Timestamp: #inst “2016-01-26T16:43:00” Title: “HTML templates” ID: templates

HTML templates

The final step of a generation pipeline is the actual static page generation. It is usually achieved using an HTML templating engine of sorts. In λ-blog, default HTML templates are pretty spartan and defined using the S-HTML Clojure DSL. It so to encourage experimentation, after all customizability is the guiding principle behind λ-blog.

A template is just a function that takes an entity as an argument and returns processed HTML as a result:

(defn template [{:keys [contents]}]
  (str "<div class=\"container\">" contents "</div>"))

Or in case of S-HTML:

(defn template [{:keys [contents]}]
  (div {:class :container}
       contents))

Using templates with nested entities

To make it easier to generate HTML from nested entities, λ-blog defines a bunch of handy functions:

• (generate! entity key template & args) - generates a page using entity and (entity key) values, by combining them and passing the result along with additional args to the template.

• (generate-all! key template & args) - same as generate!, but generates a sequence of pages from a sequence of subentities.

Detailed descriptions of these functions can be found in the lambda-blog.generator namespace.

Defining custom HTML templates

λ-blog templates are built using S-HTML, so a sensible way of going about defining custom templates is to reuse existing templates and extend them with some more S-HTML:

(require '[lambda-blog.templates.page :refer [page]])
(require '[s-html.tags :as html])

(defn my-custom-contents [{:keys [contents title]}]
  (html/div {:class :container}
            (html/h1 title)
            (html/p contents)))

(def my-template (partial page my-custom-contents))

A somewhat more detailed description of S-HTML can be found here.

Of course, you can just as easily use any other HTML generation/templating library - just make sure to return stringified HTML from your template functions.