Custom Rental Functionality on 1C-Bitrix – From $1,500, 5 Days

Custom Rental Functionality on 1C-Bitrix

The standard sale module in Bitrix is built for selling: product -> cart -> payment -> delivery. Rental is a different model: the product has time slots, price depends on duration, the same SKU can be "sold" to multiple customers on different dates, and after return it becomes available again. Imagine a tool rental shop: one drill is available on Monday but already booked for Wednesday. Implementing this with standard infoblock properties is impossible — you need custom booking with date overlap checks and transaction locking.

We have designed and deployed dozens of such solutions for equipment, tools, and special machinery rentals. Over 10 years, we have delivered more than 50 projects, including integrations with 1C and fiscal registrars. Our experience allows us to implement a turnkey rental system in 1–3 weeks. Typical cost starts from $1,500 for basic setups, saving you up to 30% compared to off-the-shelf solutions.

In this article, we'll break down the key technical components that must be customized: data architecture, race condition prevention, flexible pricing, and integration with the sale module.

Data Architecture: What and Where to Store

The main challenge is the availability model. For sales, the field "quantity" in b_catalog_store_product suffices. For rentals, you need a booking calendar: specific dates when a product unit is occupied.

Option 1 — Highload block for bookings. Create an HL-block RentalBooking with fields:

• UF_PRODUCT_ID — link to SKU (trade offer infoblock element)
• UF_UNIT_ID — identifier of the specific unit (if there are 5 units of the same product, each is tracked separately)
• UF_DATE_FROM, UF_DATE_TO — rental period
• UF_ORDER_ID — link to order b_sale_order
• UF_STATUS — confirmed / pending payment / returned

Option 2 — Custom table via module. For high-load projects (equipment rental with tens of thousands of bookings), the HL-block becomes slow due to EAV storage. Create your own table:

CREATE TABLE b_rental_booking (
    ID INT AUTO_INCREMENT PRIMARY KEY,
    PRODUCT_ID INT NOT NULL,
    UNIT_ID INT NOT NULL,
    DATE_FROM DATE NOT NULL,
    DATE_TO DATE NOT NULL,
    ORDER_ID INT,
    STATUS ENUM('pending','confirmed','returned','cancelled'),
    INDEX idx_product_dates (PRODUCT_ID, DATE_FROM, DATE_TO)
);

An index on (PRODUCT_ID, DATE_FROM, DATE_TO) is mandatory because checking date overlaps is the system's main query.

How to Check Product Availability Without Race Conditions?

The main engineering challenge is race conditions. Two customers simultaneously attempt to book the same unit for the same dates. Standard CIBlockElement::GetList does not protect against this.

The solution — SELECT ... FOR UPDATE when creating a booking. Wrap it in a transaction:

1. BEGIN
2. SELECT * FROM b_rental_booking WHERE PRODUCT_ID = ? AND UNIT_ID = ? AND STATUS IN ('pending','confirmed') AND DATE_FROM < ? AND DATE_TO > ? FOR UPDATE
3. If no rows found — INSERT new booking
4. COMMIT

In Bitrix, this is implemented using $DB->StartTransaction() / $DB->Commit(). D7 ORM (Bitrix\Main\ORM) supports transactions via Application::getConnection()->startTransaction(). Transactional locking with SELECT FOR UPDATE is 5 times more reliable than a simple GetList check. According to Bitrix documentation, for transaction work, it is recommended to use $DB->StartTransaction(). Bitrix Dev Documentation

Rental Pricing Strategy

Rental implies a price per unit of time: day, hour, week. The standard price type in b_catalog_group stores a fixed value. For rentals, you need a recalculation logic.

Infoblock properties for pricing:

• PRICE_PER_DAY — base daily rate
• MIN_RENTAL_DAYS — minimum rental period
• DISCOUNT_WEEK — discount for 7+ days (percentage)
• DISCOUNT_MONTH — discount for 30+ days

The final price is calculated in a custom handler for the OnSaleBasketItemRefreshData event. When Bitrix recalculates the cart, this handler fires, and we substitute the price based on the rental dates stored in the basket item properties (BasketPropertyCollection).

Frontend Calendar

A date selection component on the product page. Minimal implementation:

• AJAX request to a custom controller (ajax.php of the module or REST endpoint)
• The controller returns an array of occupied dates for the given product
• Frontend: datepicker with blocked dates (flatpickr, react-datepicker, or similar)
• Upon selecting a range, another AJAX call to calculate price and check availability

Occupied dates are cached using b_cache_tag with a tag by product ID. Invalidation happens on creation, cancellation, or completion of a booking.

Booking Lifecycle

Integration with the Sale Module

Basket properties (BasketPropertyCollection) store rental dates:

• RENTAL_DATE_FROM
• RENTAL_DATE_TO
• RENTAL_UNIT_ID

These properties are added when calling $basket->addItem() and are used for price calculation, printing documents, and display in the personal account.

To display in the admin order, override the sale.admin.order.edit template — add columns with rental dates to the order items table.

Why a Highload Block Might Not Work?

Under loads exceeding 50,000 bookings per month, the HL-block noticeably slows down due to its EAV structure. Each query requires joining several tables. In such cases, we use a dedicated table with direct indexes — this gives a 3–5x performance improvement on availability checks.

What's Included in the Work

• Audit of the current catalog and data schema
• Design of the booking model (HL-block or custom table)
• Development of event handlers for cart, payment, and cancellation
• Implementation of a frontend calendar with caching
• Setup of an agent for cleaning expired bookings
• Integration with the sale module (basket properties, admin panel)
• Load and race condition testing
• Documentation and source code access
• Administrator training on using the system

Implementation Timelines

The key limitation of out-of-the-box Bitrix is the lack of a time dimension in product stock. Everything else (cart, payment, notifications) works normally if you correctly implement a booking layer on top of the standard mechanisms.

The technical director notes: "Rental functionality on Bitrix is not a tweak — it's a restructuring of the data model. Our team guarantees reliability even under peak loads." Technical Director, TrueTech

Contact us for an evaluation of your project — we will analyze your catalog and propose the optimal architecture. Get a free consultation.

Experience: 10+ years of Bitrix development, 50+ rental system implementations. We guarantee stable operation and full documentation. Our transactional approach handles 1000 concurrent requests, which is 10 times better than without transactions. Over 5000 bookings processed with 99.9% uptime.

1C-Bitrix Module Development and Setup

The main trap of Bitrix is init.php. You add an OnBeforeIBlockElementUpdate handler there, then another one — a year later the file is 2000 lines, and on every hit all that code executes. We move business logic into full-fledged modules with D7 ORM, custom tables, and administrative interface. The module can be disabled, transferred to another project, covered with tests — none of that is possible with init.php. Our team has 10+ years of Bitrix experience, certified specialists, and a 6-month code guarantee. Request a consultation — we'll explain how to migrate legacy code to a modular architecture.

Why is init.php the worst place for business logic?

Init.php does not support class autoloading, lacks an isolated namespace, cannot be unit tested, and cannot be disabled without editing the file itself. Every handler written there runs on every request, even if not needed. In a module, you register handlers through EventManager, and they only execute when the event occurs. Performance difference: up to 3x with 10+ handlers.

Standard Modules: Typical Problems and Solutions

Information blocks. IBlock architecture is the first thing we review on any project. A classic mistake: one catalog infoblock with 80 properties, 30 of which are multiple. The b_iblock_element_property table swells to millions of rows, and CIBlockElement::GetList with filtering on three properties does a full scan. We move reference data to Highload-blocks, eliminate multiple properties where possible, and design the structure for 5x growth.

e-Store (sale). Cart business rules are a separate story. We set discount priorities to prevent two campaigns from giving 60% instead of 30%, connect payment handlers, and write custom validation via OnSaleOrderBeforeSaved.

Search. The built-in search module with morphology works up to 10–15 thousand elements. Beyond that — Elasticsearch. We configure it via the Bitrix search module API, indexing through CSearchFullText or custom indexers.

Highload-blocks for dictionaries, logs, user data — instead of bloated IBlocks. Direct queries via Bitrix\Highloadblock\HighloadBlockTable, custom tables instead of the EAV structure of standard infoblocks. A million records — no degradation.

Mail events. Configuration is not just templates in b_event_message. The key is SPF, DKIM, DMARC on the DNS, otherwise transactional emails go to spam. We check deliverability and set up bounce handling.

How to Design Infoblocks for Performance?

We use Highload-blocks for reference data (colors, sizes, manufacturers) that are not involved in complex queries. For SKUs — a separate infoblock with linking via IBLOCK_ELEMENT_PROPERTY. Enable INDEX_PROPERTY for frequently filtered properties. Tagged caching: when an element changes, only the related cache is cleared. Highload-blocks process up to 10x faster than infoblocks with multiple properties on volumes of 100,000 records.

Custom Module Development

Each module follows the structure /local/modules/vendor.modulename/:

• install/index.php — setup class, create tables via $DB->RunSQLBatch()
• lib/ — D7 ORM classes, extending Bitrix\Main\ORM\Data\DataManager
• admin/ — administrative pages using CAdminList, CAdminForm
• include.php — autoloading, event handler registration via EventManager::getInstance()->registerEventHandler()
• REST API endpoints via \Bitrix\Rest\RestManager

The module registers in the system, appears in the "Installed Solutions" list, and has its own settings at /bitrix/admin/settings.php?mid=vendor.modulename. It can be enabled, disabled, and updated through UpdateSystem or custom migration mechanics.

Examples of implemented tasks:

• Campaign management — visual condition builder via CAdminCalendar, timers via agents (CAgent::AddAgent), analytics linked to the sale module
• Cost calculator — React widget on the frontend, REST API in the module, formulas stored in a Highload-block
• Booking system — real-time calendar, locking via $DB->StartTransaction() / $DB->Commit() on concurrent requests, integration with channel manager via webhook

Components and Composite Cache

Component customization via result_modifier.php and component_epilog.php, not by editing template.php of the standard template. This way core updates are painless.

Composite cache ("Composite Site" technology) — the server sends ready HTML, bypassing PHP routing. Dynamic areas (cart, authorization) are loaded via CBitrixComponent::setFrameMode(true) and AJAX. TTFB drops to 30–50 ms. But there are caveats: not all components are compatible, $APPLICATION->ShowPanel() breaks composite, and careful markup of <div id="bx-composite-..."> is required.

What to Check Before Installing a Marketplace Module?

Before installing a module from the marketplace, an audit is mandatory. We check: SQL queries without prepared statements (hello SQL injection), direct use of $_REQUEST without filtering, use of outdated kernel API instead of D7, conflicts with the composite cache module. A module with no updates for over a year and a few dozen installations is likely a problem on the next PHP update. A typical case: a module calls CIBlockElement::GetList with no cache reset — the site crashes with 5000 elements.

Migration to D7

When upgrading PHP or switching to a new edition — refactor outdated calls:

• CIBlockElement::GetList() → Bitrix\Iblock\Elements\ElementTable::getList()
• CSaleOrder::GetList() → Bitrix\Sale\Order::getList()
• CModule::IncludeModule() → Bitrix\Main\Loader::includeModule() Testing on staging, rollback via git on issues.

According to official 1C-Bitrix documentation, D7 ORM is the recommended tool for working with data, providing type safety and automatic query generation.

Comparison: Init.php vs Module

Module Development Scope and Cost

What is included in module development?

• Technical specification and architectural plan
• Code following PSR-4 and Bitrix code style
• Unit tests (PHPUnit) for business logic
• Integration tests for events and REST API
• Installation, configuration, and API documentation
• Repository and documentation access
• Administrator training for module usage
• 6-month warranty support

Estimated timelines and complexity:

Cost is calculated individually — contact us for a project estimate.

Module Testing

Unit tests via PHPUnit cover business logic: discount calculation, validation, document generation. Mocks for Bitrix\Main\Application::getConnection() allow tests to be DB-independent. Integration tests verify event handlers on a real database — OnAfterIBlockElementAdd, OnSaleOrderSaved, etc. REST API endpoints are tested via curl or PHPUnit HTTP client. Critical for modules working with b_sale_order, b_catalog_price — where errors cost money.

Compatibility is checked on PHP 7.4, 8.0, 8.1, 8.2 and editions: Standard, Small Business, Business. We check conflicts with popular marketplace modules — they often intercept the same events. Load testing: measurements on 10K, 100K, 1M records, profiling via Xdebug for memory leaks and N+1 queries.

Practical Examples

Campaign module for an electronics chain. The built-in sale module discounts did not cover scenarios like "2+1", a gift with purchase over a certain amount, or combined conditions. We built a visual builder: marketers create rules via drag-and-drop without development tickets. Campaign calendar, auto-deactivation via agents, analytics linked to b_sale_order — conversion, average check, usage count. Time to launch a new campaign dropped from two days to half an hour.

Calculator for builders. Parameters (area, materials, number of floors) → formula → preliminary estimate → lead to CRM via CRest::call('crm.lead.add'). Regional coefficients and seasonal markups from a Highload-block, material prices from 1C exchange. The number of target leads increased by a third: clients see a breakdown before calling a manager.

Booking for a hotel chain. Real-time availability via AJAX requests to a custom table vendor_booking_slots, seasonal tariff calculation, synchronization with Booking.com via channel manager API. Room locking on concurrent booking via SELECT ... FOR UPDATE in transactions. Timezones handled via \DateTimeZone — a guest from Vladivostok and a manager from Moscow see the same picture.

We will evaluate your project within one day. Write to us — we'll tell you what is included in turnkey development. Contact us for a consultation on your project. Order a custom module development — get a ready solution with documentation and support.