Kiwi

# Standard Kiwi

We have the school name but we want to keep a list of students. Not only that but we need to store each student's ID. Each student may or may not have unique names but they definitely will have unique IDs. Let us store students IDs corresponding to their names in a hash map.

# Old practices

# Add a new key to store students

// Imports
import _ "github.com/sdslabs/kiwi/values/hash"

// Main
if err := store.AddKey("students", "hash"); err != nil {
  panic(err)
}

# Add student

_, err := store.Do("students", "INSERT", 123, "SDSLabs")
if err != nil {
  panic(err)
}

Error

Hash is a string-string map. When we call the above function, the INSERT action expects a string key and string value, but instead it gets an integer which results in an error.

# Solution

One work-around for this can be defining type safe wrappers and use them instead of Doing all the time. Well... we did it for you. The stdkiwi package defines such types and methods so you can invoke actions without encountering unnecessary errors. Let's see how we can update our code to use this package.

# New stdkiwi store

Firstly we need to update our store. Instead of using kiwi.Store, we need to create a stdkiwi.Store. It's pretty simple -- just replace kiwi.NewStore or kiwi.NewStoreFromSchema with stdkiwi.NewStore or stdkiwi.NewStoreFromSchema respectively.

// Imports
import "github.com/sdslabs/kiwi/stdkiwi"

// Main
store := stdkiwi.NewStore()

Don't worry. Changing into stdkiwi.Store won't break any of the previous code. This store is defined as such that it is compatible with the kiwi.Store.

Note

You can also clean-up your imports. stdkiwi imports all the standard value types, i.e., the ones defined in github.com/sdslabs/kiwi/values.

# Invoking actions

Now that we have our special store, we can use the types and methods it provides us to safely execute our actions.

students := store.Hash("students") // assumes "students" key is of hash type

if err := students.Insert("123", "SDSLabs"); err != nil {
  panic(err)
}

# Final program

package main

import (
  "github.com/sdslabs/kiwi/stdkiwi"
)

func main() {
  store := stdkiwi.NewStore()

  if err := store.AddKey("school_name", "str"); err != nil {
    panic(err)
  }

  if err := store.AddKey("students", "hash"); err != nil {
    panic(err)
  }

  _, err = store.Do("school_name", "UPDATE", "My School Name")
  if err != nil {
    panic(err)
  }

  students := store.Hash("students") // assumes "students" key is of hash type

  if err := students.Insert("123", "SDSLabs"); err != nil {
    panic(err)
  }

  if err := students.Insert("007", "Kiwi"); err != nil {
    panic(err)
  }
}

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