Atomex

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Atomex is an ATOM 1.0 feed builder with a focus on RFC4287 compliance, security and extensibility. It is safe to use it with user content: everything is escaped by default. Built on top of xml_builder.

API reference is available here: https://hexdocs.pm/atomex/api-reference.html

TODO

  • [x] Feed required params (id, title, updated)
  • [x] Feed recommended params (author, link)
  • [x] Feed optional params

    • [x] category
    • [x] contributor
    • [x] generator
    • [x] icon
    • [x] logo
    • [x] rights
    • [x] subtitle
  • [x] Entry required params (id, title, updated)
  • [x] Entry recommended params (author, content, link, summary)
  • [ ] Entry optional params

    • [x] category
    • [x] contributor
    • [x] published
    • [x] rights
    • [ ] source
  • [ ] Validator

Installation

def deps do
  [
    {:atomex, "0.2.0"}
  ]
end

Basic usage

Required field are always passed in new functions. There are however recommended fields that you should not ignore. See Validating your feed below.

alias Atomex.{Feed, Entry}

def build_feed(comments) do
  Feed.new("https://example.com", DateTime.utc_now, "My incredible feed")
  |> Feed.author("John Doe", email: "JohnDoe@example.com")
  |> Feed.link("https://example.com/feed", rel: "self")
  |> Feed.entries(Enum.map(comments, &get_entry/1))
  |> Feed.build()
  |> Atomex.generate_document()
end

defp get_entry(_comment = %{id, text, inserted_at, user}) do
  Entry.new("https://example.com/comments/#{id}", inserted_at, "New comment by #{user.name}")
  |> Entry.author(user.name, uri: "https://example.com/users/#{user.id}")
  |> Entry.content("<h1>Content here will be properly escaped! Text: #{text}</h1>", type: "html")
  |> Entry.build()
end

To avoid escaping, you can pass a tuple as value like this (be careful though, a user may break it with malicious content):

Entry.content(entry, {:cdata, "<h1>Amazing</h1>"}, type: "html")
# Render as => <content type="html"><![CDATA[<h1>Amazing</h1>]]></content>

Extending the default API

  • You can specify custom schemas
Feed.build(feed, %{"xmlns:georss" => "http://www.georss.org/georss"})
# <?xml version="1.0" encoding="UTF-8"?>
# <rss version="2.0" xmlns="http://www.w3.org/2005/Atom" xmlns:georss="http://www.georss.org/georss">
#...
  • And custom fields
Feed.new(...)
|> Feed.add_field(:custom_field, %{attribute: 42}, "Foobar")
|> Feed.build()
|> Atomex.generate_document()
# ...
# <custom_field attribute="42">Foobar</custom_field>

For more complicated use cases, content can also be given a xml element directly. Use XmlBuilder to achieve that.

Validating your feed

Use this tool from W3C