The main goal of persisted query approach is to reduce the amount of data transfered from the client to the server within a POST body containing GraphQl Document. However, current module extends the usage of persisted queries to actually cache the responses in Varnish or CDN node for fast responses. (avg. 5ms vs 5000ms on dev machine)
- Varnish
- Redis
- PHP ext-phpredis is suggested for faster serialization and deserialization
For the convenience there are additional flags available for php bin/magento setup:config:set command:
--pq-host[mandatory] - persisted query redis host (redis for ScandiPWA docker setup)
--pq-port[mandatory] - persisted query redis port (6379 for ScandiPWA docker setup)
--pq-database[mandatory] - persisted query redis database (5 for ScandiPWA docker setup)
--pq-scheme[mandatory] - persisted query redis scheme
--pq-password[optional, empty password is not allowed] - persisted query redis password
Configuration for custom Redis storage, where hashes and GraphQl documents are kept in environment config
(app/etc/env.php) -> cache/persisted-query and can be configured manually:
'persisted-query' => [
'redis' => [
'host' => 'redis',
'scheme' => 'tcp',
'port' => '6379',
'database' => '5'
]
]
Available from v1.3.0
CLI command magento cache:flush and admin panel Cache Management has necessary logic to flush GraphQl responses
stored in varnish.
persisted_query_response - can be disabled, controls varnish caches (graphql response caches).
bin/magento scandipwa:pq:flush - flushes persisted query REDIS storage(query body)
Dynamic persisted query suppose Client to register unknown queries with a series of request-response.
Recommended usage:
- Optimistically request query execution, referencing query by hash, passing necessary query variables as request
parameters:
GET /graphql?hash=135811058&hideChildren=true - Server has multiple options:
- respond with resolved query (status code
200) - respond with Unknown query error (status code
410)
- Status code
410- client must issue PUT request, with the same hash and entire GraphQl query document within the body.PUT /graphql?hash=135811058 - Server responds with status code
201on successful query registration. - Server will now executes the registered query referenced by hash
GET /graphql?hash=135811058
In order to effectively utilize persisted query mechanism and avoid unnecessary time-consuming request-response interactions GraphQl query must utilize variables.
Variables must be passed in pseudo-json format. You must keep the structure, but skip usage of quotes.
Array is a list of values, separated with coma, i.e.: cmsBlocks_identifiers=homepage-promo-categories,homepage-top-items,homepage-about-us
Let's consider the details:
cmsBlocks_identifiers - GraphQl variable name
homepage-promo-categories,homepage-top-items,homepage-about-us - Array of values
Complex structures must keep structures described with special chars {, }, :.
Array within complex structs MUST use special chars: [, ].
Example:
_filter={category_url_path:{eq:men},max_price:{lteq:300},color:{in:[74,75]}}
Let's consider the details:
_filter - GraphQl variable name
{ category_url_path: { eq:men }, max_price:{ lteq:300 }, color:{ in:[74,75] } } - "Object", passed as GET parameter. It has not quotation marks, as these are automatically added by the server
during the processing.
Query body:
query ($cmsBlocks_identifiers:[String]) {cmsBlocks:cmsBlocks(identifiers:$cmsBlocks_identifiers){ items{ title, content, identifier } }}
Request URI:
GET /graphql?hash=2443957263&cmsBlocks_identifiers=homepage-promo-categories,homepage-top-items,homepage-about-us
Query body:
"query ($_currentPage:Int!, $_pageSize:Int!, $_filter:ProductFilterInput!, $category_url_path:String!) {products(currentPage:$_currentPage, pageSize:$_pageSize, filter:$_filter){ total_count, items{ id, name, short_description, url_key, special_price, sku, categories{ name, url_path, breadcrumbs{ category_name, category_url_key } }, price{ regularPrice{ amount{ value, currency } }, minimalPrice{ amount{ value, currency } } }, thumbnail, thumbnail_label, small_image, small_image_label, brand, color, size, shoes_size, type_id }, filters{ name, request_var, filter_items{ label, value_string, ... on SwatchLayerFilterItem { label, swatch_data{ type, value } } } } }, category:category(url_path:$category_url_path){ id, name, description, url_path, image, url_key, product_count, meta_title, meta_description, breadcrumbs{ category_name, category_url_key, category_level }, children{ id, name, description, url_path, image, url_key, product_count, meta_title, meta_description, breadcrumbs{ category_name, category_url_key, category_level } } }}"
Request URI:
https://scandipwa.local/graphql?hash=1713013963&_currentPage=1&_pageSize=12&_filter={category_url_path:{eq:men},max_price:{lteq:300}}&category_url_path=men