feat: add proj and raster extensions

Includes two new traits:

- `Fields` for getting and setting fields, including prefixed ones
- `Extension` for defining extension schema urls and prefixes

stac/src/asset.rs

@@ -1,3 +1,4 @@
+use crate::{Extensions, Fields};
 use serde::{Deserialize, Serialize};
 use serde_json::{Map, Value};
 use std::collections::HashMap;
@@ -54,6 +55,9 @@ pub struct Asset {
     /// Additional fields on the asset.
     #[serde(flatten)]
     pub additional_fields: Map<String, Value>,
+
+    #[serde(skip)]
+    extensions: Vec<String>,
 }
 
 /// Trait implemented by anything that has assets.
@@ -107,10 +111,29 @@ impl Asset {
             created: None,
             updated: None,
             additional_fields: Map::new(),
+            extensions: Vec::new(),
         }
     }
 }
 
+impl Fields for Asset {
+    fn fields(&self) -> &Map<String, Value> {
+        &self.additional_fields
+    }
+    fn fields_mut(&mut self) -> &mut Map<String, Value> {
+        &mut self.additional_fields
+    }
+}
+
+impl Extensions for Asset {
+    fn extensions(&self) -> &Vec<String> {
+        &self.extensions
+    }
+    fn extensions_mut(&mut self) -> &mut Vec<String> {
+        &mut self.extensions
+    }
+}
+
 #[cfg(test)]
 mod tests {
     use super::Asset;

stac/src/catalog.rs

@@ -1,4 +1,4 @@
-use crate::{Error, Extensions, Href, Link, Links, Result, STAC_VERSION};
+use crate::{Error, Extensions, Fields, Href, Link, Links, Result, STAC_VERSION};
 use serde::{Deserialize, Serialize};
 use serde_json::{Map, Value};
 
@@ -33,8 +33,9 @@ pub struct Catalog {
 
     /// A list of extension identifiers the `Catalog` implements.
     #[serde(rename = "stac_extensions")]
-    #[serde(skip_serializing_if = "Option::is_none")]
-    pub extensions: Option<Vec<String>>,
+    #[serde(skip_serializing_if = "Vec::is_empty")]
+    #[serde(default)]
+    pub extensions: Vec<String>,
 
     /// Identifier for the `Catalog`.
     pub id: String,
@@ -74,7 +75,7 @@ impl Catalog {
         Catalog {
             r#type: CATALOG_TYPE.to_string(),
             version: STAC_VERSION.to_string(),
-            extensions: None,
+            extensions: Vec::new(),
             id: id.to_string(),
             title: None,
             description: description.to_string(),
@@ -122,9 +123,21 @@ impl TryFrom<Map<String, Value>> for Catalog {
     }
 }
 
+impl Fields for Catalog {
+    fn fields(&self) -> &Map<String, Value> {
+        &self.additional_fields
+    }
+    fn fields_mut(&mut self) -> &mut Map<String, Value> {
+        &mut self.additional_fields
+    }
+}
+
 impl Extensions for Catalog {
-    fn extensions(&self) -> Option<&[String]> {
-        self.extensions.as_deref()
+    fn extensions(&self) -> &Vec<String> {
+        &self.extensions
+    }
+    fn extensions_mut(&mut self) -> &mut Vec<String> {
+        &mut self.extensions
     }
 }
 
@@ -154,7 +167,7 @@ mod tests {
         assert_eq!(catalog.description, "a description");
         assert_eq!(catalog.r#type, "Catalog");
         assert_eq!(catalog.version, STAC_VERSION);
-        assert!(catalog.extensions.is_none());
+        assert!(catalog.extensions.is_empty());
         assert_eq!(catalog.id, "an-id");
         assert!(catalog.links.is_empty());
     }

stac/src/collection.rs

@@ -1,4 +1,4 @@
-use crate::{Asset, Assets, Error, Extensions, Href, Link, Links, Result, STAC_VERSION};
+use crate::{Asset, Assets, Error, Extensions, Fields, Href, Link, Links, Result, STAC_VERSION};
 use serde::{Deserialize, Serialize};
 use serde_json::{Map, Value};
 use std::collections::HashMap;
@@ -36,8 +36,9 @@ pub struct Collection {
 
     /// A list of extension identifiers the `Collection` implements.
     #[serde(rename = "stac_extensions")]
-    #[serde(skip_serializing_if = "Option::is_none")]
-    pub extensions: Option<Vec<String>>,
+    #[serde(skip_serializing_if = "Vec::is_empty")]
+    #[serde(default)]
+    pub extensions: Vec<String>,
 
     /// Identifier for the `Collection` that is unique across the provider.
     pub id: String,
@@ -171,7 +172,7 @@ impl Collection {
         Collection {
             r#type: COLLECTION_TYPE.to_string(),
             version: STAC_VERSION.to_string(),
-            extensions: None,
+            extensions: Vec::new(),
             id: id.to_string(),
             title: None,
             description: description.to_string(),
@@ -253,9 +254,21 @@ impl Assets for Collection {
     }
 }
 
+impl Fields for Collection {
+    fn fields(&self) -> &Map<String, Value> {
+        &self.additional_fields
+    }
+    fn fields_mut(&mut self) -> &mut Map<String, Value> {
+        &mut self.additional_fields
+    }
+}
+
 impl Extensions for Collection {
-    fn extensions(&self) -> Option<&[String]> {
-        self.extensions.as_deref()
+    fn extensions(&self) -> &Vec<String> {
+        &self.extensions
+    }
+    fn extensions_mut(&mut self) -> &mut Vec<String> {
+        &mut self.extensions
     }
 }
 
@@ -311,7 +324,7 @@ mod tests {
             assert!(collection.assets.is_empty());
             assert_eq!(collection.r#type, "Collection");
             assert_eq!(collection.version, STAC_VERSION);
-            assert!(collection.extensions.is_none());
+            assert!(collection.extensions.is_empty());
             assert_eq!(collection.id, "an-id");
             assert!(collection.links.is_empty());
         }

stac/src/error.rs

@@ -60,6 +60,10 @@ pub enum Error {
     #[error("value is not a collection")]
     NotACollection(Value),
 
+    /// This value is not an object.
+    #[error("not an object")]
+    NotAnObject(serde_json::Value),
+
     /// Returned when trying to read from a url but the `reqwest` feature is not enabled.
     #[error("reqwest is not enabled")]
     ReqwestNotEnabled,