Phoenix.Template

Templates are used by Phoenix on rendering.

Since many views require rendering large contents, for example a whole HTML file, it is common to put those files in the file system into a particular directory, typically “web/templates”.

This module provides conveniences for reading all files from a particular directory and embedding them into a single module. Imagine you have a directory with templates:

# templates/foo.html.eex
Hello <%= @name %>

# templates.ex
defmodule Templates do
  use Phoenix.Template, root: "templates"
end

Now the template foo can be directly rendered with:

Templates.render("foo.html", %{name: "John Doe"})

In practice though, developers rarely use Phoenix.Template directly. Instead they use Phoenix.View which wraps the template functionality and adds some extra conveniences.

Terminology

Here is a quick introduction into Phoenix templates terms:

Custom Template Engines

Phoenix supports custom template engines. Engines tell Phoenix how to convert a template path into quoted expressions. Please check Phoenix.Template.Engine for more information on the API required to be implemented by custom engines.

Once a template engine is defined, you can tell Phoenix about it via the template engines option:

config :phoenix, :template_engines,
  eex: Phoenix.Template.EExEngine,
  exs: Phoenix.Template.ExsEngine

Format encoders

Besides template engines, Phoenix has the concept of format encoders. Format encoders work per format and are responsible for encoding a given format to string once the view layer finishes processing.

A format encoder must export a function called encode_to_iodata!/1 which receives the rendering artifact and returns iodata.

New encoders can be added via the format encoder option:

config :phoenix, :format_encoders,
  html: Phoenix.HTML.Engine,
  json: Poison
Source

Summary

engines()

Returns a keyword list with all template engines extensions followed by their modules

find_all(root)

Returns all template paths in a given template root

format_encoder(template_name)

Returns the format encoder for the given template name

hash(root)

Returns the hash of all template paths in the given root

module_to_template_root(module, base, suffix)

Converts a module, without the suffix, to a template root

template_path_to_name(path, root)

Converts the template path into the template name

Types

name :: binary

path :: binary

root :: binary

Functions

engines()

Specs:

  • engines :: %{atom => module}

Returns a keyword list with all template engines extensions followed by their modules.

Source
find_all(root)

Specs:

Returns all template paths in a given template root.

Source
format_encoder(template_name)

Specs:

  • format_encoder(name) :: module | nil

Returns the format encoder for the given template name.

Source
hash(root)

Specs:

  • hash(root) :: binary

Returns the hash of all template paths in the given root.

Used by Phoenix to check if a given root path requires recompilation.

Source
module_to_template_root(module, base, suffix)

Converts a module, without the suffix, to a template root.

Examples

iex> Phoenix.Template.module_to_template_root(MyApp.UserView, MyApp, "View")
"user"

iex> Phoenix.Template.module_to_template_root(MyApp.Admin.User, MyApp, "View")
"admin/user"

iex> Phoenix.Template.module_to_template_root(MyApp.Admin.User, MyApp.Admin, "View")
"user"

iex> Phoenix.Template.module_to_template_root(MyApp.View, MyApp, "View")
""

iex> Phoenix.Template.module_to_template_root(MyApp.View, MyApp.View, "View")
""
Source
template_path_to_name(path, root)

Specs:

Converts the template path into the template name.

Examples

iex> Phoenix.Template.template_path_to_name(
...>   "lib/templates/admin/users/show.html.eex",
...>   "lib/templates")
"admin/users/show.html"
Source