Otera.Loader (otera v0.2.0)

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Loads the templates that {% extends %}, {% include %} and {% import %} name, like the loaders of Jinja2.

The :loader option of Otera.parse/2, Otera.load/2 and Otera.render/3 is one of these:

  • A map from names to sources, like the DictLoader of Jinja2:

    Otera.render(~s({% include "header.html" %}), %{}, loader: %{"header.html" => "<h1>Hi</h1>"})
#=> {:ok, "<h1>Hi</h1>"}

  • A function that gets a name and returns {:ok, source}, or :error when there is no template with that name, like the FunctionLoader of Jinja2. It can also return {:ok, source, uptodate}, where uptodate is a function without arguments that returns false when the template changed, for Otera.Cache.

  • file_system/1, which reads the templates from directories, like the FileSystemLoader of Jinja2.

The values of a map and the results of a function can also be templates that Otera.parse/2 made. During a render, Otera loads and parses each template once. To keep the parsed templates for many renders, give an Otera.Cache with the :cache option.

Summary

Types

result()
t()

Functions

file_system(root)

Returns a loader that reads the template name from the file name in root, a directory or a list of directories that it tries in order.

get_source(loader, name)

Returns the template name from loader: {:ok, source_or_template}, {:ok, source, uptodate}, or :error.

Types

result()

@type result() ::
  {:ok, String.t() | Otera.Template.t()}
  | {:ok, String.t(), (-> boolean())}
  | :error

t()

@type t() ::
  %{required(String.t()) => String.t() | Otera.Template.t()}
  | (String.t() -> result())

Functions

file_system(root)

@spec file_system(Path.t() | [Path.t()]) :: (String.t() -> result())

Returns a loader that reads the template name from the file name in root, a directory or a list of directories that it tries in order.

The loader gives an uptodate function with each source, which returns false when the modification time or the size of the file changed, for Otera.Cache.

The parts of a name are separated by /. As in Jinja2, a name with a .. part is not found, and Otera also refuses a backslash and a null byte, so a template cannot be outside the directories. An empty part and a . part do nothing, so /a.html is the file a.html in a directory. The files are UTF-8.

get_source(loader, name)

@spec get_source(t(), String.t()) :: result()

Returns the template name from loader: {:ok, source_or_template}, {:ok, source, uptodate}, or :error.