Tooling for offline transaction creation and signing.
Those familiar with
transaction builder will see resemblance in
There is a couple of commands that can be used to:
- prepare a transaction:
newcreate a new empty transaction;
finalizethe transaction for signing:
- create witnesses and add the witnesses:
sealthe transaction, ready to send to the blockchain
There are also functions to help decode and display the content information of a transaction:
idto get the Transaction ID of the transaction
to-messageto get the hexadecimal encoded message, ready to send with
cli rest message
The following example focuses on using an utxo as input, the few differences when transfering from an account will be pointed out when necessary. There is also a script here to send a transaction from a faucet account to a specific address which could be used as a reference.
Let's use the following utxo as input and transfer 50 lovelaces to the destination address
|UTXO's transaction ID||55762218e5737603e6d27d36c8aacf8fcd16406e820361a8ac65c7dc663f6d1c|
|UTXO's output index||0|
jcli transaction new > tx
For the input, we need to reference the uxto with the UTXO's transaction ID and UTXO'S output index fields and we need to specify how much coins are there with the associated value field.
jcli transaction add-input 55762218e5737603e6d27d36c8aacf8fcd16406e820361a8ac65c7dc663f6d1c 0 100 --staging tx
If the input is an account, the command is slightly different
jcli transaction add-account account_address account_funds --staging tx
For the output, we need the address we want to transfer to, and the amount.
jcli transaction add-output ca1qvnr5pvt9e5p009strshxndrsx5etcentslp2rwj6csm8sfk24a2wlqtdj6 50 --staging tx
We want to get the change in the same address that we are sending from (the associated address of the utxo). We also specify how to compute the fees.
You can leave out the
--fee-constant 5 --fee-coefficient 2 part if those are both 0.
jcli transaction finalize ca1q09u0nxmnfg7af8ycuygx57p5xgzmnmgtaeer9xun7hly6mlgt3pjyknplu --fee-constant 5 --fee-coefficient 2 --staging tx
Now, if you run
jcli transaction info --fee-constant 5 --fee-coefficient 2 --staging tx
You should see something like this
Transaction `0df39a87d3f18a188b40ba8c203f85f37af665df229fb4821e477f6998864273' (finalizing) Input: 100 Output: 89 Fees: 11 Balance: 0 - 55762218e5737603e6d27d36c8aacf8fcd16406e820361a8ac65c7dc663f6d1c:0 100 + ca1qvnr5pvt9e5p009strshxndrsx5etcentslp2rwj6csm8sfk24a2wlqtdj6 50 + ca1q09u0nxmnfg7af8ycuygx57p5xgzmnmgtaeer9xun7hly6mlgt3pjyknplu 39
For signing the transaction, you need the private key associated with the input address (the one that's in the utxos) and the hash of the genesis block of the network you are connected to.
The genesis' hash is needed for ensuring that the transaction cannot be re-used in another blockchain and for security concerns on offline transaction signing, as we are signing the transaction for the specific blockchain started by this block0 hash.
The following command takes the private key in the key.prv file and creates a witness in a file named witness in the current directory.
jcli transaction make-witness --genesis-block-hash abcdef987654321... --type utxo txid witness key.prv
When using an account as input, the command takes
account as the type and an additional parameter:
--account-spending-counter, that should be increased every time the account is used as input.
jcli transaction make-witness --genesis-block-hash abcdef987654321... --type account --account-spending-counter 0 witness key.prv
jcli transaction add-witness witness --staging tx
jcli transaction seal --staging tx
jcli transaction to-message --staging tx > txmsg
Send it using the rest api
jcli rest v0 message post -f txmsg --host http://127.0.0.1:8443/api
You can check if the transaction was accepted by checking the node logs, for example, if the transaction is accepted
jcli rest v0 message logs -h http://127.0.0.1:8443/api
--- - fragment_id: d6ef0b2148a51ed64531efc17978a527fd2d2584da1e344a35ad12bf5460a7e2 last_updated_at: "2019-06-11T15:38:17.070162114Z" received_at: "2019-06-11T15:37:09.469101162Z" received_from: Rest status: InABlock: "4.707"
Where the InABlock status means that the transaction was accepted in the block with date "4.707".
The status here could also be:
Pending: if the transaction is received and is pending being added in the blockchain (or rejected).
Rejected: with an attached message of the reason the transaction was rejected.