@env0/dynamo-easy
Version:
DynamoDB client for NodeJS and browser with a fluent api to build requests. We take care of the type mapping between JS and DynamoDB, customizable trough typescript decorators.
75 lines • 4.16 kB
JavaScript
import { promiseTap } from '../../../helper/promise-tap.function';
import { randomExponentialBackoffTimer } from '../../../helper/random-exponential-backoff-timer.generator';
import { createLogger } from '../../../logger/logger';
import { createToKeyFn, fromDb } from '../../../mapper/mapper';
import { batchGetItemsFetchAll } from '../../batchget/batch-get-utils';
import { BATCH_GET_DEFAULT_TIME_SLOT, BATCH_GET_MAX_REQUEST_ITEM_COUNT } from '../../batchget/batch-get.const';
import { BaseRequest } from '../base.request';
/**
* Request class for BatchGetItem operation which supports a single model class only.
*/
export class BatchGetSingleTableRequest extends BaseRequest {
constructor(dynamoDBWrapper, modelClazz, keys) {
super(dynamoDBWrapper, modelClazz);
this.mapResponse = (response) => {
let items = [];
if (response.Responses && Object.keys(response.Responses).length && response.Responses[this.tableName]) {
const mapped = response.Responses[this.tableName].map(attributeMap => fromDb(attributeMap, this.modelClazz));
items = mapped;
}
return {
Items: items,
UnprocessedKeys: response.UnprocessedKeys,
ConsumedCapacity: response.ConsumedCapacity,
};
};
this.logger = createLogger('dynamo.request.BatchGetSingleTableRequest', modelClazz);
if (keys.length > BATCH_GET_MAX_REQUEST_ITEM_COUNT) {
throw new Error(`you can request at max ${BATCH_GET_MAX_REQUEST_ITEM_COUNT} items per request`);
}
this.params.RequestItems = {
[this.tableName]: {
Keys: keys.map(createToKeyFn(modelClazz)),
},
};
}
consistentRead(value = true) {
this.params.RequestItems[this.tableName].ConsistentRead = value;
return this;
}
/**
* fetch all entries and return the raw response (without parsing the attributes to js objects)
* @param backoffTimer when unprocessed keys are returned the next value of backoffTimer is used to determine how many time slots to wait before doing the next request
* @param throttleTimeSlot the duration of a time slot in ms
*/
execNoMap(backoffTimer = randomExponentialBackoffTimer, throttleTimeSlot = BATCH_GET_DEFAULT_TIME_SLOT) {
return this.fetch(backoffTimer, throttleTimeSlot);
}
/**
* fetch all entries and return an object containing the mapped items and the other response data
* @param backoffTimer when unprocessed keys are returned the next value of backoffTimer is used to determine how many time slots to wait before doing the next request
* @param throttleTimeSlot the duration of a time slot in ms
*/
execFullResponse(backoffTimer = randomExponentialBackoffTimer, throttleTimeSlot = BATCH_GET_DEFAULT_TIME_SLOT) {
return this.fetch(backoffTimer, throttleTimeSlot)
.then(this.mapResponse)
.then(promiseTap(response => this.logger.debug('mapped items', response.Items)));
}
/**
* fetch all entries and return the parsed items
* @param backoffTimer when unprocessed keys are returned the next value of backoffTimer is used to determine how many time slots to wait before doing the next request
* @param throttleTimeSlot the duration of a time slot in ms
*/
exec(backoffTimer = randomExponentialBackoffTimer, throttleTimeSlot = BATCH_GET_DEFAULT_TIME_SLOT) {
return this.fetch(backoffTimer, throttleTimeSlot)
.then(this.mapResponse)
.then(r => r.Items)
.then(promiseTap(items => this.logger.debug('mapped items', items)));
}
fetch(backoffTimer = randomExponentialBackoffTimer, throttleTimeSlot = BATCH_GET_DEFAULT_TIME_SLOT) {
this.logger.debug('request', this.params);
return batchGetItemsFetchAll(this.dynamoDBWrapper, Object.assign({}, this.params), backoffTimer(), throttleTimeSlot)
.then(promiseTap(response => this.logger.debug('response', response)));
}
}
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