Get Filecoin information for a Piece

To retrieve a Data Aggregation Proof (including PoDSI) you can issue a filecoin/info invocation to the web3.storage service.

Using the JS client

Piece CIDs are calculated by the client before data is uploaded and are made available in the onShardStored callback of uploadFile, uploadDirectory or uploadCAR.

If you did not store the piece CID when your content was uploaded you can query content claims (opens in a new tab) for an equivalency claim.

Later, you can use the piece CID to retrieve a Data Aggregation Proof:

const result = await client.capability.filecoin.info(piece)

The result contains aggregate piece CIDs and inclusion proofs (PoDSI):

for (const { aggregate, inclusion } of result.ok.aggregates) {
  console.log(`Aggregate CID: ${aggregate}`)
  console.log(`Inclusion Proof: ${inclusion}`)
}

Inclusion proofs can be verified using the @web3-storage/data-segment library:

import { Proof, Piece } from '@web3-storage/data-segment'
 
const result = Proof.verify(inclusion.subtree, {
  tree: Piece.fromLink(aggregate).root,
  node: Piece.fromLink(piece).root
})

The result also contains details of storage providers and deals the aggregate appears in:

for (const { provider, aux } of result.ok.deals) {
  console.log(`Storage Provider: f0${provider}`)
  console.log(`Deal ID: ${aux.dataSource.dealID}`)
}

Using the CLI

Piece CIDs are calculated by the client before data is uploaded and will be printed to the terminal if you pass the --verbose option to w3 up.

If you did not store the piece CID when your content was uploaded you can query content claims (opens in a new tab) for an equivalency claim.

Later, you can use the piece CID to print out Data Aggregation Proof information:

$ w3 can filecoin info bafkzcibe52kq2dtip2bmrrw5qhphsa35onsxxvkuxl33dnotq2allfpz7tdxlhc5di
 
Piece CID: bafkzcibe52kq2dtip2bmrrw5qhphsa35onsxxvkuxl33dnotq2allfpz7tdxlhc5di
Deals: 
  Aggregate: bafkzcibcaapbrpjpxk32treyrtw5kamyh5ayxoj7rp4obkeoloydktubycnkufy
    Provider: 1392893
    Deal ID: 65895671
 
  Aggregate: bafkzcibcaapbrpjpxk32treyrtw5kamyh5ayxoj7rp4obkeoloydktubycnkufy
    Provider: 1771403
    Deal ID: 65895759
 
  Aggregate: bafkzcibcaapbrpjpxk32treyrtw5kamyh5ayxoj7rp4obkeoloydktubycnkufy
    Provider: 97777
    Deal ID: 65903995
 
  Aggregate: bafkzcibcaapbrpjpxk32treyrtw5kamyh5ayxoj7rp4obkeoloydktubycnkufy
    Provider: 717969
    Deal ID: 65922477
 
  Aggregate: bafkzcibcaapbrpjpxk32treyrtw5kamyh5ayxoj7rp4obkeoloydktubycnkufy
    Provider: 20378
    Deal ID: 65929686

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