The Invoke function

The Invoke function is called when the client invokes a specific function to process the transaction proposal. The ChaincodeStubInterface interface has the GetFunctionAndParameters method. This method extracts the function name and arguments and dispatches code to different functions based on the first argument. In our assetmgr, we need to call the Order, Ship, and Distribute functions, and then update the status for each step and the orgAsset information in the ledger. We can also define the query and query history functions, to get orgAsset information from the ledger.

You will notice that the Order method passes parameters from the command-line input. We use stub.GetState(assetId) to query the asset data from the blockchain, then we verify to make sure the current asset status is correct. We update the orgAsset info and then convert the asset data to byte data by calling json.Marshal(orgAsset). Finally, we save the data into the blockchain via stub.PutState. If there are no errors, the function will return a successful response to the client.