Schema generators for Drift, SQLDelight and Room

Author: simolus3

.changeset/hot-peaches-lay.md

@@ -0,0 +1,5 @@
+---
+'@powersync/service-sync-rules': minor
+---
+
+Add schema generator for Drift, SQLDelight and Room.

packages/sync-rules/src/schema-generators/RoomSchemaGenerator.ts

@@ -0,0 +1,62 @@
+import { SqlSyncRules } from '../SqlSyncRules.js';
+import { SourceSchema } from '../types.js';
+import { SchemaGenerator } from './SchemaGenerator.js';
+
+/**
+ * Generates a schema to use with the [Room library](https://docs.powersync.com/client-sdk-references/kotlin-multiplatform/libraries/room).
+ */
+export class RoomSchemaGenerator extends SchemaGenerator {
+  readonly key = 'kotlin-room';
+  readonly label = 'Room (Kotlin Multiplatform)';
+  readonly mediaType = 'text/x-kotlin';
+  readonly fileName = 'Entities.kt';
+
+  generate(source: SqlSyncRules, schema: SourceSchema): string {
+    let buffer = `import androidx.room.ColumnInfo
+import androidx.room.Entity
+import androidx.room.PrimaryKey
+`;
+    const tables = super.getAllTables(source, schema);
+    for (const table of tables) {
+      // @Entity(tableName = "todo_list_items") data class TodoListItems(
+      buffer += `\n@Entity(tableName = "${table.name}")\n`;
+      buffer += `data class ${snakeCaseToKotlin(table.name, true)}(\n`;
+
+      // Id column
+      buffer += '  @PrimaryKey val id: String,\n';
+
+      for (const column of table.columns) {
+        const sqliteType = this.columnType(column);
+        const kotlinType = {
+          text: 'String',
+          real: 'Double',
+          integer: 'Long'
+        }[sqliteType];
+
+        // @ColumnInfo(name = "author_id") val authorId: String,
+        buffer += `  @ColumnInfo("${column.name}") val ${snakeCaseToKotlin(column.name, false)}: ${kotlinType},\n`;
+      }
+
+      buffer += ')\n';
+    }
+
+    return buffer;
+  }
+}
+
+function snakeCaseToKotlin(source: string, initialUpper: boolean): string {
+  let result = '';
+  for (const chunk of source.split('_')) {
+    if (chunk.length == 0) continue;
+
+    const firstCharUpper = result.length > 0 || initialUpper;
+    if (firstCharUpper) {
+      result += chunk.charAt(0).toUpperCase();
+      result += chunk.substring(1);
+    } else {
+      result += chunk;
+    }
+  }
+
+  return result;
+}

packages/sync-rules/src/schema-generators/SchemaGenerator.ts

@@ -33,7 +33,7 @@ export abstract class SchemaGenerator {
    * @param def The column definition to generate the type for.
    * @returns The SDK column type for the given column definition.
    */
-  columnType(def: ColumnDefinition): string {
+  columnType(def: ColumnDefinition): 'text' | 'real' | 'integer' {
     const { type } = def;
     if (type.typeFlags & TYPE_TEXT) {
       return 'text';

packages/sync-rules/src/schema-generators/SqlSchemaGenerator.ts

@@ -0,0 +1,39 @@
+import { SqlSyncRules } from '../SqlSyncRules.js';
+import { SourceSchema } from '../types.js';
+import { GenerateSchemaOptions, SchemaGenerator } from './SchemaGenerator.js';
+
+/**
+ * Generates a schema as `CREATE TABLE` statements, useful for libraries like drift or SQLDelight which can generate
+ * typed rows or generate queries based on that.
+ */
+export class SqlSchemaGenerator extends SchemaGenerator {
+  readonly key = 'sql';
+  readonly mediaType = 'application/sql';
+
+  constructor(
+    readonly label: string,
+    readonly fileName: string
+  ) {
+    super();
+  }
+
+  generate(source: SqlSyncRules, schema: SourceSchema, options?: GenerateSchemaOptions): string {
+    let buffer =
+      '-- Note: These definitions are only used to generate typed code. PowerSync manages the database schema.\n';
+    const tables = super.getAllTables(source, schema);
+
+    for (const table of tables) {
+      buffer += `CREATE TABLE ${table.name}(\n`;
+
+      buffer += '  id TEXT NOT NULL PRIMARY KEY';
+      for (const column of table.columns) {
+        const type = this.columnType(column).toUpperCase();
+        buffer += `,\n  ${column.name} ${type}`;
+      }
+
+      buffer += '\n);\n';
+    }
+
+    return buffer;
+  }
+}

packages/sync-rules/src/schema-generators/schema-generators.ts

@@ -1,8 +1,15 @@
+import { SchemaGenerator } from './SchemaGenerator.js';
+import { SqlSchemaGenerator } from './SqlSchemaGenerator.js';
+
 export * from './DartSchemaGenerator.js';
 export * from './DotNetSchemaGenerator.js';
 export * from './generators.js';
 export * from './JsLegacySchemaGenerator.js';
 export * from './KotlinSchemaGenerator.js';
+export * from './RoomSchemaGenerator.js';
 export * from './SchemaGenerator.js';
 export * from './SwiftSchemaGenerator.js';
 export * from './TsSchemaGenerator.js';
+
+export const driftSchemaGenerator = new SqlSchemaGenerator('Drift', 'tables.drift');
+export const sqlDelightSchemaGenerator = new SqlSchemaGenerator('SQLDelight', 'tables.sq');

packages/sync-rules/test/src/generate_schema.test.ts

@@ -6,10 +6,13 @@ import {
   DotNetSchemaGenerator,
   JsLegacySchemaGenerator,
   KotlinSchemaGenerator,
+  RoomSchemaGenerator,
   SqlSyncRules,
   StaticSchema,
   SwiftSchemaGenerator,
-  TsSchemaGenerator
+  TsSchemaGenerator,
+  driftSchemaGenerator,
+  sqlDelightSchemaGenerator
 } from '../../src/index.js';
 
 import { PARSE_OPTIONS } from './util.js';
@@ -231,6 +234,30 @@ val schema = Schema(
 )`);
   });
 
+  test('room', () => {
+    expect(new RoomSchemaGenerator().generate(rules, schema)).toEqual(`import androidx.room.ColumnInfo
+import androidx.room.Entity
+import androidx.room.PrimaryKey
+
+@Entity(tableName = "assets1")
+data class Assets1(
+  @PrimaryKey val id: String,
+  @ColumnInfo("name") val name: String,
+  @ColumnInfo("count") val count: Long,
+  @ColumnInfo("owner_id") val ownerId: String,
+)
+
+@Entity(tableName = "assets2")
+data class Assets2(
+  @PrimaryKey val id: String,
+  @ColumnInfo("name") val name: String,
+  @ColumnInfo("count") val count: Long,
+  @ColumnInfo("other_id") val otherId: String,
+  @ColumnInfo("foo") val foo: String,
+)
+`);
+  });
+
   test('swift', () => {
     expect(new SwiftSchemaGenerator().generate(rules, schema)).toEqual(`import PowerSync
 
@@ -331,4 +358,30 @@ class AppSchema
   });
 }`);
   });
+
+  describe('sql', () => {
+    const expected = `-- Note: These definitions are only used to generate typed code. PowerSync manages the database schema.
+CREATE TABLE assets1(
+  id TEXT NOT NULL PRIMARY KEY,
+  name TEXT,
+  count INTEGER,
+  owner_id TEXT
+);
+CREATE TABLE assets2(
+  id TEXT NOT NULL PRIMARY KEY,
+  name TEXT,
+  count INTEGER,
+  other_id TEXT,
+  foo TEXT
+);
+`;
+
+    test('drift', () => {
+      expect(driftSchemaGenerator.generate(rules, schema)).toEqual(expected);
+    });
+
+    test('sqldelight', () => {
+      expect(sqlDelightSchemaGenerator.generate(rules, schema)).toEqual(expected);
+    });
+  });
 });