JSON RPC calls using Parity. Difference between Infura and Geth?

Question

I began by trying to follow the article on front running bancor with Python. I thought it would be easy to send an api request to my full node then replicate the same request in Python--all following the tutorial. The only difference was that the author used Geth and I am running Parity. The inability to figure out how to use JSON RPC has led me down a rabbit hole. I don't really know (1) what I'm doing wrong or (2) if I even conceptually understand JSON RPC at this point.

The problem:

I should be able to run this curl command: curl -X POST --data \ '{"jsonrpc":"2.0","method":"eth_getTransactionByHash", \ "params":["0x314e0246cfc55bc0882cbf165145c168834e99924e3ff7619ebd8290e713386d"], \ "id":123}' localhost:8545

And get a result like this:

{"jsonrpc":"2.0","id":123, "result":{ "blockHash":"0x42ea1578c23b159186853961dfbdfcdec6b40d23d8f1d971827412bc6948386b", "blockNumber":"0x3dfb88", "From":"0xcaf82fcb3a0323566c0f306684376e3e66d6284b", "To":"0x77a77eca75445841875ebb67a33d0a97dc34d924", "gasPrice":"0xba43b7400", "hash":"0x314e0246cfc55bc0882cbf165145c168834e99924e3ff7619ebd8290e713386d", "value":"0x6c6b935b8bbd400000", ...}}

Howevever when I run it with localnode connected to parity I only get:

Supplied content type is not allowed. Content-Type: application/json is required

I found the Parity JSON-RPC API documentation and realized the formatting is different.

So I reformatted the curl command to look like this:

curl --data '{"jsonrpc":"2.0","method":"eth_getTransactionByHash",
"params":["0x314e0246cfc55bc0882cbf165145c168834e99924e3ff7619ebd8290e713386d"], "id":1, "jsonrpc":"2.0"}' -H "Content-Type: application/json" -X POST localhost:8545

I solved the Content Type error but then got a null result:

{"jsonrpc":"2.0","result":null,"id":1}

Then looking at this stack exchange article I realized that Parity has it's own Web3 console. So, I thought maybe I don't have to use curl at all, and can just run.

web3.eth.getTransaction('0x314e0246cfc55bc0882cbf165145c168834e99924e3ff7619ebd8290e713386d')

and I still get null return.

As a side note I have also tried to do the call using Infura's api

curl --include \
 --header "Content-Type: application/json" \
 --header "Accept: application/json" \

'https://api.infura.io/v1/jsonrpc/mainet/getTransaction?params=0x314e0246cfc55bc0882cbf165145c168834e99924e3ff7619ebd8290e713386d'

But am getting 404 return.

I really want to understand what I am doing wrong but I don't know where exactly to find the resources to teach myself, and feel a little stuck. Thanks in advance for anything that can point me in the right direction.

Answer 1

Call it like this

curl --data '{"method":"web3_clientVersion","params":[],"id":1,"jsonrpc":"2.0"}' \
-H "Content-Type: application/json" \
-X POST localhost:8545

It need

-H "Content-Type: application/json"

Answer 2

The call you provided seems proper, and it works on my local parity - you might've had blockchain not completely synced up.