# Elasticsearch service/utils

## Connecting to Elasticsearch with a Custom Service

This service wraps the [Elasticsearch Node.js client](https://www.elastic.co/guide/en/elasticsearch/client/javascript-api/current/index.html) and provides the following implementation:

* Get a list of records (with Pagination and Filters handling)
* Get a simple record
* Create a record
* Update an existing record
* Delete a record

{% tabs %}
{% tab title="Prototype" %}

```javascript
const { Client } = require('@elastic/elasticsearch');

// Our own utils that transform ForestAdmin filters to Elasticsearch one
const { esTranslateFilter } = require('../utils/filter-translator');

class ElasticsearchHelper {
  // Allow to create a ElasticsearchHelper on your elastic index
  constructor({
    index,
    filterDefinition,
    mappingFunction,
    sort,
  }); 

  // Get a List of Records based on the query (page, filter, search, sort)
  functionSearch ({
    pageSize, page, filters, options,
  });

  // Get a Record by Id
  getRecord(recordId);

  // Create a Record in your Elasticsearch index
  createRecord(recordToCreate);

  // Update a Record in from your Elasticsearch index
  updateRecord(recordToUpdate);

  // Remove a by Id
  removeRecord(recordId);
  
  // Remove multiple Ids
  removeRecords(recordsIdsToDelete);
}

module.exports = ElasticsearchHelper;
```

{% endtab %}

{% tab title="Full implementation" %}
{% code title="service/elasticsearch-helper.js" %}

```javascript
const { Client } = require('@elastic/elasticsearch');

const { esTranslateFilter } = require('../utils/filter-translator');


function baseMappingFunction(id, source) {
  return {
    id,
    ...source,
  };
}

class ElasticsearchHelper {

  constructor({
    index,
    filterDefinition,
    mappingFunction = baseMappingFunction,
    sort,
  }) {

    if (!index) {
      throw new Error('Your elasticsearch index for this collection is required !');
    }

    this.index = index;
    this.filterDefinition = filterDefinition;
    this.mappingFunction = mappingFunction;
    this.sort = sort;

    this.elasticsearchClient = new Client({ node: 'http://localhost:9200' });
  }

  /**
   * @param {{
   *  pageSize?: number
   *  page?: number
   * }} params
   * @param {any} booleanQuery Elasticsearch bool query
   * @returns {Promise<Array<Record>>}
   */
  async  esSearch({
    pageSize, page,
  }, booleanQuery) {
    const size = pageSize || 20;
    const from = ((page || 1) - 1) * size;

    const response = await this.elasticsearchClient.search({
      index: this.index,
      body: {
        query: {
          bool: {
            ...booleanQuery,
          },
        },
        sort: this.sort,
      },
      size,
      from,
    });

    return response.body.hits.hits
      .map((hit) => this.mappingFunction(hit._id, hit._source));
  }

  /**
   * @param {any} booleanQuery Elasticsearch bool query
   * @returns {Promise<number>}
   */
  async esCount(booleanQuery) {
    const response = await this.elasticsearchClient.count({
      index: this.index,
      body: {
        query: {
          bool: {
            ...booleanQuery,
          },
        },
      },
    });

    return Number(response.body.count);
  }

  /**
   * @param {{
   *  pageSize?: number
   *  page?: number
   *  filters: any
   *  options: any
   * }} params
   * @returns {Promise<{
   *  count: number;
   *  results: Array<Record>
   * }>}
   */
  async functionSearch({
    pageSize, page, filters, options,
  }) {
    const esFilter = esTranslateFilter(this.filterDefinition, filters, options);

    const [results, count] = await Promise.all([
      this.esSearch(
        { page, pageSize },
        { filter: esFilter },
      ),
      this.esCount({ filter: esFilter }),
    ]);

    return {
      results,
      count,
    };
  }

  /**
   * @param {string} id
   * @returns {Promise<Record>}
   */
  async getRecord(id) {
    const response = await this.elasticsearchClient.search({
      index: this.index,
      body: {
        query: {
          bool: {
            filter: {
              term: {
                _id: id,
              },
            },
          },
        },
      },
    });

    const hit = response.body.hits.hits[0];

    if (!hit) {
      return null;
    }

    return this.mappingFunction(hit._id, hit._source);
  }

  /**
   * @param {any} recordToCreate
   * @returns {Promise<Record>}
   */
  async createRecord(recordToCreate) {
    const response = await this.elasticsearchClient.index({
      index: this.index,
      body: recordToCreate,
      op_type: 'create',
      refresh: true,
    });
  
    return this.getRecord(response.body._id);
  }

  /**
   * @param {any} recordToUpdate
   * @returns {Promise<Record>}
   */
  async updateRecord(recordToUpdate) {
    const { id, ...propertiesToUpdate } = recordToUpdate;

    await this.elasticsearchClient.update({
      id,
      index: this.index,
      body: {
        doc: {
          ...propertiesToUpdate,
        }
      },
      refresh: true,
    });

    return this.getRecord(id);
  }

  /**
   * @param {any} id
   * @returns {Promise}
   */
  async removeRecord(id) {
    await this.elasticsearchClient.delete({
      id,
      index: this.index,
      refresh: true,
    });
  }
  
 /**
   * @param {Array<any>} idsToDelete
   * @returns {Promise}
   */
  async removeRecords(idsToDelete) {
    const body = idsToDelete.map(id => {
      return {
        delete: {
          _index: this.index,
          _id: id
        }
      };
    });

    await this.elasticsearchClient.bulk({
      body,
      refresh: true,
    });
  }
}

module.exports = ElasticsearchHelper;
```

{% endcode %}
{% endtab %}
{% endtabs %}

{% hint style="info" %}
You need to add Elasticsearch Node.js client to your project`npm install @elastic/elasticsearch`
{% endhint %}

## Creating utils to convert Express query filters to Elasticsearch one

This utils takes an object representing a filter from the ForestAdmin UI and transforms it into a filter for Elasticsearch.

* Date filters
* Number filters
* Text filters
* Enum filters

{% tabs %}
{% tab title="Full implementation" %}
{% code title="utils/filter-translator.js" %}

```javascript
const { BaseOperatorDateParser } = require('forest-express-sequelize');
const moment = require('moment');
/**
 * @enum {string}
 */
const DATE_OPERATORS = {
  today: 'today',
  yesterday: 'yesterday',
  previous_week: 'previous_week',
  previous_month: 'previous_month',
  previous_quarter: 'previous_quarter',
  previous_year: 'previous_year',
  previous_week_to_date: 'previous_week_to_date',
  previous_month_to_date: 'previous_month_to_date',
  previous_quarter_to_date: 'previous_quarter_to_date',
  previous_year_to_date: 'previous_year_to_date',
  previous_x_days: 'previous_x_days',
  previous_x_days_to_date: 'previous_x_days_to_date',
  past: 'past',
  future: 'future',
  before_x_hours_ago: 'before_x_hours_ago',
  after_x_hours_ago: 'after_x_hours_ago',
};

/**
 * @typedef {{
 *  field: string;
 *  operator: 'before' | 'after' | 'equal' | 'not_equal' | 'present' | 'blank' | 'today'
 *    | 'yesterday' | 'previous_x_days' | 'previous_week' | 'previous_month' | 'previous_quarter'
 *    | 'previous_year' | 'previous_x_days_to_date' | 'previous_week_to_date'
 *    | 'previous_month_to_date' | 'previous_quarter_to_date' | 'previous_year_to_date'
 *    | 'past' | 'future' | 'before_x_hours_ago' | 'after_x_hours_ago'
 *  value: string | null;
 * }} OneFilter
 *
 * @typedef {{
 *  aggregator: 'and' | 'or'
 *  conditions: OneFilter[]
 * }} FilterCombination
 *
 * @typedef {{
 *  timezone: string
 * }} FilterOptions
 */

/**
 * @enum {string}
 */
const FIELD_DEFINITIONS = {
  date: 'date',
  keyword: 'keyword',
  text: 'text',
  number: 'number',
};

/**
 * @param {FieldDefinition} fieldDefinition
 * @param {OneFilter} oneFilter
 * @param {FilterOptions} options
 */
function equal(fieldDefinition, oneFilter, options) {
  switch (fieldDefinition) {
    case FIELD_DEFINITIONS.date: {
      const date = moment.tz(oneFilter.value, options.timezone);

      return {
        term: {
          [oneFilter.field]: date.toISOString(),
        },
      };
    }

    case FIELD_DEFINITIONS.keyword:
    case FIELD_DEFINITIONS.text:
    case FIELD_DEFINITIONS.number: {
      return {
        terms: {
          [oneFilter.field]: Array.isArray(oneFilter.value)
            ? oneFilter.value
            : [oneFilter.value],
        },
      };
    }

    default: throw new Error('Invalid field type for operator equal');
  }
}

/**
 * @param {(fieldDefinition: FieldDefinition, oneFilter: OneFilter, options: FilterOptions) => any}
 * @param {FieldDefinition} fieldDefinition
 * @param {OneFilter} oneFilter
 * @param {FilterOptions} options
 */
function not(mapper, fieldDefinition, oneFilter, options) {
  return {
    bool: {
      must_not: mapper(fieldDefinition, oneFilter, options),
    },
  };
}

/**
 * @param {FieldDefinition} fieldDefinition
 * @param {OneFilter} oneFilter
 */
function present(fieldDefinition, oneFilter) {
  return {
    exists: {
      field: oneFilter.field,
    },
  };
}

/**
 * @param {'gt' | 'lt'} rangeOperator
 * @param {FieldDefinition} fieldDefinition
 * @param {OneFilter} oneFilter
 * @param {FilterOptions} options
 */
function dateInRange(rangeOperator, fieldDefinition, oneFilter, options) {
  if (fieldDefinition !== FIELD_DEFINITIONS.date) {
    throw new Error('Invalid field type for operator after');
  }

  return {
    range: {
      [oneFilter.field]: {
        [rangeOperator]: oneFilter.value,
        time_zone: options.timezone,
      },
    },
  };
}

/**
 * @param {FieldDefinition} fieldDefinition
 * @param {OneFilter} oneFilter
 */
function startsWith(fieldDefinition, oneFilter) {
  if (![FIELD_DEFINITIONS.keyword, FIELD_DEFINITIONS.text].includes(fieldDefinition)) {
    throw new Error('Unsupported operator starts_with');
  }

  return {
    wildcard: {
      [oneFilter.field]: {
        value: `${oneFilter.value}*`,
        case_insensitive: true,
      },
    },
  };
}

/**
 * @param {FieldDefinition} fieldDefinition
 * @param {OneFilter} oneFilter
 */
function endsWith(fieldDefinition, oneFilter) {
  if (![FIELD_DEFINITIONS.keyword, FIELD_DEFINITIONS.text].includes(fieldDefinition)) {
    throw new Error('Unsupported operator ends_with');
  }

  return {
    wildcard: {
      [oneFilter.field]: {
        value: `*${oneFilter.value}`,
        case_insensitive: true,
      },
    },
  };
}

/**
 * @param {FieldDefinition} fieldDefinition
 * @param {OneFilter} oneFilter
 */
function contains(fieldDefinition, oneFilter) {
  if (![FIELD_DEFINITIONS.keyword, FIELD_DEFINITIONS.text].includes(fieldDefinition)) {
    throw new Error('Unsupported operator contains');
  }

  return {
    wildcard: {
      [oneFilter.field]: {
        value: `*${oneFilter.value}*`,
        case_insensitive: true,
      },
    },
  };
}

/**
 * @param {FieldDefinition} fieldDefinition
 * @param {OneFilter} oneFilter
 */
 function numberInRange(rangeOperator, fieldDefinition, oneFilter) {
  if (![FIELD_DEFINITIONS.number].includes(fieldDefinition)) {
    throw new Error(`Unsupported operator ${rangeOperator}`);
  }

  return {
    range: {
      [oneFilter.field]: {
        [rangeOperator]: oneFilter.value,
      },
    },
  };
}

/**
 * @param {BaseOperatorDateParser} operatorDateParser
 * @param {OneFilter} filter
 * @param {FilterOptions} options
 * @returns { range: any}
 */
function mapDateOperator(operatorDateParser, filter, options) {
  return {
    range: {
      [filter.field]: {
        ...operatorDateParser.getDateFilter(filter.operator, filter.value),
        time_zone: options.timezone,
      },
    },
  };
}

const MAPPING = {
  equal,
  not_equal: not.bind(undefined, equal),
  present,
  blank: not.bind(undefined, present),
  before: dateInRange.bind(undefined, 'lt'),
  after: dateInRange.bind(undefined, 'gt'),
  starts_with: startsWith,
  ends_with: endsWith,
  contains,
  not_contains: not.bind(undefined, contains),
  greater_than: numberInRange.bind(undefined, 'gt'),
  less_than: numberInRange.bind(undefined, 'lt'),
};

/**
 * @param {Record<string, FIELD_DEFINITIONS>} fieldDefinitions
 * @param {BaseOperatorDateParser} operatorDateParser
 * @param {FilterOptions} options
 * @param {OneFilter} oneFilter
 */
function mapFilter(fieldDefinitions, operatorDateParser, options, oneFilter) {
  if (fieldDefinitions[oneFilter.field] === FIELD_DEFINITIONS.date
    && Object.values(DATE_OPERATORS).includes(oneFilter.operator)) {
    return mapDateOperator(operatorDateParser, oneFilter, options);
  }

  const mapper = MAPPING[oneFilter.operator];
  const fieldDefinition = fieldDefinitions[oneFilter.field];

  if (!mapper) { throw new Error(`Unknown operator ${oneFilter.operator}, you need to define it !`); }
  if (!fieldDefinition) { throw new Error(`Unknown field ${oneFilter.field}, your field hasn't any field definition. Please check your ElasticsearchHelper configuration`); }

  return mapper(fieldDefinition, oneFilter, options);
}

/**
 * Takes an object representing a filter from the UI
 * and transforms it into a filter for elasticSearch
 * @param {Record<string, FIELD_DEFINITIONS>} fieldDefinitions
 * @param {FilterCombination | OneFilter} filters
 * @param {FilterOptions} options
 * @returns {any} A valid ES filter
 */
function esTranslateFilter(fieldDefinitions, filters, options) {
  if (!filters) { return []; }

  const operatorDateParser = new BaseOperatorDateParser({
    timezone: options.timezone,
    operators: {
      GTE: 'gte',
      LTE: 'lte',
      GT: 'gt',
      LT: 'lt',
    },
  });

  if (!filters.aggregator) {
    return [mapFilter(fieldDefinitions, operatorDateParser, options, filters)];
  }

  const mapped = filters.conditions.map(
    mapFilter.bind(undefined, fieldDefinitions, operatorDateParser, options),
  );

  if (filters.aggregator === 'and') {
    return mapped;
  }

  return {
    bool: {
      should: mapped,
      minimum_should_match: 1,
    },
  };
}

exports.esTranslateFilter = esTranslateFilter;
exports.FIELD_DEFINITIONS = FIELD_DEFINITIONS;

```

{% endcode %}
{% endtab %}
{% endtabs %}

{% hint style="warning" %}
We expose utils to parse filters through **forest-express-sequelize** since version **7.6.0**
{% endhint %}

### &#x20;<a href="#implementing-the-get-all-records" id="implementing-the-get-all-records"></a>


---

# Agent Instructions: Querying This Documentation

If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter:

```
GET https://docs.forestadmin.com/woodshop/how-tos/create-a-smart-collection-with-elasticsearch/elasticsearch-service-utils.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.