Receipt


After a transaction is confirmed in the blockchain, a transaction response would be returned along with a receipt.

Example of a transaction response with the receipt structure:

{
"id": "1",
"jsonrpc": "2.0",
"result": {
// others
"receipt": {
"accepted": true,
"cumulative_gas": "878",
"epoch_num": "589742",
"success": true,
"transitions": [
{
"addr": "0x9a65df55b2668a0f9f5f749267cb351a37e1f3d9",
"depth": 0,
"msg": {
"_amount": "50000000000000",
"_recipient": "0xc0e28525e9d329156e16603b9c1b6e4a9c7ed813",
"_tag": "onFundsReceived",
"params": []
}
}
]
},
"senderPubKey": "0x03DE40DF885B0E334D53FF5E5554589AAF46F2339FEBEE93213F2CCE52D1F488F4",
"signature": "0xB19AB66C4410EE4833A9C5DEE600471DB4D711F6B61D2312988E6E70CC655409F18BB42BB6940B6263C8EA5CE08CAEC06111BDF19BE00D7E15F25515CAA45DAA",
"toAddr": "9a65df55b2668a0f9f5f749267cb351a37e1f3d9",
"version": "65537"
}
}

Depending on the type of transaction (e.g. payment, contract call, chain contract call) being processed, the receipt may return different data.

Params

This section lists all the possible receipt returned values.

NameDescription
cumulative_gasThe total amount of gas used when it is executed in the particular block
epoch_numThe block number when this transaction is allocated to
errorsContains the error code if the transaction has any errors
event_logsContains the parameters of the contract transition being invoked
exceptionsReturns the exception messages if there is an error when invoking contract
transitionsContains the parameters used to call the specific transition
successReturns true if the transaction is successfully executed, false otherwise

Events

event_logs are events created as a result of invoking the contract calls.

For instance, in the following sample contract code, calling setHello transition would trigger a "setHello" event name.

(* HelloWorld Sample *)
transition setHello (msg : String)
is_owner = builtin eq owner _sender;
match is_owner with
| False =>
e = {_eventname : "setHello()"; code : not_owner_code};
event e
| True =>
welcome_msg := msg;
e = {_eventname : "setHello()"; code : set_hello_code}; (* trigger event here *)
event e
end
end

If we execute this transition, the returned receipt is as follows:

{
"id": "1",
"jsonrpc": "2.0",
"result": {
// others
"receipt": {
"accepted": false,
"cumulative_gas": "668",
"epoch_num": "1474081",
"event_logs": [
{
"_eventname": "setHello()",
"address": "0xde8d3637aec06d6c7da49aeb9c7409ac44a98138",
"params": [
{
"type": "Int32",
"value": "2",
"vname": "code"
}
]
}
],
"success": true
},
}
}

Observed that the setHello event is returned as the setHello transition is successfully executed by the blockchain.

Transitions

A transitions object is returned if the contract is invoking other procedures or another contract transition. A transition object provides details of the "transition chain" such as the address of the initiator, the tag (transition name), the recipient, the params .etc.

Example of a transition object:

{
"id": "1",
"jsonrpc": "2.0",
"result": {
"ID": "52605cee6955b3d14f5478927a90977b305325aff4ae0a2f9dbde758e7b92ad4",
"amount": "50000000000000",
"data": "{\"_tag\":\"sendFunds\",\"params\":[{\"vname\":\"accountValues\",\"type\":\"List (AccountValue)\",\"value\":[{\"constructor\":\"AccountValue\",\"argtypes\":[],\"arguments\":[\"0xc0e28525e9d329156e16603b9c1b6e4a9c7ed813\",\"50000000000000\"]}]}]}",
"gasLimit": "25000",
"gasPrice": "1000000000",
"nonce": "3816",
"receipt": {
"accepted": true,
"cumulative_gas": "878",
"epoch_num": "589742",
"success": true,
"transitions": [
{
"addr": "0x9a65df55b2668a0f9f5f749267cb351a37e1f3d9",
"depth": 0,
"msg": {
"_amount": "50000000000000",
"_recipient": "0xc0e28525e9d329156e16603b9c1b6e4a9c7ed813",
"_tag": "onFundsReceived",
"params": []
}
}
]
},
...
}
}

In the above example, from the data object we can observe the sendFunds transition is invoked here, presumably to send 50000000000000 to 0xc0e28525e9d329156e16603b9c1b6e4a9c7ed813. Notice that in the transitions object, the onFundsReceived procedure is subsequently invoked internally, and we can observe the recipient and amount is indeed the transmitted amount.

Exception

A exceptions object is returned if the contract specifically raise an error when it encounters issues invoking the transition, for example, invoking a transfer transition without sufficient balance .etc. A exceptions object contains the line number of the contract that raised the error and the corresponding exception message.

Example of an exceptions object:

"receipt": {
... // others
...
"exceptions": [
{
"line": 87,
"message": "Exception thrown: (Message [(_exception : (String \"Error\")) ; (code : (Int32 -2))])"
},
{
"line": 100,
"message": "Raised from IsAdmin"
},
{
"line": 137,
"message": "Raised from ConfigureUsers"
}
]
}