lotus/documentation/en/api-troubleshooting.md

API Troubleshooting

params

params must be an array. If there are no params you should still pass an empty array.

TipSet

For methods such as Filecoin.StateMinerPower, where the method accepts the argument of the type TipSet, you can pass null to use the current chain head.

curl -X POST \ 
     -H "Content-Type: application/json" \
     --data '{ "jsonrpc": "2.0", "method": "Filecoin.StateMinerPower", "params": ["t0101", null], "id": 3 }' \
     'http://127.0.0.1:1234/rpc/v0'

Sending a CID

If you do not serialize the CID as a JSON IPLD link, you will receive an error. Here is an example of a broken CURL request:

curl -X POST \
     -H "Content-Type: application/json" \
     --data '{ "jsonrpc": "2.0", "method":"Filecoin.ClientGetDealInfo", "params": ["bafyreiaxl446wlnu6t6dpq4ivrjf4gda4gvsoi4rr6mpxau7z25xvk5pl4"], "id": 0 }' \
     'http://127.0.0.1:1234/rpc/v0'

To fix it, change the params property to:

curl -X POST \
     -H "Content-Type: application/json" \
     --data '{ "jsonrpc": "2.0", "method":"Filecoin.ClientGetDealInfo", "params": [{"/": "bafyreiaxl446wlnu6t6dpq4ivrjf4gda4gvsoi4rr6mpxau7z25xvk5pl4"}], "id": 0 }' \
     'http://127.0.0.1:1234/rpc/v0'