Hyperledger Composer NodeJS SDK - Submiting Transactions
In my previous article, I spoke about how to setup the Hyperledger Composer NodeJS SDK with expressJS to build your own RESTFul API for a Composer Business Network. And this article is a continuation of it where it’s about how to create and submit transactions.
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Create Asset Definition
As the first step, let’s create an asset say “Car” in our example, which has set of properties. Define them in your model file of composer (.cto)
The above defined asset Car has three properties named id, name, owner. And in order to create a Car we need to have a transaction, thus define a transaction model as below.
As you can notice, here we’re not mentioning the owner while creating the car, since we’ll be using the
getCurrentParticipant() method inside transaction processor function to get the current user and define the owner.
Now since we’ve everything in our network, let’s update the network with the following commands.
Creating EndPoint For Transaction
Next up is to create an endpoint for transaction submission. We do it with express js as follows.
This is very similar to the ping method, we’re getting the transaction data from the request and passing it to
createCar method in our MyNetwork Class.
This returns a
null if the transaction is submitted successfully, else catch block is called with the captured error.
The only thing to have in mind is that we need to specify the
$class in transactionData and convert it to resource format from JSON before passing it to