Create Customer segments.md

Author: unicoder88

xx. Magento Commerce Features/Customer segments.md

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+# Customer Segments
+
+Conditions:
+
+- customer address attributes
+- customer attributes
+- cart item, total qty, totals
+- products in cart, in wishlist, viewed products, ordered products, viewed date, ordered date
+- order address, totals, number of orders, average total amount, order date, order status - only logged in
+
+Listens all model evetns, matches conditions by \Magento\CustomerSegment\Model\Segment\Condition\Order\Address::getMatchedEvents
+
+
+## Database
+
+- magento_customersegment_segment - name, conditions, actions
+- magento_customersegment_website - many-to-many
+- magento_customersegment_customer - website, added/updated date
+- magento_customersegment_event - after saving segment rule, holds events that related to selected conditions
+
+
+## Admin conditions
+
+namespace  Magento\CustomerSegment;
+
+Admin form - old widget style tabs:
+
+- Block\Adminhtml\Customersegment\Edit\Tab\General
+- Block\Adminhtml\Customersegment\Edit\Tab\Conditions
+
+Rendering conditions form:
+
+render conditions -> renderer \Magento\Rule\Block\Conditions -> segment.getConditions -> root Model\Segment\Condition\Combine\Root
+
+
+Condition classes - hold matching rules:
+
+- Model\Condition\Combine\AbstractCombine
+- Model\Segment\Condition\Order\Address - order_address join sales_order join customer_entity
+- Model\Segment\Condition\Sales\Combine
+  - Model\Segment\Condition\Sales\Ordersnumber - COUNT(*)
+  - Model\Segment\Condition\Sales\Salesamount - sum/avg sales_order.base_grand_total
+  - Model\Segment\Condition\Sales\Purchasedquantity - sum/avg sales_order.total_qty_ordered
+- Model\Segment\Condition\Customer\Address
+  - Model\Segment\Condition\Customer\Address\DefaultAddress
+
+
+## Refresh Segment Data
+
+Some conditions don't work for guest visitors, despite description! Example - cart grand total amount:
+
+- click "Refresh" inside segment admin
+- Controller\Adminhtml\Report\Customer\Customersegment\Refresh::execute
+- Model\Segment::matchCustomers
+- Model\ResourceModel\Segment::aggregateMatchedCustomers
+- Model\ResourceModel\Segment::processConditions
+- Model\Segment\Condition\Combine\Root::getSatisfiedIds
+- // individual conditions
+- Model\Segment\Condition\Shoppingcart\Amount::getSatisfiedIds
+
+```SQL
+SELECT `quote`.`customer_id` FROM `quote`
+WHERE (quote.is_active=1) AND (quote.store_id IN('1')) AND (quote.base_grand_total >= '100') AND (customer_id IS NOT NULL)
+```
+
+
+## Viewed product index
+
+Condition by recently viewed events **SEEMS BROKEN** when full page cache is enabled.
+This condition relies on `report_viewed_product_index` table, which is handled by report module.
+
+Configuration:
+
+- `reports/options/enabled`
+- `reports/options/product_view_enabled`
+
+\Magento\Reports\Model\ReportStatus::isReportEnabled
+
+\Magento\Reports\Model\Product\Index\Viewed
+
+`catalog_controller_product_view` -> \Magento\Reports\Observer\CatalogProductViewObserver
+- save into  `report_viewed_product_index`
+- save into `report_event`, take customer from session
+
+This does not work when full page cache is enabled and Varnish returns HTML directly.
+
+
+## Listening to events and updating matched customers
+
+Segments needs to listen to some events related to conditions. After segment with conditions is saved,
+table `magento_customersegment_event` holds events that it listens to.
+
+Segment rule table holds rendered `condition_sql` column with placeholders:
+- :customer_id
+- :website_id
+- :quote_id
+- :visitor_id
+
+Updating customer segments on events:
+
+- event `customer_login`
+- Observer\ProcessEventObserver::execute
+- Model\Customer::processEvent
+- Model\Customer::getActiveSegmentsForEvent
+- Model\ResourceModel\Segment\Collection::addEventFilter - join table `magento_customersegment_event`
+- Model\Customer::_processSegmentsValidation
+- Model\Segment::validateCustomer
+  * visitor_id, quote_id passed for guest
+- Model\Segment\Condition\Combine\Root::isSatisfiedBy
+  * all conditions[].isSatisfiedBy
+  * all conditions[].Model\Condition\Combine\AbstractCombine::getConditionsSql
+
+
+Result:
+
+- Matched segments are added to `magento_customersegment_customer`
+- http context \Magento\CustomerSegment\Helper\Data::CONTEXT_SEGMENT = 'customer_segment' is updated with new segments
+- customerSession.setCustomerSegmentIds
+
+
+Event -> interested segment rules.
+
+
+## Impact on performance
+
+1. Customer segments are added to full page cache keys
+
+    \Magento\CustomerSegment\Helper\Data::CONTEXT_SEGMENT = 'customer_segment'
+
+    \Magento\PageCache\Model\App\Response\HttpPlugin::beforeSendResponse
+    \Magento\Framework\App\Response\Http::sendVary
+    \Magento\Framework\App\Http\Context::getVaryString
+
+    Example:
+
+    ```php
+    sha1($this->serializer->serialize([
+        'customer_group' => '1',
+        'customer_logged_in' => true,
+        'customer_segment' => ["1"]
+    ]))
+    ```
+
+    This lowers chances of hitting cached page, increasing load on the server.
+
+1. Listens to many object save events, calculates matching conditions
+
+
+## DepersonalizePlugin
+
+Does 2 things:
+
+1. Makes sure customerSession.CustomerSegmentIds is not deleted by Customer module DepersonalizePlugin
+1. Sets full page cache key httpContext->setValue(Data::CONTEXT_SEGMENT)
+
+
+\Magento\Framework\Pricing\Render\Layout::loadLayout:
+```
+        $this->layout->getUpdate()->load();
+          // 1. \Magento\Customer\Model\Layout\DepersonalizePlugin::beforeGenerateXml:
+          // - remember customerGroupId and formKey from session
+          // 2. \Magento\CustomerSegment\Model\Layout\DepersonalizePlugin::beforeGenerateXml:
+          // - remember customerSegmentIds from customer session
+        $this->layout->generateXml();
+        $this->layout->generateElements();
+          // 3. \Magento\PageCache\Model\Layout\DepersonalizePlugin::afterGenerateElements:
+          // - event `depersonalize_clear_session`
+          // - session_write_close();
+          // - clear message session
+          // 4. \Magento\Customer\Model\Layout\DepersonalizePlugin::afterGenerateElements:
+          // - clear customer session
+          // - restore session._form_key
+          // - restore customer session.customerGroupId, empty customer object with customer group
+          // 5. \Magento\Catalog\Model\Layout\DepersonalizePlugin::afterGenerateElements:
+          // - clear catalog session
+          // 6. \Magento\Persistent\Model\Layout\DepersonalizePlugin::afterGenerateElements:
+          // - clear persistent session
+          // 7. \Magento\CustomerSegment\Model\Layout\DepersonalizePlugin::afterGenerateElements:
+          // - httpContext->setValue(Data::CONTEXT_SEGMENT)
+          // - restore customerSession->setCustomerSegmentIds
+          // 8. \Magento\Checkout\Model\Layout\DepersonalizePlugin::afterGenerateElements:
+          // - clear checkout session
+```
+
+## All Depersonalize examples
+
+\Magento\Catalog\Model\Layout\DepersonalizePlugin::afterGenerateElements:
+- clear catalog session
+
+
+
+## Catalog frontend action
+
+Magento has alternative implementation of recently viewed products, handled by Catalog module.
+It works with full page cache, but:
+
+- is **not integrated** into customer segment conditions
+- frontend synchronization must be enabled, adding extra calls on every page
+
+When sync is enabled, it makes 2 AJAX calls with every page opening:
+- synchronize recently viewed products from local storage
+- synchronize recently compared products from local storage
+
+Configuration:
+
+- `catalog/recently_products/synchronize_with_backend` = 0
+- `catalog/recently_products/recently_viewed_lifetime` = 1000
+- `catalog/recently_products/scope` - store view, store, website
+
+Other:
+
+- db table `catalog_product_frontend_action`
+- cron `catalog_product_frontend_actions_flush` - every minute \Magento\Catalog\Cron\FrontendActionsFlush:
+- deletes compared, viewed older than (default 1000) seconds
+- frontend controller 'catalog/product_frontend_action/synchronize'
+
+Notable classes:
+
+- Magento\Catalog\Model\FrontendStorageConfigurationPool
+- Magento\Catalog\Model\Widget\RecentlyViewedStorageConfiguration
+
+
+\Magento\Catalog\Block\FrontendStorageManager:
+
+- recently_viewed_product
+- recently_compared_product
+- product_data_storage
+- vendor/magento/module-catalog/view/frontend/web/js/storage-manager.js
+
+customer data section:
+
+- recently_viewed_product
+- recently_compared_product
+- product_data_storage
+
+Triggering recently viewed update on frontend:
+
+- catalog_product_view.xml
+- Magento\Catalog\Block\Ui\ProductViewCounter
+- vendor/magento/module-catalog/view/frontend/templates/product/view/counter.phtml
+- vendor/magento/module-catalog/view/frontend/web/js/product/view/provider.js
+
+\Magento\Catalog\Model\ProductRender - DTO
+
+\Magento\Catalog\Ui\DataProvider\Product\ProductRenderCollectorComposite::collect:
+
+- Url - url, addToCartButton, addToCompareButton
+- AdditionalInfo - isSalable, type, name, id
+- Image - images
+- Price - priceInfo
+- ... wishlist, review, tax, gift card, bundle price
+
+
+widget `catalog_recently_compared` template `product/widget/compared/list.phtml`:
+
+- UI component `widget_recently_compared` - listing, columns
+- Magento_Catalog/js/product/provider-compared.js
+- Magento_Catalog/js/product/storage/storage-service.js
+- Magento_Catalog/js/product/storage/data-storage.js - get product data from customer section. recently viewed, compared