162 lines
5.7 KiB
HTML
162 lines
5.7 KiB
HTML
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<html>
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<head>
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<meta charset="utf-8">
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<meta name="viewport" content="width=device-width, initial-scale=1">
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</head>
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<body>
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<ul id="files"></ul>
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<p>
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<input type="file" id="file" multiple capture="user" accept="image/*">
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<button id="addFile">Add</button>
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<button id="drop">Delete all</button>
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</p>
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<script type="text/javascript">
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function reqAsPromise(req) {
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return new Promise((resolve, reject) => {
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req.onsuccess = () => resolve(req);
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req.onerror = (err) => reject(err);
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});
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}
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function fetchResults(cursor, isDone, resultMapper) {
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return new Promise((resolve, reject) => {
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const results = [];
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cursor.onerror = (event) => {
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reject(new Error("Query failed: " + event.target.errorCode));
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};
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// collect results
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cursor.onsuccess = (event) => {
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const cursor = event.target.result;
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if (!cursor) {
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resolve(results);
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return; // end of results
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}
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results.push(resultMapper(cursor));
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if (!isDone(results)) {
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cursor.continue();
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} else {
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resolve(results);
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}
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};
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});
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}
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class Storage {
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constructor(databaseName) {
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this._databaseName = databaseName;
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this._database = null;
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}
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async open() {
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const req = window.indexedDB.open(this._databaseName);
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req.onupgradeneeded = (ev) => {
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const db = ev.target.result;
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const oldVersion = ev.oldVersion;
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this._createStores(db, oldVersion);
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};
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await reqAsPromise(req);
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this._database = req.result;
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}
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async drop() {
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if (this._database) {
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this._database.close();
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this._database = null;
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}
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await reqAsPromise(window.indexedDB.deleteDatabase(this._databaseName));
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}
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_createStores(db) {
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db.createObjectStore("files", {keyPath: "id"});
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}
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async storeFile(file) {
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const id = Math.floor(Math.random() * 10000000000);
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console.log(`adding a file as id ${id}`);
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const tx = this._database.transaction(["files"], "readwrite");
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const store = tx.objectStore("files");
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await reqAsPromise(store.add({id, file}));
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}
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getFiles() {
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const tx = this._database.transaction(["files"], "readonly");
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const store = tx.objectStore("files");
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const cursor = store.openCursor();
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return fetchResults(cursor,
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() => false,
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(cursor) => cursor.value);
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}
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}
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async function reloadFiles(storage, fileList) {
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const files = await storage.getFiles();
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const fileNodes = files.map(f => {
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const {type, size, name} = f.file;
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const txt = document.createTextNode(`${f.id} - ${name} of type ${type} - size: ${Math.round(size / 1024, 2)}kb`);
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const li = document.createElement("li");
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li.addEventListener("click", async () => {
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const reader = new FileReader();
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const promise = new Promise((resolve, reject) => {
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reader.onload = e => resolve(e.target.result);
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reader.onerror = e => reject(e.target.error);
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});
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reader.readAsArrayBuffer(f.file);
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try {
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const buf = await promise;
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alert(`read blob, len is ${buf.byteLength}`);
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} catch(e) {
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alert(e.message);
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}
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});
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li.appendChild(txt);
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return li;
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});
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fileList.innerHTML = "";
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for(const li of fileNodes) {
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fileList.appendChild(li);
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}
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}
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async function main() {
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let storage = new Storage("idb-store-files-test");
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await storage.open();
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const fileList = document.getElementById("files");
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const dropButton = document.getElementById("drop");
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const addButton = document.getElementById("addFile");
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const filePicker = document.getElementById("file");
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addButton.addEventListener("click", async () => {
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const files = Array.from(filePicker.files);
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try {
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for(const file of files) {
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await storage.storeFile(file);
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}
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alert(`stored ${files.length} files!`);
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reloadFiles(storage, fileList);
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} catch(e) {
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alert(e.message);
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}
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});
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dropButton.addEventListener("click", async () => {
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try {
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if (storage) {
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await storage.drop();
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storage = null;
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alert("dropped db");
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}
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} catch(e) {
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alert(e.message);
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}
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});
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reloadFiles(storage, fileList);
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}
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main();
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</script>
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</body>
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</html>
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