import FungibleToken from 0xf233dcee88fe0abe import NonFungibleToken from 0x1d7e57aa55817448 /// This contract implements the metadata standard proposed /// in FLIP-0636. /// /// Ref: https://github.com/onflow/flow/blob/master/flips/20210916-nft-metadata.md /// /// Structs and resources can implement one or more /// metadata types, called views. Each view type represents /// a different kind of metadata, such as a creator biography /// or a JPEG image file. /// pub contract MetadataViews { /// Provides access to a set of metadata views. A struct or /// resource (e.g. an NFT) can implement this interface to provide access to /// the views that it supports. /// pub resource interface Resolver { pub fun getViews(): [Type] pub fun resolveView(_ view: Type): AnyStruct? } /// A group of view resolvers indexed by ID. /// pub resource interface ResolverCollection { pub fun borrowViewResolver(id: UInt64): &{Resolver} pub fun getIDs(): [UInt64] } /// NFTView wraps all Core views along `id` and `uuid` fields, and is used /// to give a complete picture of an NFT. Most NFTs should implement this /// view. /// pub struct NFTView { pub let id: UInt64 pub let uuid: UInt64 pub let display: Display? pub let externalURL: ExternalURL? pub let collectionData: NFTCollectionData? pub let collectionDisplay: NFTCollectionDisplay? pub let royalties: Royalties? pub let traits: Traits? init( id : UInt64, uuid : UInt64, display : Display?, externalURL : ExternalURL?, collectionData : NFTCollectionData?, collectionDisplay : NFTCollectionDisplay?, royalties : Royalties?, traits: Traits? ) { self.id = id self.uuid = uuid self.display = display self.externalURL = externalURL self.collectionData = collectionData self.collectionDisplay = collectionDisplay self.royalties = royalties self.traits = traits } } /// Helper to get an NFT view /// /// @param id: The NFT id /// @param viewResolver: A reference to the resolver resource /// @return A NFTView struct /// pub fun getNFTView(id: UInt64, viewResolver: &{Resolver}) : NFTView { let nftView = viewResolver.resolveView(Type()) if nftView != nil { return nftView! as! NFTView } return NFTView( id : id, uuid: viewResolver.uuid, display: self.getDisplay(viewResolver), externalURL : self.getExternalURL(viewResolver), collectionData : self.getNFTCollectionData(viewResolver), collectionDisplay : self.getNFTCollectionDisplay(viewResolver), royalties : self.getRoyalties(viewResolver), traits : self.getTraits(viewResolver) ) } /// Display is a basic view that includes the name, description and /// thumbnail for an object. Most objects should implement this view. /// pub struct Display { /// The name of the object. /// /// This field will be displayed in lists and therefore should /// be short an concise. /// pub let name: String /// A written description of the object. /// /// This field will be displayed in a detailed view of the object, /// so can be more verbose (e.g. a paragraph instead of a single line). /// pub let description: String /// A small thumbnail representation of the object. /// /// This field should be a web-friendly file (i.e JPEG, PNG) /// that can be displayed in lists, link previews, etc. /// pub let thumbnail: AnyStruct{File} init( name: String, description: String, thumbnail: AnyStruct{File} ) { self.name = name self.description = description self.thumbnail = thumbnail } } /// Helper to get Display in a typesafe way /// /// @param viewResolver: A reference to the resolver resource /// @return An optional Display struct /// pub fun getDisplay(_ viewResolver: &{Resolver}) : Display? { if let view = viewResolver.resolveView(Type()) { if let v = view as? Display { return v } } return nil } /// Generic interface that represents a file stored on or off chain. Files /// can be used to references images, videos and other media. /// pub struct interface File { pub fun uri(): String } /// View to expose a file that is accessible at an HTTP (or HTTPS) URL. /// pub struct HTTPFile: File { pub let url: String init(url: String) { self.url = url } pub fun uri(): String { return self.url } } /// View to expose a file stored on IPFS. /// IPFS images are referenced by their content identifier (CID) /// rather than a direct URI. A client application can use this CID /// to find and load the image via an IPFS gateway. /// pub struct IPFSFile: File { /// CID is the content identifier for this IPFS file. /// /// Ref: https://docs.ipfs.io/concepts/content-addressing/ /// pub let cid: String /// Path is an optional path to the file resource in an IPFS directory. /// /// This field is only needed if the file is inside a directory. /// /// Ref: https://docs.ipfs.io/concepts/file-systems/ /// pub let path: String? init(cid: String, path: String?) { self.cid = cid self.path = path } /// This function returns the IPFS native URL for this file. /// Ref: https://docs.ipfs.io/how-to/address-ipfs-on-web/#native-urls /// /// @return The string containing the file uri /// pub fun uri(): String { if let path = self.path { return "ipfs://".concat(self.cid).concat("/").concat(path) } return "ipfs://".concat(self.cid) } } /// Optional view for collections that issue multiple objects /// with the same or similar metadata, for example an X of 100 set. This /// information is useful for wallets and marketplaces. /// An NFT might be part of multiple editions, which is why the edition /// information is returned as an arbitrary sized array /// pub struct Edition { /// The name of the edition /// For example, this could be Set, Play, Series, /// or any other way a project could classify its editions pub let name: String? /// The edition number of the object. /// For an "24 of 100 (#24/100)" item, the number is 24. pub let number: UInt64 /// The max edition number of this type of objects. /// This field should only be provided for limited-editioned objects. /// For an "24 of 100 (#24/100)" item, max is 100. /// For an item with unlimited edition, max should be set to nil. /// pub let max: UInt64? init(name: String?, number: UInt64, max: UInt64?) { if max != nil { assert(number <= max!, message: "The number cannot be greater than the max number!") } self.name = name self.number = number self.max = max } } /// Wrapper view for multiple Edition views /// pub struct Editions { /// An arbitrary-sized list for any number of editions /// that the NFT might be a part of pub let infoList: [Edition] init(_ infoList: [Edition]) { self.infoList = infoList } } /// Helper to get Editions in a typesafe way /// /// @param viewResolver: A reference to the resolver resource /// @return An optional Editions struct /// pub fun getEditions(_ viewResolver: &{Resolver}) : Editions? { if let view = viewResolver.resolveView(Type()) { if let v = view as? Editions { return v } } return nil } /// View representing a project-defined serial number for a specific NFT /// Projects have different definitions for what a serial number should be /// Some may use the NFTs regular ID and some may use a different /// classification system. The serial number is expected to be unique among /// other NFTs within that project /// pub struct Serial { pub let number: UInt64 init(_ number: UInt64) { self.number = number } } /// Helper to get Serial in a typesafe way /// /// @param viewResolver: A reference to the resolver resource /// @return An optional Serial struct /// pub fun getSerial(_ viewResolver: &{Resolver}) : Serial? { if let view = viewResolver.resolveView(Type()) { if let v = view as? Serial { return v } } return nil } /// View that defines the composable royalty standard that gives marketplaces a /// unified interface to support NFT royalties. /// pub struct Royalty { /// Generic FungibleToken Receiver for the beneficiary of the royalty /// Can get the concrete type of the receiver with receiver.getType() /// Recommendation - Users should create a new link for a FlowToken /// receiver for this using `getRoyaltyReceiverPublicPath()`, and not /// use the default FlowToken receiver. This will allow users to update /// the capability in the future to use a more generic capability pub let receiver: Capability<&AnyResource{FungibleToken.Receiver}> /// Multiplier used to calculate the amount of sale value transferred to /// royalty receiver. Note - It should be between 0.0 and 1.0 /// Ex - If the sale value is x and multiplier is 0.56 then the royalty /// value would be 0.56 * x. /// Generally percentage get represented in terms of basis points /// in solidity based smart contracts while cadence offers `UFix64` /// that already supports the basis points use case because its /// operations are entirely deterministic integer operations and support /// up to 8 points of precision. pub let cut: UFix64 /// Optional description: This can be the cause of paying the royalty, /// the relationship between the `wallet` and the NFT, or anything else /// that the owner might want to specify. pub let description: String init(receiver: Capability<&AnyResource{FungibleToken.Receiver}>, cut: UFix64, description: String) { pre { cut >= 0.0 && cut <= 1.0 : "Cut value should be in valid range i.e [0,1]" } self.receiver = receiver self.cut = cut self.description = description } } /// Wrapper view for multiple Royalty views. /// Marketplaces can query this `Royalties` struct from NFTs /// and are expected to pay royalties based on these specifications. /// pub struct Royalties { /// Array that tracks the individual royalties access(self) let cutInfos: [Royalty] pub init(_ cutInfos: [Royalty]) { // Validate that sum of all cut multipliers should not be greater than 1.0 var totalCut = 0.0 for royalty in cutInfos { totalCut = totalCut + royalty.cut } assert(totalCut <= 1.0, message: "Sum of cutInfos multipliers should not be greater than 1.0") // Assign the cutInfos self.cutInfos = cutInfos } /// Return the cutInfos list /// /// @return An array containing all the royalties structs /// pub fun getRoyalties(): [Royalty] { return self.cutInfos } } /// Helper to get Royalties in a typesafe way /// /// @param viewResolver: A reference to the resolver resource /// @return A optional Royalties struct /// pub fun getRoyalties(_ viewResolver: &{Resolver}) : Royalties? { if let view = viewResolver.resolveView(Type()) { if let v = view as? Royalties { return v } } return nil } /// Get the path that should be used for receiving royalties /// This is a path that will eventually be used for a generic switchboard receiver, /// hence the name but will only be used for royalties for now. /// /// @return The PublicPath for the generic FT receiver /// pub fun getRoyaltyReceiverPublicPath(): PublicPath { return /public/GenericFTReceiver } /// View to represent, a file with an correspoiding mediaType. /// pub struct Media { /// File for the media /// pub let file: AnyStruct{File} /// media-type comes on the form of type/subtype as described here /// https://developer.mozilla.org/en-US/docs/Web/HTTP/Basics_of_HTTP/MIME_types /// pub let mediaType: String init(file: AnyStruct{File}, mediaType: String) { self.file=file self.mediaType=mediaType } } /// Wrapper view for multiple media views /// pub struct Medias { /// An arbitrary-sized list for any number of Media items pub let items: [Media] init(_ items: [Media]) { self.items = items } } /// Helper to get Medias in a typesafe way /// /// @param viewResolver: A reference to the resolver resource /// @return A optional Medias struct /// pub fun getMedias(_ viewResolver: &{Resolver}) : Medias? { if let view = viewResolver.resolveView(Type()) { if let v = view as? Medias { return v } } return nil } /// View to represent a license according to https://spdx.org/licenses/ /// This view can be used if the content of an NFT is licensed. /// pub struct License { pub let spdxIdentifier: String init(_ identifier: String) { self.spdxIdentifier = identifier } } /// Helper to get License in a typesafe way /// /// @param viewResolver: A reference to the resolver resource /// @return A optional License struct /// pub fun getLicense(_ viewResolver: &{Resolver}) : License? { if let view = viewResolver.resolveView(Type()) { if let v = view as? License { return v } } return nil } /// View to expose a URL to this item on an external site. /// This can be used by applications like .find and Blocto to direct users /// to the original link for an NFT. /// pub struct ExternalURL { pub let url: String init(_ url: String) { self.url=url } } /// Helper to get ExternalURL in a typesafe way /// /// @param viewResolver: A reference to the resolver resource /// @return A optional ExternalURL struct /// pub fun getExternalURL(_ viewResolver: &{Resolver}) : ExternalURL? { if let view = viewResolver.resolveView(Type()) { if let v = view as? ExternalURL { return v } } return nil } /// View to expose the information needed store and retrieve an NFT. /// This can be used by applications to setup a NFT collection with proper /// storage and public capabilities. /// pub struct NFTCollectionData { /// Path in storage where this NFT is recommended to be stored. pub let storagePath: StoragePath /// Public path which must be linked to expose public capabilities of this NFT /// including standard NFT interfaces and metadataviews interfaces pub let publicPath: PublicPath /// Private path which should be linked to expose the provider /// capability to withdraw NFTs from the collection holding NFTs pub let providerPath: PrivatePath /// Public collection type that is expected to provide sufficient read-only access to standard /// functions (deposit + getIDs + borrowNFT) /// This field is for backwards compatibility with collections that have not used the standard /// NonFungibleToken.CollectionPublic interface when setting up collections. For new /// collections, this may be set to be equal to the type specified in `publicLinkedType`. pub let publicCollection: Type /// Type that should be linked at the aforementioned public path. This is normally a /// restricted type with many interfaces. Notably the `NFT.CollectionPublic`, /// `NFT.Receiver`, and `MetadataViews.ResolverCollection` interfaces are required. pub let publicLinkedType: Type /// Type that should be linked at the aforementioned private path. This is normally /// a restricted type with at a minimum the `NFT.Provider` interface pub let providerLinkedType: Type /// Function that allows creation of an empty NFT collection that is intended to store /// this NFT. pub let createEmptyCollection: ((): @NonFungibleToken.Collection) init( storagePath: StoragePath, publicPath: PublicPath, providerPath: PrivatePath, publicCollection: Type, publicLinkedType: Type, providerLinkedType: Type, createEmptyCollectionFunction: ((): @NonFungibleToken.Collection) ) { pre { publicLinkedType.isSubtype(of: Type<&{NonFungibleToken.CollectionPublic, NonFungibleToken.Receiver, MetadataViews.ResolverCollection}>()): "Public type must include NonFungibleToken.CollectionPublic, NonFungibleToken.Receiver, and MetadataViews.ResolverCollection interfaces." providerLinkedType.isSubtype(of: Type<&{NonFungibleToken.Provider, NonFungibleToken.CollectionPublic, MetadataViews.ResolverCollection}>()): "Provider type must include NonFungibleToken.Provider, NonFungibleToken.CollectionPublic, and MetadataViews.ResolverCollection interface." } self.storagePath=storagePath self.publicPath=publicPath self.providerPath = providerPath self.publicCollection=publicCollection self.publicLinkedType=publicLinkedType self.providerLinkedType = providerLinkedType self.createEmptyCollection=createEmptyCollectionFunction } } /// Helper to get NFTCollectionData in a way that will return an typed Optional /// /// @param viewResolver: A reference to the resolver resource /// @return A optional NFTCollectionData struct /// pub fun getNFTCollectionData(_ viewResolver: &{Resolver}) : NFTCollectionData? { if let view = viewResolver.resolveView(Type()) { if let v = view as? NFTCollectionData { return v } } return nil } /// View to expose the information needed to showcase this NFT's /// collection. This can be used by applications to give an overview and /// graphics of the NFT collection this NFT belongs to. /// pub struct NFTCollectionDisplay { // Name that should be used when displaying this NFT collection. pub let name: String // Description that should be used to give an overview of this collection. pub let description: String // External link to a URL to view more information about this collection. pub let externalURL: ExternalURL // Square-sized image to represent this collection. pub let squareImage: Media // Banner-sized image for this collection, recommended to have a size near 1200x630. pub let bannerImage: Media // Social links to reach this collection's social homepages. // Possible keys may be "instagram", "twitter", "discord", etc. pub let socials: {String: ExternalURL} init( name: String, description: String, externalURL: ExternalURL, squareImage: Media, bannerImage: Media, socials: {String: ExternalURL} ) { self.name = name self.description = description self.externalURL = externalURL self.squareImage = squareImage self.bannerImage = bannerImage self.socials = socials } } /// Helper to get NFTCollectionDisplay in a way that will return a typed /// Optional /// /// @param viewResolver: A reference to the resolver resource /// @return A optional NFTCollection struct /// pub fun getNFTCollectionDisplay(_ viewResolver: &{Resolver}) : NFTCollectionDisplay? { if let view = viewResolver.resolveView(Type()) { if let v = view as? NFTCollectionDisplay { return v } } return nil } /// View to expose rarity information for a single rarity /// Note that a rarity needs to have either score or description but it can /// have both /// pub struct Rarity { /// The score of the rarity as a number pub let score: UFix64? /// The maximum value of score pub let max: UFix64? /// The description of the rarity as a string. /// /// This could be Legendary, Epic, Rare, Uncommon, Common or any other string value pub let description: String? init(score: UFix64?, max: UFix64?, description: String?) { if score == nil && description == nil { panic("A Rarity needs to set score, description or both") } self.score = score self.max = max self.description = description } } /// Helper to get Rarity view in a typesafe way /// /// @param viewResolver: A reference to the resolver resource /// @return A optional Rarity struct /// pub fun getRarity(_ viewResolver: &{Resolver}) : Rarity? { if let view = viewResolver.resolveView(Type()) { if let v = view as? Rarity { return v } } return nil } /// View to represent a single field of metadata on an NFT. /// This is used to get traits of individual key/value pairs along with some /// contextualized data about the trait /// pub struct Trait { // The name of the trait. Like Background, Eyes, Hair, etc. pub let name: String // The underlying value of the trait, the rest of the fields of a trait provide context to the value. pub let value: AnyStruct // displayType is used to show some context about what this name and value represent // for instance, you could set value to a unix timestamp, and specify displayType as "Date" to tell // platforms to consume this trait as a date and not a number pub let displayType: String? // Rarity can also be used directly on an attribute. // // This is optional because not all attributes need to contribute to the NFT's rarity. pub let rarity: Rarity? init(name: String, value: AnyStruct, displayType: String?, rarity: Rarity?) { self.name = name self.value = value self.displayType = displayType self.rarity = rarity } } /// Wrapper view to return all the traits on an NFT. /// This is used to return traits as individual key/value pairs along with /// some contextualized data about each trait. pub struct Traits { pub let traits: [Trait] init(_ traits: [Trait]) { self.traits = traits } /// Adds a single Trait to the Traits view /// /// @param Trait: The trait struct to be added /// pub fun addTrait(_ t: Trait) { self.traits.append(t) } } /// Helper to get Traits view in a typesafe way /// /// @param viewResolver: A reference to the resolver resource /// @return A optional Traits struct /// pub fun getTraits(_ viewResolver: &{Resolver}) : Traits? { if let view = viewResolver.resolveView(Type()) { if let v = view as? Traits { return v } } return nil } /// Helper function to easily convert a dictionary to traits. For NFT /// collections that do not need either of the optional values of a Trait, /// this method should suffice to give them an array of valid traits. /// /// @param dict: The dictionary to be converted to Traits /// @param excludedNames: An optional String array specifying the `dict` /// keys that are not wanted to become `Traits` /// @return The generated Traits view /// pub fun dictToTraits(dict: {String: AnyStruct}, excludedNames: [String]?): Traits { // Collection owners might not want all the fields in their metadata included. // They might want to handle some specially, or they might just not want them included at all. if excludedNames != nil { for k in excludedNames! { dict.remove(key: k) } } let traits: [Trait] = [] for k in dict.keys { let trait = Trait(name: k, value: dict[k]!, displayType: nil, rarity: nil) traits.append(trait) } return Traits(traits) } }

🎉Happy diving into the flow

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🎉Happy diving into the flow