JSON- RPC no response

Question

I'm trying to use jscon-rpc but I dont get any response. After installing geth and loading the rinkeby test net does the ethereum node start ? I used "localhost" as the IP and "8545" as the port number. Have I missed out on anything? Please help

String callGeth(String inputJSON)

{

HTTPClient http;
http.begin("http://IP address of my PC(have geth running) :8545/");
http.addHeader("Content-Type", "application/json");
int httpCode = http.POST(inputJSON);
String JSONResult = http.getString();
Serial.println(JSONResult); http.end(); return JSONResult;

}

StaticJsonBuffer<1000> JSONbuffer;   
JsonObject& gethQueryJSON = JSONbuffer.createObject(); 
gethQueryJSON["jsonrpc"] = "2.0";
gethQueryJSON["method"] = "eth_call";
JsonArray&  gethQueryParams = gethQueryJSON.createNestedArray("params");
JsonObject& gethCallParams = JSONbuffer.createObject();
gethCallParams["to"] = "0xC2eafE628dB80634Fdd657965B38136Ec6F3338A";
gethCallParams["data"] = "0x9de4d683";
gethQueryParams.add(gethCallParams);
gethQueryParams.add("account3");
gethQueryJSON["id"] = 1;
String gethStringJSON;
gethQueryJSON.printTo(gethStringJSON);
Serial.println("First Geth query JSON message isLightTurnedOn function: ");
Serial.println(gethStringJSON);  
String gethResult = callGeth(gethStringJSON); 
Serial.println(gethResult);

Can you explain what "don't get any response" means? Does the connection time out? Do you get an error? If you try a different port, e.g. 9999, does the same thing happen or something different? — user19510, Feb 10 '18 at 03:35
What programming language and environment are you using? The code kind of looks like it's for an Arduino, but surely you're not running geth on an Arduino? — user19510, Feb 11 '18 at 04:32
I have geth installed on my PC. In the callGeth function the IP address used is the IP of the PC. Is it right ? — Sheetal Singala, Feb 11 '18 at 05:31
Your question says you used "localhost," which is not the IP address of your PC. — user19510, Feb 11 '18 at 05:56
I personally won't try to help if I'm given false information like that. Hopefully others are more charitable. — user19510, Feb 11 '18 at 06:15

score 1 · Answer 1 · answered Feb 10 '18 at 03:03

1

You need to pass --rpc on the command line to enable it, as per https://github.com/ethereum/wiki/wiki/JSON-RPC#go.

answered Feb 10 '18 at 03:03

user19510

27,999
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I id that.Still no response – Sheetal Singala Feb 10 '18 at 03:12
Can you share the code you're using to make the JSON-RPC request? – user19510 Feb 10 '18 at 03:16
I've edited the question. I cant figure out whats wrong – Sheetal Singala Feb 10 '18 at 03:31

score 1 · Accepted Answer · answered Feb 10 '18 at 19:44

as already mentioned by @smarx make sur to enable rpc on your node. For example

--rpc --rpcaddr 'localhost' --rpcport 8545 --rpcapi 'personal,db,eth,net,web3,txpool,miner'

then regarding your python code I've publish a full working example for deploying and interacting with a smart contract using raw HTTP JSON-RPC requests. I am pretty sure you'll find helpful hints. Here is my post https://ethereum.stackexchange.com/a/38965/30452

I hope this helps

score 1 · Answer 3 · edited Jun 16 '20 at 10:58

As per your reply. If you enabled rpc port. Then there might a chance of geth client is not mining.

If you want to post any thing. You should start mining. Your transactions in UTX or pending. By default geth will not start mining.

So add --mine as a option in geth.

Otherwise if your eth client is running you can connect attach via ipc or rpc url and port

$> geth attach 127.0.01:8585

geth> miner.start()

Then execute your code

JSON- RPC no response

3 Answers3