My Sinatra Project discoveries

Thank you Brian Emory!

When I was planning my Sinatra Project, I was pretty confident in my idea (based on my work experience). I didn’t have any issues with Model-View-Controller (MVC) structure, as I already had a picture of my database in my mind. But there was some things that I was worried about (environment,config). Just before i started the project I learned that simple line of code will create complete Sinatra template with all files in the right places.

gem install corneal

With this line all magic starts, and you can learn more by visiting - https://thebrianemory.github.io/corneal/. Once you install gem, create your app and run bundle, I would suggest using corneal scaffold NAME command. It’s creates model and adds views and controllers for that model. Thank you Brian Emory for creating this super useful Gem.

Slug

Each record in database table has unique ID number, but it’s not the most convienient way to identify records by just a number. It would be way better to have something more readable. Therefore in my database tables have at least one more unique column. instructors, courses & course_groups tables have 1 common column - name. http://localhost:9393/instructors/anna looks and feels a lot better than http://localhost:9393/instructors/1, right? In the course we’ve learned about slug - human-readable, unique identifier. So if you check this url - http://localhost:9393/instructors/anna - anna is a slug. How do we get it and how do we access records with slug, it’s not part of the database?

How do we create a slug? - we can use the method below
```
def slug
 name.downcase.strip.gsub(' ', '-').gsub(/[^\w-]/, '')
  end
```
it will turn name value into slug (i.e. Nick Solony => nick-solony)
How do we find object by slug?
```
def find_by_slug(url)
 find {|object| object.slug == (url)}
end
```
These methods can be added to each model, but in order to keep code DRY it’s best to create a module in concerns folder and use it in each model. So in order for me to be able to re-use same modules in all of my models, I used same column name - “name”. While writing this post, I actually found a slugify gem - https://rubygems.org/gems/slugify/versions/1.0.7. Feel free to explore it.

CRUD / delete/ a href

While working on navigation in my app, I’ve encountered following problem, I used a href links to navigate my app and to access edit function. When I tried to do the same for delete, my app broke. So I started looking into this issue. Lets break it apart:

<a href="/instructors/<%=instructor.slug%>/edit"><%=instructor.last_name%>, <%=instructor.first_name%></a>

if we click on the link created by code above it would reach into GET method get "/instructors/:slug/edit". However, delete requires DELETE method and it can’t be accessed via GET method.

Therefore, I had to switch all of my edit links to be buttons.

<button class ="button" onclick="window.location.href='/instructors/<%=@instructor.slug%>/edit'">Edit Profile</button>

and used delete form in order to ge to DELETE method

<form action="/instructors/<%=@instructor.slug%>/delete" method="post">
      <input type="hidden" name="_method" value="DELETE">
      <input class = "button" type="submit" value="Delete Instructor">
  </form>

Conclusion

Each new project brings new chalenges, but they allow me to practice an art of Google-fu. As I was once told, don’t try to invent the wheel, 99% of things already exist you just need to know how to find it. So I think it’s important to learn how to find answers: ask friends, mentors, google!