# Using the SDK
## Installation
VeraxSDK is a [npm package](https://www.npmjs.com/package/verax-sdk/).
```
# npm
npm i --save @verax-attestation-registry/verax-sdk
```
```
# yarn
yarn add @verax-attestation-registry/verax-sdk
```
***
## Getting Started
### 1. Import VeraxSdk
```
// CommonJS
var VeraxSdk = require("@verax-attestation-registry/verax-sdk");
```
```
// ES6
import { VeraxSdk } from "@verax-attestation-registry/verax-sdk";
```
### 2. Instantiate VeraxSdk
// Default configuration for Linea Sepolia
// Frontend
const veraxSdk = new VeraxSdk(VeraxSdk.DEFAULT_LINEA_SEPOLIA_FRONTEND);
// Backend
const veraxSdk = new VeraxSdk(VeraxSdk.DEFAULT_LINEA_SEPOLIA);
Or:
```javascript
// Default configuration for Linea Mainnet
// Frontend
const veraxSdk = new VeraxSdk(VeraxSdk.DEFAULT_LINEA_MAINNET_FRONTEND);
// Backend
const veraxSdk = new VeraxSdk(VeraxSdk.DEFAULT_LINEA_MAINNET);
```
Or:
```javascript
// Custom configuration
import { optimism } from "viem/chains";
const myVeraxConfiguration = {
chain: optimism,
mode: SDKMode.BACKEND,
subgraphUrl: "https://my.subgraph.url",
portalRegistryAddress: "0xMyPortalRegistryAddress",
moduleRegistryAddress: "0xMyModuleRegistryAddress",
schemaRegistryAddress: "0xMySchemaRegistryAddress",
attestationRegistryAddress: "0xMyAttestationRegistryAddress",
};
const veraxSdk = new VeraxSdk(myVeraxConfiguration);
```
***
## Read and write objects
### 1. Get DataMappers
```javascript
// Each Verax class has its corresponding DataMapper
// Get them from the SDK instance
const portalDataMapper = veraxSdk.portal; // RW Portals
const schemaDataMapper = veraxSdk.schema; // RW Schemas
const moduleDataMapper = veraxSdk.module; // RW Modules
const attestationDataMapper = veraxSdk.attestation; // RW Attestations
const utilsDataMapper = veraxSdk.utils; // Utils
```
### 2. Read content (one object)
Each DataMapper comes with the method `findOneById` to get one object by ID.
{% code fullWidth="true" %}
```javascript
const myPortal = await portalDataMapper.findOneById("0x34798a866f52949208e67fb57ad36244024c50c0");
const mySchema = await schemaDataMapper.findOneById(
"0xce2647ed39aa89e6d1528a56deb6c30667ed2aae1ec2378ec3140c0c5d98a61e",
);
const myModule = await moduleDataMapper.findOneById("0x4bb8769e18f1518c35be8405d43d7cc07ecf501c");
const mySchema = await schemaDataMapper.findOneById(
"0xce2647ed39aa89e6d1528a56deb6c30667ed2aae1ec2378ec3140c0c5d98a61e",
);
const myAttestation = await attestationDataMapper.findOneById(
"0x000000000000000000000000000000000000000000000000000000000000109b",
);
```
{% endcode %}
### 3. Read content (list / many objects)
Each DataMapper comes with the method `findBy` to get objects by criteria. Each DataMapper comes with the method `findBy` to get objects by criteria.
{% code fullWidth="true" %}
```javascript
//
// args:
// - criteria: object {property1: value1, property2: value2, ...}
// - page: integer (optional, default 0)
// - offset: integer (optional, default 50, max= 500)
// - orderBy: string (optional, default createdAt)
// - order(property?): enum string "ASC", "DESC" (optional, default "DESC")
//
const myAttestations = await attestationDataMapper.findBy(
{ portalId: "37773", subject: "John" },
4,
30,
"schemaId",
"ASC",
);
console.log(myAttestations);
//
// totalNumber: 147,
// page: 0,
// objects: [
// {id: "12345", schemaId: "99AE34", portalId: "37773", subject: "Florian", ...},
// {id: "2221E", schemaId: "AAF77E", portalId: "37773", subject: "Florian", ...},
// ...
// ]
//
```
{% endcode %}
### 4. Write content
Each dataMapper comes with methods to write data that may vary depending on the class. See the detail of write method per class dataMapper.
{% code fullWidth="true" %}
```javascript
const portalAddress = "0xeea25bc2ec56cae601df33b8fc676673285e12cc";
const attestationPayload = {
schemaId: "0x9ba590dd7fbd5bd1a7d06cdcb4744e20a49b3520560575cd63de17734a408738",
expirationDate: 1693583329,
subject: "0x828c9f04D1a07E3b0aBE12A9F8238a3Ff7E57b47",
attestationData: [{ isBuidler: true }],
};
const validationPayloads = [];
const newAttestation = await this.veraxSdk.portal.attest(portalAddress, attestationPayload, validationPayloads);
```
{% endcode %}
***
## Other operations
\[Work in progress] The class `veraxSdk.utils` extends the capabilities:
* precompute the ID of an attestation
* encode decode payload
---
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