We know that, without a good founder to drive implementation, even the best ideas will surely fail. In fact, most give up at the first sign of real challenge, and their ideas never see the light of day. So while we spend time evaluating the viability of the idea, we must also consider if the founder has what it takes. Here are the 5 traits we look for:

1. Tenacious belief. Some traits can be learned or honed; this is not one of them. Startups are inherently difficult, demanding, and full of unknowns and disappointment. To make it through, a founder needs confidence, determination, passion, and the like - things you can't have without first believing. We're not talking about simply believing you have a good idea. We're also not talking about blind belief to the point of delusion. This is believing strongly enough in your vision that, despite the uncertainties and inevitable struggles in your path, you will do whatever it takes to see it through.

2. Domain expertise. Serious founders need to understand their market as much as possible. Ideally, you can directly relate to the problem you're trying to solve - or - you have extensive experience that gives you insight on your target market. Even then, the best founders do everything they can to consistently learn and absorb new information.

3. Communication. The greatest entrepreneurs are masters of communication. Not all start out that way, but its something to be conscious of and constantly improve. A good founder has the ability to communicate clearly, confidently, and candidly. They can clearly explain their thoughts and ideas. They use confidence to sell themselves and their vision, as well as to lead others. They can candidly express their feelings, while maintaining control of their emotions.

4. Head in the clouds, feet on the ground. Growing a startup requires constant innovation. A good founder has vision; they dream big and consistently ask themselves, "what's next?" However, that vision will never materialize unless a founder can execute in the present. A good founder can keep their eyes to the future while practicing self awareness, focus, patience, and responsible decision making.

5. Flexibility. The survival of a business, like in nature, depends on its ability to adapt. No matter how much a founder plans, new information will arise and circumstances will change; a good founder is prepared and willing to respond. Some changes will inevitably result in failures. A founder must have the resilience to pick themselves up, learn from the failures, and push on.

6. Enjoys the ride. I know I said 5 traits, but this one's pretty important too. Yes, starting a business is difficult, risky, blah blah blah...but what's the point if you can't enjoy it? Having fun will not only make your life (feel) easier; attracting advocates, customers, employees, and investors will be easier as well.

Now these aren't the ONLY things a founder needs to build a successful business, nor do they guarantee success, but we'd bet on you. So if you have a great idea and "what it takes" (see above), we should meet.

News

10/18/17

ChangeMaker Launches!

In a world where marches and protests are making weekly headlines, people are always looking for the next cause to get behind.

But what do you do when a cause or issue you’re passionate about needs more awareness and support? How do you find people to come together? How do you organize people, activities, events, and whatever else you might need to do? And if you do find people, how do you manage all the different moving parts?

And, well, what does that have to do with us at 20spokes?

Meet ChangeMaker -- a project we recently completed and launched.

Similar to sites like Kickstarter or Indiegogo, ChangeMaker allows organizations to add a project and find fellow activists to donate to or join the cause as a volunteer. The interface provides organizations the ability to detail an issue or problem, outline a solution, and how donors or volunteers can help. When people join the project as a volunteer, they can specify their particular skillset in fields such as marketing, design, legal, or data so project managers can delegate tasks to the right people.

With funding from donations, users can work on projects for their cause by using the free website. While most project management tools have some sort of fancy, pay-to-use features, ChangeMaker is completely free to use because it is donor funded and donor maintained.

We branded, designed, and coded the ChangeMaker platform in a Rails environment. We also integrated Stripe Connect, which enables organizations to receive those donations they need to power their projects.

Putting all this together sounds like it would take a good chunk of time, right? But we kicked off this project on August 8 and launched the website this week. A little more than two months. Not too shabby, eh? Just in time for the Newfounders Conference. ChangeMaker will have a big presence at the conference with donors ready to help out organizations that have ready-to-pitch projects for its demo night. Nothing is too small or too large for ChangeMaker to help its users and organizations tackle.

Give ChangeMaker a whirl at changemaker.newfounders.us.