datasette-json-html 0.3

Datasette plugin for rendering HTML based on JSON values

datasette-json-html

Datasette plugin for rendering HTML based on JSON values

Note that this does not currently work with Datasette master - it uses a new plugin hook that is being developed in the plugin-hook-cell branch - see issue 352 for details.

This plugin looks for Database values that match a very specific JSON format and converts them into HTML when they are rendered by the Datasette interface.

It currently supports two formats.

Links

{
    "href": "https://simonwillison.net/",
    "label": "Simon Willison"
}

Will be rendered as an <a href=""> link:

<a href="https://simonwillison.net/">Simon Willison</a>

List of links

[
    {
        "href": "https://simonwillison.net/",
        "label": "Simon Willison"
    },
    {
        "href": "https://github.com/simonw/datasette",
        "label": "Datasette"
    }
]

Will be rendered as a comma-separated list of <a href=""> links:

<a href="https://simonwillison.net/">Simon Willison</a>,
<a href="https://github.com/simonw/datasette">Datasette</a>

The href property must begin with https:// or http:// or /, to avoid potential XSS injection attacks (for example URLs that begin with javascript:).

Images

The image tag is more complex. The most basic version looks like this:

{
    "img_src": "https://placekitten.com/200/300"
}

This will render as:

<img src="https://placekitten.com/200/300">

But you can also include one or more of alt, caption, width and href.

If you include width or alt, they will be added as attributes:

{
    "img_src": "https://placekitten.com/200/300",
    "alt": "Kitten",
    "width": 200
}

Produces:

<img src="https://placekitten.com/200/300"
    alt="Kitten" width="200">

The href key will cause the image to be wrapped in a link:

{
    "img_src": "https://placekitten.com/200/300",
    "href": "http://www.example.com"
}

Produces:

<a href="http://www.example.com">
    <img src="https://placekitten.com/200/300">
</a>

The caption key wraps everything in a fancy figure/figcaption block:

{
    "img_src": "https://placekitten.com/200/300",
    "caption": "Kitten caption"
}

Produces:

<figure>
    <img src="https://placekitten.com/200/300"></a>
    <figcaption>Kitten caption</figcaption>
</figure>

Using these with SQLite JSON functions

The most powerful way to make use of this plugin is in conjunction with SQLite's JSON functions. For example:

select json_object(
    "href", "https://simonwillison.net/",
    "label", "Simon Willison"
);

You can use these functions to construct JSON objects that work with the plugin from data in a table:

select id, json_object(
    "href", url, "label", text
) from mytable;

The urllib_quote_plus() SQL function

Since this plugin is designed to be used with SQL that constructs the underlying JSON structure, it is likely you will need to construct dynamic URLs from results returned by a SQL query.

This plugin registers a custom SQLite function called urllib_quote_plus() to help you do that. It lets you use Python's urllib.parse.quote_plus() function from within a SQL query.

Here's an example of how you might use it:

select id, json_object(
    "href",
    "/mydatabase/other_table?_search=" || urllib_quote_plus(text)
    "label", text
) from mytable;