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use crate::{Band, DataType, Result, Statistics};
use indexmap::IndexMap;
use serde::{Deserialize, Serialize};
use serde_json::{Map, Value};
use stac_derive::Fields;
/// An Asset is an object that contains a URI to data associated with the [Item](crate::Item) that can be downloaded or streamed.
#[derive(Debug, Serialize, Deserialize, PartialEq, Clone, Fields)]
pub struct Asset {
/// URI to the asset object.
///
/// Relative and absolute URIs are both allowed.
pub href: String,
/// The displayed title for clients and users.
#[serde(skip_serializing_if = "Option::is_none")]
pub title: Option<String>,
/// A description of the Asset providing additional details, such as how it was processed or created.
///
/// [CommonMark 0.29](http://commonmark.org/) syntax MAY be used for rich text representation.
#[serde(skip_serializing_if = "Option::is_none")]
pub description: Option<String>,
/// [Media type](crate::mime) of the asset.
///
/// See the [common media types](https://github.com/radiantearth/stac-spec/blob/master/best-practices.md#common-media-types-in-stac) in the best practice doc for commonly used asset types.
#[serde(skip_serializing_if = "Option::is_none")]
pub r#type: Option<String>,
/// The semantic roles of the asset, similar to the use of rel in [Links](crate::Link).
#[serde(skip_serializing_if = "Vec::is_empty")]
#[serde(default)]
pub roles: Vec<String>,
/// Creation date and time of the corresponding data, in UTC.
///
/// This identifies the creation time of the data.
///
/// This is a [common
/// metadata](https://github.com/radiantearth/stac-spec/blob/master/item-spec/common-metadata.md)
/// field.
#[serde(skip_serializing_if = "Option::is_none")]
pub created: Option<String>,
/// Date and time the metadata was updated last, in UTC.
///
/// This identifies the updated time of the data.
///
/// This is a [common
/// metadata](https://github.com/radiantearth/stac-spec/blob/master/item-spec/common-metadata.md)
/// field.
#[serde(skip_serializing_if = "Option::is_none")]
pub updated: Option<String>,
/// An array of available bands where each object is a [Band].
#[serde(skip_serializing_if = "Vec::is_empty", default)]
pub bands: Vec<Band>,
/// Value used to identify no-data.
///
/// The extension specifies that this can be a number or a string, but we
/// just use a f64 with a custom (de)serializer.
///
/// TODO write custom (de)serializer.
#[serde(skip_serializing_if = "Option::is_none")]
pub nodata: Option<f64>,
/// The data type of the values.
#[serde(skip_serializing_if = "Option::is_none")]
pub data_type: Option<DataType>,
/// Statistics of all the values.
#[serde(skip_serializing_if = "Option::is_none")]
pub statistics: Option<Statistics>,
/// Unit of measurement of the value.
#[serde(skip_serializing_if = "Option::is_none")]
pub unit: Option<String>,
/// Additional fields on the asset.
#[serde(flatten)]
pub additional_fields: Map<String, Value>,
}
/// Trait implemented by anything that has assets.
///
/// As of STAC v1.0.0, this is [Collection](crate::Collection) and [Item](crate::Item).
pub trait Assets {
/// Returns a reference to this object's assets.
///
/// # Examples
///
/// [Item](crate::Item) has assets:
///
/// ```
/// use stac::{Item, Assets};
/// let item: Item = stac::read("examples/simple-item.json").unwrap();
/// assert!(!item.assets().is_empty());
/// ```
fn assets(&self) -> &IndexMap<String, Asset>;
/// Returns a mut reference to this object's assets.
///
/// # Examples
///
/// [Item](crate::Item) has assets:
///
/// ```
/// use stac::{Item, Asset, Assets};
/// let mut item: Item = stac::read("examples/simple-item.json").unwrap();
/// item.assets_mut().insert("foo".to_string(), Asset::new("./asset.tif"));
/// ```
fn assets_mut(&mut self) -> &mut IndexMap<String, Asset>;
/// Makes all asset hrefs absolute.
fn make_assets_absolute(&mut self, base: &str) -> Result<()> {
for asset in self.assets_mut().values_mut() {
asset.href = crate::href::make_absolute(&asset.href, base)?.into();
}
Ok(())
}
}
impl Asset {
/// Creates a new asset with the provided href.
///
/// # Examples
///
/// ```
/// # use stac::Asset;
/// let asset = Asset::new("an-href");
/// assert_eq!(asset.href, "an-href");
/// ```
pub fn new(href: impl ToString) -> Asset {
Asset {
href: href.to_string(),
title: None,
description: None,
r#type: None,
roles: Vec::new(),
created: None,
updated: None,
bands: Vec::new(),
data_type: None,
nodata: None,
statistics: None,
unit: None,
additional_fields: Map::new(),
}
}
/// Adds a role to this asset, returning the modified asset.
///
/// Useful for builder patterns.
///
/// # Examples
///
/// ```
/// use stac::Asset;
/// let asset = Asset::new("asset/dataset.tif").role("data");
/// assert_eq!(asset.roles, vec!["data"]);
/// ```
pub fn role(mut self, role: impl ToString) -> Asset {
self.roles.push(role.to_string());
self.roles.dedup();
self
}
}
impl From<String> for Asset {
fn from(value: String) -> Self {
Asset::new(value)
}
}
impl<'a> From<&'a str> for Asset {
fn from(value: &'a str) -> Self {
Asset::new(value)
}
}
#[cfg(test)]
mod tests {
use super::{Asset, Assets};
use crate::Item;
#[test]
fn new() {
let asset = Asset::new("an-href");
assert_eq!(asset.href, "an-href");
assert!(asset.title.is_none());
assert!(asset.description.is_none());
assert!(asset.r#type.is_none());
assert!(asset.roles.is_empty());
}
#[test]
fn skip_serializing() {
let asset = Asset::new("an-href");
let value = serde_json::to_value(asset).unwrap();
assert!(value.get("title").is_none());
assert!(value.get("description").is_none());
assert!(value.get("type").is_none());
assert!(value.get("roles").is_none());
}
#[test]
fn make_absolute() {
let asset = Asset::new("an-href");
let mut item = Item::new("an-item");
let _ = item.assets.insert("data".into(), asset);
item.make_assets_absolute("http://rustac.test").unwrap();
assert_eq!(item.assets["data"].href, "http://rustac.test/an-href");
}
}