How to change field type in Ecto?
You have to use modify/3 to change the type. add/3 is only for adding new columns. alter table(:editables) do modify :content, :binary end
phoenix-framework
Testing a file upload in phoenix/elixir
Put a file in your test directory somewhere (maybe test/fixtures) then use the Plug.Upload struct: upload = %Plug.Upload{path: “test/fixtures/example.png”, filename: “example.png”} conn() |> post(“/api/v1/originals”, %{ :image => upload })
Start Phoenix app with cowboy server on different port
Yep! Make sure you set the mix config to reference the env port, i.e. config :my_app, MyApp.Endpoint, http: [port: {:system, “PORT”}], Then from the terminal: $ PORT=4001 mix phoenix.server $ PORT=4002 mix phoenix.server $ PORT=4003 mix phoenix.server
Return statement in Elixir
This is an interesting problem because you need to perform multiple checks, exit early, and in the process transform some state (connection). I typically approach this problem as follows: I implement each check as a function which takes state as an input and returns {:ok, new_state} or {:error, reason}. Then, I build a generic function … Read more
Many to Many relationship in Ecto
This is an old question and the previously accepted answer was no longer the de facto way. Ecto now supports HABTM or many to many associations. https://hexdocs.pm/ecto/Ecto.Schema.html#many_to_many/3 many_to_many :users, MyApp.User, join_through: “chat_group_users”
Count the Number of Entries in an Ecto Repository
The options that Dogbert has provided are both correct and should be used for Ecto 1.x. In Ecto 2.0 you can use Repo.aggregate/4 Repo.aggregate(Post, :count, :id)
How to check if a string is blank in Elixir
String.trim/1 seems to do the trick as of Elixir 1.3.0. strip still works, but it was soft deprecated in the 1.3.0 release and it isn’t listed in the String docs.
Get current environment name
Mix.env() doesn’t work in production or other environments where you use compiled releases (built using Exrm / Distillery) or when Mix just isn’t available. The solution is to specify it in your config/config.exs file: config :your_app, env: Mix.env() You can then get the environment atom in your application like this: Application.get_env(:your_app, :env) #=> :prod Update … Read more
Data Types in Ecto – “value too long for type character varying(255)”
The error you get is from the underlying database where the column type is set to varchar which is what’s created by default when you specify the column type as string in a migration. To store a variable length string over 255 characters, you need to specify the column type as text in the migration. … Read more
Modify foreign key in Ecto
I’m not sure when this was added to Ecto, but at least in 2.1.6 there’s no need for raw SQL anymore. drop/1 now supports constraints (drop_if_exists/1 doesn’t though): def up do drop constraint(:videos, “videos_user_id_fkey”) alter table(:videos) do modify :user_id, references(:users, on_delete: :delete_all) end end def down do drop constraint(:videos, “videos_user_id_fkey”) alter table(:videos) do modify :user_id, … Read more