monolith/docs/arch/0008-base-tag.md

8. Base Tag

Date: 2020-11-22

Status

Accepted

Context

HTML documents may contain base tag within head, which influences URL resolution prefix for anchor and relative links as well as dynamically loaded resources. Sometimes to make certain saved pages function closer to how they originally operated, the base tag specifying the source page's URL may need to be added to the document.

Decision

Adding the base tag should be optional. Saved documents should not contain the base tag unless it was requested by the user, or unless the document originally had the base tag in it. Only documents donwloaded from remote resources should be able to obtain a new base tag, existing base tags within documents saved from data URLs and local resources should be kept intact. The existing href attribute's value of the original base tag should be used for resolving document's relative links instead of document's own URL. There can be only one such tag. If multiple base tags are provided, only the first encountered tag will end up being used.

Consequences

In case the remote document had the base tag in it:

• By default: the href attribute should be resolved to a full URL if it's relative, kept empty in case it was empty or non-existent, all other attributes of that tag should be kept intact.
• If base tag was requested to be added: the exsting base tag's href attribute should be set to page's full URL, all other attributes should be kept intact.

In case the remote document didn't have the base tag in it:

• By default: no base tag is added to the document, it gets saved to disk without having one.
• If base tag was requested to be added: the added base tag should contain only one attribute href, equal to the remote URL of that HTML document.