Use Cases ========= .. _use-cases: For most apps, the Graph Protocol is a good choice when wanting to expose contract storage to HTTPS clients. But with Attestate's crawler, a tight integration into a decentralized application's process is possible. The crawler allows being spun up side-to-side to node software without the necessity of requesting calls from an external network. Below are the use cases we're eliciting. Self-contained chain synchronization ------------------------------------ Modern peer to peer "dapps" like `Farcaster `_ implement reconciliation algorithms using on-chain identity management via digital signatures. Their algorithm considers a post valid, if its signed by an address registered in the on-chain registry. This prevents denial of service attacks by increasing a spammer's cost when signing up with the protocol. But for that to work, a hub must always replicate the registry's storage. It ideally does so without integrating many moving parts (e.g. through external requests) or points of centralization. Attestate's Crawler is a good match for these types of applications as its embeddable JavaScript helps the p2p app stay up to date with Ethereum's network. Since its self-contained, it reduces the complexity of the anyhow complex peer to peer reconciliation. It implements stage-separated data retrieval work flows. By separating extraction from transformation and loading, that means repeated network retrieval of contract storage is unnecessary, even if transformation or loading phases fail. Stage-separation also enables quick turn-arounds for fixing an application. Since all extraction data is kept isolated, when it breaks the transformation or loader pipeline, these mismatches in schema can be fixed quickly. To retrieve Farcaster's identity registry data and to compute its NFT timeline, Attestate Crawler could be connected to Infura and Alchemy without the risk of getting rate-limited, as a request-pooling algorithm prevents the crawler's worker from triggering rate limits. Considering the scale of Farcaster's future name registry, by co-locating the hub to an Erigon node, it can synchronize the registry at disk-speed (GigaBytes per second!) without having to make costly network requests. Generating derivative data -------------------------- A second use case is that of producing derivative data with Attestate's crawler. While the Graph Protocol is great for replicating contract storage, an entire NFT collection's token and ownership history may not be useful for every application. For music NFT players like `Spinamp `_ or `MusicOS `_, their backends identify a list of all unique tracks registered on Ethereum by downloading and parsing all NFT meta data. As there can be many NFTs per track (e.g., editions), replicating an collection's contract storage is only a stepping stone for then extracting the unique list of tracks. We call this "generating derivative data," as we're not interested in the token and ownership information, but what song's it exposes. Attestate's crawler was purpose-built for such use cases. Upon completing the extraction phase, developers write custom transformation and loading scripts to derive new data. Metadata is processed, media files are converted and tokens filtered into a list of unique tracks.