webrequest/ts/index.ts

import * as plugins from './webrequest.plugins.js';

export interface IWebrequestContructorOptions {
  logging?: boolean;
}

/**
 * web request
 */
export class WebRequest {

  public cacheStore = new plugins.webstore.WebStore({
    dbName: 'webrequest',
    storeName: 'webrequest',
  });

  public options: IWebrequestContructorOptions;

  constructor(public optionsArg: IWebrequestContructorOptions = {}) {
    this.options = {
      logging: true,
      ...optionsArg,
    };
  }

  public async getJson(urlArg: string, useCacheArg: boolean = false) {
    const response: Response = await this.request(urlArg, {
      method: 'GET',
      useCache: useCacheArg,
    });
    const responseText = await response.text();
    const responseResult = plugins.smartjson.parse(responseText);
    return responseResult;
  }

  /**
   * postJson
   */
  public async postJson(urlArg: string, requestBody?: any, useCacheArg: boolean = false) {
    const response: Response = await this.request(urlArg, {
      method: 'POST',
      headers: {
        'Content-Type': 'application/json',
      },
      body: plugins.smartjson.stringify(requestBody),
      useCache: useCacheArg,
    });
    const responseText = await response.text();
    const responseResult = plugins.smartjson.parse(responseText);
    return responseResult;
  }

  /**
   * put js
   */
  public async putJson(urlArg: string, requestBody?: any, useStoreAsFallback: boolean = false) {
    const response: Response = await this.request(urlArg, {
      method: 'PUT',
      headers: {
        'Content-Type': 'application/json',
      },
      body: plugins.smartjson.stringify(requestBody),
    });
    const responseText = await response.text();
    const responseResult = plugins.smartjson.parse(responseText);
    return responseResult;
  }

  /**
   * put js
   */
  public async deleteJson(urlArg: string, useStoreAsFallback: boolean = false) {
    const response: Response = await this.request(urlArg, {
      headers: {
        'Content-Type': 'application/json',
      },
      method: 'GET',
    });
    const responseText = await response.text();
    const responseResult = plugins.smartjson.parse(responseText);
    return responseResult;
  }

  public async request(
    urlArg: string,
    optionsArg: {
      method: 'GET' | 'POST' | 'PUT' | 'DELETE';
      body?: any;
      headers?: HeadersInit;
      useCache?: boolean;
      timeoutMs?: number;
    }
  ) {
    optionsArg = {
      timeoutMs: 60000,
      useCache: false,
      ...optionsArg,
    };

    let controller = new AbortController();
    plugins.smartdelay.delayFor(optionsArg.timeoutMs).then(() => {
      controller.abort();
    });
    let cachedResponseDeferred = plugins.smartpromise.defer<Response>();
    let cacheUsed = false;
    if (optionsArg.useCache && (await this.cacheStore.check(urlArg))) {
      const responseBuffer: ArrayBuffer = await this.cacheStore.get(urlArg);
      cachedResponseDeferred.resolve(new Response(responseBuffer, {}));
    } else {
      cachedResponseDeferred.resolve(null);
    }
    let response: Response = await fetch(urlArg, {
        signal: controller.signal,
        method: optionsArg.method,
        headers: {
          ...(optionsArg.headers || {}),
        },
        body: optionsArg.body,
      })
      .catch(async (err) => {
        if (optionsArg.useCache && (await cachedResponseDeferred.promise)) {
          cacheUsed = true;
          const cachedResponse = cachedResponseDeferred.promise;
          return cachedResponse;
        } else {
          return err;
        }
      });
    if (optionsArg.useCache && (await cachedResponseDeferred.promise) && response.status === 500) {
      cacheUsed = true;
      response = await cachedResponseDeferred.promise;
    }
    if (!cacheUsed && optionsArg.useCache && response.status < 300) {
      const buffer = await response.clone().arrayBuffer();
      await this.cacheStore.set(urlArg, buffer);
    }
    this.log(`${urlArg} answers with status: ${response.status}`);
    return response;
  }

  /**
   * a multi endpoint, fault tolerant request function
   */
  public async requestMultiEndpoint(
    urlArg: string | string[],
    optionsArg: {
      method: 'GET' | 'POST' | 'PUT' | 'DELETE';
      body?: any;
      headers?: HeadersInit;
    }
  ): Promise<Response> {
    
    let allUrls: string[];
    let usedUrlIndex = 0;

    // determine what we got
    if (Array.isArray(urlArg)) {
      allUrls = urlArg;
    } else {
      allUrls = [urlArg];
    }

    const requestHistory: string[] = []; // keep track of the request history

    const doHistoryCheck = async (
      // check history for a
      historyEntryTypeArg: string
    ) => {
      requestHistory.push(historyEntryTypeArg);
      if (historyEntryTypeArg === '429') {
        console.log('got 429, so waiting a little bit.');
        await plugins.smartdelay.delayFor(Math.floor(Math.random() * (2000 - 1000 + 1)) + 1000); // wait between 1 and 10 seconds
      }

      let numOfHistoryType = 0;
      for (const entry of requestHistory) {
        if (entry === historyEntryTypeArg) numOfHistoryType++;
      }
      if (numOfHistoryType > 2 * allUrls.length * usedUrlIndex) {
        usedUrlIndex++;
      }
    };

    // lets go recursive
    const doRequest = async (urlToUse: string): Promise<any> => {
      if (!urlToUse) {
        throw new Error('request failed permanently');
      }
      this.log(`Getting ${urlToUse} with method ${optionsArg.method}`);
      const response = await fetch(urlToUse, {
        method: optionsArg.method,
        headers: {
          'Content-Type': 'application/json',
          ...(optionsArg.headers || {}),
        },
        body: optionsArg.body,
      });
      this.log(`${urlToUse} answers with status: ${response.status}`);

      if (response.status >= 200 && response.status < 300) {
        return response;
      } else {
        // lets perform a history check to determine failed urls
        await doHistoryCheck(response.status.toString());
        // lets fire the request
        const result = await doRequest(allUrls[usedUrlIndex]);
        return result;
      }
    };

    const finalResponse: Response = await doRequest(allUrls[usedUrlIndex]);
    return finalResponse;
  }

  public log(logArg: string) {
    if (this.options.logging) {
      console.log(logArg);
    }
  }
}