comments

Author: maximiliani

src/utils/IndexedDBUtil.ts

@@ -6,7 +6,12 @@ import { DBSchema, openDB } from '@tempfix/idb';
 const dbName: string = 'pid-component';
 const dbVersion: number = undefined;
 
-interface PIDComponentDB extends DBSchema {
+/**
+ * The database schema for the PID component.
+ * @interface PIDComponentDB
+ * @extends DBSchema
+ */
+export interface PIDComponentDB extends DBSchema {
   entities: {
     key: string;
     value: {
@@ -36,6 +41,11 @@ interface PIDComponentDB extends DBSchema {
   };
 }
 
+/**
+ * Opens the indexedDB database for the PID component and creates the object stores and indexes if they do not exist.
+ * @type {Promise<IDBPDatabase<PIDComponentDB>>}
+ * @const
+ */
 const dbPromise = openDB<PIDComponentDB>(dbName, dbVersion, {
   upgrade(db) {
     const entityStore = db.createObjectStore('entities', {
@@ -46,16 +56,23 @@ const dbPromise = openDB<PIDComponentDB>(dbName, dbVersion, {
     const relationStore = db.createObjectStore('relations', {
       autoIncrement: true,
     });
+
+    // Create indexes for the relations
     relationStore.createIndex('by-start', 'start', { unique: false });
     relationStore.createIndex('by-description', 'description', { unique: false });
     relationStore.createIndex('by-end', 'end', { unique: false });
   },
 });
 
+/**
+ * Adds an entity to the database.
+ * @param {GenericIdentifierType} renderer The renderer to add to the database.
+ */
 export async function addEntity(renderer: GenericIdentifierType) {
   const context = document.documentURI;
   const db = await dbPromise;
 
+  // Add the entity to the entities object store
   await db
     .add('entities', {
       value: renderer.value,
@@ -71,16 +88,19 @@ export async function addEntity(renderer: GenericIdentifierType) {
     });
   console.debug('added entity', renderer);
 
+  // Add the relations to the relations object store
+  // Start a new transaction
   const tx = db.transaction('relations', 'readwrite');
   const promises = [];
 
   for (const item of renderer.items) {
+    // Create a relation object
     const relation = {
       start: renderer.value,
       description: item.keyTitle,
       end: item.value,
-      // connectionType: "startToEnd"
     };
+    // Check if the relation already exists
     const index = tx.store.index('by-start');
     let cursor = await index.openCursor();
     while (cursor) {
@@ -90,13 +110,20 @@ export async function addEntity(renderer: GenericIdentifierType) {
       }
       cursor = await cursor.continue();
     }
+    // Add the relation to the relations object store if it does not exist
     promises.push(tx.store.add(relation));
   }
   promises.push(tx.done);
   await Promise.all(promises);
   console.debug('added relations', promises);
 }
 
+/**
+ * Gets an entity from the database. If the entity does not exist, it is created.
+ * @returns {Promise<GenericIdentifierType>} The renderer for the entity.
+ * @param {string} value The stringified value of the entity, e.g. the PID.
+ * @param {{type: string, values: {name: string, value: any}[]}[]} settings The settings for all renderers.
+ */
 export const getEntity = async function (
   value: string,
   settings: {
@@ -107,6 +134,7 @@ export const getEntity = async function (
     }[];
   }[],
 ): Promise<GenericIdentifierType> {
+  // Try to get the entity from the database
   try {
     const db = await dbPromise;
     const entity:
@@ -120,39 +148,49 @@ export const getEntity = async function (
       | undefined = await db.get('entities', value);
 
     if (entity !== undefined) {
+      // If the entity was found, check if the TTL has expired
       console.debug('Found entity for value in db', entity, value);
       const entitySettings = settings.find(value => value.type === entity.rendererKey)?.values;
       const ttl = entitySettings?.find(value => value.name === 'ttl');
 
       if (ttl != undefined && ttl.value != undefined && (new Date().getTime() - entity.lastAccess.getTime() > ttl.value || ttl.value === 0)) {
+        // If the TTL has expired, delete the entity from the database and move on to creating a new one (down below)
         console.log('TTL expired! Deleting entry in db', ttl.value, new Date().getTime() - entity.lastAccess.getTime());
         await deleteEntity(value);
       } else {
+        // If the TTL has not expired, get a new renderer and return it
         console.log('TTL not expired or undefined', new Date().getTime() - entity.lastAccess.getTime());
         const renderer = new (renderers.find(renderer => renderer.key === entity.rendererKey).constructor)(value, entitySettings);
-        // if (renderer.hasCorrectFormat()) {
         renderer.settings = entitySettings;
         await renderer.init(entity.lastData);
         return renderer;
-        // }
       }
     }
   } catch (error) {
     console.error('Could not get entity from db', error);
   }
 
+  // If no entity was found, create a new one, initialize it and it to the database
   console.debug('No valid entity found for value in db', value);
   const renderer = await Parser.getBestFit(value, settings);
-  // renderer.settings = settings.find(value => value.type === renderer.getSettingsKey())?.values
-  // await renderer.init()
+  renderer.settings = settings.find(value => value.type === renderer.getSettingsKey())?.values;
+  await renderer.init();
   await addEntity(renderer);
   console.debug('added entity to db', value, renderer);
   return renderer;
 };
 
+/**
+ * Deletes an entity from the database.
+ * @param value The value of the entity to delete.
+ */
 export async function deleteEntity(value: string) {
   const db = await dbPromise;
+
+  // Delete the entity
   await db.delete('entities', value);
+
+  // Delete all relations for the entity
   const tx = db.transaction('relations', 'readwrite');
   const index = tx.store.index('by-start');
   let cursor = await index.openCursor();
@@ -166,13 +204,13 @@ export async function deleteEntity(value: string) {
   await tx.done;
 }
 
-export async function deleteAllByContext(context: string) {
+/**
+ * Clears all entities from the database.
+ * @returns {Promise<void>} A promise that resolves when all entities have been deleted.
+ */
+export async function clearEntities() {
   const db = await dbPromise;
-  const tx = db.transaction('entities', 'readwrite');
-  const entities = await tx.store.index('by-context').getAll(context);
-  for (const entity of entities) {
-    await deleteEntity(entity.value);
-  }
-  console.log('deleted all entities for context', context);
-  await tx.done;
+  await db.clear('entities');
+  await db.clear('relations');
+  console.log('cleared entities');
 }