# signAccessUrl

```ts
function signAccessUrl(
   publicUrl, 
   signingKey, 
opts): Promise<string>;
```

Defined in: packages/asset-client/dist/index.d.ts:88

Turn a PUBLIC-tree URL into a signed PRIVATE-tree URL.

  https://8ok.uk/5/v/<sha16>-lg.webp
    → https://8ok.uk/a/5/v/<sha16>-lg.webp?exp=…&sig=…

Accepts a URL that is already under `/a/` and re-signs it, so calling twice
is not an error and does not produce `/a/a/`.

## Parameters

| Parameter | Type |
| ------ | ------ |
| `publicUrl` | `string` |
| `signingKey` | `string` |
| `opts` | [`SignAccessOptions`](/api/nitida/sdk/type-aliases/signaccessoptions/) |

## Returns

`Promise`\<`string`\>