Initial commit

Author: Bart Huijgen

.vscode/settings.json

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+{
+  "deno.enable": true
+}

LICENSE

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+The MIT License (MIT)
+
+Copyright (c) 2022
+
+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.

mod.ts

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+export * from "./src/mod.ts";

readme.md

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+# Kysely Deno Postgres driver
+
+## usage
+
+```ts
+import { Kysely } from "https://cdn.jsdelivr.net/npm/[email protected]/dist/esm/index-nodeless.js";
+import { PostgresDialect } from "[not hosted yet]";
+
+const db = new Kysely<{}>({
+  dialect: new PostgresDialect({
+    // ...
+  }),
+});
+```
+
+## Reference
+
+Based on node driver for postgres https://github.com/koskimas/kysely/tree/master/src/dialect/postgres

src/deps/kysely.ts

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+export * from "https://cdn.jsdelivr.net/npm/[email protected]/dist/esm/index-nodeless.js";

src/deps/postgres.ts

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+export * from "https://deno.land/x/[email protected]/mod.ts";

src/mod.ts

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+export { PostgresDialect } from "./postgres/postgres-dialect.ts";

src/postgres/postgres-adapter.ts

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+import { DialectAdapterBase } from "../deps/kysely.ts";
+import type { Kysely } from "../deps/kysely.ts";
+
+// Random id for our transaction lock.
+const LOCK_ID = "3853314791062309107";
+
+export class PostgresAdapter extends DialectAdapterBase {
+  get supportsTransactionalDdl(): boolean {
+    return true;
+  }
+
+  get supportsReturning(): boolean {
+    return true;
+  }
+
+  async acquireMigrationLock(db: Kysely<any>): Promise<void> {
+    // Acquire a transaction level advisory lock.
+    await db.raw(`select pg_advisory_xact_lock(${LOCK_ID})`).execute();
+  }
+
+  async releaseMigrationLock(): Promise<void> {
+    // Nothing to do here. `pg_advisory_xact_lock` is automatically released at the
+    // end of the transaction and since `supportsTransactionalDdl` true, we know
+    // the `db` instance passed to acquireMigrationLock is actually a transaction.
+  }
+}

src/postgres/postgres-dialect-config.ts

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+import type { ClientOptions } from "../deps/postgres.ts";
+
+export type PostgresDialectConfig = ClientOptions;

src/postgres/postgres-dialect.ts

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+import { PostgresDriver } from "./postgres-driver.ts";
+import { PostgresIntrospector } from "./postgres-introspector.ts";
+import { PostgresQueryCompiler } from "./postgres-query-compiler.ts";
+import { PostgresAdapter } from "./postgres-adapter.ts";
+import type { PostgresDialectConfig } from "./postgres-dialect-config.ts";
+import { Kysely } from "../deps/kysely.ts";
+import type {
+  Driver,
+  DialectAdapter,
+  DatabaseIntrospector,
+  Dialect,
+  QueryCompiler,
+} from "../deps/kysely.ts";
+
+export class PostgresDialect implements Dialect {
+  readonly #config: PostgresDialectConfig;
+
+  constructor(config: PostgresDialectConfig) {
+    this.#config = config;
+  }
+
+  createDriver(): Driver {
+    return new PostgresDriver(this.#config);
+  }
+
+  createQueryCompiler(): QueryCompiler {
+    return new PostgresQueryCompiler();
+  }
+
+  createAdapter(): DialectAdapter {
+    return new PostgresAdapter();
+  }
+
+  createIntrospector(db: Kysely<any>): DatabaseIntrospector {
+    return new PostgresIntrospector(db);
+  }
+}

src/postgres/postgres-driver.ts

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+import { Pool } from "../deps/postgres.ts";
+import type { PoolClient, ClientOptions } from "../deps/postgres.ts";
+import { CompiledQuery } from "../deps/kysely.ts";
+import type {
+  DatabaseConnection,
+  QueryResult,
+  Driver,
+  TransactionSettings,
+} from "../deps/kysely.ts";
+
+const PRIVATE_RELEASE_METHOD = Symbol();
+
+export class PostgresDriver implements Driver {
+  readonly #config: ClientOptions;
+  readonly #connections = new WeakMap<PoolClient, DatabaseConnection>();
+  #pool: Pool | null = null;
+
+  constructor(config: ClientOptions) {
+    this.#config = config;
+  }
+
+  async init(): Promise<void> {
+    // TODO: size is required unlike the node `pg` module.
+    // Need to figure out what is a good value to use here
+    this.#pool = new Pool(this.#config, 1);
+  }
+
+  async acquireConnection(): Promise<DatabaseConnection> {
+    const client = await this.#pool!.connect();
+    let connection = this.#connections.get(client);
+
+    if (!connection) {
+      connection = new PostgresConnection(client);
+      this.#connections.set(client, connection);
+
+      // The driver must take care of calling `onCreateConnection` when a new
+      // connection is created. The `pg` module doesn't provide an async hook
+      // for the connection creation. We need to call the method explicitly.
+      // if (this.#config.onCreateConnection) {
+      //   await this.#config.onCreateConnection(connection);
+      // }
+    }
+
+    return connection;
+  }
+
+  async beginTransaction(
+    connection: DatabaseConnection,
+    settings: TransactionSettings
+  ): Promise<void> {
+    if (settings.isolationLevel) {
+      await connection.executeQuery(
+        CompiledQuery.raw(
+          `start transaction isolation level ${settings.isolationLevel}`
+        )
+      );
+    } else {
+      await connection.executeQuery(CompiledQuery.raw("begin"));
+    }
+  }
+
+  async commitTransaction(connection: DatabaseConnection): Promise<void> {
+    await connection.executeQuery(CompiledQuery.raw("commit"));
+  }
+
+  async rollbackTransaction(connection: DatabaseConnection): Promise<void> {
+    await connection.executeQuery(CompiledQuery.raw("rollback"));
+  }
+
+  // deno-lint-ignore require-await
+  async releaseConnection(connection: DatabaseConnection): Promise<void> {
+    const pgConnection = connection as PostgresConnection;
+    pgConnection[PRIVATE_RELEASE_METHOD]();
+  }
+
+  async destroy(): Promise<void> {
+    if (this.#pool) {
+      const pool = this.#pool;
+      this.#pool = null;
+      await pool.end();
+    }
+  }
+}
+
+class PostgresConnection implements DatabaseConnection {
+  #client: PoolClient;
+
+  constructor(client: PoolClient) {
+    this.#client = client;
+  }
+
+  async executeQuery<O>(compiledQuery: CompiledQuery): Promise<QueryResult<O>> {
+    const result = await this.#client.queryObject<O>(
+      compiledQuery.sql,
+      ...compiledQuery.parameters
+    );
+
+    if (result.command === "UPDATE" || result.command === "DELETE") {
+      return {
+        numUpdatedOrDeletedRows: BigInt(result.rowCount!),
+        rows: result.rows ?? [],
+      };
+    }
+
+    return {
+      rows: result.rows ?? [],
+    };
+  }
+
+  [PRIVATE_RELEASE_METHOD](): void {
+    this.#client.release();
+  }
+}

src/postgres/postgres-introspector.ts

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+import {
+  Kysely,
+  MIGRATION_TABLE,
+  MIGRATION_LOCK_TABLE,
+} from "../deps/kysely.ts";
+import type {
+  ColumnDataType,
+  DatabaseIntrospector,
+  DatabaseMetadata,
+  DatabaseMetadataOptions,
+  TableMetadata,
+} from "../deps/kysely.ts";
+
+const freeze = Object.freeze;
+
+export class PostgresIntrospector implements DatabaseIntrospector {
+  readonly #db: Kysely<any>;
+
+  constructor(db: Kysely<any>) {
+    this.#db = db;
+  }
+
+  async getMetadata(
+    options: DatabaseMetadataOptions = { withInternalKyselyTables: false }
+  ): Promise<DatabaseMetadata> {
+    let query = this.#db
+      .selectFrom("pg_catalog.pg_attribute as a")
+      .innerJoin("pg_catalog.pg_class as c", "a.attrelid", "c.oid")
+      .innerJoin("pg_catalog.pg_tables as t", "t.tablename", "c.relname")
+      .innerJoin("pg_catalog.pg_type as typ", "a.atttypid", "typ.oid")
+      .select([
+        "a.attname as column",
+        "a.attnotnull as not_null",
+        "t.tablename as table",
+        "t.schemaname as schema",
+        "typ.typname as type",
+      ])
+      .where("t.schemaname", "!~", "^pg_")
+      .where("t.schemaname", "!=", "information_schema")
+      .where("a.attnum", ">=", 0) // No system columns
+      .where("a.attisdropped", "!=", true)
+      .castTo<RawColumnMetadata>();
+
+    if (!options.withInternalKyselyTables) {
+      query = query
+        .where("t.tablename", "!=", MIGRATION_TABLE)
+        .where("t.tablename", "!=", MIGRATION_LOCK_TABLE);
+    }
+
+    const rawColumns = await query.execute();
+
+    return {
+      tables: this.#parseTableMetadata(rawColumns),
+    };
+  }
+
+  #parseTableMetadata(columns: RawColumnMetadata[]): TableMetadata[] {
+    return columns.reduce<TableMetadata[]>((tables, it) => {
+      let table = tables.find(
+        (tbl) => tbl.name === it.table && tbl.schema === it.schema
+      );
+
+      if (!table) {
+        table = freeze({
+          name: it.table,
+          schema: it.schema,
+          columns: [],
+        });
+
+        tables.push(table);
+      }
+
+      table.columns.push(
+        freeze({
+          name: it.column,
+          dataType: it.type,
+          isNullable: !it.not_null,
+        })
+      );
+
+      return tables;
+    }, []);
+  }
+}
+
+interface RawColumnMetadata {
+  column: string;
+  table: string;
+  schema: string;
+  not_null: boolean;
+  type: ColumnDataType;
+}

src/postgres/postgres-query-compiler.ts

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+import { DefaultQueryCompiler } from "../deps/kysely.ts";
+
+export class PostgresQueryCompiler extends DefaultQueryCompiler {
+  protected getCurrentParameterPlaceholder(): string {
+    return "$" + this.numParameters;
+  }
+
+  protected override getLeftIdentifierWrapper(): string {
+    return '"';
+  }
+
+  protected override getRightIdentifierWrapper(): string {
+    return '"';
+  }
+}