Function not returning expected value [duplicate]

Question

This question already has an answer here:

• What is the difference between a transaction and a call? 2 answers

I have a function in my contract which normally return uint

function insertPerson(
  bytes32 personAddress, 
  bytes32 email, 
  bytes32 fname,
  bytes32 lname) 
  public
  returns(uint index)
{
  if(isPerson(personAddress)) return; 
  persons[personAddress].email     = email;
  persons[personAddress].fname     = fname;
  persons[personAddress].lname     = lname;
  persons[personAddress].index     = personIndex.push(personAddress)-1;
  LogNewPerson(
    personAddress, 
    persons[personAddress].index, 
    email, 
    fname,
    lname);
  return personIndex.length-1;
}

but instead of getting the index i'm getting information about the transaction something like this

{"tx":"0xcfe28fe4cffeb7aa97c2db856920f7a3275d55a656f0550e7f78b76d446970b8","receipt":{"transactionHash":"0xcfe28fe4cffeb7aa97c2db856920f7a3275d55a656f0550e7f78b76d446970b8","transactionIndex":0,"blockHash":"0xcaa35831f7652155de33af8a349e4d5727026d20ec2f280c45d5a8109c8ca1e4","blockNumber":14,"gasUsed":134146,"cumulativeGasUsed":134146,"contractAddress":null,"logs":[{"logIndex":0,"transactionIndex":0,"transactionHash":"0xcfe28fe4cffeb7aa97c2db856920f7a3275d55a656f0550e7f78b76d446970b8","blockHash":"0xcaa35831f7652155de33af8a349e4d5727026d20ec2f280c45d5a8109c8ca1e4","blockNumber":14,"address":"0xf3b5fccbaea5a0bd10542d13c58d808e18aaef9f","data":"0x0000000000000000000000000000000000000000000000000000000000000008646576407369622e636f6d000000000000000000000000000000000000000000646576000000000000000000000000000000000000000000000000000000000061646d696e000000000000000000000000000000000000000000000000000000","topics":["0xa7cb2773240099bbe7a853382f1c2141cd85ac771e1ca8b9c8778fa5a901076e","0x3035343734393837000000000000000000000000000000000000000000000000"],"type":"mined"}],"status":1},"logs":[{"logIndex":0,"transactionIndex":0,"transactionHash":"0xcfe28fe4cffeb7aa97c2db856920f7a3275d55a656f0550e7f78b76d446970b8","blockHash":"0xcaa35831f7652155de33af8a349e4d5727026d20ec2f280c45d5a8109c8ca1e4","blockNumber":14,"address":"0xf3b5fccbaea5a0bd10542d13c58d808e18aaef9f","type":"mined","event":"LogNewPerson","args":{"personAddress":"0x3035343734393837000000000000000000000000000000000000000000000000","index":"8","email":"0x646576407369622e636f6d000000000000000000000000000000000000000000","fname":"0x6465760000000000000000000000000000000000000000000000000000000000","lname":"0x61646d696e000000000000000000000000000000000000000000000000000000"}}]}

can someone help me please, thanks.

Answer 1

It's not very clear how do you invoke your method. But from the response, I assume you're calling it using Web3 or other RPC API.

The idea is that the return values of functions which need to be included into transactions are not returned by Web3.

You have two options:

1. Using Solidity Events. You should refer to the Events documentation, they're designed to be readable and even "catchable" by the client. Also, check out the Web3 documentation page about working with contract events.

2. Invoke the function call using Web3 call(). It won't make any changes to your contract state because the method only simulates the "real" call locally without sending any transactions or modifying state, but you will be able to get the function return values.