Some recommendations

[andytudhope]

1. Get rid of the growl dependency as it is causing a security warning in the repo. I would also recommend cutting down all your dependencies in general - checking through them all is a real pain and will almost always result in security issues like the one GH has already picked up.

2. Are you sure that you want people to register their attendance on chain, and then store that info? What happens if I host a conference with 3000 people attending, like DevCon 4? That's going to get very expensive very quickly. Not a fan of that pattern at all. If their attendance registered on chain has some effect - a la BlockParty - that would be more acceptable to me, but as it is, this is not good thinking.

3. So much of the way you have written that first smart contract depends on returning dynamic arrays (in one of which the members of the array are structs, which is - I presume - why it remains commented out). This is not best practice, and I suggest you readthedocs to get a better sense of how to write good, safe, and optimised SCs.

4. Some info on how to run this all locally would be helpful. I use Embark, not Truffle, and have not kept up to date with changes in Truffle, so am unsure how to get it all set up - a few leading hints would be very useful for any reviewer.

[aj07]

@andytudhope Thanks for your suggestion.

1. growl old version is causing securty issue., we have upgraded it and now its working fine. Also, we did some security auto-fix and fix few error/waring we were getting. We haven't cut all the dependencies because they're all part of the official 'react truffle box' and we may need them while developing the front-end.

2. On the data part, we wanted to use decentralized system completely for storing data like IPFS. BigchainDB is also another option. Data won't be stored on chain or any centralized system. May be we need some pointers from you based on your experience.

3. We are upgrading the smart contract by following the correct paradigm mentioned in readthedocs. Thanks for pointing the error there. We are fixing it and will be corrected in next patch.

4.We will update the README for info to run truffle locally. We faced some issue during EthIndia while doing the integration of Embark with metamask, so we are choosing truffle.

[andytudhope]

Nice work @aj07 👍

Yeah, the basic answer w.r.t. data is that it is hard to handle. The BlockParty contract I was referring to is here and I have highlighted the function there that they are using to register participants. You can see that they emit events and will likely use those events to store info on participants off chain in some kind of DB (BigChain being ideal, but not very usable still. Definitely extra points if you can make it work though. A content-addressed store like IPFS is likely not well-suited to this kind of thing, imo).

I hope this leads you in the right direction 😉

[aj07]

@andytudhope Will you please look into our repo. Also, please share your mailid