Prisma client extension

[franky47]

Prisma client 4.16.0 deprecates middlewares and the $use method, and favours client extensions instead.

There's a little bit of plumbing needed to use the same logic across both interfaces, and the extension could probably be refined to only handle models with encrypted fields, but this first draft seems to work.

Tasks

• Documentation (migration, version coverage)
• Better type safety
• Refactoring of common parts
• Investigate modifying only models with encrypted fields - Would require too much type-hacking
• Document explicit type cast related to Cannot type extended client in function arguments prisma/prisma#20326

Closes #63.

[github-actions]

Pull Request Test Coverage Report for Build 5637980703

• 0 of 0 changed or added relevant lines in 0 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage decreased (-0.06%) to 81.782%

---

Totals
Change from base Build 5637962771:	-0.06%
Covered Lines:	244
Relevant Lines:	289

---

💛 - Coveralls

[franky47]

Migration from 1.4.x

While the middleware interface is still exported and functional, it is recommended you upgrade your Prisma client to 4.7.0+ and switch to the client extension mechanism.

Prisma client version

For Prisma client versions 4.7.0 to 4.15.0 (included), you'll need to enable the clientExtensions feature flag:

generator client {
  provider        = "prisma-client-js"
  previewFeatures = ["clientExtensions"]
}

For Prisma client version 4.16.0+, the client extensions mechanism is generally available without the need for a preview feature flag.

Converting the middleware to an extension

This assumes you create and export your Prisma client and attach the middleware in the same file. In v1.4.0, it would have looked like this:

import { PrismaClient } from '@prisma/client'
import { fieldEncryptionMiddleware } from 'prisma-field-encryption'

export const client = new PrismaClient()

client.$use(fieldEncryptionMiddleware())

Client extensions require exporting the result of the extended client, so the equivalent code will look like this:

import { PrismaClient } from '@prisma/client'
import { fieldEncryptionExtension } from 'prisma-field-encryption'

// Create a Prisma client
const globalClient = new PrismaClient()

// Extend with encryption support and export the resulting client
export const client = globalClient.$extends(
  fieldEncryptionExtension()
)

Migrations

When calling the generated migrate function for data migrations (to rotate encryption keys), you'll have to do an explicit cast of the client type, due to an issue with Prisma types not allowing to precisely represent extended clients in function arguments (see prisma/prisma#20326):

// Import from your generated client location, not @prisma/client
import { PrismaClient } from '.prisma/client' // or custom path
import { migrate } from './where/you/want/your/migrations'
import { fieldEncryptionExtension } from 'prisma-field-encryption'

const client = new PrismaClient().$extends(fieldEncryptionExtension())

// Explicit cast needed here ↴
await migrate(client as PrismaClient)

[PrawiraGenestonlia]

Hi @franky47.. This is an extremely useful feature.. Are there anything that I can help to get this PR merged and release?

[franky47]

The only downside I see right now is the need for an explicit cast when calling the migration functions. Which is not an issue at all, and all other feedback is good, so it can be merged. I'll do that tonight.

[github-actions]

🎉 This PR is included in version 1.5.0 🎉

The release is available on:

• npm package (@latest dist-tag)
• GitHub release

Your semantic-release bot 📦🚀