Support for STAC 1.1

Author: tschaub

asset.go

@@ -13,6 +13,7 @@ type Asset struct {
 	Description string      `json:"description,omitempty"`
 	Created     string      `json:"created,omitempty"`
 	Roles       []string    `json:"roles,omitempty"`
+	Bands       []*Band     `json:"bands,omitempty"`
 	Extensions  []Extension `json:"-"`
 }
 
@@ -47,6 +48,16 @@ func EncodeAssets(assets map[string]*Asset) (map[string]any, []string, error) {
 				return nil, nil, err
 			}
 		}
+
+		bandMaps, uris, err := EncodeBands(asset.Bands)
+		if err != nil {
+			return nil, nil, err
+		}
+		if len(bandMaps) > 0 {
+			extensionUris = append(extensionUris, uris...)
+			assetMap["bands"] = bandMaps
+		}
+
 		assetsMap[key] = assetMap
 	}
 	return assetsMap, extensionUris, nil

asset_test.go

@@ -5,7 +5,7 @@ import (
 	"testing"
 
 	"github.com/planetlabs/go-stac"
-	"github.com/planetlabs/go-stac/extensions/pl"
+	"github.com/planetlabs/go-stac/extensions/pl/v1"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 )

band.go

@@ -0,0 +1,72 @@
+package stac
+
+import (
+	"regexp"
+
+	"github.com/go-viper/mapstructure/v2"
+)
+
+var bandExtensions = newExtensionRegistry()
+
+func RegisterBandExtension(pattern *regexp.Regexp, provider ExtensionProvider) {
+	bandExtensions.register(pattern, provider)
+}
+
+func GetBandExtension(uri string) Extension {
+	return bandExtensions.get(uri)
+}
+
+type Band struct {
+	Name        string      `json:"name,omitempty"`
+	Description string      `json:"description,omitempty"`
+	NoData      any         `json:"nodata,omitempty"`
+	DataType    string      `json:"data_type,omitempty"`
+	Statistics  *Statistics `json:"statistics,omitempty"`
+	Unit        string      `json:"unit,omitempty"`
+	Extensions  []Extension `json:"-"`
+}
+
+type Statistics struct {
+	Mean         *float64 `json:"mean,omitempty"`
+	Minimum      *float64 `json:"minimum,omitempty"`
+	Maximum      *float64 `json:"maximum,omitempty"`
+	Stdev        *float64 `json:"stdev,omitempty"`
+	ValidPercent *float64 `json:"valid_percent,omitempty"`
+	Count        *int     `json:"count,omitempty"`
+}
+
+func encodeBand(band *Band) (map[string]any, []string, error) {
+	extensionUris := []string{}
+	bandMap := map[string]any{}
+	decoder, err := mapstructure.NewDecoder(&mapstructure.DecoderConfig{
+		TagName: "json",
+		Result:  &bandMap,
+	})
+	if err != nil {
+		return nil, nil, err
+	}
+	if err := decoder.Decode(band); err != nil {
+		return nil, nil, err
+	}
+	for _, extension := range band.Extensions {
+		extensionUris = append(extensionUris, extension.URI())
+		if err := extension.Encode(bandMap); err != nil {
+			return nil, nil, err
+		}
+	}
+	return bandMap, extensionUris, nil
+}
+
+func EncodeBands(bands []*Band) ([]map[string]any, []string, error) {
+	extensionUris := []string{}
+	bandMaps := make([]map[string]any, len(bands))
+	for i, band := range bands {
+		bandMap, uris, err := encodeBand(band)
+		if err != nil {
+			return nil, nil, err
+		}
+		bandMaps[i] = bandMap
+		extensionUris = append(extensionUris, uris...)
+	}
+	return bandMaps, extensionUris, nil
+}

catalog.go

@@ -2,6 +2,7 @@ package stac
 
 import (
 	"encoding/json"
+	"errors"
 	"fmt"
 	"regexp"
 
@@ -116,6 +117,9 @@ func (catalog *Catalog) UnmarshalJSON(data []byte) error {
 			continue
 		}
 		if err := extension.Decode(catalogMap); err != nil {
+			if errors.Is(err, ErrExtensionDoesNotApply) {
+				continue
+			}
 			return fmt.Errorf("decoding error for %s: %w", uri, err)
 		}
 		catalog.Extensions = append(catalog.Extensions, extension)

collection.go

@@ -2,9 +2,11 @@ package stac
 
 import (
 	"encoding/json"
+	"errors"
 	"fmt"
 	"regexp"
 
+	"github.com/Masterminds/semver/v3"
 	"github.com/go-viper/mapstructure/v2"
 )
 
@@ -20,6 +22,7 @@ type Collection struct {
 	Summaries   map[string]any    `json:"summaries,omitempty"`
 	Links       []*Link           `json:"links"`
 	Assets      map[string]*Asset `json:"assets,omitempty"`
+	ItemAssets  map[string]*Asset `json:"item_assets,omitempty"`
 	Extensions  []Extension       `json:"-"`
 }
 
@@ -78,6 +81,36 @@ func (collection Collection) MarshalJSON() ([]byte, error) {
 	extensionUris := []string{}
 	lookup := map[string]bool{}
 
+	assetsMap, assetExtensionUris, err := EncodeAssets(collection.Assets)
+	if err != nil {
+		return nil, err
+	}
+	if len(assetsMap) > 0 {
+		collectionMap["assets"] = assetsMap
+	}
+
+	for _, uri := range assetExtensionUris {
+		if !lookup[uri] {
+			extensionUris = append(extensionUris, uri)
+			lookup[uri] = true
+		}
+	}
+
+	itemAssetsMap, itemAssetExtensionUris, err := EncodeAssets(collection.ItemAssets)
+	if err != nil {
+		return nil, err
+	}
+	if len(itemAssetsMap) > 0 {
+		collectionMap["item_assets"] = itemAssetsMap
+	}
+
+	for _, uri := range itemAssetExtensionUris {
+		if !lookup[uri] {
+			extensionUris = append(extensionUris, uri)
+			lookup[uri] = true
+		}
+	}
+
 	for _, extension := range collection.Extensions {
 		if err := extension.Encode(collectionMap); err != nil {
 			return nil, err
@@ -140,11 +173,33 @@ func (collection *Collection) UnmarshalJSON(data []byte) error {
 			continue
 		}
 		if err := extension.Decode(collectionMap); err != nil {
+			if errors.Is(err, ErrExtensionDoesNotApply) {
+				continue
+			}
 			return fmt.Errorf("decoding error for %s: %w", uri, err)
 		}
 		collection.Extensions = append(collection.Extensions, extension)
 	}
 
+	if err := decodeExtendedAssets(collectionMap, "assets", collection.Assets, extensionUris); err != nil {
+		return err
+	}
+
+	// Item assets were added  to collections in version 1.1.0
+	itemAssetsConstraint, err := semver.NewConstraint(">= 1.1.0")
+	if err != nil {
+		return fmt.Errorf("could not parse version constraint: %w", err)
+	}
+
+	if collectionVersion, err := semver.NewVersion(collection.Version); err == nil && itemAssetsConstraint.Check(collectionVersion) {
+		if err := decodeExtendedAssets(collectionMap, "item_assets", collection.ItemAssets, extensionUris); err != nil {
+			return err
+		}
+	} else {
+		// prior to 1.1.0, the item assets extension is used
+		collection.ItemAssets = nil
+	}
+
 	if err := decodeExtendedLinks(collectionMap, collection.Links, extensionUris); err != nil {
 		return err
 	}