Initial commit
This commit is contained in:
commit
4a0cbeb094
GPG key ID:
617773CACE89052C
48 changed files with 4072 additions and 0 deletions
301
AGENTS.md
Normal file
301
AGENTS.md
Normal file
|
|
@ -0,0 +1,301 @@
|
|||
This is a web application written using the Phoenix web framework.
|
||||
|
||||
## Project guidelines
|
||||
|
||||
- Use `mix precommit` alias when you are done with all changes and fix any pending issues
|
||||
- Use the already included and available `:req` (`Req`) library for HTTP requests, **avoid** `:httpoison`, `:tesla`, and `:httpc`. Req is included by default and is the preferred HTTP client for Phoenix apps
|
||||
### Phoenix v1.8 guidelines
|
||||
|
||||
- **Always** begin your LiveView templates with `<Layouts.app flash={@flash} ...>` which wraps all inner content
|
||||
- The `MyAppWeb.Layouts` module is aliased in the `my_app_web.ex` file, so you can use it without needing to alias it again
|
||||
- Anytime you run into errors with no `current_scope` assign:
|
||||
- You failed to follow the Authenticated Routes guidelines, or you failed to pass `current_scope` to `<Layouts.app>`
|
||||
- **Always** fix the `current_scope` error by moving your routes to the proper `live_session` and ensure you pass `current_scope` as needed
|
||||
- Phoenix v1.8 moved the `<.flash_group>` component to the `Layouts` module. You are **forbidden** from calling `<.flash_group>` outside of the `layouts.ex` module
|
||||
- Out of the box, `core_components.ex` imports an `<.icon name="hero-x-mark" class="w-5 h-5"/>` component for for hero icons. **Always** use the `<.icon>` component for icons, **never** use `Heroicons` modules or similar
|
||||
- **Always** use the imported `<.input>` component for form inputs from `core_components.ex` when available. `<.input>` is imported and using it will will save steps and prevent errors
|
||||
- If you override the default input classes (`<.input class="myclass px-2 py-1 rounded-lg">)`) class with your own values, no default classes are inherited, so your
|
||||
custom classes must fully style the input
|
||||
|
||||
<!-- usage-rules-start -->
|
||||
<!-- phoenix:elixir-start -->
|
||||
## Elixir guidelines
|
||||
|
||||
- Elixir lists **do not support index based access via the access syntax**
|
||||
|
||||
**Never do this (invalid)**:
|
||||
|
||||
i = 0
|
||||
mylist = ["blue", "green"]
|
||||
mylist[i]
|
||||
|
||||
Instead, **always** use `Enum.at`, pattern matching, or `List` for index based list access, ie:
|
||||
|
||||
i = 0
|
||||
mylist = ["blue", "green"]
|
||||
Enum.at(mylist, i)
|
||||
|
||||
- Elixir variables are immutable, but can be rebound, so for block expressions like `if`, `case`, `cond`, etc
|
||||
you *must* bind the result of the expression to a variable if you want to use it and you CANNOT rebind the result inside the expression, ie:
|
||||
|
||||
# INVALID: we are rebinding inside the `if` and the result never gets assigned
|
||||
if connected?(socket) do
|
||||
socket = assign(socket, :val, val)
|
||||
end
|
||||
|
||||
# VALID: we rebind the result of the `if` to a new variable
|
||||
socket =
|
||||
if connected?(socket) do
|
||||
assign(socket, :val, val)
|
||||
end
|
||||
|
||||
- **Never** nest multiple modules in the same file as it can cause cyclic dependencies and compilation errors
|
||||
- **Never** use map access syntax (`changeset[:field]`) on structs as they do not implement the Access behaviour by default. For regular structs, you **must** access the fields directly, such as `my_struct.field` or use higher level APIs that are available on the struct if they exist, `Ecto.Changeset.get_field/2` for changesets
|
||||
- Elixir's standard library has everything necessary for date and time manipulation. Familiarize yourself with the common `Time`, `Date`, `DateTime`, and `Calendar` interfaces by accessing their documentation as necessary. **Never** install additional dependencies unless asked or for date/time parsing (which you can use the `date_time_parser` package)
|
||||
- Don't use `String.to_atom/1` on user input (memory leak risk)
|
||||
- Predicate function names should not start with `is_` and should end in a question mark. Names like `is_thing` should be reserved for guards
|
||||
- Elixir's builtin OTP primitives like `DynamicSupervisor` and `Registry`, require names in the child spec, such as `{DynamicSupervisor, name: MyApp.MyDynamicSup}`, then you can use `DynamicSupervisor.start_child(MyApp.MyDynamicSup, child_spec)`
|
||||
- Use `Task.async_stream(collection, callback, options)` for concurrent enumeration with back-pressure. The majority of times you will want to pass `timeout: :infinity` as option
|
||||
|
||||
## Mix guidelines
|
||||
|
||||
- Read the docs and options before using tasks (by using `mix help task_name`)
|
||||
- To debug test failures, run tests in a specific file with `mix test test/my_test.exs` or run all previously failed tests with `mix test --failed`
|
||||
- `mix deps.clean --all` is **almost never needed**. **Avoid** using it unless you have good reason
|
||||
<!-- phoenix:elixir-end -->
|
||||
<!-- phoenix:phoenix-start -->
|
||||
## Phoenix guidelines
|
||||
|
||||
- Remember Phoenix router `scope` blocks include an optional alias which is prefixed for all routes within the scope. **Always** be mindful of this when creating routes within a scope to avoid duplicate module prefixes.
|
||||
|
||||
- You **never** need to create your own `alias` for route definitions! The `scope` provides the alias, ie:
|
||||
|
||||
scope "/admin", AppWeb.Admin do
|
||||
pipe_through :browser
|
||||
|
||||
live "/users", UserLive, :index
|
||||
end
|
||||
|
||||
the UserLive route would point to the `AppWeb.Admin.UserLive` module
|
||||
|
||||
- `Phoenix.View` no longer is needed or included with Phoenix, don't use it
|
||||
<!-- phoenix:phoenix-end -->
|
||||
<!-- phoenix:ecto-start -->
|
||||
## Ecto Guidelines
|
||||
|
||||
- **Always** preload Ecto associations in queries when they'll be accessed in templates, ie a message that needs to reference the `message.user.email`
|
||||
- Remember `import Ecto.Query` and other supporting modules when you write `seeds.exs`
|
||||
- `Ecto.Schema` fields always use the `:string` type, even for `:text`, columns, ie: `field :name, :string`
|
||||
- `Ecto.Changeset.validate_number/2` **DOES NOT SUPPORT the `:allow_nil` option**. By default, Ecto validations only run if a change for the given field exists and the change value is not nil, so such as option is never needed
|
||||
- You **must** use `Ecto.Changeset.get_field(changeset, :field)` to access changeset fields
|
||||
- Fields which are set programatically, such as `user_id`, must not be listed in `cast` calls or similar for security purposes. Instead they must be explicitly set when creating the struct
|
||||
<!-- phoenix:ecto-end -->
|
||||
<!-- phoenix:html-start -->
|
||||
## Phoenix HTML guidelines
|
||||
|
||||
- Phoenix templates **always** use `~H` or .html.heex files (known as HEEx), **never** use `~E`
|
||||
- **Always** use the imported `Phoenix.Component.form/1` and `Phoenix.Component.inputs_for/1` function to build forms. **Never** use `Phoenix.HTML.form_for` or `Phoenix.HTML.inputs_for` as they are outdated
|
||||
- When building forms **always** use the already imported `Phoenix.Component.to_form/2` (`assign(socket, form: to_form(...))` and `<.form for={@form} id="msg-form">`), then access those forms in the template via `@form[:field]`
|
||||
- **Always** add unique DOM IDs to key elements (like forms, buttons, etc) when writing templates, these IDs can later be used in tests (`<.form for={@form} id="product-form">`)
|
||||
- For "app wide" template imports, you can import/alias into the `my_app_web.ex`'s `html_helpers` block, so they will be available to all LiveViews, LiveComponent's, and all modules that do `use MyAppWeb, :html` (replace "my_app" by the actual app name)
|
||||
|
||||
- Elixir supports `if/else` but **does NOT support `if/else if` or `if/elsif`. **Never use `else if` or `elseif` in Elixir**, **always** use `cond` or `case` for multiple conditionals.
|
||||
|
||||
**Never do this (invalid)**:
|
||||
|
||||
<%= if condition do %>
|
||||
...
|
||||
<% else if other_condition %>
|
||||
...
|
||||
<% end %>
|
||||
|
||||
Instead **always** do this:
|
||||
|
||||
<%= cond do %>
|
||||
<% condition -> %>
|
||||
...
|
||||
<% condition2 -> %>
|
||||
...
|
||||
<% true -> %>
|
||||
...
|
||||
<% end %>
|
||||
|
||||
- HEEx require special tag annotation if you want to insert literal curly's like `{` or `}`. If you want to show a textual code snippet on the page in a `<pre>` or `<code>` block you *must* annotate the parent tag with `phx-no-curly-interpolation`:
|
||||
|
||||
<code phx-no-curly-interpolation>
|
||||
let obj = {key: "val"}
|
||||
</code>
|
||||
|
||||
Within `phx-no-curly-interpolation` annotated tags, you can use `{` and `}` without escaping them, and dynamic Elixir expressions can still be used with `<%= ... %>` syntax
|
||||
|
||||
- HEEx class attrs support lists, but you must **always** use list `[...]` syntax. You can use the class list syntax to conditionally add classes, **always do this for multiple class values**:
|
||||
|
||||
<a class={[
|
||||
"px-2 text-white",
|
||||
@some_flag && "py-5",
|
||||
if(@other_condition, do: "border-red-500", else: "border-blue-100"),
|
||||
...
|
||||
]}>Text</a>
|
||||
|
||||
and **always** wrap `if`'s inside `{...}` expressions with parens, like done above (`if(@other_condition, do: "...", else: "...")`)
|
||||
|
||||
and **never** do this, since it's invalid (note the missing `[` and `]`):
|
||||
|
||||
<a class={
|
||||
"px-2 text-white",
|
||||
@some_flag && "py-5"
|
||||
}> ...
|
||||
=> Raises compile syntax error on invalid HEEx attr syntax
|
||||
|
||||
- **Never** use `<% Enum.each %>` or non-for comprehensions for generating template content, instead **always** use `<%= for item <- @collection do %>`
|
||||
- HEEx HTML comments use `<%!-- comment --%>`. **Always** use the HEEx HTML comment syntax for template comments (`<%!-- comment --%>`)
|
||||
- HEEx allows interpolation via `{...}` and `<%= ... %>`, but the `<%= %>` **only** works within tag bodies. **Always** use the `{...}` syntax for interpolation within tag attributes, and for interpolation of values within tag bodies. **Always** interpolate block constructs (if, cond, case, for) within tag bodies using `<%= ... %>`.
|
||||
|
||||
**Always** do this:
|
||||
|
||||
<div id={@id}>
|
||||
{@my_assign}
|
||||
<%= if @some_block_condition do %>
|
||||
{@another_assign}
|
||||
<% end %>
|
||||
</div>
|
||||
|
||||
and **Never** do this – the program will terminate with a syntax error:
|
||||
|
||||
<%!-- THIS IS INVALID NEVER EVER DO THIS --%>
|
||||
<div id="<%= @invalid_interpolation %>">
|
||||
{if @invalid_block_construct do}
|
||||
{end}
|
||||
</div>
|
||||
<!-- phoenix:html-end -->
|
||||
<!-- phoenix:liveview-start -->
|
||||
## Phoenix LiveView guidelines
|
||||
|
||||
- **Never** use the deprecated `live_redirect` and `live_patch` functions, instead **always** use the `<.link navigate={href}>` and `<.link patch={href}>` in templates, and `push_navigate` and `push_patch` functions LiveViews
|
||||
- **Avoid LiveComponent's** unless you have a strong, specific need for them
|
||||
- LiveViews should be named like `AppWeb.WeatherLive`, with a `Live` suffix. When you go to add LiveView routes to the router, the default `:browser` scope is **already aliased** with the `AppWeb` module, so you can just do `live "/weather", WeatherLive`
|
||||
- Remember anytime you use `phx-hook="MyHook"` and that js hook manages its own DOM, you **must** also set the `phx-update="ignore"` attribute
|
||||
- **Never** write embedded `<script>` tags in HEEx. Instead always write your scripts and hooks in the `assets/js` directory and integrate them with the `assets/js/app.js` file
|
||||
|
||||
### LiveView streams
|
||||
|
||||
- **Always** use LiveView streams for collections for assigning regular lists to avoid memory ballooning and runtime termination with the following operations:
|
||||
- basic append of N items - `stream(socket, :messages, [new_msg])`
|
||||
- resetting stream with new items - `stream(socket, :messages, [new_msg], reset: true)` (e.g. for filtering items)
|
||||
- prepend to stream - `stream(socket, :messages, [new_msg], at: -1)`
|
||||
- deleting items - `stream_delete(socket, :messages, msg)`
|
||||
|
||||
- When using the `stream/3` interfaces in the LiveView, the LiveView template must 1) always set `phx-update="stream"` on the parent element, with a DOM id on the parent element like `id="messages"` and 2) consume the `@streams.stream_name` collection and use the id as the DOM id for each child. For a call like `stream(socket, :messages, [new_msg])` in the LiveView, the template would be:
|
||||
|
||||
<div id="messages" phx-update="stream">
|
||||
<div :for={{id, msg} <- @streams.messages} id={id}>
|
||||
{msg.text}
|
||||
</div>
|
||||
</div>
|
||||
|
||||
- LiveView streams are *not* enumerable, so you cannot use `Enum.filter/2` or `Enum.reject/2` on them. Instead, if you want to filter, prune, or refresh a list of items on the UI, you **must refetch the data and re-stream the entire stream collection, passing reset: true**:
|
||||
|
||||
def handle_event("filter", %{"filter" => filter}, socket) do
|
||||
# re-fetch the messages based on the filter
|
||||
messages = list_messages(filter)
|
||||
|
||||
{:noreply,
|
||||
socket
|
||||
|> assign(:messages_empty?, messages == [])
|
||||
# reset the stream with the new messages
|
||||
|> stream(:messages, messages, reset: true)}
|
||||
end
|
||||
|
||||
- LiveView streams *do not support counting or empty states*. If you need to display a count, you must track it using a separate assign. For empty states, you can use Tailwind classes:
|
||||
|
||||
<div id="tasks" phx-update="stream">
|
||||
<div class="hidden only:block">No tasks yet</div>
|
||||
<div :for={{id, task} <- @stream.tasks} id={id}>
|
||||
{task.name}
|
||||
</div>
|
||||
</div>
|
||||
|
||||
The above only works if the empty state is the only HTML block alongside the stream for-comprehension.
|
||||
|
||||
- **Never** use the deprecated `phx-update="append"` or `phx-update="prepend"` for collections
|
||||
|
||||
### LiveView tests
|
||||
|
||||
- `Phoenix.LiveViewTest` module and `LazyHTML` (included) for making your assertions
|
||||
- Form tests are driven by `Phoenix.LiveViewTest`'s `render_submit/2` and `render_change/2` functions
|
||||
- Come up with a step-by-step test plan that splits major test cases into small, isolated files. You may start with simpler tests that verify content exists, gradually add interaction tests
|
||||
- **Always reference the key element IDs you added in the LiveView templates in your tests** for `Phoenix.LiveViewTest` functions like `element/2`, `has_element/2`, selectors, etc
|
||||
- **Never** tests again raw HTML, **always** use `element/2`, `has_element/2`, and similar: `assert has_element?(view, "#my-form")`
|
||||
- Instead of relying on testing text content, which can change, favor testing for the presence of key elements
|
||||
- Focus on testing outcomes rather than implementation details
|
||||
- Be aware that `Phoenix.Component` functions like `<.form>` might produce different HTML than expected. Test against the output HTML structure, not your mental model of what you expect it to be
|
||||
- When facing test failures with element selectors, add debug statements to print the actual HTML, but use `LazyHTML` selectors to limit the output, ie:
|
||||
|
||||
html = render(view)
|
||||
document = LazyHTML.from_fragment(html)
|
||||
matches = LazyHTML.filter(document, "your-complex-selector")
|
||||
IO.inspect(matches, label: "Matches")
|
||||
|
||||
### Form handling
|
||||
|
||||
#### Creating a form from params
|
||||
|
||||
If you want to create a form based on `handle_event` params:
|
||||
|
||||
def handle_event("submitted", params, socket) do
|
||||
{:noreply, assign(socket, form: to_form(params))}
|
||||
end
|
||||
|
||||
When you pass a map to `to_form/1`, it assumes said map contains the form params, which are expected to have string keys.
|
||||
|
||||
You can also specify a name to nest the params:
|
||||
|
||||
def handle_event("submitted", %{"user" => user_params}, socket) do
|
||||
{:noreply, assign(socket, form: to_form(user_params, as: :user))}
|
||||
end
|
||||
|
||||
#### Creating a form from changesets
|
||||
|
||||
When using changesets, the underlying data, form params, and errors are retrieved from it. The `:as` option is automatically computed too. E.g. if you have a user schema:
|
||||
|
||||
defmodule MyApp.Users.User do
|
||||
use Ecto.Schema
|
||||
...
|
||||
end
|
||||
|
||||
And then you create a changeset that you pass to `to_form`:
|
||||
|
||||
%MyApp.Users.User{}
|
||||
|> Ecto.Changeset.change()
|
||||
|> to_form()
|
||||
|
||||
Once the form is submitted, the params will be available under `%{"user" => user_params}`.
|
||||
|
||||
In the template, the form form assign can be passed to the `<.form>` function component:
|
||||
|
||||
<.form for={@form} id="todo-form" phx-change="validate" phx-submit="save">
|
||||
<.input field={@form[:field]} type="text" />
|
||||
</.form>
|
||||
|
||||
Always give the form an explicit, unique DOM ID, like `id="todo-form"`.
|
||||
|
||||
#### Avoiding form errors
|
||||
|
||||
**Always** use a form assigned via `to_form/2` in the LiveView, and the `<.input>` component in the template. In the template **always access forms this**:
|
||||
|
||||
<%!-- ALWAYS do this (valid) --%>
|
||||
<.form for={@form} id="my-form">
|
||||
<.input field={@form[:field]} type="text" />
|
||||
</.form>
|
||||
|
||||
And **never** do this:
|
||||
|
||||
<%!-- NEVER do this (invalid) --%>
|
||||
<.form for={@changeset} id="my-form">
|
||||
<.input field={@changeset[:field]} type="text" />
|
||||
</.form>
|
||||
|
||||
- You are FORBIDDEN from accessing the changeset in the template as it will cause errors
|
||||
- **Never** use `<.form let={f} ...>` in the template, instead **always use `<.form for={@form} ...>`**, then drive all form references from the form assign as in `@form[:field]`. The UI should **always** be driven by a `to_form/2` assigned in the LiveView module that is derived from a changeset
|
||||
<!-- phoenix:liveview-end -->
|
||||
<!-- usage-rules-end -->
|
||||
Loading…
Add table
Add a link
Reference in a new issue