> For the complete documentation index, see [llms.txt](https://docs.sign.global/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.sign.global/for-builders/index/index/indexing-service.md).

# Usage & Examples

## Schemas

### Querying Schemas

```typescript
async function querySchemaList(query: {
  id?: string;
  registrant?: string;
  mode?: "offchain" | "onchain";
  page: number;
  size?: number;
}): Promise<
  PageInfo & {
    rows: SchemaInfo[];
  }
>;
```

#### Parameters

| Name        | Type / Value          | Description                                                      |
| ----------- | --------------------- | ---------------------------------------------------------------- |
| id?         | `string`              | The schema ID you are querying for.                              |
| registrant? | `string`              | Find schemas that were created by a specific registrant address. |
| mode?       | `offchain`, `onchain` | The schema's location.                                           |
| page        | `number`              | The page to fetch.                                               |
| size?       | `number`              | The number of results to return.                                 |

#### Example

```typescript
const res = await indexService.querySchemaList({
  id: "onchain_evm_11155111_0xd",
  registrant: "0x526dDf0Cc975E0b5B039c85b5cD7ba1e1300500e",
  mode: "onchain",
  page: 1,
  size: 2,
});
```

### Getting a Schema By ID

```typescript
async function querySchema(schemaId: string): Promise<SchemaInfo | null>;
```

#### Parameters

| Name     | Type     | Description                       |
| -------- | -------- | --------------------------------- |
| schemaId | `string` | The ID of the schema to retrieve. |

#### Example

```typescript
const res = await indexService.querySchema("onchain_evm_11155111_0xd");
```

## Attestations

### Querying Attestations

```typescript
async function queryAttestationList(query: {
  id?: string;
  schemaId?: string;
  attester?: string;
  page: number;
  mode?: "offchain" | "onchain";
  indexingValue?: string;
}): Promise<
  PageInfo & {
    rows: AttestationInfo[];
  }
>;
```

#### Parameters

| Name           | Type / Value          | Description                                            |
| -------------- | --------------------- | ------------------------------------------------------ |
| id?            | `string`              | The attestation ID you are querying for.               |
| schemaId?      | `string`              | Find attestations that belong to a specific schema ID. |
| attester?      | `string`              | Find attestations that a specific attester created.    |
| page           | `number`              | The page to fetch.                                     |
| mode?          | `offchain`, `onchain` | The attestation's location.                            |
| indexingValue? | `string`              | Find attestations with a specific indexing value.      |

#### Example

```typescript
const res = await indexService.queryAttestationList({
  id: "",
  schemaId: "",
  attester: "",
  page: 1,
  mode: "onchain",
  indexingValue: "",
});
```

### Getting an Attestation By ID

```typescript
async function queryAttestation(
  attestationId: string
): Promise<AttestationInfo | null>;
```

#### Parameters

| Name          | Type     | Description                       |
| ------------- | -------- | --------------------------------- |
| attestationId | `string` | The ID of the schema to retrieve. |

#### Example

```typescript
const res = await indexService.queryAttestation("onchain_evm_11155111_0x5");
```

## Utils

### Decoding Attestation Data

```typescript
function decodeOnChainData(
  data: any,
  dataLocation: DataLocationOnChain,
  schemaData: SchemaItem[]
): any;
```

#### Parameters

| Name                | Type / Value          | Description                                                     |
| ------------------- | --------------------- | --------------------------------------------------------------- |
| data                | `string`              | The hex string retrieved from an onchain attestation object.    |
| DataLocationOnChain | `DataLocationOnChain` | Location of the data. Either `ONCHAIN`, `ARWEAVE`, or `IPFS`.   |
| schemaData          | `string`              | The data string of the schema that this attestation belongs to. |

#### Example

<pre class="language-typescript"><code class="lang-typescript">const { decodeOnChainData } from "@ethsign/sp-sdk";

const attestationData = "0x0000000000000000000000000000000000000000000000000000000000000040000000000000000000000000b1987e041b79727cd2a190b53d86c2d1cd2869ef0000000000000000000000000000000000000000000000000000000000000012486f6d65776f726b2f446166742050756e6b0000000000000000000000000000";
<strong>const schemaData = `[{"name":"contractDetails","type":"string"},{"name":"signer","type":"address"}]`;
</strong>const res = decodeOnChainData(
  attestationData,
  DataLocationOnChain.ONCHAIN,
  JSON.parse(schemaData)
);
</code></pre>


---

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