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Using queries

Query classes provide an object-orientated way to build queries and run them. They can also be used with a Query Manager to help run multiple queries.

Example usage

Create a query by instantiating the Query class.

Example usage:

use Strata\Data\Query\Query;

// Setup query
$page = 2;
$query = (new Query())
        ->setUri('posts')
        ->addParam('page', $page)
        ->setCurrentPage($page)
        ->setTotalResults('[meta][total_results]')
        ->setRootPropertyPath('[data]')
;

The above example does the following:

  • Queries the URI: /posts?page=$page
  • Sets a few fields to enable automated pagination
  • Tells the query that data should be returned from the data element
// Run directly via a query
$query->setDataProvider($api);
$posts = $query->getCollection();

// Or run via a query manager
$manager->add('posts', $query);
$posts = $query->getCollection('posts');

This:

  • Runs the query
  • Returns a collection of results along with a pagination object

Property paths

In the example above the total results data is set as [meta][total_results] which is a property path pointing to $data['meta']['total_results']

See property paths for more information on how to use these.

Query classes

There are a number of base query classes you can use to construct queries. It's recommended to create your own child query classes where you can set up the query in your constructor. Base query classes do not set constructors to make creating your own query classes easier.

Strata\Data\Query\Query

Intended for REST API queries. Requires a Strata\Data\Http\Rest data provider. Defaults to a GET query.

Strata\Data\Query\GraphQLQuery

Intended for GraphQL queries. Requires a Strata\Data\Http\GraphQL data provider.

Has object-orientated methods to help build GraphQL queries. You can also set complex GraphQL queries from files. See GraphQL queries.

Strata\Data\Query\GraphQLMutation

Intended for GraphQL mutation queries. Requires a Strata\Data\Http\GraphQL data provider.

By default, mutation queries are set to not run concurrently and do not cache.

Setting up a query

A query has a number of methods to set it up. All setup methods return the Query object so you can use a fluent interface and chain methods together.

Each query must have a data provider and a URI in order to run.

setDataProvider

Set the data provider to use with the query. This must be an object of the Strata\Data\Http\Rest class.

  • Parameters
    • DataProviderInterface $dataProvider

You don't need to use this method if you are using the query manager, instead the query has a data provider assigned to it when you add the query to the query manager.

setUri

Set the URI to use for this query.

  • Parameters
    • string $uri URI to run the query, relative to the data provider base URL

Optional query settings

There are a lot of optional settings you can apply to a query.

addParam

Add a single parameter to send with this query. This is sent as a GET param with the request.

  • Parameters
    • string $key Param name
    • mixed $value Param value

setParams

Set array of parameters to send with this query. These are sent as GET parameters with the request.

  • Parameters
    • array $params

setOptions

Set options for the HTTP request for just this query.

  • Parameters
    • array $options

For example to set headers:

$query->setOptions([
    'headers' => [
        'Content-Type' => 'text/plain'
    ]
]));

To set an auth bearer token:

$query->setOptions([
    'auth_bearer' => 'ABC123'
]));

concurrent

All queries default to running concurrently when used with a query manager, you can disable this by calling concurrent(false).

  • Parameters
    • bool $concurrent = true

setSubRequest

Mark the query as a sub-request, this suppresses errors in the HTTP request.

  • Parameters
    • bool $subRequest Defaults to true

setFields

Set fields to return for this query. To use this method you must first set the field parameter.

  • Parameters
    • array $fields

Example usage:

$query->setFields(['name', 'title', 'email']);

Default functionality is to set the GET paramfields=name,title,email for the request.

setFieldParameter

The parameter to set to define fields to return with setFields. This defaults to "fields".

  • Parameters
    • string $fieldParameter

setRootPropertyPath

Set the root property path to retrieve data from, e.g. '[data]' to return data from the array key 'data' in the response. If this is not called then data is read from the root element.

  • Parameters
    • string $path Property path to root data element

setCurrentPage

Set pagination current page data.

  • Parameters
    • string|int $currentPage Property path in returned data to current page, or the actual value

Example usage:

// Set page to the current page variable
$query->setCurrentPage($page);

// Or set to a data field returned by the query
$query->setCurrentPage('[meta][current_page]');

setResultsPerPage

Set pagination results per page data.

  • Parameters
    • string|int $resultsPerPage Property path in returned data to results per page, or the actual value

setTotalResults

Set pagination total results data.

  • Parameters
    • string|int $totalResults Property path in returned data to total results, or the actual value

setPaginationDataFromHeaders

By default pagination data is read from the returned data. Some API responses set pagination data in the headers rather than the response data. Use this method to tell the query to retrieve pagination data from headers.

  • Parameters
    • bool $paginationDataFromHeaders Defaults to true

setMultipleValuesSeparator

When arrays are passed to params they are automatically converted into strings, separate by ','

You can alter the character used to separate multiple values with this method.

  • Parameters
    • string $multipleValuesSeparator

Caching

By default, automatic caching for data requests happens if the data provider used by the query has caching enabled. This can also be controlled on the query level.

Also see more details on caching.

cache

Manually set this query to cache. If no valid cache is set to the data provider this does nothing.

  • Parameters
    • ?int $lifetime = null Lifetime in seconds for the cache

doNotCache

Manually set this query to not cache.

cacheTags

Set the following cache tags when storing this query to the cache. These are added to any other cache tags already set.

  • Parameters
    • array $tags = []

Retrieving data

Query responses are lazy loaded for performance. If the cache is enabled, query responses are immediately fetched. If a live HTTP request is required then queries are executed when you access data.

You can also manually run a query via the run() method.

get

You can return a single item of data using get(). This automatically retrieves and decodes the query response and returns data.

This normally returns an array, though the return type is not fixed so child query classes have flexibility on what data is returned.

getCollection

Return a Collection object which contains an iterable collection of data and pagination information.

You can set the root property path to select collection data from in the response. If you don't set this in your query then the root data element is used as the collection (this will throw an exception if it is not iterable).

To build pagination you can set the current page, results per page and total results fields respectively.

$collection = $manager->getCollection('queryName');
$pagination = $collection->getPagination();

Whether the data was returned by the cache

You can find out if the query response was returned from the cache via $query->isHit() which returns a boolean. This is a shortcut to the CacheableResponse::isHit method.

getResponse

You can also get access to the response object itself via the getResponse() method. This returns a CacheableResponse object. This is identical to a standard Symfony HttpClient response with the addition of the isHit() method to indicate whether the response came from the cache or was requested live.

You can use standard HttpClient methods to convert data to an array:

$response = $query->getResponse();
$data = $query->getDataProvider()->toArray();

Or you can grab the data provider for this query and use the decode method.

$response = $query->getResponse();
$data = $query->getDataProvider()->decode($response);

Re-running a query

By default, once a query is run it stores its response and does not re-run the live request again.

If you want to force the query to re-run, simply call the clearResponse() method:

$query->clearResponse();

Then any subsequent calls on get(), getCollection() or getResponse() will re-run the live query. Please note if caching is enabled for this query, then a cached response will still be returned if it exists.