How to use an array of strings in a solidity mapping? - ethereum

Question

I need to store a mapping between a string to items which are 128 bytes long in a solidity contract. The problem is that the longest bytes data type is bytes32, which is not long enough, and if I try to store my strings in a string array I get the following error:
This type is only supported in the experimental ABI encoder. Use "pragma experimental abiencoderv2;" to enable this feature
So I cannot use bytes32 because it's not big enough. I cannot use bytes because it's not supported. And I cannot use string[] because it's experimental and not recommended in production.
Any solution?
This is the contract I'm using:
pragma solidity ^0.4.24;
contract SomeData {
struct Data {
string id;
string[3] items;
}
mapping (string => Data) dataItems;
function addData(string id, string[3] items) public {
Data memory data = Data(id, items);
data.id = id;
data.items = items;
dataItems[id] = data;
}
function getDataItems(string id) public view returns (string[3]){
return dataItems[id].items;
}
}

Answer 1

Since you know the maximum length of each individual string, you can use a static 2 dimensional array:
contract SomeData {
struct Data {
string id;
byte[128][100] items;
}
mapping (string => Data) dataItems;
function addData(string id, byte[128][100] items) public {
Data memory data = Data(id, items);
data.id = id;
data.items = items;
dataItems[id] = data;
}
function getDataItems(string id) public view returns (byte[128][100]){
return (dataItems[id].items);
}
}
Note, only 2-dimensional dynamic arrays are not allowed. You could even use byte[128][] if you wanted to.