NFTMetaDataExample.cdc

import NonFungibleToken from 0xNONFUNGIBLETOKEN

pub contract NFTMetaDataExample: NonFungibleToken {

    // The immutable data for an NFT, this is the actual NFT
    //
    pub resource NFT: NonFungibleToken.INFT {
        pub let id: UInt64
        pub let metadata: {String: TenantService.MetadataField}

        init(metadata: {String: TenantService.MetadataField}) {
            self.id = ...
            self.metadata = metadata
        }
    }

    // =====================================
    // Metadata
    // =====================================

    // The type of a meta data field
    //
    pub enum MetadataFieldType: UInt8 {
        pub case STRING
        pub case NUMBER
        pub case BOOLEAN
        pub case DATE
        pub case DATE_TIME
        pub case URL
        pub case URL_WITH_HASH
        pub case GEO_POINT
    }

    // a meta data field of variable type
    //
    pub struct MetadataField {
        pub let type: MetadataFieldType
        pub let value: AnyStruct

        init(_ type: MetadataFieldType, _ value: AnyStruct) {
            self.type = type
            self.value = value
        }

        pub fun getStringValue(): String? {
            if self.type != MetadataFieldType.STRING {
                return nil
            }
            return self.value as? String
        }

        pub fun getNumberValue(): String? {
            if self.type != MetadataFieldType.NUMBER {
                return nil
            }
            return self.value as? String
        }

        pub fun getBooleanValue(): Bool? {
            if self.type != MetadataFieldType.BOOLEAN {
                return nil
            }
            return self.value as? Bool
        }

        pub fun getURLValue(): String? {
            if self.type != MetadataFieldType.URL {
                return nil
            }
            return self.value as? String
        }

        pub fun getDateValue(): String? {
            if self.type != MetadataFieldType.DATE {
                return nil
            }
            return self.value as? String
        }

        pub fun getDateTimeValue(): String? {
            if self.type != MetadataFieldType.DATE_TIME {
                return nil
            }
            return self.value as? String
        }

        pub fun getURLWithHashValue(): URLWithHash? {
            if self.type != MetadataFieldType.URL_WITH_HASH {
                return nil
            }
            return self.value as? URLWithHash
        }

        pub fun getGeoPointValue(): GeoPoint? {
            if self.type != MetadataFieldType.GEO_POINT {
                return nil
            }
            return self.value as? GeoPoint
        }
    }

    // A url with a hash of the contents found at the url
    //
    pub struct URLWithHash {
        pub let url: String
        pub let hash: String?
        pub let hashAlgo: String?
        init(_ url: String, _ hash: String, _ hashAlgo: String?) {
            self.url = url
            self.hash = hash
            self.hashAlgo = hashAlgo
        }
    }

    // A geo point without any specific projection
    //
    pub struct GeoPoint {
        pub let lat: UFix64
        pub let lng: UFix64
        init(_ lat: UFix64, _ lng: UFix64) {
            self.lat = lat
            self.lng = lng
        }
    }
}