Chapter 4 Day 1.md

Quest Chapter 4 Day 1 🆗

1. Explain what lives inside of an account.

There are two things that live inside accounts on Flow:

• Contract Code

  • Once a developer deploys a contract to an account to put on Mainnet, it lives inside that account. Multiple contract scan be deployed to and live inside an account

• Account Storage

  • All the data of an account gets stored in account storage

2. What is the difference between the /storage/, /public/, and /private/ paths?

The difference between these three paths is that each path allows a developer to get to certain data. The /storage/ path can only be accessed by the account owner (otherwise, someone malicious could steal all of your data) and ALL of the account's data lives here. Data in the /public/ path is available to everyone. Data in the /private/ path is available to the account owner and people who the account owner gives access to.

3. What does .save() do? What does .load() do? What does .borrow() do?

.save() saves something to the /storage/ path.

.load() takes something out of /storage/.

.borrow() lets us only look at something in /storage/.

4. Explain why we couldn't save something to our account storage inside of a script.

We couldn't save something to account storage inside of a script because in order to access /storage/, we need to use our AuthAccount type. We can only use our AUthAccount type by signing a transaction in the prepare phase.

5. Explain why I couldn't save something to your account.

You couldn't save something to my account because only I, the account owner, can access my own /storage/ path. The only way you would be able to save something to my account is if I give you permission through the /private/ path.

6. Define a contract that returns a resource that has at least 1 field in it. Then, write 2 transactions:

pub contract SportsCars {

 pub resource Hardtops {
  pub var auto: String 
  init () {
   self.auto = "Lotus Exige"
  }
 }
 
 pub fun createHardtops(): @Hardtops {
  return <- create Hardtops()
 }
 
}

i. A transaction that first saves the resource to account storage, then loads it out of account storage, logs a field inside the resource, and destroys it.

I didn't know how to combine the two into one transaction, I tried different ways of combining but kept getting errors.

import SportsCars from 0x01
transaction() {
 prepare(signer: AuthAccount) {
   let testDrive <- SportsCars.createHardtops()
   signer.save(<- testDrive, to: /storage/MyTestDrive)
  
 }
  
 execute {
  
 }
}

import SportsCars from 0x01
transaction() {
  prepare(signer: AuthAccount) {
      let testDrive <- signer.load<@SportsCars.Hardtops>(from: /storage/MyTestDrive)
                    ?? panic("A `@SportsCars.Hardtops` resource does not live here.")
      log(testDrive.auto)
  
      destroy testDrive
  }

  execute {

  }
}

ii.A transaction that first saves the resource to account storage, then borrows a reference to it, and logs a field inside the resource.

THE NEW TRANSACTION ANSWER:

THE OLD TRANSACTION ANSWER:

import SportsCars from 0x01
transaction() {
  prepare(signer: AuthAccount) {
      let testDrive = signer.borrow<&SportsCars.Hardtops>(from: /storage/MyTestDrive)
                    ?? panic("A `@SportsCars.Hardtops` resource does not live here.")
  log(testDrive.auto)

  }

  execute {

  }
}

I don't know why the program is panicking and not logging the value here, all of the other transactions worked fine.