feat: Add sql.js fallback for sqlite in wasm

.github/workflows/sqlite-wasm.yml

@@ -0,0 +1,37 @@
+name: Tests WASM
+
+on:
+ push:
+ branches: [main]
+ pull_request:
+ types: [opened, synchronize, reopened, auto_merge_enabled]
+
+# Allow parallel jobs on `main`, so that each commit is tested. For PRs, run only the latest commit.
+concurrency:
+ group: ${{ github.workflow }}-${{ github.head_ref || github.run_id }}
+ cancel-in-progress: true
+
+jobs:
+ test:
+ runs-on: ubuntu-latest
+ timeout-minutes: 5
+ name: Node.js ${{ matrix.node }}
+
+ strategy:
+ fail-fast: true
+ matrix:
+ node: [18]
+
+ steps:
+ - uses: actions/checkout@v4
+ - uses: actions/setup-node@v4
+ with:
+ node-version: ${{ matrix.node }}
+ cache: 'npm'
+
+ - run: npm ci
+ # Remove better-sqlite3 to force switching to sql.js
+ - run: npm install sql.js && rm -rf node_modules/better-sqlite3/
+ - run: npm test -w sqlite -- --maxWorkers=1
+ env:
+ FORCE_COLOR: true

sqlite/lib/SQLiteService.js

@@ -1,6 +1,13 @@
 const { SQLService } = require('@cap-js/db-service')
-const cds = require('@sap/cds')
-const sqlite = require('better-sqlite3')
+const cds = require('@sap/cds/lib')
+let sqlite
+try {
+ sqlite = require('better-sqlite3')
+} catch (err) {
+ // When failing to load better-sqlite3 it fallsback to sql.js (wasm version of sqlite)
+ sqlite = require('./sql.js.js')
+}
+
 const $session = Symbol('dbc.session')
 const convStrm = require('stream/consumers')
 const { Readable } = require('stream')
@@ -20,9 +27,10 @@ class SQLiteService extends SQLService {
  get factory() {
  return {
  options: { max: 1, ...this.options.pool },
- create: tenant => {
+ create: async tenant => {
  const database = this.url4(tenant)
  const dbc = new sqlite(database)
+ await dbc.ready
 
  const deterministic = { deterministic: true }
  dbc.function('session_context', key => dbc[$session][key])

sqlite/lib/sql.js.js

@@ -0,0 +1,84 @@
+const initSqlJs = require('sql.js');
+
+const init = initSqlJs({})
+
+class WasmSqlite {
+ constructor(/*database*/) {
+ // TODO: load / store database file contents
+ this.ready = init
+ .then(SQL => { this.db = new SQL.Database() })
+
+ this.memory = true
+ this.gc = new FinalizationRegistry(stmt => { stmt.free() })
+ }
+
+ prepare(sql) {
+ const stmt = this.db.prepare(sql)
+ const ret = {
+ run: (params) => {
+ try {
+ stmt.bind(params)
+ stmt.step()
+ return { changes: this.db.getRowsModified(stmt) }
+ } catch (err) {
+ if (err.message.indexOf('NOT NULL constraint failed:') === 0) {
+ err.code = 'SQLITE_CONSTRAINT_NOTNULL'
+ }
+ throw err
+ }
+ },
+ get: (params) => {
+ const columns = stmt.getColumnNames()
+ stmt.bind(params)
+ stmt.step()
+ const row = stmt.get()
+ const ret = {}
+ for (let i = 0; i < columns.length; i++) {
+ ret[columns[i]] = row[i]
+ }
+ return ret
+ },
+ all: (params) => {
+ const columns = stmt.getColumnNames()
+ const ret = []
+ stmt.bind(params)
+ while (stmt.step()) {
+ const row = stmt.get()
+ const obj = {}
+ for (let i = 0; i < columns.length; i++) {
+ obj[columns[i]] = row[i]
+ }
+ ret.push(obj)
+ }
+ return ret
+ }
+ }
+ this.gc.register(ret, stmt)
+ return ret
+ }
+
+ exec(sql) {
+ try {
+ const { columns, values } = this.db.exec(sql)
+ return !Array.isArray(values) ? values : values.map(val => {
+ const ret = {}
+ for (let i = 0; i < columns.length; i++) {
+ ret[columns[i]] = val[i]
+ }
+ return ret
+ })
+ } catch (err) {
+ // REVISIT: address transaction errors
+ if (sql === 'BEGIN' || sql === 'ROLLBACK') { return }
+ throw err
+ }
+ }
+
+ function(name, config, func) {
+ this.db.create_function(name, func || config)
+ }
+
+ close() { this.db.close() }
+}
+
+module.exports = WasmSqlite

sqlite/package.json

@@ -33,6 +33,9 @@
  "@cap-js/db-service": "^1.9.0",
  "better-sqlite3": "^10.0.0"
  },
+ "optionalDependencies": {
+ "sql.js": "^1.10.3"
+ },
  "peerDependencies": {
  "@sap/cds": ">=7.6"
  },