neoneo-go/pkg/interop/native/oracle/oracle.go

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/*
Package oracle provides interface to OracleContract native contract.
Oracles allow you to get external (non-blockchain) data using HTTPS or NeoFS
protocols.
*/
package oracle
import (
"github.com/nspcc-dev/neo-go/pkg/interop"
"github.com/nspcc-dev/neo-go/pkg/interop/contract"
)
// These are potential response codes you get in your callback completing
// oracle request. Resulting data is only passed with Success code, it's
// nil otherwise.
const (
Success = 0x00
ProtocolNotSupported = 0x10
ConsensusUnreachable = 0x12
NotFound = 0x14
Timeout = 0x16
Forbidden = 0x18
ResponseTooLarge = 0x1a
InsufficientFunds = 0x1c
Error = 0xff
)
// Hash represents Oracle contract hash.
const Hash = "\x58\x87\x17\x11\x7e\x0a\xa8\x10\x72\xaf\xab\x71\xd2\xdd\x89\xfe\x7c\x4b\x92\xfe"
// MinimumResponseGas is the minimum response fee permitted for request (that is
// you can't attach less than that to your request). It's 0.1 GAS at the moment.
const MinimumResponseGas = 10_000_000
// Request makes an oracle request. It can only be successfully invoked by
// deployed contract and it takes the following parameters:
//
// url
// URL to fetch, only https and neofs URLs are supported like
// https://example.com/some.json or
// neofs:6pJtLUnGqDxE2EitZYLsDzsfTDVegD6BrRUn8QAFZWyt/5Cyxb3wrHDw5pqY63hb5otCSsJ24ZfYmsA8NAjtho2gr
//
// filter
// JSONPath filter to process the result, if specified it will be
// applied to the data returned from HTTP/NeoFS and you'll only get
// filtered data in your callback method.
//
// cb
// name of the method that will process oracle data, it must be a method
// of the same contract that invokes Request and it must have the following
// signature for correct invocation:
//
// Method(url string, userData interface{}, code int, result []byte)
//
// where url is the same url specified for Request, userData is anything
// passed in the next parameter, code is the status of the reply and
// result is data returned from request if any.
//
// userData
// data to pass to the callback function.
//
// gasForResponse
// GAS attached to this request for reply callback processing,
// note that it's different from the oracle request price, this
// GAS is used for oracle transaction's network and system fees,
// so it should be enough to pay for reply data as well as
// its processing.
func Request(url string, filter []byte, cb string, userData interface{}, gasForResponse int) {
contract.Call(interop.Hash160(Hash), "request",
contract.States|contract.AllowNotify,
url, filter, cb, userData, gasForResponse)
}
// GetPrice returns current oracle request price.
func GetPrice() int {
return contract.Call(interop.Hash160(Hash), "getPrice", contract.ReadStates).(int)
}
// SetPrice allows to set oracle request price. This method can only be
// successfully invoked by the committee.
func SetPrice(amount int) {
contract.Call(interop.Hash160(Hash), "setPrice", contract.States, amount)
}