add CSV support #27

src/db.worker.js

@@ -0,0 +1,98 @@
+import registerPromiseWorker from 'promise-worker/register'
+import initSqlJs from 'sql.js/dist/sql-wasm.js'
+import dbUtils from '@/dbUtils'
+
+const sqlModuleReady = initSqlJs()
+let db = null
+
+function onModuleReady (SQL) {
+  function createDb (data) {
+    if (db != null) db.close()
+    db = new SQL.Database(data)
+    return db
+  }
+
+  const data = this
+
+  switch (data && data.action) {
+    case 'open':
+      const buff = data.buffer
+      createDb(buff && new Uint8Array(buff))
+      return {
+        ready: true
+      }
+    case 'exec':
+      if (db === null) {
+        createDb()
+      }
+      if (!data.sql) {
+        throw new Error('exec: Missing query string')
+      }
+      return db.exec(data.sql, data.params)
+    case 'each':
+      if (db === null) {
+        createDb()
+      }
+      const callback = function callback (row) {
+        return {
+          row: row,
+          finished: false
+        }
+      }
+      const done = function done () {
+        return {
+          finished: true
+        }
+      }
+      return db.each(data.sql, data.params, callback, done)
+    case 'import':
+      createDb()
+      const values = data.values
+      const columns = data.columns
+      const chunkSize = 1500
+      db.exec(dbUtils.getCreateStatement(columns, values))
+      const chunks = dbUtils.generateChunks(values, chunkSize)
+      const chunksAmount = Math.ceil(values.length / chunkSize)
+      let count = 0
+      const insertStr = dbUtils.getInsertStmt(columns)
+      const insertStmt = db.prepare(insertStr)
+
+      postMessage({ progress: 0, id: data.progressCounterId })
+      for (const chunk of chunks) {
+        db.exec('BEGIN')
+        for (const row of chunk) {
+          insertStmt.run(row)
+        }
+        db.exec('COMMIT')
+        count++
+        postMessage({ progress: 100 * (count / chunksAmount), id: data.progressCounterId })
+      }
+
+      return {
+        finish: true
+      }
+    case 'export':
+      return db.export()
+    case 'close':
+      if (db) {
+        db.close()
+      }
+      return {
+        finished: true
+      }
+    default:
+      throw new Error('Invalid action : ' + (data && data.action))
+  }
+}
+
+function onError (err) {
+  return {
+    error: new Error(err.message)
+  }
+}
+
+registerPromiseWorker(data => {
+  return sqlModuleReady
+    .then(onModuleReady.bind(data))
+    .catch(onError)
+})