@oraclize-support the problem was due to update() called in the constructor. apparently, it can be called only once before it starts throwing the "gas estimation" error. I deployed the contract after removing the
update() function from the constructor. the function fired correctly (the transaction succeeded) once after deploying the contract. however, I did not get any results (temperature of London) back. if i try executing update() again I get the gas estimation error.
Hello @oraclize-support
Did the migration complete correctly? Service is still not working.
Same error on ethereum_bridge.
New error on test_query website. Screenshot: https://imgur.com/a/WykhkEo
1 reply
@mel_elices - the migration is almost complete, at which point your bridge will spring back to life.
i see the __callback in is getting called in the contract but lastResult is not set after the call back
i want to get my result into an ApiResult structure instead of storing the entire json
// SPDX-License-Identifier: MIT
pragma solidity ^0.6.12;
import "github.com/provable-things/ethereum-api/provableAPI_0.6.sol";
// example of calling an API
contract Example is usingProvable {
struct ApiResult {
string clientSeed;
string serverSeed;
string hash;
}
string public lastResult;
mapping (bytes32 => bool) private validIds;
event LogMessage(string description);
constructor() public {}
function __callback(bytes32 requestId, string memory result) override public {
require(validIds[requestId], "query id is invalid!!!");
require(msg.sender == provable_cbAddress(), "invalid sender detected!!!");
lastResult = result;
}
function getRamdon(string memory clientSeed) public {
require(bytes(clientSeed).length > 0, "client seed is required!!!");
if (provable_getPrice("URL") > address(this).balance) {
emit LogMessage("Contract out of gas!");
} else {
bytes32 requestId = provable_query("URL", string(abi.encodePacked("json(https://oracles.azurewebsites.net/Random/GetRandomHash/", clientSeed, ").path.to[\"clientSeed\", \"serverSeed\", \"hash\"]")));
validIds[requestId] = true;
}
}
}
not sure if there is a gas difference
been using https://app.provable.xyz/home/test_query
can't seem to format a query that will return anything usable beside entire json or 1 property
I know you said it can be done before I've seen it in chat history but it's not working for me
a working example would be AMAZING
I've tried this in test query and not working
json(https://oracles.azurewebsites.net/Random/GetRandomHash/test).path.to["clientSeed", "serverSeed", "hash"]
Have you tried with json(https://oracles.azurewebsites.net/Random/GetRandomHash/test).["clientSeed","serverSeed","hash"] ?
do I need to escape the double quotes?
when I've escaped the double quotes it return but appear to be empty message does that mean I need to decode it?
@simplemachine92 yes you should use the computation ds as shown here for instance https://github.com/provable-things/ethereum-examples/blob/c0431a147f24519a135d07f9d5c17db73498e0e7/solidity/truffle-examples/url-requests/contracts/UrlRequests.sol#L57
Also, does it support POST method?
how to handle the error?
Hi @oraclize-support , I'm relatively new to smart contract development so I was wondering if you could give me a hand here. I've setup a wallet on the Ropsten Test Network and tried to use your API, but for some reason even though my event logging shows that provable_query was called, the __callback method is never executed. Here's the contract: https://ropsten.etherscan.io/address/0xB303D6E13d2a61C59D95A7E0DF07fac3bAd141Ce#events
And the source code: https://pastebin.com/G03L2ykN
Might need to disable adblocker to see the pastebin, don't know what's up with that
@Dhanush - you'll have to dive into the matic documentation to learn how to interact with its accounts.