Core Module

This module has main functions, which are used to manage NFT schema, NFT Data, and Actions. We can use these 3 data models to provide mutable metadata on the NFT Chain.

Metadata Schema

In order to work with metadata dynamically , we need to define basic information of the NFT from origin chain ( Ethereum, Klaytn or EVM chain ), attributes which will be maintained on NFT Data chain and also actions that process those attributes.

Name	Data Type	Description
code	string	unique code to identify your NFT.
name	string	Name of the NFT
owner	string	Cosmos-based address who create the this schema
system_actioners	array	Array of addresses that has permission to perform actions
origin_data	object	Information from origin chain
origin_base_uri	string	Base URI representing metadata on origin chain
uri_retrieval_method	string	Retrieval method of the origin metadata ("base", "token").
origin_chain	string	Origin chain which NFT Smart Contract is deployed ( "ethereum" , "klaytn" )
origin_contract_address	string	Smart Contract address
attribute_overriding	string	When there is an attribute designed to manage on data chain with the same attribute on the origin chain, this indicator will determine which value will be presented from the data chain's metadatabase URI.
metadata_format	string	To indicate the format when metadata was presented.
origin_attributes	list of attribute definition	list of origin attributes
- name	string	Attribute name
- data_type	string	Data type of attributes. One of number, string, boolean and float
- display_value_field	string	The field name represents the attribute's value when displayed in a marketplace format. For example, "opensea." See the whole example below.
- display_option	object	Attribute format represent attribute data in marketplace format. For example , { "opensea": { "trait_type": "Background L" } }
onchain_data	object	Dynamic part of metadata
nft_attributes	list of attribute definition	A list of attributes in which every token metadata has the same value can only be changed by the NFT creator, not the token holder. Same structure as attributes in origin part
token_attributes	list of attribute definition	A list of metadata attributes is stored on the chain for each token of the NFT. Attribute Definition is the same structure as attributes in the original part
actions	list of Action	A list of actions (a logic to update attribute value) pre-designed for users to perform
- name	string	Action name which is used to referred for invoking
- desc	string	A description of the action
- when	string	Conditions to validate to be valid before invoking Action
- then	list of sub-actions	A list of line s of action to make changes on the attribute. For example, if we need to decrease one attribute by 1, the code will be like this -> "meta.SetNumber('percent_discount_10',meta.GetNumber('percent_discount_10') - 1)"
- params	list of object params	A list of parameters of actions. Some action required the parameter to make it able to perform.

To explain easily how we can create the schema, we can use the command line built from CosmosSDK

sixnftd tx nftmngr create-nft-schema --from alice \
    <BASE64 schema>

<BASE64 schema> is the NFT Schema from the above table in JSON encoded by base64.

NFT Data

There are 2 important parts to the NFT Data. One is data from the origin chain and those attributes maintained in Data Chain. See the table below:

Name	Data Type	Description
nft_schema_code	string	Code reference to a unique schema
token_id	string	NFT Token iD
token_owner	string	A Cosmos-based account that owns the token.
origin_image	string	an image URL originally defined
onchain_image	string	As an option, a new image URL in case there is a business case to change an image after some actions
token_uri	string	URI By token, used if present. If not schema's origin_base_uri is used.
origin_attributes	list of attribute value	List of attributes which has the same value as in original metadata. It's read-only and should never be changed after minting is started
onchain_attributes	list of attribute value	List of attributes with a mutable value that can be modified by calling actions.

Available function

Function	Desc
meta.GetImage()	It will find and return onchain_image from nft_metadata, when onchain_image is empty it will return origin_image form nft_metadata instead
meta.SetImage(string)	To set new onchain_image of nft_metadata
meta.GetNumber(attribute_name)	It will return value of attribute type number
meta.GetFloat(attribute_name)	It will return value of attribute type float
meta.GetString(attribute_name)	It will return value of attribute type string
meta.GetBoolean(attribute_name)	It will return value of attribute type boolean
meta.SetString(attribute_name,new_value)	To set new value of attribute type string
meta.SetNumber(attribute_name,new_value)	To set new value of attribute type number
meta.SetFloat(attribute_name,new_value)	To set new value of attribute type float
meta.SetBoolean(attribute_name,new_value)	To set new value of attribute type boolean
meta.ReplaceAllString(string,to_replace,replace_with)	To place string according to regex that we find
meta.SetDisplayArribute(attribute_name,new_value)	To hide/show attribute from marketplace (new_value should be true/false)
meta.TransferNumber(attribute_name,target_id,value)	Transfer attribute type number to target token. Ex: transfer points

meta.{Utils}

Function	Desc
meta.GetBlockHeight()	It will return current blocktime of chain
meta.GetUTCBlockTimestamp(format)	It will return current UTC blocktime of chain in which format that we input. >> Go Time Format Layout <<
meta.GetBlockTimestampByZone(zone,format)	It will return current blocktime according to input zone and format. >> TimeZone (List TZ database name)<<
meta.BlockTimeUTCBefore(target_time,format)	Validate current time is before time of input and its format (return true/false)
meta.BlockTimeUTCAfter(target_time,format)	Validate current time is after time of input and its format (return true/false)
meta.BlockTimeBeforeByZone(target_time,zone,format)	Validate current time is before time of input time, zone and its format (return true/false)
meta.BlockTimeAfterByZone(target_time,zone,format)	Validate current time is after time of input time, zone and its format (return true/false)