Bastian Köcher
f3bf5c1acd
The `xcm` crate was renamed to `staging-xcm` to be able to publish it to crates.io as someone as squatted `xcm`. The problem with this rename is that the `TypeInfo` includes the crate name which ultimately lands in the metadata. The metadata is consumed by downstream users like `polkadot-js` or people building on top of `polkadot-js`. These people are using the entire `path` to find the type in the type registry. Thus, their code would break as the type path would now be [`staging_xcm`, `VersionedXcm`] instead of [`xcm`, `VersionedXcm`]. This pull request fixes this by renaming the path segment `staging_xcm` to `xcm`. This requires: https://github.com/paritytech/scale-info/pull/197 --------- Co-authored-by: Francisco Aguirre <franciscoaguirreperez@gmail.com>
Transaction Storage Pallet
Indexes transactions and manages storage proofs.
Allows storing arbitrary data on the chain. Data is automatically removed after StoragePeriod blocks, unless the
storage is renewed. Validators must submit proof of storing a random chunk of data for block N - StoragePeriod when
producing block N.
Running a chain
The following describes how to set up a new storage chain.
Start with generating a chain spec.
cargo run --release -- build-spec --chain=local > sc_init.json
Edit the json chain spec file to customise the chain. The storage chain genesis params are configured in the
transactionStorage section. Note that storagePeriod is specified in blocks and changing it also requires code
changes at the moment.
Build a raw spec from the init spec.
cargo run --release build-spec --chain=sc_init.json --raw > sc.json
Run a few validator nodes.
cargo run --release -- --chain=sc.json -d /tmp/alice --storage-chain --keep-blocks=100800 --ipfs-server --validator --alice
cargo run --release -- --chain=sc.json -d /tmp/bob --storage-chain --keep-blocks=100800 --ipfs-server --validator --bob
--storage-chain enables transaction indexing. --keep-blocks=100800 enables block pruning. The value here should be
greater or equal than the storage period. --ipfs-server enables serving stored content over IPFS.
Once the network is started, any other joining nodes need to sync with --sync=fast. Regular sync will fail because
block pruning removes old blocks. The chain does not keep full block history.
cargo run --release -- --chain=sc.json -d /tmp/charlie --storage-chain --keep-blocks=100800 --ipfs-server --validator --charlie --sync=fast
Making transactions
To store data use the transactionStorage.store extrinsic. And IPFS CID can be generated from the Blake2-256 hash of
the data.
const util_crypto = require('@polkadot/util-crypto');
const keyring_api = require('@polkadot/keyring');
const polkadot_api = require('@polkadot/api');
const fs = require('fs');
const multihash = require('multihashes');
const CID = require('cids')
const wsProvider = new polkadot_api.WsProvider();
const api = await polkadot_api.ApiPromise.create({ provider: wsProvider });
const keyring = new keyring_api.Keyring({ type: "sr25519" });
const alice = keyring.addFromUri("//Alice");
const file = fs.readFileSync('cute_kitten.jpeg');
const hash = util_crypto.blake2AsU8a(file)
const encoded_hash = multihash.encode(hash, 'blake2b-256');
const cid = new CID(1, 'blake2b-256', encoded_hash)
console.log(cid.toString());
const txHash = await api.tx.transactionStorage.store('0x' + file.toString('hex')).signAndSend(alice);
Data can be queried over IPFS
ipfs swarm connect <substrate peer address>
ipfs block get /ipfs/<CID> > kitten.jpeg
To renew data and prevent it from being disposed after the storage period, use transactionStorage.renew(block, index)
where block is the block number of the previous store or renew transction, and index is the index of that transaction
in the block.
License: Apache-2.0