Dwij Patel

Background biking, brief introduction of yourself. So hi. I'm Josh Patel. I'm full stack developer. I have experience in, like, building secure and scalable products in web 2 and web 3. So apart from my, regular day to day job, like, I participate in many hackathons, like, create personal projects. So, like, I have wide range of, you know, like, idea of, like, wide range of frame bugs and all. So, yeah, I'm comfortable, to, you know, work on any back end or, like, front end framework even if, you know, I don't, knew them before. So yeah.

How might you implement a rollback mechanism in Advantages for transaction that feel how might you implement a rollback mechanism just for transition that failed forcefully on, blockchain. Okay. Mhmm. Okay. So, basically, for a rollback, So, like, if it, I'm not sure which rollback it's about. Like, if the transaction failed on the blockchain, and, like, there's nothing, you know, like, if it's failed, then there is a no state change. But if you are talking about, like, once you submitted a transaction and, like, you are changing some DB related thing and all, then I think, like, you can create a one, you know, queue, like, where you know, insert your all submitted TX. So once you get the, you know, status of the TX, like, you can, you know, what add a logic, you know, if you know, added some updated some DB related thing, you can give it back and all.

You want set of what call, how would you organize and call them using to transfer?

so yeah. Like, first of all, we will be using the web 3 JS. Okay. Sorry. what would be planned to ensure the security and integrated user inputs in a d f built with the Node. Js and, Ethereum. We will be open to Azure security into user inputs in a d f. Okay. so, yeah, first of all, like, smart, the smart contact logic should be a secure. Like, for example, if it is an incremental identifier or something, like, we don't take them as, like, input from the user. Otherwise, they can, you know, replace some, you know, others, state. For example, you have, you know, a map where, keys, integer, and value is something structured. and now if you are taking that, you know, like, having a function which modified, you know, some value on that map and you are taking the key from the user, then, yeah, they can, you know, manipulate any of the key. So, like, restrict the inputs and, you know, plan those key values or even variable in such manner that they are, you know, like, internally auto incremental and, other kind of things. So always, you know, use the, like, message dot sender, in a function. So you can directly, you know, modify the things for the user which calling it. So apart from that, yeah, like, use, you know, config kind of things. Like, it's, you know, the normal in

How would how would you implement a caching mechanism in Node just to enhance the performance of Ethereum based application? Okay. So, basically, you can use the GraphQL and on a, sorry, GraphQL client. And in that GraphQL client, you can use the memory caching and all of stuff. apart from that, yeah, you can use the browser's local storage, to, you know, cache some of the things. So I think the, apart from that, only call the, you know, the methods, only when, you know, required, like, you know, every time you log in and you need to call some smart contract function, you know, do not create some kind of function. you can, you know, create a sign base, you know, key sign base login, like sign in with sign with, you know, MetaMask and all kind of thing. Create your back end to, you know, authenticate user. Do not, like, use some smart contract and all for those kind of things.

Optimal data serialization method for storing blockchain transaction in postscript. Optimal, I think that JSON suits well, like, or even, you know, like, we can, convert to the, like, we can use any Prisma and something kind of, you know, ORM solution, like, which, you know, converts the web 3, you know, transaction data to that o ORM. So that core modular code we can write, which we can use at multiple places. Otherwise, by default that, like, RPC nodes, you know, mostly RPC nodes returns data in a JSON. So, like, JSON's also, yeah, suitable option.

In the course snapshot using the ID and JS, submit a very screen. We've been great. How misunderstanding how the middle is intended to do. I did. Okay. This was a middle has been created. However, might be an interest to identify. Okay. So send request response and next. Okay. Request. Make Okay. So I think the middleware is, you know, start to, like, it's fixed between the start to the end. Like, it's not, you know, go from end to start. So here, response dot status thing will be, not useful. so, yeah, a request made to is, yeah, writing, like, we are logging that, like, whatever URL is getting called and, like, then we directly, you know, call the next, await that next, but, yeah, this response dot status is not, you know, correct.

That seems to be Given this type of error, there seems to be an issue with the type assignment. Okay. That user okay. Mhmm. Username. Okay. So, yeah, I think the inside the user, there is, you know, no username, you know, key or item, inside the type. So, yeah, like, that is wrong. it should be a name instead of username.

How do you manage the state consistency between postgreSQL database and the state of the smart contracts on the Ethereum? Okay. Very good question. So basically, you know, like, the graph, right, the graph, like, does all of thing for us. So, like, it's better to use the graph. But if we are creating our own solution, like, we can, you know, keep, straight off, like, inside the PostgreSQL, till which block we, you know, scan the things. Like, so, like, if we, if server gets, you know, like, crash or something, like, we can continue from that, you know, block number. So, like, we're able to, you know, grab the all events, and all here. So apart from that, like, it's event related thing I said. But if you wanted to, you know, keep track of every, you know, storage variable inside the smart contract, like, keep still, you need to maintain a state, till where the, you know, blocks, got scanned. So, like, suppose you scan till x now, keep checking every blocks. And if there is a transaction related, your account or smart contract, okay, then, you know, if it is account, like, got involved in the, you know, transaction, like, explore, site check, it's, you know, storage slot variables, slot thing, and, yeah, you can record, if previous slot and current slot is different, then, yeah, you can record the time on your post.

What pattern will you utilize to manage dependency in large editing, videos? Just project. Okay. so if you are talking about the, like, first of all thing, like, for utility, like, we can create our own NPM module, and we can use that NPM module. like, for example, in a large, there is a different modules, and all those modules, you know, like, somehow utilizing the common, you know, helper or utilities. So create them as a NPM package and use them all in, you know, inside all of those, you know, modules. So I think, what it call like, there is a, you know, library p n p m or something like what exactly, how you pronounce it. I'm not, able to recall it. Where is PNPM? kind of tools we can use.

Can you discuss some method to secure being used by blockchain applications? Yeah. like, first of all, secure those endpoints with the JWT, and this JWT can be, you know, generated by, taking the signature of taking the signature from, you know, signature, like, MetaMask sign kind of thing by which you can, like, log in the user. So, secure your endpoints with the JWT so non login user can't access them. Apart from that, like, CRS, yeah, implement the CRS, implement the, you know, protection for the SQL injections. Use the, you know, application firewalls to, like, from AWS or any cloud providers to, you know, block attacks. So apart from that, like, you know, implement, the, you know, rate limitings. Yeah. So there are many other options we can implement and which depends on the, you know, depends on the application we are building. So for blockchain, I think the JWT rate limiting, yeah, and also, like, use the nuns kind of thing, to, you know, to prevent, the, you know, user can't, you know, use the same payload again, to, you know, claim something and all. So use the none's kind of thing. Yeah.