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