Designated Fee Delegation

The TX-fee-delegation mechanism (both VIP-191 and MPP) on VeChainThor. The demo is built using tools connex-framework and connex.driver-nodejs that implement the Connex interface in a NodeJS environment.
There are three accounts used in the demo:
1.SENDER whose address begins with 0xd551,
2.DELEGATOR (or gas-payer) whose address begins with 0xe466, and
3.RECIPIENT whose address begins with 0x9143. To demonstrate VIP-191, I created one TX from SENDER to RECIPIENT. The TX was co-signed by SENDER and DELEGATOR to allow TX fee paid by DELEGATOR.
To demonstrate MPP, I created two TXs sent from DELEGATOR to call functions of the built-in contract Prototype to add a payer-user relation and funding plan as described above. I then created one TX from SENDER to DELEGATOR to demonstrate the effect of MPP. Note that DELEGATOR is the master of itself since it is a normal account rather than a contract. The TX can only be sent to DELEGATOR or otherwise it wouldn't be funded by DELEGATOR according to the rules set by MPP.
CONNEX INTERFACE FOR VIP-191
The Connex interface has been updated to support VIP-191. I want to show you that it is pretty easy to use Connex to construct a VIP-191 enabled TX.
There are two extra things you need to do on top of the normal procedure of constructing a TX:
Create your own function with the following definition:
function (unsignedTx: { raw: string, origin: string }): Promise
This function is typically responsible for send data to the gas-payer, waiting for its response and returns a Promise, if resolved, carrying the gas-payer's digital signature on the corresponding TXID.
Pass the function to the instance of Connex.Vendor.TxSigningService, as you've already created for TX construction, via the delegate method. For instance, you may add a line such as:
signingService.delegate(MyFunc);
That's it!
Note that the function I made in the demo code is NOT a typical function you would see in a real application. It is created purely for this demo and should not be considered as an example of creating such a function.
Results output
--------------------------
VIP-191
--------------------------
TXID       = 0xb58e1d1bf9da3414c24df51926003ebcbac7eb10246dd25548ccfd9202d4276e
From       = 0xd55100eedb61f1e553a38c33a234ce07952c43f2
To         = 0x91436f1E5008B2E6093E114A25842F060012685d
GasPayer   = 0xe4660c72dea1d9fc2a0dc2b3a42107d37edc6327
GasUsed    = 21000
...
The first part shows information of the VIP-191 enabled TX. It can be seen that the actual gas-payer was indeed DELEGATOR rather than SENDER.
--------------------------
MPP - Add User
--------------------------
TXID       = 0x508f50692c88054c5f8df982937b2871cae3cde002a4bc58e975277acca53c87
From       = 0xe4660c72dea1d9fc2a0dc2b3a42107d37edc6327
To         = 0x000000000000000000000050726f746f74797065
GasPayer   = 0xe4660c72dea1d9fc2a0dc2b3a42107d37edc6327
GasUsed    = 25074
...
--------------------------
MPP - Add Credit Plan
--------------------------
TXID       = 0x57329507daadb47a8ea68375577f9699fce3f1329df4703451be36d3804aa853
From       = 0xe4660c72dea1d9fc2a0dc2b3a42107d37edc6327
To         = 0x000000000000000000000050726f746f74797065
GasPayer   = 0xe4660c72dea1d9fc2a0dc2b3a42107d37edc6327
GasUsed    = 44811
...
The second part shows information of the two TXs DELEGATOR sent to the built-in contract Prototype to activate MPP for SENDER. The overhead costs for adding a user and a credit plan are 25k and 45k gas, respectively.
--------------------------
MPP - User Sends TX
--------------------------
TXID       = 0x87b68a65105f2cc5746b88e1e0fd5e1cf4f6d2dbf8459bb8ef2599957ffcb655
From       = 0xd55100eedb61f1e553a38c33a234ce07952c43f2
To         = 0xe4660c72dea1d9fc2a0dc2b3a42107d37edc6327
GasPayer   = 0xe4660c72dea1d9fc2a0dc2b3a42107d37edc6327
GasUsed    = 21000
The last part shows the TX sent from SENDER to DELEGATOR is indeed paid by DELEGATOR under MPP.
Upgrading Dependencies from Connex1 to Connex2
Transaction Dependency
Last modified 1mo ago