Woo Multi Stock

A WordPress plugin that synchronises warehouse stock quantities from a remote semicolon-delimited CSV file to the custom meta field _stock_CMT on WooCommerce products and variations.

Important: This plugin updates a custom meta field (_stock_CMT) and does not modify the native WooCommerce stock (_stock, _stock_status, or manage_stock). WooCommerce's own inventory management, low-stock notifications, and out-of-stock behaviour are completely unaffected.

Table of Contents

1. Requirements
2. Installation
3. Configuration
4. How It Works
5. CSV Format
6. Reading the Meta Field
7. Hooks & Filters
8. File Structure
9. Frequently Asked Questions

Requirements

Installation

1. Copy the wp-multi-magazzino/ directory into wp-content/plugins/.
2. In the WordPress admin, go to Plugins → Installed Plugins.
3. Activate Woo Multi Stock.
4. The plugin will appear as Multi Stock under the WooCommerce menu.

Configuration

Navigate to WooCommerce → Multi Stock and fill in:

Click Save Settings before running a sync.

How It Works

[Admin clicks "Start Sync"]
        │
        ▼
AJAX: woo_multi_stock_download
  • WordPress fetches the CSV via wp_remote_get()
  • Parses every row (skips header, converts quantity format)
  • Caches all rows in a WordPress transient (TTL: 1 hour)
  • Returns: { total: N }
        │
        ▼  (loop until is_done === true)
AJAX: woo_multi_stock_process_batch  (offset = 0, 50, 100 …)
  • Reads rows[offset … offset+49] from the transient
  • For each row: looks up the SKU with wc_get_product_id_by_sku()
    ├── Found  → update_post_meta( id, '_stock_CMT', qty )
    └── Not found → increments the "not found" counter
  • Returns: { processed, not_found, updated, next_offset, is_done }
        │
        ▼
UI updates progress bar and counters after every batch.
Final summary: "Processed X products, Y SKUs not found, Z SKUs updated."

Batch size

Each AJAX request processes 50 rows. This keeps individual requests well within PHP's max_execution_time on shared hosting while minimising total request count for large files.

Transient caching

The CSV is downloaded once per sync session and stored in a WordPress transient (woo_multi_stock_csv_rows, TTL 1 hour). If the sync takes longer than 1 hour or the transient is cleared by a caching plugin mid-sync, clicking Start Sync again will re-download the file and restart from the beginning.

CSV Format

• Delimiter: semicolon (;)
• First row: header — always skipped automatically
• Column 0: SKU (must match a WooCommerce product or variation SKU exactly)
• Column 1: Quantity — uses a comma as the decimal separator

Example file

SKU;QTY
01.02.0317;1,0000000000000
01.02.0318;24,0000000000000
01.02.0319;0,0000000000000
01.02.9999;5,5000000000000

Quantity conversion

The quantity is converted from the European decimal format to an integer:

"1,0000000000000"  →  str_replace(',', '.')  →  "1.0000000000000"
                   →  (float)                →  1.0
                   →  (int)                  →  1

Decimal quantities are truncated (not rounded): "5,5000000000000" → 5.

Reading the Meta Field

Once synced, the quantity is stored as a plain integer in wp_postmeta:

// Get the CMT stock for a product.
$cmt_stock = (int) get_post_meta( $product_id, '_stock_CMT', true );

// In a WC_Product context.
$product   = wc_get_product( $product_id );
$cmt_stock = (int) $product->get_meta( '_stock_CMT' );

You can also reference the meta key constant directly:

use WooMultiStock\Stock_Updater;

$cmt_stock = (int) get_post_meta( $product_id, Stock_Updater::META_KEY, true );

Hooks & Filters

woo_multi_stock_before_processing (action)

Fires at the beginning of every batch, before any update_post_meta() calls.

/**
 * @param int $total_rows  Total number of rows in the CSV (all batches combined).
 */
add_action( 'woo_multi_stock_before_processing', function( int $total_rows ): void {
    error_log( 'WMS: starting batch. Total rows in CSV: ' . $total_rows );
} );

woo_multi_stock_after_row_update (action)

Fires after each successful update_post_meta() call — i.e. once per matched SKU. Useful for logging, triggering webhooks, or writing additional meta fields.

Note: The third argument to add_action() must be 3 to receive all three parameters.

/**
 * @param int    $product_id  Post ID of the updated product or variation.
 * @param string $sku         The SKU matched from the CSV.
 * @param int    $qty         The quantity written to _stock_CMT.
 */
add_action( 'woo_multi_stock_after_row_update', function( int $product_id, string $sku, int $qty ): void {
    // Example: also store the timestamp of the last CMT update.
    update_post_meta( $product_id, '_stock_CMT_updated_at', current_time( 'mysql' ) );
}, 10, 3 );

woo_multi_stock_download_timeout (filter)

Controls the HTTP timeout (in seconds) used when downloading the CSV with wp_remote_get(). Default: 60. Increase this for very large files or slow remote servers.

/**
 * @param int $seconds  Timeout in seconds (default 60).
 * @return int
 */
add_filter( 'woo_multi_stock_download_timeout', function( int $seconds ): int {
    return 120; // Allow up to 2 minutes for the download.
} );

File Structure

wp-multi-magazzino/
│
├── woo-multi-stock.php        Main plugin file: headers, PSR-4 autoloader,
│                              HPOS compatibility, bootstrap on plugins_loaded.
│
├── includes/
│   ├── Class-Admin.php        Admin settings page (WordPress Settings API),
│   │                          asset enqueueing, sync UI rendering.
│   │
│   ├── Class-Processor.php    AJAX handlers: CSV download, transient caching,
│   │                          batch processing loop, JSON responses.
│   │
│   └── Class-Stock-Updater.php  SKU lookup (wc_get_product_id_by_sku) and
│                                  update_post_meta(_stock_CMT) write.
│
├── assets/
│   └── admin-script.js        jQuery AJAX loop, progress bar, live counters,
│                              error handling, sync summary.
│
├── index.php                  Empty security file ("Silence is golden").
├── .gitignore                 Standard WordPress plugin gitignore.
└── README.md                  This file.

Namespace

All PHP classes are in the WooMultiStock namespace and loaded by the inline PSR-4-style autoloader in woo-multi-stock.php:

WordPress options stored

Frequently Asked Questions

Does this plugin change WooCommerce stock levels? No. It writes only to _stock_CMT. The native _stock, _stock_status, and manage_stock meta fields are never touched.

Does it work with variable products and variations? Yes. wc_get_product_id_by_sku() returns the post ID of any product type, including individual variations. The meta is written to whichever post ID matches the SKU.

What happens if the same SKU appears twice in the CSV? Both rows are processed. The second write overwrites the first. The final value of _stock_CMT will be the quantity from the last occurrence of the SKU in the file.

What if the CSV URL is password-protected? wp_remote_get() supports HTTP Basic Authentication via the headers argument. You can extend the download request using the woo_multi_stock_download_timeout filter pattern as a reference, or use a child plugin that hooks into pre_http_request to inject credentials.

Can I increase the batch size beyond 50? The batch size is defined as BATCH_SIZE = 50 in Class-Processor.php and mirrored in Admin::enqueue_assets() as wmsData.batchSize. Change both values to the same number. Larger batches reduce total request count but increase per-request execution time — test on your specific hosting environment.

The sync stops mid-way. What should I do? The CSV rows are cached in a WordPress transient for 1 hour. If your caching plugin clears transients mid-sync, the next batch request will return an error ("CSV data has expired"). Click Start Sync again to re-download and restart.

Plugin developed by Mavida s.n.c.