The node implements sticker packs as [ERC721 token](https://eips.ethereum.org/EIPS/eip-721) and contain a set of stickers. The node stores these stickers
inside the sticker pack as a set of hyperlinks pointing to IPFS storage. These hyperlinks are publicly available and can be accessed by any user inside the status chat.
At the moment of writing, the current main Status app uses the [Infura](https://infura.io/) gateway. However, clients could choose a different gateway or to run own IPFS node.
derived from the hash of the file. This ensures that a file can't be overridden, and an end-user of the IPFS will receive the same file at a given address.
The IPFS gateway acts as an end-user of the IPFS and allows users of the gateway to access IPFS without connection to the P2P network.
Usage of a gateway introduces potential risk for the users of that gateway provider. In case of a compromise in the security of the provider, meta information such as IP address, User-Agent and other of its users can be leaked.
To send a sticker in chat, a user of Status should buy or install a sticker pack.
To be available for installation a Sticker Pack should be submitted to Sticker market by an author.
#### Submit a sticker
To submit a sticker pack, the author should upload all assets to IPFS. Then generate a payload including name, author, thumbnail, preview and a list of stickers in the [EDN format](https://github.com/edn-format/edn). Following this structure:
All asset fields, are contenthash fields as per [EIP 1577](https://eips.ethereum.org/EIPS/eip-1577).
The node also uploads this payload to IPFS, and the node uses the IPFS address in the content field of the Sticker Market contract. See [Sticker Market spec](https://github.com/status-im/sticker-market/blob/651e88e5f38c690e57ecaad47f46b9641b8b1e27/docs/specification.md) for a detailed description of the contract.
To install a sticker pack, the node fetches all sticker packs available in Sticker Market. The node needs the following steps to fetch all sticker packs:
ID's are represented as `uint256` and are incremental from `0` to total number of sticker packs in the contract, received in the previous step. To get a sticker pack call `getPackData(sticker-pack-id)`, the return type is `["bytes4[]" "address" "bool" "uint256" "uint256" "bytes"]` which represents the following fields: `[category owner mintable timestamp price contenthash]`. Price is the SNT value in wei set by sticker pack owner. The contenthash is the IPFS address described in the [submit description](#submit-a-sticker) above. Other fields specification could be found in [Sticker Market spec](https://github.com/status-im/sticker-market/blob/651e88e5f38c690e57ecaad47f46b9641b8b1e27/docs/specification.md)
The current Status app fetches owned sticker packs during the open of any sticker view (a screen which shows a sticker pack, or the list of sticker packs).
To get owned packs, get all owned tokens for the current account address, by calling `balanceOf(address)` where address is the address for the current account. This method returns a `uint256` representing the count of available tokens. Using `tokenOfOwnerByIndex(address,uint256)` method, with the address of the user and ID in form of a `uint256` which is an incremented int from 0 to the total number of tokens, gives the token id. To get the sticker pack id from a token call`tokenPackId(uint256)` where `uint256` is the token id. This method will return an `uint256` which is the id of the owned sticker pack.
To buy a sticker pack call `approveAndCall(address,uint256,bytes)` where `address` is the address of buyer,`uint256` is the price and third parameters `bytes` is the callback called if approved. In the callback, call `buyToken(uint256,address,uint256)`, first parameter is sticker pack id, second buyers address, and the last is the price.
