rustac-core

rustac-core

The rustac-core crate provides Rust types for working with SpatioTemporal Asset Catalog (STAC) entities, including:

• Items
• Collections
• Catalogs

Data Types

All objects can be serialized from JSON using serde and serde_json.

This library tries to be consistent in how it maps a STAC type to a Rust type. Any STAC attributes that are required are represented as one of the Rust types listed below. Any optional STAC attributes are represented as an Option with a value that is one of the Rust types listed below.

STAC Type	Rust Type
string	[String]
number	[f32]
array	[Vec]
datetime	[chrono::DateTime] with [chrono::FixedOffset]
geometry	[geojson::Geometry]
bbox	[geojson::Bbox]
stac_version	[semver::Version]

Additional Fields & Extensions

STAC objects may contain fields not included in the core STAC spec itself. These fields are not serialized into "primitive" Rust types, but instead are flattened into a serde_json::Value in the extra_fields field on the struct. This includes fields that may be defined as part of a STAC Extension.

I plan on adding support for accessing extension fields as Rust types in a separate stac-extensions crate.

Validation

This crate does not do any validation of STAC objects beyond ensuring that they can be properly deserialized. For validation of STAC entities using JSON Schema, see the stac-validate crate.

Examples

Create an [Item] by deserializing one of the example JSON files.

use rustac_core::Item;
use rustac_core::error::{STACError, STACResult};
use semver::Version;
use serde_json::json;

fn main() -> STACResult<()> {
    let example = json!({
    "stac_version": "1.0.0-rc.2",
    "stac_extensions": [],
    "type": "Feature",
    "id": "20201211_223832_CS2",
    "bbox": [172.91173669923782, 1.3438851951615003, 172.95469614953714, 1.3690476620161975],
    "geometry": {
      "type": "Polygon",
      "coordinates": [
        [
          [172.91173669923782, 1.3438851951615003],
          [172.95469614953714, 1.3438851951615003],
          [172.95469614953714, 1.3690476620161975],
          [172.91173669923782, 1.3690476620161975],
          [172.91173669923782, 1.3438851951615003]
        ]
      ]
    },
    "properties": {
      "datetime": "2020-12-11T22:38:32.125000Z"
    },
    "collection": "simple-collection",
    "links": [
      {
        "rel": "collection",
        "href": "./collection.json",
        "type": "application/json",
        "title": "Simple Example Collection"
      },
      {
        "rel": "root",
        "href": "./collection.json",
        "type": "application/json"
      }
    ],
    "assets": {
      "visual": {
        "href": "https://storage.googleapis.com/open-cogs/stac-examples/20201211_223832_CS2.tif",
        "type": "image/tiff; application=geotiff; profile=cloud-optimized",
        "title": "3-Band Visual",
        "roles": [
          "visual"
        ]
      },
      "thumbnail": {
        "href": "https://storage.googleapis.com/open-cogs/stac-examples/20201211_223832_CS2.jpg",
        "title": "Thumbnail",
        "type": "image/jpeg",
        "roles": [
          "thumbnail"
        ]
      }
    }
  });

  let item: Item = serde_json::from_value(example)?;

  assert_eq!(item.stac_version, Version::parse("1.0.0-rc.2")?);
  assert_eq!(item.type_, String::from("Feature"));

  Ok(())
}