NFT standards
This article provides a standard NFT Metadata format to facilitate users to integrate the NFT module of the Bounce platform.
The NFT standard is divided into two protocols: ERC721 and ERC1155 (as Enjin first proposed both, we will follow Enjin's Metadata standard).
Metadata enables NFTs’ subsidiary functions, which can describe each NFT, including pictures, names, descriptions, etc. The details are as follows:
{ "title": "Asset Metadata", "type": "object", "properties": { "name": { "type": "string", "description": "Identifies the asset to which this NFT represents" }, "description": { "type": "string", "description": "Describes the asset to which this NFT represents" }, "image": { "type": "string", "description": "A URI pointing to a resource with mime type image/* representing the asset to which this NFT represents. Consider making any images at a width between 320 and 1080 pixels and aspect ratio between 1.91:1 and 4:5 inclusive." } }}
Metadata is obtained on ERC721 by reading the tokenURI function, and in the ERC1155 contract by reading the URI function. Take the tokenURI of a certain NFT in Burger as an example: https://raw.githubusercontent.com/burgernft/nft_assets/master/ETH-1.json
Burger puts Metadata information into GitHub, and users can see the current information of Metadata and also its modification records. A user can obtain the URL through the tokenURI, and then read the JSON format data through the URL.
This is how the Metadata data looks like on the Bounce platform:
{ "title": "Never Forget The Girl", "type": "art", "properties": { "name": { "type": "string", "description": "Cindy Yi" }, "description": { "type": "string", "description": "An irreplaceable girl." }, "image": { "type": "string", "description": "https://shalomhu.github.io/bounce/NFT/images/img_01.jpg" } }}{ "title": "Token Metadata", "type": "object", "properties": { "name": { "type": "string", "description": "Identifies the asset to which this token represents", }, "decimals": { "type": "integer", "description": "The number of decimal places that the token amount should display - e.g. 18, means to divide the token amount by 1000000000000000000 to get its user representation.", }, "description": { "type": "string", "description": "Describes the asset to which this token represents", }, "image": { "type": "string", "description": "A URI pointing to a resource with mime type image/* representing the asset to which this token represents. Consider making any images at a width between 320 and 1080 pixels and aspect ratio between 1.91:1 and 4:5 inclusive.", }, "properties": { "type": "object", "description": "Arbitrary properties. Values may be strings, numbers, object or arrays.", }, "localization": { "type": "object", "required": ["uri", "default", "locales"], "properties": { "uri": { "type": "string", "description": "The URI pattern to fetch localized data from. This URI should contain the substring `{locale}` which will be replaced with the appropriate locale value before sending the request." }, "default": { "type": "string", "description": "The locale of the default data within the base JSON" }, "locales": { "type": "array", "description": "The list of locales for which data is available. These locales should conform to those defined in the Unicode Common Locale Data Repository (http://cldr.unicode.org/)." } } }, }}