Elixir Phoenix Plugs

Gotta admit, once I got the auth working and the deployment going, I was a bit hesitant to start adding to the project again. Because that meant, failed builds, unknown errors, and a general sense of failing. We just got things working! But's the sayin' "if it's not broken, you're not working hard enough"? So back at it I guess.

The layout and details

Routes

/ root of the app will eventually be an aggregate of incoming from Micro.Blog + our own feed (maybe) /profile ‘Settings’ this is where we’ll be able to add targets for our re-posting feature ‘echo’ add token keys and incorporate 3rd party API’s /profile/posts list of current users posts /posting this is the ‘editor’ with fields for title and content Successful ‘post’ returns the user to an updated list of posts Authorization now that we have authentication out of the way. Let’s deal with only that user can post to that users account.

Just do it already!

MB:postit> mix phx.gen.html Posting Post posts title:string content:text * creating lib/postit_web/controllers/post_controller.ex * creating lib/postit_web/templates/post/edit.html.eex * creating lib/postit_web/templates/post/form.html.eex * creating lib/postit_web/templates/post/index.html.eex * creating lib/postit_web/templates/post/new.html.eex * creating lib/postit_web/templates/post/show.html.eex * creating lib/postit_web/views/post_view.ex * creating test/postit_web/controllers/post_controller_test.exs * creating lib/postit/posting/post.ex * creating priv/repo/migrations/20190717045929_create_posts.exs * creating lib/postit/posting.ex * injecting lib/postit/posting.ex * creating test/postit/posting_test.exs * injecting test/postit/posting_test.exs Add the resource to your browser scope in lib/postit_web/router.ex: resources "/posts", PostController remember to update your repository by running migrations: $ mix ecto.migrate MB:postit>

That didn’t take long. Our first error. 😭

assign @current_user not available in eex template. so it looks like we’ve hit an error in the form that is created when we ran the generator.

we’d forgotten to add the security plug to get for auth and the conditional in our Navbar is looking for current_user in order to render the login or logout buttons. happy that was simple.

The question is now, I have defined the secure function twice for both events and posts. Is there a place for those types of functions that i will be using in multiple controllers? Option 1 seems to be helpers Option 2 as found in Chris Bell Sharing Methods between controllers
Turns out the web.ex file has this cool macro __using__ def controller do quote do use Phoenix.Controller, namespace: PostitWeb import Plug.Conn import PostitWeb.Gettext alias PostitWeb.Router.Helpers, as: Routes end end

Create a controller helper and add it in here!

I ended up with a ‘controller helper’ and accidently build a plug Plugs: what did i learn [dot] info plugs feel conceptually a lot like express middleware, where it takes the connection or request and does a function on it, then returns the conn / request for the next plug or middleware

There are two types of plugs in the Phoenix. They are module plugs and function plugs. We are going to cover both of them in this article.

module has init and call HAHAH we had a function plug, I just had no idea that is what it was or called Where do we want the plug triggered?

having stumbled into it in an effort to ‘DRY’ out our code. And really, there will probably be more controllers in our app over time and I feel like I have really hit the sweet spot of learning

question - how do i reuse a function in multiple controllers start with a helper add it to the web.ex for controller that is called as a macro for every controller to import the helper use that helper function on a plug for the controller, just make it a plug function or module Alias vs Import

What is the difference between alias and import ?

Docs! straight to the point doc alias
they are referred to as directives

alias use shorter name instead of the fully qualified name or prefix

is also lexically scoped, so it’s only available in the block / function you define it “An alias in Elixir is a capitalized identifier (like String, Keyword, etc) which is converted to an atom during compilation. For instance, the String alias translates by default to the atom :"Elixir.String":” require require this module in order to use it’s macros import import functions from module so you don’t have to use the prefix (macro) use invokes the custom code defined in that module as an extension point Terms

changeset

possibly an ecto term? @doc false def changeset(post, attrs) do post |> cast(attrs, [:title, :content]) |> validate_required([:title, :content]) end

conn

Short for … connection

defp

Inside a module, we can define functions with def/2 and private functions with defp/2. A function defined with def/2 can be invoked from other modules while a private function can only be invoked locally. Picks Resources

Elixir Casts Pheonix Contexts

Alchemist Camp

Elixir Phoenix Realworld

Pheonix Conn CheatSheet

indieweb

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JavaScript to Elm

Twitter: @jstoelm
Email: [email protected]

Jesse Tomchak

Twitter: @jtomchak