CODEWITHSUNDEEP
hyperledger-fabrichyperledgerhyperledger-composer
Mr Davron
Mr Davron

Reputation: 466

How would Hyperledger Composer work?

I am new to composer, and now practicing some of the tutorials and examples. But while doing this I can not understand some of the features, so here are the questions which I do not clearly understand:

  1. Are queries restricted by .acl file (when, for example, we use them in rest server)?
  1. Do the rules written in the .acl restrict some of the transactions which are allowed for certain participant to submit? (For example, for participantA it is not allowed to CREATE new participants, but what happens if participantA submits the transaction(which is allowed for him to submit)which creates another participant, will this transaction fail?
  1. Could cards be created by rest api server?(I know that participants could be created using JS api, but is it possible to create and issue the identity for those participants through RestServerApi?)
  1. What happens when PeerAdmin upgrade certain node to a new version? How do other nodes act in this case? Do they upgrade themself automaticly?(Also found that upgrade takes a lot of time(2-4 minutes) when deployed locally, whereas in browser for local connection it takes 3-4 seconds)
  1. Does Hyperledger fabric allow some of the ledger data be stored in one private network, whereas other network connected to the private one would not store this part of ledger( or the data will be simply crypted)? The same question regarding the transactions: will the be executed on outer networks?

Upvotes: 0

Views: 148

Answers (1)

Paul O'Mahony
Paul O'Mahony

Reputation: 6740

  1. Yes Composer Queries (and therein, results) are subject to ACL restrictions or filters.

  2. It will still fail due to ACL rule restriction. Once denied to create, always denied as that is the final operation (in this scenario). The actual transaction would fail.

  3. Yes of course use POST /system/identities/issue REST endpoint (eg http://localhost:3001/api/system/identities/issue) - see an example here -> https://medium.com/@CazChurchUk/developing-multi-user-application-using-the-hyperledger-composer-rest-server-b3b88e857ccc

  4. An administrator with PeerAdmin capability has responsibility to install new version on his peers (in his Org). The other Org peer Admins are responsible for theirs, that's how a blockchain consortium with different Orgs will work. They will agree the 'what' and when but will need to install the new version on own Org's peers, so the new version can be started on the same channel. Of course, there will be a difference between a Fabric infrastructure response time, and that of a web connection using local storage.

  5. Channels in Fabric implement privacy. You can have one or more business networks on that channel (ledger), therefore transactions in that business network are private to that ledger. It is the client's responsibility to encrypt data or not. Hyperledger Composer can allow call one business network from another, on the same channel, or if permitted to do so, on different channels too - see https://hyperledger.github.io/composer/latest/tutorials/invoke-composer-network

Upvotes: 4

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