Initial implementation of 3D Print Demand plugin

Dashboard plugin for InvenTree showing aggregated demand for 3D printed
parts across open build and sales orders, with colour-coded deficit column.

README.md

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+# InvenTree 3D Print Demand Plugin
+
+Dashboard plugin for InvenTree that shows aggregated demand for 3D printed parts across all open build orders and sales orders.
+
+## Features
+
+- Dashboard panel showing all parts from a configured category
+- Aggregates stock, allocations, and demand from build and sales orders
+- Colour-coded deficit column (red = shortage, green = surplus)
+- Configurable part category with optional subcategory inclusion
+
+## Installation
+
+```bash
+cd Projects/02-engineering/inventree/inventree-print-demand
+pip install -e .
+```
+
+Then restart InvenTree and enable the plugin in **Admin > Plugins**.
+
+## Configuration
+
+In plugin settings, set:
+
+- **Part Category** - select the category containing your 3D printed parts
+- **Include Subcategories** - whether to include parts from subcategories (default: true)
+
+## API
+
+`GET /plugin/print-demand/api/demand/` returns a JSON array of parts sorted by deficit:
+
+```json
+[
+  {
+    "pk": 123,
+    "name": "Housing Top",
+    "IPN": "MP-001",
+    "in_stock": 50,
+    "allocated_build": 30,
+    "allocated_sales": 10,
+    "available": 10,
+    "required_build": 45,
+    "required_sales": 15,
+    "deficit": -10
+  }
+]
+```

inventree_print_demand/plugin.py

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+"""InvenTree plugin to display aggregated 3D print demand."""
+
+from django.http import JsonResponse
+from django.urls import re_path
+
+from plugin import InvenTreePlugin
+from plugin.mixins import SettingsMixin, UrlsMixin, UserInterfaceMixin
+
+from part.models import Part, PartCategory
+from stock.models import StockItem
+
+
+class PrintDemandPlugin(SettingsMixin, UrlsMixin, UserInterfaceMixin, InvenTreePlugin):
+
+    AUTHOR = 'Micromelon'
+    DESCRIPTION = 'Dashboard panel showing aggregated 3D print demand across open orders'
+    VERSION = '0.1.0'
+    NAME = 'PrintDemand'
+    SLUG = 'print-demand'
+    TITLE = '3D Print Demand'
+
+    SETTINGS = {
+        'PART_CATEGORY': {
+            'name': 'Part Category',
+            'description': 'Category containing 3D printed parts',
+            'model': 'part.partcategory',
+        },
+        'INCLUDE_SUBCATEGORIES': {
+            'name': 'Include Subcategories',
+            'description': 'Include parts from subcategories of the selected category',
+            'default': True,
+            'validator': bool,
+        },
+    }
+
+    def setup_urls(self):
+        return [
+            re_path(r'^api/demand/', self.api_demand, name='api-demand'),
+        ]
+
+    def get_ui_panels(self, request, **kwargs):
+        return []
+
+    def get_ui_dashboard_items(self, request, **kwargs):
+        return [
+            {
+                'key': 'print-demand',
+                'title': '3D Print Demand',
+                'description': 'Aggregated demand for 3D printed parts',
+                'source': self.plugin_static_file('print_demand/dashboard.js'),
+            },
+        ]
+
+    def api_demand(self, request):
+        """Return aggregated demand data for all parts in the configured category."""
+        category_pk = self.get_setting('PART_CATEGORY')
+
+        if not category_pk:
+            return JsonResponse(
+                {'error': 'No part category configured. Set PART_CATEGORY in plugin settings.'},
+                status=400,
+            )
+
+        try:
+            category = PartCategory.objects.get(pk=category_pk)
+        except PartCategory.DoesNotExist:
+            return JsonResponse({'error': 'Configured category does not exist.'}, status=404)
+
+        include_sub = self.get_setting('INCLUDE_SUBCATEGORIES')
+
+        if include_sub:
+            categories = category.get_descendants(include_self=True)
+        else:
+            categories = PartCategory.objects.filter(pk=category.pk)
+
+        parts = Part.objects.filter(category__in=categories, active=True)
+
+        results = []
+
+        for part in parts:
+            in_stock = part.total_stock
+            allocated_build = part.allocation_count(
+                build_order_allocations=True,
+                sales_order_allocations=False,
+            )
+            allocated_sales = part.allocation_count(
+                build_order_allocations=False,
+                sales_order_allocations=True,
+            )
+            available = max(0, in_stock - allocated_build - allocated_sales)
+
+            required_build = part.required_build_order_quantity()
+            required_sales = part.required_sales_order_quantity()
+
+            total_required = required_build + required_sales
+            total_allocated = allocated_build + allocated_sales
+            deficit = in_stock - total_required
+
+            results.append({
+                'pk': part.pk,
+                'name': part.name,
+                'IPN': part.IPN or '',
+                'in_stock': float(in_stock),
+                'allocated_build': float(allocated_build),
+                'allocated_sales': float(allocated_sales),
+                'available': float(available),
+                'required_build': float(required_build),
+                'required_sales': float(required_sales),
+                'deficit': float(deficit),
+            })
+
+        results.sort(key=lambda x: x['deficit'])
+
+        return JsonResponse(results, safe=False)

inventree_print_demand/static/print_demand/dashboard.js

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+/**
+ * 3D Print Demand dashboard panel for InvenTree.
+ *
+ * Fetches aggregated demand data from the plugin API and renders
+ * a colour-coded table showing stock vs demand for every 3D-printed part.
+ */
+
+export function renderDashboardItem(context) {
+    const target = context.target;
+
+    target.innerHTML = '<em>Loading 3D print demand data...</em>';
+
+    const headers = {
+        'Accept': 'application/json',
+    };
+
+    // Include CSRF token if available
+    const csrfToken = getCookie('csrftoken');
+    if (csrfToken) {
+        headers['X-CSRFToken'] = csrfToken;
+    }
+
+    fetch('/plugin/print-demand/api/demand/', { headers, credentials: 'same-origin' })
+        .then(response => {
+            if (!response.ok) {
+                return response.json().then(data => { throw new Error(data.error || response.statusText); });
+            }
+            return response.json();
+        })
+        .then(data => {
+            if (!data.length) {
+                target.innerHTML = '<em>No parts found in the configured category.</em>';
+                return;
+            }
+            target.innerHTML = buildTable(data);
+        })
+        .catch(err => {
+            target.innerHTML = `<em style="color:#c00;">Error: ${escapeHtml(err.message)}</em>`;
+        });
+}
+
+function buildTable(parts) {
+    const rows = parts.map(p => {
+        const deficitStyle = p.deficit < 0
+            ? 'color:#c00;font-weight:bold;'
+            : (p.deficit > 0 ? 'color:#080;' : '');
+
+        return `<tr>
+            <td><a href="/part/${p.pk}/">${escapeHtml(p.IPN ? p.IPN + ' - ' + p.name : p.name)}</a></td>
+            <td style="text-align:right;">${fmt(p.in_stock)}</td>
+            <td style="text-align:right;">${fmt(p.allocated_build + p.allocated_sales)}</td>
+            <td style="text-align:right;">${fmt(p.available)}</td>
+            <td style="text-align:right;">${fmt(p.required_build + p.required_sales)}</td>
+            <td style="text-align:right;${deficitStyle}">${fmt(p.deficit)}</td>
+        </tr>`;
+    }).join('');
+
+    return `
+        <div style="overflow-x:auto;">
+            <table style="width:100%;border-collapse:collapse;font-size:0.9em;">
+                <thead>
+                    <tr style="border-bottom:2px solid #ccc;text-align:left;">
+                        <th style="padding:6px 8px;">Part</th>
+                        <th style="padding:6px 8px;text-align:right;">In Stock</th>
+                        <th style="padding:6px 8px;text-align:right;">Allocated</th>
+                        <th style="padding:6px 8px;text-align:right;">Available</th>
+                        <th style="padding:6px 8px;text-align:right;">Required</th>
+                        <th style="padding:6px 8px;text-align:right;">Deficit</th>
+                    </tr>
+                </thead>
+                <tbody>${rows}</tbody>
+            </table>
+        </div>`;
+}
+
+function fmt(n) {
+    return Number.isInteger(n) ? n.toString() : n.toFixed(1);
+}
+
+function escapeHtml(str) {
+    const div = document.createElement('div');
+    div.textContent = str;
+    return div.innerHTML;
+}
+
+function getCookie(name) {
+    const match = document.cookie.match(new RegExp('(^| )' + name + '=([^;]+)'));
+    return match ? decodeURIComponent(match[2]) : null;
+}

setup.py

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+from setuptools import setup, find_packages
+
+setup(
+    name='inventree-print-demand',
+    version='0.1.0',
+    description='InvenTree plugin to show aggregated 3D print demand across open orders',
+    author='Micromelon',
+    license='MIT',
+    packages=find_packages(),
+    include_package_data=True,
+    install_requires=['inventree'],
+    entry_points={
+        'inventree_plugins': [
+            'PrintDemandPlugin = inventree_print_demand.plugin:PrintDemandPlugin',
+        ],
+    },
+)