ElixirDrops

Prevent race conditions with `Ecto.Query.lock/2`

Two users buying the last item simultaneously can cause overselling. Use PostgreSQL row locks with lock: "FOR UPDATE" to prevent concurrent updates fr...

almirsarajcic

47 minutes ago

Use `temporary_assigns` for large lists in LiveView

Sending entire lists over the socket on every LiveView update kills performance. Mark list assigns as temporary to send them once and drop them from s...

almirsarajcic

7 days ago

Use `send_update_after/4` for delayed LiveComponent updates

Manual timer management with Process.send_after/3 in LiveComponents creates cleanup complexity. LiveView's send_update_after/4 handles delayed updates...

almirsarajcic

14 days ago

Use router `on_mount` hooks instead of duplicating LiveView mount logic

Copy-pasting the same assigns across every LiveView mount/3 function creates maintenance nightmares. Router-level on_mount hooks run automatically bef...

almirsarajcic

21 days ago

Stop mixing LiveView handlers with JavaScript hooks

Handling the same event in both Phoenix and JavaScript creates race conditions and unpredictable behavior. Keep server logic in LiveView handlers and ...

almirsarajcic

27 days ago

The amazing v/1 helper function

I may be late on this one but today I learned about the v/1, a helper function that retrieves the value from a previous expression by its line number ...

jrowah

1 month ago

Phoenix contexts should return tuples, not raise

Phoenix context functions that raise exceptions break LiveView error handling and force try/catch everywhere. Tagged tuples enable composable error ha...

almirsarajcic

1 month ago

Prevent duplicate Oban jobs with `unique` worker options

Multiple button clicks or retries can enqueue the same background job multiple times, causing duplicate charges, emails, or API calls. Oban's built-in...

almirsarajcic

1 month ago

Stop rewriting Ecto queries from scratch - use `Ecto.Query.exclude/2` instead

Building complex queries often means starting with a base query, then customizing it for different use cases. Most developers duplicate the entire que...

almirsarajcic

1 month ago

Fixing `Ecto.StaleEntryError` with optimistic locking patterns

Race conditions in concurrent updates cause cryptic Ecto.StaleEntryError crashes in production. The error happens when multiple processes try to updat...

almirsarajcic

1 month ago

Phoenix application configuration

The config folder plays a pivotal role in any phoenix application. Its constituents are normally config.exs, dev.exs, prod.exs, runtime.exs and test.e...

Deankinyua

1 month ago

Hunting down flaky tests with `--repeat-until-failure`

Nothing destroys developer confidence like tests that randomly fail in CI. One day your build is green, the next it's red with the exact same code. Th...

almirsarajcic

2 months ago

Impelementing Infinite Scroll in Phoenix

Infinite scroll is a listing-page design approach seen a lot on widely used apps such as TikTok and Instagram to keep the user engaged, loading additi...

Deankinyua

2 months ago

Preventing atom exhaustion attacks with `String.to_existing_atom`

Using String.to_atom/1 on user input is a critical security vulnerability that can crash your entire BEAM VM through atom exhaustion. Here are two app...

almirsarajcic

2 months ago

Executing OS processes using Elixir Ports

Ports in Elixir provide us an interface for communicating with external processes by sending and receiving messages. They make it easy to start and ma...

Deankinyua

2 months ago