65 lines
2 KiB
TypeScript
65 lines
2 KiB
TypeScript
import { KeyValueStorage } from "./basic";
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function protectKey(key: string): string {
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return encodeURIComponent(key);
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}
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type RestClient = (method: "GET" | "POST" | "PUT" | "DELETE", uri: string, body?: string) => Promise<string | null>
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export const HEADER_REQUESTER = "X-TK-Storage-App"
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export const HEADER_REPLYIER = "X-TK-Storage-Control"
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/**
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* Storage on a remote server, directly usable using HTTP REST verbs
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*/
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export class RestRemoteStorage implements KeyValueStorage {
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readonly appname: string
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readonly base_url: string
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readonly client: RestClient
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constructor(appname: string, url: string) {
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this.appname = appname;
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this.base_url = (url[url.length - 1] != "/") ? url + "/" : url;
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this.client = this.createClient();
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}
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async get(key: string): Promise<string | null> {
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key = protectKey(key);
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return await this.client("GET", key);
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}
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async set(key: string, value: string | null): Promise<void> {
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key = protectKey(key);
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if (value === null) {
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await this.client("DELETE", key);
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} else {
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await this.client("PUT", key, value);
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}
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}
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private createClient(): RestClient {
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const Request: typeof XMLHttpRequest = (typeof XMLHttpRequest === "undefined") ? require("xmlhttprequest").XMLHttpRequest : XMLHttpRequest;
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const client: RestClient = (method, path, body?) => new Promise((resolve, reject) => {
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const xhr = new Request();
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xhr.open(method, `${this.base_url}${path}`);
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xhr.responseType = 'text';
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xhr.setRequestHeader(HEADER_REQUESTER, this.appname);
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xhr.onload = function () {
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if (xhr.getResponseHeader(HEADER_REPLYIER) != "ok") {
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reject("storage not compatible with tk-storage");
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} else if (xhr.status == 200) {
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resolve(xhr.responseText);
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} else if (xhr.status == 404) {
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resolve(null);
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} else {
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reject(`http error ${xhr.status}: ${xhr.statusText}`);
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}
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};
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xhr.onerror = function () {
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reject("unknown error");
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};
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xhr.send(body);
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});
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return client;
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}
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}
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