is there a way to do a certain kind of Transaction on a daily basis (at a certain time) using the logic.js file? I know that there are timestamps that you can add to an asset, but I don´t see how that could be used to haven an automatic transaction. Is there some other solution maybe? Or do i need an application wrapped around hyperledger fabric for that?
Thx in advance
You couldn't do it from the logic.js file, but you could use the Composer Node API to call the transaction every day, achieving what you want to do?
Example of a Transaction
You are right, that is an application wrapped around. But it's pretty lightweight, the only issues I had were getting my head around authentication. Here is a utility script to help with that.
Related
Please advise if it is possible to somehow remove old blocks from hyperledger fabric ?
I understand that it must be immutable, but what if we do not want to store years old data?
There is no "Archive" feature in Fabric at the moment, but there is an "Epic" in the jira system for an Archive feature. It has been around for quite a while but it now looks like a high priority.
Here are the details.
No, you can not remove transaction from the chain itself. Since otherwise you would destroy the whole thing (merkle tree properties).
But only 'recent' data will be stored in the StateDBs. This is data which is labeled as not deleted. Deleted data will be moved out of this DB. So you could actually think of this as a cache where you can 'quickly' access up to date data. (maybe read docs about StateDB and Ledger etc in Fabric to get more insights on this)
I successfully completed a hyperledger composer and working it well.
I just created explorer for the same network using the git https://github.com/hyperledger/blockchain-explorer. This explorer is slow to load. I just decide to create own explorer using Node.js . My questions is
How to get blocks number, hash, etc using node.js.(I already visited the site node api link . But do not see any example how to use it)??
Have any idea to increase the speed of existing hyperledger explorer.??
Please give any suggestion for my problem. Thanks in advance
Fabric 1.1.0
Composer 0.19.16
Os: Ubuntu 16.04
Hyperledger Explorer has to traverse the blockchain to build its view of the ledger (stored in a PostgreSQL DB). If you have a large number of blocks, this can take some time. However, once this has been built, new blocks should be picked up as fast as your network can supply them.
However, if you want to look at improving it, why not just start with the existing code? This is after all the whole point of open-source software :)
Hyperledger explorer is provide API such as http://localhost:8080/blocks/{channel name}/{block number}
We can easily implement the front end and call the API at back end. Hope you help you. Thanks
I have been researching online a lot, and I have hit a roadblock.
My current situation is that I have a hash inside my blockchain, and this would reference a file that will return this from off chain. My question is that would using IPFS and Storj even be possible using Hyperledger Composer? If so, how would the integration process work? My case right now would require the use of Hyperledger due to its architecture over Ethereum, so it is much preferable to use Hyperledger.
Besides this, I would also like to create a custom front end. Is it possible to work on custom CSS and code, for example, using Angular?
yes - firstly see storage options discussed in this thread -> Best practice to save files in blockchain -
In Composer you could store the hash as a string on an asset in your model etc etc and you can retrieve via IPFS client search etc once you've got your asset (eg by name or ID) etc .- lastly see this announce for current status of Composer FYI
I am developing a micro money-lending platform where I am using hyperledger -composer to model the business network, but I am getting stuck on how to implement the payment processing system in my solution as hyperledger-composer doesn't have any currencies associated with it.
How can I do this?
Hyperledger Fabric might not be the best tool for this task. If you want to use it, you can use it just like a relational database, with your users as Participants, other entities as Assets etc etc. But you can't use it for passing money from one person to another -- you'll have to use other means.
The Composer's model consists of javascript code, entities, query definitions, and access rules. As I understand, everything becomes some kind of executable code after deployment, since Fabric doesn't have anything like that.
What exactly is happening during the deployment process? Is everything compiled into a sort of bytecode? For example, Composer's transaction functions are somehow becoming a part of the Fabric's Invoke method, but how exactly one maps onto the other?
I am asking because I want to add a capability to Composer to run js-based queries, and they need to be somehow mapped to the Fabric's Query method.
You need to study the architecture of Hyperledger Composer.
What you are looking for is the composer-runtime which interact with the underlaying Fabric.
Check out these slides :
link