71 lines
2.0 KiB
TypeScript
71 lines
2.0 KiB
TypeScript
import { KeyValueStorage } from "./basic.ts";
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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 = (
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method: "GET" | "POST" | "PUT" | "DELETE",
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uri: string,
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body?: string,
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) => 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 client: RestClient = async (method, path, body?) => {
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const response = await fetch(`${this.base_url}${path}`, {
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method,
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body,
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headers: {
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[HEADER_REQUESTER]: this.appname,
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},
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});
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// the body is consumed here to not leak resource, but it would
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// be better to consume it only when needed, once
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// https://github.com/denoland/deno/issues/4735 is fixed
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const text = await response.text();
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if (response.headers.get(HEADER_REPLYIER) != "ok") {
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throw new Error("storage not compatible with tk-storage");
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} else if (response.status == 200) {
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return text;
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} else if (response.status == 404) {
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return null;
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} else {
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throw new Error(
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`http error ${response.status}: ${response.statusText}`,
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);
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}
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};
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return client;
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}
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}
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