Resources

The ResourceRepository manages modality resources (whiteboards, worksheets, lesson plans, assessments) in PostgreSQL.

Models

ResourceRow

Full resource with snapshot bytes (used for single-resource fetches):

pub struct ResourceRow {
    pub id: String,
    pub name: String,
    pub description: Option<String>,
    pub modality: String,
    pub snapshot: Option<Vec<u8>>,
    pub folder_id: Option<String>,
    pub cover_image_url: Option<String>,
    pub is_public: bool,
    pub is_replicable: bool,
    pub forked_from: Option<String>,
    pub created_by: String,
    pub created_at: DateTime<Utc>,
    pub updated_at: DateTime<Utc>,
    pub last_viewed_at: Option<DateTime<Utc>>,
}

ResourceSummaryRow

Without snapshot bytes (used for listings):

pub struct ResourceSummaryRow {
    // Same fields as ResourceRow minus `snapshot`
}

CreateResource

pub struct CreateResource {
    pub name: String,
    pub description: Option<String>,
    pub modality: String,
    pub snapshot: Option<Vec<u8>>,
    pub folder_id: Option<String>,
}

Repository Methods

Method	Purpose
`get(id)`	Fetch single resource with snapshot
`list(ids)`	Fetch multiple resources
`create(input)`	Insert new resource
`create_with_id(id, input)`	Insert with specific ID
`push_update(id, snapshot)`	Merge snapshot bytes (Loro document merge)
`fork(id, user_id)`	Fork resource (copy with `forked_from` reference)
`forks_of(id)`	List all forks of a resource
`duplicate_many(ids, user_id)`	Batch duplicate with new IDs
`delete(id)`	Delete single resource
`delete_many(ids)`	Batch delete
`update_last_viewed(id)`	Touch last-viewed timestamp
`list_connection(params)`	Cursor-based paginated listing

Snapshot Merging

push_update doesn’t replace the snapshot — it merges the incoming bytes with the existing Loro document:

pub async fn push_update(&self, id: &str, snapshot: &[u8]) -> Result<()> {
    let existing = self.get(id).await?;
    let doc = LoroDoc::new();
    if let Some(existing_bytes) = existing.snapshot {
        doc.import(&existing_bytes)?;
    }
    doc.import(snapshot)?;
    let merged = doc.export_snapshot();
    // UPDATE resources SET snapshot = $1 WHERE id = $2
}

This ensures concurrent edits from multiple clients are merged via Loro CRDT, not overwritten.

Keyset Pagination

list_connection uses keyset pagination for stable cursor-based results:

Decode cursor → (sort_field_value, id)
Apply filter WHERE (sort_field, id) > (cursor_value, cursor_id)
Fetch N+1 rows to determine has_next_page
Return N rows + page info

Pagination Types

pub struct ResourceConnectionParams {
    pub first: Option<i32>,
    pub after: Option<String>,
    pub last: Option<i32>,
    pub before: Option<String>,
    pub sort: ResourceSort,
    pub direction: PaginationDirection,
    pub filter: Option<ResourceFilterInput>,
}

pub enum ResourceSort {
    CreatedAt,
    UpdatedAt,
    Name,
    LastViewed,
    Modality,
}

pub struct ResourceConnectionResult {
    pub rows: Vec<ResourceSummaryRow>,
    pub has_next_page: bool,
    pub has_previous_page: bool,
    pub total_count: i64,
}

Migrations

Migration	Purpose
`001`	Create `resources` table
`003`	Add `folder_id` to resources
`004`	Add `cover_image_url`, `last_viewed_at`
`006`	Add `is_public`, `is_replicable`, `forked_from`

Folders — folder organization for resources
Bundles — assessment algorithm data
GraphQL — resolvers that use this repository
Auth — Oso Cloud fact management alongside writes