.. _customization: Customization ============= Datasette provides a number of ways of customizing the way data is displayed. Custom CSS and JavaScript ------------------------- When you launch Datasette, you can specify a custom metadata file like this:: datasette mydb.db --metadata metadata.json Your ``metadata.json`` file can include links that look like this:: { "extra_css_urls": [ "https://simonwillison.net/static/css/all.bf8cd891642c.css" ], "extra_js_urls": [ "https://code.jquery.com/jquery-3.2.1.slim.min.js" ] } The extra CSS and JavaScript files will be linked in the ```` of every page. You can also specify a SRI (subresource integrity hash) for these assets:: { "extra_css_urls": [ { "url": "https://simonwillison.net/static/css/all.bf8cd891642c.css", "sri": "sha384-9qIZekWUyjCyDIf2YK1FRoKiPJq4PHt6tp/ulnuuyRBvazd0hG7pWbE99zvwSznI" } ], "extra_js_urls": [ { "url": "https://code.jquery.com/jquery-3.2.1.slim.min.js", "sri": "sha256-k2WSCIexGzOj3Euiig+TlR8gA0EmPjuc79OEeY5L45g=" } ] } Modern browsers will only execute the stylesheet or JavaScript if the SRI hash matches the content served. You can generate hashes using `www.srihash.org `_ Every default template includes CSS classes in the body designed to support custom styling. The index template (the top level page at ``/``) gets this:: The database template (``/dbname``) gets this:: The custom SQL template (``/dbname?sql=...``) gets this:: The table template (``/dbname/tablename``) gets:: The row template (``/dbname/tablename/rowid``) gets:: The ``db-x`` and ``table-x`` classes use the database or table names themselves if they are valid CSS identifiers. If they aren't, we strip any invalid characters out and append a 6 character md5 digest of the original name, in order to ensure that multiple tables which resolve to the same stripped character version still have different CSS classes. Some examples:: "simple" => "simple" "MixedCase" => "MixedCase" "-no-leading-hyphens" => "no-leading-hyphens-65bea6" "_no-leading-underscores" => "no-leading-underscores-b921bc" "no spaces" => "no-spaces-7088d7" "-" => "336d5e" "no $ characters" => "no--characters-59e024" ```` and ```` elements also get custom CSS classes reflecting the database column they are representing, for example::
id name
1 SMITH
Custom templates ---------------- By default, Datasette uses default templates that ship with the package. You can over-ride these templates by specifying a custom ``--template-dir`` like this:: datasette mydb.db --template-dir=mytemplates/ Datasette will now first look for templates in that directory, and fall back on the defaults if no matches are found. It is also possible to over-ride templates on a per-database, per-row or per- table basis. The lookup rules Datasette uses are as follows:: Index page (/): index.html Database page (/mydatabase): database-mydatabase.html database.html Custom query page (/mydatabase?sql=...): query-mydatabase.html query.html Canned query page (/mydatabase/canned-query): query-mydatabase-canned-query.html query-mydatabase.html query.html Table page (/mydatabase/mytable): table-mydatabase-mytable.html table.html Row page (/mydatabase/mytable/id): row-mydatabase-mytable.html row.html Table of rows and columns include on table page: _table-table-mydatabase-mytable.html _table-mydatabase-mytable.html _table.html Table of rows and columns include on row page: _table-row-mydatabase-mytable.html _table-mydatabase-mytable.html _table.html If a table name has spaces or other unexpected characters in it, the template filename will follow the same rules as our custom ```` CSS classes - for example, a table called "Food Trucks" will attempt to load the following templates:: table-mydatabase-Food-Trucks-399138.html table.html You can find out which templates were considered for a specific page by viewing source on that page and looking for an HTML comment at the bottom. The comment will look something like this:: This example is from the canned query page for a query called "tz" in the database called "mydb". The asterisk shows which template was selected - so in this case, Datasette found a template file called ``query-mydb-tz.html`` and used that - but if that template had not been found, it would have tried for ``query-mydb.html`` or the default ``query.html``. It is possible to extend the default templates using Jinja template inheritance. If you want to customize EVERY row template with some additional content you can do so by creating a ``row.html`` template like this:: {% extends "default:row.html" %} {% block content %}

EXTRA HTML AT THE TOP OF THE CONTENT BLOCK

This line renders the original block:

{{ super() }} {% endblock %} Note the ``default:row.html`` template name, which ensures Jinja will inherit from the default template. The ``_table.html`` template is included by both the row and the table pages, and a list of rows. The default ``_table.html`` template renders them as an HTML template and `can be seen here `_. You can provide a custom template that applies to all of your databases and tables, or you can provide custom templates for specific tables using the template naming scheme described above. If you want to present your data in a format other than an HTML table, you can do so by looping through ``display_rows`` in your own ``_table.html`` template. You can use ``{{ row["column_name"] }}`` to output the raw value of a specific column. If you want to output the rendered HTML version of a column, including any links to foreign keys, you can use ``{{ row.display("column_name") }}``. Here is an example of a custom ``_table.html`` template:: {% for row in display_rows %}

{{ row["title"] }}

{{ row["description"] }}

Category: {{ row.display("category_id") }}

{% endfor %}