user-posts-note.md

Example: User Posts a Note

Note: This example is a component of the parent Solid specification; the parent spec and all its components are versioned as a whole.

This example is taken from W3C Social Web WG's user stories, where it is called "user posts a note":

1. Eric writes a short note to be shared with his followers.
2. After posting the note, he notices a spelling error. He edits the note and re-posts it.
3. Later, Eric decides that the information in the note is incorrect. He deletes the note.

Here is how Solid would handle the three steps, using curl as the client application:

1. Eric writes a short note to be shared with his followers. The Slug header is optional but useful for controlling the resulting URL.

curl -H"Content-Type: text/turtle" \
     -H"Slug: social-web-2015" \
     -X POST \
     --data ' @prefix as: <http://www.w3.org/ns/activitystreams#>. <> a as:Note; as:content "Going to Social Web WG".' \
     https://eric.example.org/notes/

The URL of the new note can be found in the Location header returned by the server. In this example it is likely to be https://eric.example.org/notes/social-web-2015 (since the social-web-2015 part was politely requested by the Slug header).

2. After posting the note, he notices a spelling error. He edits the note and re-posts it. Solid servers can handle updates in two different ways: a PUT (overwrite) or a PATCH with application/sparql-update content type.

Use HTTP PUT, when you just want to replace the data:

curl -H"Content-Type: text/turtle" \
     -X PUT \
     --data ' @prefix as: <http://www.w3.org/ns/activitystreams#>. <> a as:Note; as:content "Going to Social Web WG in Paris".' \
     https://eric.example.org/notes/social-web-2015

Or you can use HTTP PATCH with SPARQL if you only want to change certain parts of the resource, leaving the others unchanged (perhaps because other applications are modifying them):

curl -H"Content-Type: application/sparql-update" \
     -X PATCH \
     --data 'DELETE DATA {<> <http://www.w3.org/ns/activitystreams#content> "Going to Social Web WG" .}; INSERT DATA {<> <http://www.w3.org/ns/activitystreams#content> "Going to Social Web WG in Paris" .} ' \
     https://eric.example.org/notes/social-web-2015

If no match is found for the triple to DELETE, the request safely aborts without changing any data.

3. Later, Eric decides that the information in the note is incorrect. He deletes the note.

curl -X DELETE https://eric.example.org/notes/social-web-2015

Note that all three actions have been performed through RESTful HTTP requests.

In these example, data was sent to the server using text/turtle (which is mandated by LDP), but other content types (such as JSON-LD) could be used if implemented by servers.