API: Retrieve references of an existing zettel

The endpoint to retrieve references of a specific zettel is /r/{ID}, where {ID} is a placeholder for the zettel identifier.

A zettel may contain references to external material, in the form of an URI. External material may be referenced via Zettelmarkup links, inline embedding, or a block transclusion. It may also be referenced within the metadata of a zettel, when a key of type URL is given.

To calculate the references of a zettel, its parsed form is used.

For example, to retrieve references of the zettel about CommonMark, just send a HTTP GET request to the endpoint /r/00001008010500¹:

# curl 'http://127.0.0.1:23123/r/00001008010500'
https://commonmark.org/
https://commonmark.org/
https://xkcd.com/927/
https://github.github.com/gfm/
https://spec.commonmark.org/0.31.2/
https://github.com/yuin/goldmark

If you just want metadata external references, add a query parameter part=meta:

# curl 'http://127.0.0.1:23123/r/00001008010500?part=meta'
https://commonmark.org/

Similarly, to retrieve only references of the zettel content, use the query parameter part=content:

# curl 'http://127.0.0.1:23123/r/00001008010500?part=content'
https://commonmark.org/
https://xkcd.com/927/
https://github.github.com/gfm/
https://spec.commonmark.org/0.31.2/
https://github.com/yuin/goldmark

These examples should make clean, that no duplicates are removed and no sorting takes place. The client must handle this, e.g.:

# curl 'http://127.0.0.1:23123/r/00001008010500' | sort -u
https://commonmark.org/
https://github.com/yuin/goldmark
https://github.github.com/gfm/
https://spec.commonmark.org/0.31.2/
https://xkcd.com/927/

If you add the query parameter enc=data, the result will be encoded as a symbolic expression:

# curl 'http://127.0.0.1:23123/r/00001008010500?enc=data'
("https://commonmark.org/" "https://commonmark.org/" "https://xkcd.com/927/" "https://github.github.com/gfm/" "https://spec.commonmark.org/0.31.2/" "https://github.com/yuin/goldmark")

Of course, you can combine the different query parameters, e.g. to retrieve an Sx list of all metadata URIs.

HTTP Status codes

200

Retrieval was successful, the body contains an appropriate data value.

400

Request was not valid.
There are several reasons for this. Maybe the zettel identifier did not consist of exactly 14 digits or enc / part contained illegal values.

403

You are not allowed to retrieve data of the given zettel.

404

Zettel not found. You probably used a zettel identifier that is not used in the Zettelstore.

1. If authentication is enabled, you must include a valid access token in the Authorization header ↩︎