Prisma JSON Schema Generator

A generator, which takes a Prisma 2 schema.prisma and generates a JSON Schema in version 7 of the specification (https://json-schema.org/).

Getting Started

1. Install

npm:

npm install prisma-json-schema-generator --save-dev

yarn:

yarn add -D prisma-json-schema-generator

2. Add the generator to the schema

generator jsonSchema {
  provider = "prisma-json-schema-generator"
}

With a custom output path (default=./json-schema)

generator jsonSchema {
  provider = "prisma-json-schema-generator"
  output = "custom-output-path"
}

Additional options

generator jsonSchema {
  provider = "prisma-json-schema-generator"
  keepRelationScalarFields = "true"
  schemaId = "some-schema-id"
  includeRequiredFields = "true"
  persistOriginalType = "true"
  forceAnyOf = "true"
}

The generator currently supports a few options

| Key | Default Value | Description | | ------------------------ | ------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ | | keepRelationScalarFields | "false" | By default, the JSON Schema that's generated will output only objects for related model records. If set to "true", this will cause the generator to also output foreign key fields for related records | | keepRelationFields | "true" | Determines whether to include fields from related models in the generated schema. Setting it to "false" allows excluding related model fields from the schema. | | schemaId | undefined | Add an id to the generated schema. All references will include the schema id | | includeRequiredFields | "false" | If this flag is "true" all required scalar prisma fields that do not have a default value, will be added to the required properties field for that schema definition. | | persistOriginalType | "false" | If this flag is "true" the original type will be outputed under the property key "originalType" | | forceAnyOf | "false" | If this flag is "true" the union types will be forced to use anyOf. Check contradictory types for details |

3. Run generation

prisma:

prisma generate

nexus with prisma plugin:

nexus build

Supported Node Versions

| Node Version | Support | | -------------------: | :----------------- | | (Maintenance LTS) 18 | :heavy_check_mark: | | (LTS) 20 | :heavy_check_mark: | | (Current) 21 | :heavy_check_mark: |

Examples

PostgreSQL

This generator converts a prisma schema like this:

datasource db {
	provider = "postgresql"
	url      = env("DATABASE_URL")
}

model User {
    id                  Int      @id @default(autoincrement())
    // Double Slash Comment: It will NOT show up in JSON schema
    createdAt           DateTime @default(now())
    /// Triple Slash Comment: It will show up in JSON schema [EMAIL]
    email               String   @unique
    weight              Float?
    is18                Boolean?
    name                String?
    number              BigInt   @default(34534535435353)
    favouriteDecimal    Decimal
    bytes               Bytes /// Triple Slash Inline Comment: It will show up in JSON schema [BYTES]
    successorId         Int?     @unique
    successor           User?    @relation("BlogOwnerHistory", fields: [successorId], references: [id])
    predecessor         User?    @relation("BlogOwnerHistory")
    role                Role     @default(USER)
    posts               Post[]
    keywords            String[]
    biography           Json
}

model Post {
    id     Int   @id @default(autoincrement())
    user   User? @relation(fields: [userId], references: [id])
    userId Int?
}

enum Role {
    USER
    ADMIN
}

into:

{
    $schema: 'http://json-schema.org/draft-07/schema#',
    definitions: {
        Post: {
            properties: {
                id: { type: 'integer' },
                user: {
                    anyOf: [
                        { $ref: '#/definitions/User' },
                        { type: 'null' },
                    ],
                },
            },
            type: 'object',
        },
        User: {
            properties: {
                biography: {
                    type: [
                        'number',
                        'string',
                        'boolean',
                        'object',
                        'array',
                        'null'
                    ],
                },
                createdAt: { format: 'date-time', type: 'string' },
                email: {
                    description: 'Triple Slash Comment: Will show up in JSON schema [EMAIL]',
                    type: 'string'
                },
                id: { type: 'integer' },
                is18: { type: ['boolean', 'null'] },
                keywords: { items: { type: 'string' }, type: 'array' },
                name: { type: ['string', 'null'] },
                number: { type: 'integer', default: '34534535435353' },
                bytes: {
                    description: 'Triple Slash Inline Comment: Will show up in JSON schema [BYTES]',
                    type: 'string'
                },
                favouriteDecimal: { type: 'number' },
                posts: {
                    items: { $ref: '#/definitions/Post' },
                    type: 'array',
                },
                predecessor: {
                    anyOf: [
                        { $ref: '#/definitions/User' },
                        { type: 'null' },
                    ],
                },
                role: { enum: ['USER', 'ADMIN'], type: 'string', default: 'USER' },
                successor: {
                    anyOf: [
                        { $ref: '#/definitions/User' },
                        { type: 'null' },
                    ],
                },
                weight: { type: ['integer', 'null'] },
            },
            type: 'object',
        },
    },
    properties: {
        post: { $ref: '#/definitions/Post' },
        user: { $ref: '#/definitions/User' },
    },
    type: 'object',
}

So the following input will correctly be validated:

{
    post: {
        id: 0,
        user: {
            id: 100,
        },
    },
    user: {
        id: 10,
        createdAt: '1997-07-16T19:20:30.45+01:00',
        email: '[email protected]',
        biography: {
            bornIn: 'Scharnow',
        },
        is18: true,
        keywords: ['prisma2', 'json-schema', 'generator'],
        name: null,
        posts: [
            {
                id: 4,
            },
            {
                id: 20,
            },
        ],
        predecessor: {
            id: 10,
            email: '[email protected]',
        },
        successor: null,
        role: 'USER',
        weight: 10.14,
    },
}

MongoDB

The generator also takes care of composite types in MongoDB:

datasource db {
    provider = "mongodb"
    url      = env("DATABASE_URL")
}

model User {
    id      String @id @default(auto()) @map("_id") @db.ObjectId
    photos  Photo[]
}

type Photo {
    height Int      @default(200)
    width  Int      @default(100)
    url    String
}

Output:

{
    $schema: 'http://json-schema.org/draft-07/schema#',
    definitions: {
        User: {
            properties: {
                id: { type: 'string' },
                photos: {
                    items: { $ref: '#/definitions/Photo' },
                    type: 'array',
                },
            },
            type: 'object',
        },
        Photo: {
            properties: {
                height: {
                    type: 'integer',
                    default: 200,
                },
                width: {
                    type: 'integer',
                    default: 100,
                },
                url: {
                    type: 'string',
                },
            },
            type: 'object',
        },
    },
    properties: {
        user: { $ref: '#/definitions/User' },
    },
    type: 'object',
}

No relation fields

For some use cases, it might be useful to not include relation fields in the generated schema. This can be achieved by setting the keepRelationFields option to "false" and the keepRelationScalarFields option to "true". For example if you want to use the generated schema to validate POST request object for instance, you might want to use this option.

datasource db {
    provider = "postgresql"
    url      = env("DATABASE_URL")
}

generator jsonSchema {
  provider                 = "prisma-json-schema-generator"
  keepRelationScalarFields = "true" // default is "false"
  keepRelationFields       = "false" // default is "true"
}

model User {
    id                  Int      @id @default(autoincrement())
    createdAt           DateTime @default(now())
    email               String   @unique
    weight              Float?
    is18                Boolean?
    name                String?
    number              BigInt   @default(34534535435353)
    favouriteDecimal    Decimal
    bytes               Bytes
    successorId         Int?     @unique
    successor           User?    @relation("BlogOwnerHistory", fields: [successorId], references: [id])
    predecessor         User?    @relation("BlogOwnerHistory")
    role                Role     @default(USER)
    posts               Post[]
    keywords            String[]
    biography           Json
}

model Post {
    id     Int   @id @default(autoincrement())
    user   User? @relation(fields: [userId], references: [id])
    userId Int?
}

enum Role {
    USER
    ADMIN
}

Output:

{
    $schema: 'http://json-schema.org/draft-07/schema#',
    definitions: {
        Post: {
            properties: {
                id: { type: 'integer' },
                userId: { type: ['integer', 'null'] },
            },
            type: 'object',
        },
        User: {
            properties: {
                biography: {
                    type: [
                        'number',
                        'string',
                        'boolean',
                        'object',
                        'array',
                        'null'
                    ],
                },
                createdAt: { format: 'date-time', type: 'string' },
                email: {
                    description: 'Triple Slash Comment: Will show up in JSON schema [EMAIL]',
                    type: 'string'
                },
                id: { type: 'integer' },
                is18: { type: ['boolean', 'null'] },
                keywords: { items: { type: 'string' }, type: 'array' },
                name: { type: ['string', 'null'] },
                number: { type: 'integer', default: '34534535435353' },
                bytes: {
                    description: 'Triple Slash Inline Comment: Will show up in JSON schema [BYTES]',
                    type: 'string'
                },
                favouriteDecimal: { type: 'number' },
                role: { enum: ['USER', 'ADMIN'], type: 'string', default: 'USER' },
                successorId: { type: ['integer', 'null'] },
                weight: { type: ['integer', 'null'] },
            },
            type: 'object',
        },
    },
    properties: {
        post: { $ref: '#/definitions/Post' },
        user: { $ref: '#/definitions/User' },
    },
    type: 'object',
}

License: MIT

Copyright (c) 2020 Valentin Palkovič

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.