feat: add typescript typegen endpoint

Author: soedirgo

src/server/routes/generators/typescript.ts

@@ -0,0 +1,200 @@
+import { FastifyInstance } from 'fastify'
+import prettier from 'prettier'
+import { PostgresMeta, PostgresType } from '../../../lib'
+import { DEFAULT_POOL_CONFIG } from '../../constants'
+import { extractRequestForLogging } from '../../utils'
+
+export default async (fastify: FastifyInstance) => {
+  fastify.get<{
+    Headers: { pg: string }
+    Querystring: {
+      excluded_schemas?: string
+    }
+  }>('/', async (request, reply) => {
+    const connectionString = request.headers.pg
+    const excludedSchemas =
+      request.query.excluded_schemas?.split(',').map((schema) => schema.trim()) ?? []
+
+    const pgMeta: PostgresMeta = new PostgresMeta({ ...DEFAULT_POOL_CONFIG, connectionString })
+    const { data: schemas, error: schemasError } = await pgMeta.schemas.list()
+    const { data: tables, error: tablesError } = await pgMeta.tables.list()
+    const { data: functions, error: functionsError } = await pgMeta.functions.list()
+    const { data: types, error: typesError } = await pgMeta.types.list({
+      includeSystemSchemas: true,
+    })
+    await pgMeta.end()
+
+    if (schemasError) {
+      request.log.error({ error: schemasError, request: extractRequestForLogging(request) })
+      reply.code(500)
+      return { error: schemasError.message }
+    }
+    if (tablesError) {
+      request.log.error({ error: tablesError, request: extractRequestForLogging(request) })
+      reply.code(500)
+      return { error: tablesError.message }
+    }
+    if (functionsError) {
+      request.log.error({ error: functionsError, request: extractRequestForLogging(request) })
+      reply.code(500)
+      return { error: functionsError.message }
+    }
+    if (typesError) {
+      request.log.error({ error: typesError, request: extractRequestForLogging(request) })
+      reply.code(500)
+      return { error: typesError.message }
+    }
+
+    let output = `
+export type Json = string | number | boolean | null | { [key: string]: Json } | Json[]
+
+export interface Database {
+  ${schemas
+    .filter(({ name }) => !excludedSchemas.includes(name))
+    .map(
+      (schema) =>
+        `${JSON.stringify(schema.name)}: {
+          Tables: {
+            ${tables
+              .filter((table) => table.schema === schema.name)
+              .map(
+                (table) => `${JSON.stringify(table.name)}: {
+                  Row: {
+                    ${table.columns.map(
+                      (column) =>
+                        `${JSON.stringify(column.name)}: ${pgTypeToTsType(column.format, types)} ${
+                          column.is_nullable ? '| null' : ''
+                        }`
+                    )}
+                  }
+                  Insert: {
+                    ${table.columns.map((column) => {
+                      let output = JSON.stringify(column.name)
+
+                      if (column.identity_generation === 'ALWAYS') {
+                        return `${output}?: never`
+                      }
+
+                      if (
+                        column.is_nullable ||
+                        column.is_identity ||
+                        column.default_value !== null
+                      ) {
+                        output += '?:'
+                      } else {
+                        output += ':'
+                      }
+
+                      output += pgTypeToTsType(column.format, types)
+
+                      if (column.is_nullable) {
+                        output += '| null'
+                      }
+
+                      return output
+                    })}
+                  }
+                  Update: {
+                    ${table.columns.map((column) => {
+                      let output = JSON.stringify(column.name)
+
+                      if (column.identity_generation === 'ALWAYS') {
+                        return `${output}?: never`
+                      }
+
+                      output += `?: ${pgTypeToTsType(column.format, types)}`
+
+                      if (column.is_nullable) {
+                        output += '| null'
+                      }
+
+                      return output
+                    })}
+                  }
+                }`
+              )}
+          }
+          Functions: {
+            ${functions
+              .filter(
+                (function_) =>
+                  function_.schema === schema.name && function_.return_type !== 'trigger'
+              )
+              .map(
+                (function_) => `${JSON.stringify(function_.name)}: {
+                  Args: ${(() => {
+                    if (function_.argument_types === '') {
+                      return 'Record<PropertyKey, never>'
+                    }
+
+                    const splitArgs = function_.argument_types.split(',').map((arg) => arg.trim())
+                    if (splitArgs.some((arg) => arg.includes('"') || !arg.includes(' '))) {
+                      return 'Record<string, unknown>'
+                    }
+
+                    const argsNameAndType = splitArgs.map((arg) => {
+                      const [name, ...rest] = arg.split(' ')
+                      const type = types.find((_type) => _type.format === rest.join(' '))
+                      if (!type) {
+                        return { name, type: 'unknown' }
+                      }
+                      return { name, type: pgTypeToTsType(type.name, types) }
+                    })
+
+                    return `{ ${argsNameAndType.map(
+                      ({ name, type }) => `${JSON.stringify(name)}: ${type}`
+                    )} }`
+                  })()}
+                  Returns: ${pgTypeToTsType(function_.return_type, types)}
+                }`
+              )}
+          }
+        }`
+    )}
+}`
+
+    output = prettier.format(output, {
+      parser: 'typescript',
+    })
+    return output
+  })
+}
+
+// TODO: Make this more robust. Currently doesn't handle composite types - returns them as unknown.
+const pgTypeToTsType = (pgType: string, types: PostgresType[]): string => {
+  if (pgType === 'bool') {
+    return 'boolean'
+  } else if (['int2', 'int4', 'int8', 'float4', 'float8', 'numeric'].includes(pgType)) {
+    return 'number'
+  } else if (
+    [
+      'bytea',
+      'bpchar',
+      'varchar',
+      'date',
+      'text',
+      'time',
+      'timetz',
+      'timestamp',
+      'timestamptz',
+      'uuid',
+    ].includes(pgType)
+  ) {
+    return 'string'
+  } else if (['json', 'jsonb'].includes(pgType)) {
+    return 'Json'
+  } else if (pgType === 'void') {
+    return 'undefined'
+  } else if (pgType === 'record') {
+    return 'Record<string, unknown>[]'
+  } else if (pgType.startsWith('_')) {
+    return pgTypeToTsType(pgType.substring(1), types) + '[]'
+  } else {
+    const type = types.find((type) => type.name === pgType && type.enums.length > 0)
+    if (type) {
+      return type.enums.map((variant) => JSON.stringify(variant)).join('|')
+    }
+
+    return 'unknown'
+  }
+}

src/server/routes/index.ts

@@ -38,4 +38,5 @@ export default async (fastify: FastifyInstance) => {
   fastify.register(require('./triggers'), { prefix: '/triggers' })
   fastify.register(require('./types'), { prefix: '/types' })
   fastify.register(require('./views'), { prefix: '/views' })
+  fastify.register(require('./generators/typescript'), { prefix: '/generators/typescript' })
 }