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Version: V2

# Create a post

In this section you'll learn how to implement the Register Essence feature. We call essence everything that is content and related to it. Yes, it's also a NFT. It can take the form a post, an article, a soulbound token (SBT) or something completely different that's up to your imagination.

You'll notice that the process is very similar to the one is described Subscribe to profile but there is a small difference. When the user creates an essence, a non-fungible token (NFT) is only being created. The minting and transferring of the NFT is being executed in the collect essence process to the user that collects it, which you'll learn all about in the upcoming section.

## GraphQL mutations​

To register an essence, meaning to create a post for this example, is a two step process and requires two GraphQL mutations: CreateRegisterEssenceTypedData and Relay.

1. CreateRegisterEssenceTypedData is used to present data to the user in a readable format:
graphql/CreateSubscribeTypedData.ts
import { gql } from "@apollo/client";export const CREATE_REGISTER_ESSENCE_TYPED_DATA = gql  mutation CreateRegisterEssenceTypedData(    $input: CreateRegisterEssenceTypedDataInput! ) { createRegisterEssenceTypedData(input:$input) {      typedData {        id        sender        data        nonce      }    }  };
1. Relay is responsible for broadcasting the transaction, minting and transferring the NFT:
graphql/Relay.ts
import { gql } from "@apollo/client";export const RELAY = gql  mutation Relay($input: RelayInput!) { relay(input:$input) {      relayActionId    }  };
1. RelayActionStatus is used to get the relaying status:
graphql/RelayActionStatus.ts
import { gql } from "@apollo/client";export const RELAY_ACTION_STATUS = gql  query RelayActionStatus($relayActionId: ID!) { relayActionStatus(relayActionId:$relayActionId) {      ... on RelayActionStatusResult {        txHash        txStatus      }      ... on RelayActionError {        reason        lastKnownTxHash      }      ... on RelayActionQueued {        queuedAt      }    }  };

## Metadata Schema​

You can think of the Essence Metadata Schema as a standard template used to store data related to content and the NFT holding that data.

You'll notice that some of the fields are following the OpenSea Metadata Standards and this is to ensure that the NFT will be displayed properly on OpenSea and other marketplaces.

Below are all the fields for the Essence Metadata Schema accompanied by a short description on what they represent.

types.ts
/* Metadata schema for Essence NFT */interface Media {  /* The MIME type for the media */  media_type: string;  /* The URL link for the media */  media_url: string;  /* Alternative text when media can't be rendered */  alt_tag?: string;  /* The preview image for the media */  preview_image_url?: string;}interface Attribute {  /* Field indicating how you would like it to be displayed */  /* optional if the trait_type is string */  display_type?: string;  /* Name of the trait */  trait_type: string;  /* Value of the trait */  value: string;}export interface IEssenceMetadata {  /* ~~ REQUIRED ~~ */  /* Unique id for the issued item */  metadata_id: string;  /* Version of the metadata schema used for the issued item. */  version: string;  /* ~~ OPTIONAL ~~ */  /* Id of the application under which the items are being minted. */  app_id?: string;  /* Language of the content as a BCP47 language tag. */  lang?: string;  /* Creation time of the item as ISO 8601. */  issue_date?: string;  /* The content associated with the item */  content?: string;  /* Media refers to any image, video, or any other MIME type attached to the content.    Limited to max. 10 media objects. */  media?: Media[];  /* Field indicating the tags associated with the content. Limited to max. 5 tags. */  tags?: string[];  /* ~~ OPENSEA (optional) ~~ */  /* URL to the image of the item. */  image?: string;  /* SVG image data when the image is not passed. Only use this if you're not         including the image parameter. */  image_data?: string;  /* Name of the item. */  name?: string;  /* Description of the item. */  description?: string;  /* URL to a multi-media attachment for the item. */  animation_url?: string;  /* Attributes for the item. */  attributes?: Attribute[];  /* URL to the item on your site. */  external_url?: string;}
tip

Verify Essence Metadata allows you to verify the validity of an essence's metadata schema.

## Create a Post​

To create a post means to Register a Essence. The process for it does require a couple of extra steps compared to Subscribe, but those steps are only related to the data associated to the Essence NFT:

1. Construct the metadata object for the Essence NFT;
2. Upload the metadata to IPFS to get the hash;
3. Get data in a readable format and the typedDataID for it;
4. Get the user to sign the message data and get its signature;
5. Call the relay and pass it the typedDataID and signature;
components/PostBtn.tsx
/* Construct the metadata object for the Essence NFT */const metadata: IEssenceMetadata = {  metadata_id: uuidv4(),  version: "1.0.0",  app_id: "cyberconnect",  lang: "en",  issue_date: new Date().toISOString(),  content: post,  media: [],  tags: [],  image: nftImageURL ? nftImageURL : "",  image_data: !nftImageURL ? svg_data : "",  name: @${handle}'s post, description: @${handle}'s post on CyberConnect Content app,  animation_url: "",  external_url: "",  attributes: [],};/* Upload metadata to IPFS */const ipfsHash = await pinJSONToIPFS(metadata);/* Create typed data in a readable format */const typedDataResult = await createRegisterEssenceTypedData({  variables: {    input: {      /* The profile id under which the Essence is registered */      profileID: profileID,      /* Name of the Essence */      name: "Post",      /* Symbol of the Essence */      symbol: "POST",      /* URL for the json object containing data about content and the Essence NFT */      tokenURI: https://cyberconnect.mypinata.cloud/ipfs/\${ipfsHash},      /* Middleware that allows users to collect the Essence NFT for free */      middleware: {        collectFree: true,      },      /* Set if the Essence should be transferable or not */      transferable: true,    },  },});const typedData =  typedDataResult.data?.createRegisterEssenceTypedData?.typedData;const message = typedData.data;const typedDataID = typedData.id;/* Get the signature for the message signed with the wallet */const fromAddress = await signer.getAddress();const params = [fromAddress, message];const method = "eth_signTypedData_v4";const signature = await signer.provider.send(method, params);/* Call the relay to broadcast the transaction */const relayResult = await relay({  variables: {    input: {      typedDataID: typedDataID,      signature: signature,    },  },});const txHash = relayResult.data?.relay?.relayTransaction?.txHash;
info

Setting a middleware for an essence can be done either during the essence registration as presented in this section or after the registration process as described in the Middleware for Post.

tip

There are multiple available middlewares that can be implemented. Visit the Middleware section to view the full list.

In this example we simply pass as middleware the collectFree middleware that will allow users to collect the post for free. There are more options in terms of middlewares that you can choose from in the Middleware section.

If the registration of the essence (or post in our case) was successful, you can verify the transaction hash on goerli.etherscan.io.

Note that at this stage you are only registering the NFT. When a user collects a post this is when the NFT actually gets minted and transferred to the user's wallet address, which you'll learn all about in the next section Collect a Post.

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