Solidity – How to Get TX Receipt of Transaction from Within a Solidity Smart Contract

Finding all (or the last 5) transactions corresponding with a particular function call translates to: find transactions going to a specific address and then check the first bytes of the callData to match the function signature. The function signature is calculated as e.g. bytes3(sha3("myFunction(uint256,string,address)")). This is what you have to look for.

The usual libraries (e.g. web3.js) or APIs dont provide this out of the box. But you could go with e.g. this etherscan API http://api.etherscan.io/api?module=account&action=txlist&address=0x807Aa96410f7cfF5614fD8DB6CbFa82d86B7029d&sort=asc

Let's suppose you store the returned JSON object in ob, then you could extract the tx hashes of the transactions which led to a call of the function with the signature 0xdf78c1dd via

ob.result.forEach(function(element){
if(element.input.startsWith("0xdf78c1dd"))
  console.log("txHash: " + element.hash);
})

This depends if you are using the new beta version of web3.js 1.0 or the older 0.x version:

from the web3 1.0 beta documentation:

myContract.methods.myMethod(123).send({from: '0xde0B295669a9FD93d5F28D9Ec85E40f4cb697BAe'})
    .on('transactionHash', function(hash){
        console.log(hash);
})

in web3 0.x you can see here how to call a smart contract function and then look here for the return value:

var txHash = myContractInstance.myMethod(param1, param2);
console.log(txHash);