vantage-csv

CSV backend for the Vantage data framework.

Implements TableSource so that Table<Csv, E> works alongside Table<SurrealDB, E> (or any other backend) for read operations.

Type system

Like SurrealDB's AnySurrealType (backed by CBOR), vantage-csv defines AnyCsvType (backed by String) via the vantage_type_system! macro.

Column definitions on the table drive type-safe parsing:

let table = Table::<Csv, EmptyEntity>::new("product", csv)
    .with_column_of::<String>("name")
    .with_column_of::<i64>("price")
    .with_column_of::<bool>("is_deleted")
    .with_column_of::<serde_json::Value>("inventory");

When reading a CSV row, each field is parsed according to its column type:

• "300" + column type i64 → AnyCsvType { value: "300", variant: Int }
• "true" + column type bool → AnyCsvType { value: "true", variant: Bool }
• "hello" + no column defined → AnyCsvType { value: "hello", variant: String }

Values can be extracted type-safely:

let price: i64 = record["price"].try_get::<i64>().unwrap();
let name: String = record["name"].try_get::<String>().unwrap();

Usage

use vantage_csv::Csv;
use vantage_table::table::Table;
use vantage_dataset::prelude::ReadableValueSet;

let csv = Csv::new("data/");
let products = Table::<Csv, MyProduct>::new("product", csv)
    .with_column_of::<String>("name")
    .with_column_of::<i64>("price")
    .into_entity::<MyProduct>();

let all = products.list().await?;

Each table reads from {base_dir}/{table_name}.csv. The first row is treated as headers and every subsequent row becomes a record.

ID column

By default the id column is used as the record identifier. Override with:

let csv = Csv::new("data/").with_id_column("code");

If the CSV has no matching column, row indices (starting at 0) are used instead.

Embedded JSON

Object/array fields can be stored as quoted JSON strings in CSV:

id,name,inventory
1,Widget,"{""stock"":50}"

Define the column as serde_json::Value to parse it:

table.with_column_of::<serde_json::Value>("inventory")

Read-only

CSV is a read-only data source. Write operations (insert, replace, patch, delete) return errors at runtime.

License

MIT OR Apache-2.0