Template functions to enable building client side search index

[despens]

It be interesting to have functions that would support building an index for client side search engines like lunr.

To me it looks like everything is already more or less in place, except for a function that would format HTML into plain text perhaps.

If that would be there, it could be possible to generate the required json files which then could be compiled into the search index by an external tool.

[Abbe98]

Maybe the "non-html-content" example cover this use case? It generates a JSON file, not for a search index but I think the concept still applies.

https://github.com/glaciers-in-archives/snowman/tree/main/examples/non-html-content

Since that example was added the to_json function was introduced as well and together with #37 it should be made even easier.

[despens]

Yes I was looking at that one too, and thought that if there is function to retrieve HTML from an API (as in #54) you would just need another function that strips the HTML tags from such a retrieved string, leaving only plain text. That would complete the tools to create a JSON file for each page that could be compiled into an index I believe.

[Abbe98]

These are the additions I have locally and intend to fully implement:

get_remote <url> - makes a plain HTTP GET request and returns the response body as a string (#54).
from_json <string> - JSON parser that takes a JSON-string and parses it into a data structure that Go templates understand natively (#37).

Together with the unsafe-view option, and the existing to_json and safe_html functions I think we will have a very good system in place.

A question that still stands are what options get_remote should support? Headers, yes. Basic Auth, very much maybe. POST methods, also maybe.