Add playlists to sync code, DB & API and add playlist direct links #1159

This means that Tobira will store all playlist info already when syncing. I thought about the DB "array vs. table" question for some time. Here are my notes that made me decide for the array solution: Should the entries be stored as an array in a column of the `playlists` table? Or be a separate table that needs to be joined? The latter would be the traditionally "better" version, as it normalizes the data. A playlist entry contains these fields: - Opencast ID, - Type (e.g. video) - Content ID (e.g. Opencast video ID). If we store it in a separate table we also need the following fields: - Playlist: foreign key to playlist ID - Index: ordering in a table is not well defined, so to get a definite order, we need another index field. - Potentially another artificial ID? - Normalization is what you're supposed to do, right? - Allows to use LIMIT and OFFSET, i.e. only load part of all entries. (Kind of possible with arrays as well though). - Allows to modify/delete individual entries without rewriting all of them - Many situations treat the entries as one atomic value: - Harvest/sync: the API sends the full playlist object including entries. If using an extra table, we would have to delete all old entries there, then insert all new ones. - Playlist block: loads all entries. Ok but what about pagination: we don't have that yet. But we should at some point? - Even in the modifying/moving/deleting a single entry case: - Opencast's APIs require us to send all entries, so while we can do very localized updates in our DB, we have to load all entries anyway. - After changing something, the Harvest API will send an update which leads to overwriting all entries again. - Extra table requires at least two additional fields to be stored (foreign key & index) - Management of `index` adds complexity whenever somehow editing entries. Just writing all entries at once again is easier. Also: should there be DB checks that make sure the indices are always 0 to N like for blocks? Adds more complexity and we ran into problems with that once. - Even if we add pagination: apart from offering a different UX, pagination helps with performance in four spots: rendering, backend<->frontend communication, DB<->backend communication, DB loading from disk. The first three benefits we can still have, even with arrays. - Looking at how PostgreSQL stores rows, arrays shouldn't incur any meaningful overhead and might even be faster in the majority of situations.

We did not have types depending on other types before. Adding "cascade" luckily fixes this.

I only moved stuff around and fixed imports, that's all. I did that so that the reviewer can just skip this commit. It is preparation for making a general `VideoListBlock`.

Again, preparation for using that for playlists as well

This was added a long time ago. By now, the ordering is done in the frontend, so the parameter is completely unused. We can get rid of some complexity by removing it.

This only adds querying capabilities, no mutations yet.

This is a band aid fix and not perfect. When I added the `Unknown` variant to the enum, I wasn't aware that it was used when other variants fail to deserialize even with `kind: "event"`. So the warning there was misleading. It's still not perfect because I ideally want to print more information on the deseralization failure. And the `kind` strings are duplicated now. I think in the future, the `HarvestResponse` might have items of type `{ kind: String, #[serde(flatten)] body: serde_json::Value }` or something like that. And then we deserialize it manually in a second step. We will see.

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Add playlists to sync code, DB & API and add playlist direct links #1159

Add playlists to sync code, DB & API and add playlist direct links #1159

Commits on Jun 3, 2024

Add playlists to sync code, DB & API and add playlist direct links #1159

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Add playlists to sync code, DB & API and add playlist direct links #1159

Commits on Jun 3, 2024