@infect/infect-rda-sample-importer/src/APILookup.js

INFECT Sample Data Importer

import LRUCache from 'lru-cache';
import { setTimeout } from 'timers/promises';
import logd from 'logd';

const log = logd.module('APILookup');


export default class APILookup {


    constructor({
        cacheTTL = 3600,
        cacheSize = 10000,
        httpClient,
        resource,
        filterProperty = 'identifier',
        selectionField = 'id',
        selectionHeader = '*',
        filterHader = '',
    }) {
        this.selectionHeader = selectionHeader;
        this.filterHader = filterHader;

        // the resource to load
        this.httpClient = httpClient;
        this.resource = resource;
        this.property = filterProperty;

        // optional return field 
        this.field = selectionField;

        // cache looked up items
        this.cache = new LRUCache({
            max: cacheSize,
            ttl: cacheTTL * 1000,
        });
    }




    async end() {
        this.httpClient.end();
    }



    async get(key) {

        // escape commas, the api will unescape them
        key = key.replace(/,/g, ';;');
        //log.debug(`Looking up key '${key}'`);

        if (!this.cache.has(key)) {
            //log.debug(`Key '${key}' is not in the cache, querying the API`);

            let filter = `${this.property}=${key}`;

            // add a custom filter if required
            if (this.filterHader) {
                filter += `, ${this.filterHader}`;
            }

            // issue the request
            const promise = this.sendRequest(filter, key);

            this.cache.set(key, promise);
        }

        return this.cache.get(key);
    }



    async sendRequest(filter, key, retryCount = 0) {
        try {
            const response = await this.httpClient.get(`/core-data/v1/${this.resource}`)
                .setHeader('filter', filter)
                .setHeader('select', this.selectionHeader)
                .send();
            
            const data = await response.getData();
    
            if (data && data.length) { 
                if (this.field) return data[0][this.field];
                else return data[0];
            } else {
                const err = new Error(`Failed to load value for key '${key}' from ${this.httpClient.hostname}/${this.resource}`);
                err.failedLookup = true;
                err.resource = this.resource;
                err.property = this.property;
                err.unresolvedValue = key;
                throw err;
            }
        } catch (err) {
            if ((err.message.includes('NGHTTP2_REFUSED_STREAM') || err.message.includes('NGHTTP2_ENHANCE_YOUR_CALM')) && retryCount < 5) {
                const backoffTime = (retryCount + 1) * 100;

                log.warn(`API-Lookup failed: stream was closed, trying again in ${backoffTime}ms`);

                // back off a bit
                await setTimeout(backoffTime);

                // try again
                return await this.sendRequest(filter, key, retryCount + 1);
            } else {
                throw err;
            }
        }
            
        
    }
}