Add database model for defining custom units (#5268)

* Add database model for defining custom units

- Database model
- DRF serializer
- API endpoints

* Add validation hook

* Custom check for the 'definition' field

* Add settings page for custom units

- Table of units
- Create / edit / delete buttons

* Allow "unit" field to be empty

- Not actually required for custom unit definition

* Load custom unit definitions into global registry

* Docs: add core concepts page(s)

* Add some back links

* Update docs

* Add unit test for custom unit conversion

* More unit testing

* remove print statements

* Add missing table rule

InvenTree/templates/InvenTree/settings/physical_units.html

@@ -0,0 +1,21 @@
+{% extends "panel.html" %}
+
+{% load i18n %}
+{% load inventree_extras %}
+
+{% block label %}units{% endblock label %}
+
+{% block heading %}{% trans "Physical Units" %}{% endblock heading %}
+{% block actions %}
+<button class='btn btn-success' id='custom-unit-create'>
+    <span class='fas fa-plus-circle'></span>
+    {% trans "Add Unit" %}
+</button>
+{% endblock actions %}
+
+{% block content %}
+
+<table class='table table-striped table-condensed' id='physical-units-table'>
+</table>
+
+{% endblock content %}

InvenTree/templates/InvenTree/settings/settings.html

@@ -32,6 +32,7 @@
 {% include "InvenTree/settings/login.html" %}
 {% include "InvenTree/settings/barcode.html" %}
 {% include "InvenTree/settings/project_codes.html" %}
+{% include "InvenTree/settings/physical_units.html" %}
 {% include "InvenTree/settings/notifications.html" %}
 {% include "InvenTree/settings/label.html" %}
 {% include "InvenTree/settings/report.html" %}

InvenTree/templates/InvenTree/settings/settings_staff_js.html

@@ -52,6 +52,82 @@ onPanelLoad('pricing', function() {
     });
 });
 
+// Javascript for units panel
+onPanelLoad('units', function() {
+
+    console.log("units panel");
+
+    // Construct the "units" table
+    $('#physical-units-table').bootstrapTable({
+        url: '{% url "api-custom-unit-list" %}',
+        search: true,
+        columns: [
+            {
+                field: 'name',
+                title: '{% trans "Name" %}',
+            },
+            {
+                field: 'definition',
+                title: '{% trans "Definition" %}',
+            },
+            {
+                field: 'symbol',
+                title: '{% trans "Symbol" %}',
+                formatter: function(value, row) {
+                    let html = value;
+                    let buttons = '';
+
+                    buttons += makeEditButton('button-units-edit', row.pk, '{% trans "Edit" %}');
+                    buttons += makeDeleteButton('button-units-delete', row.pk, '{% trans "Delete" %}');
+
+                    html += wrapButtons(buttons);
+                    return html;
+                }
+            },
+        ]
+    });
+
+    // Callback to edit a custom unit
+    $('#physical-units-table').on('click', '.button-units-edit', function() {
+        let pk = $(this).attr('pk');
+
+        constructForm(`{% url "api-custom-unit-list" %}${pk}/`, {
+            title: '{% trans "Edit Custom Unit" %}',
+            fields: {
+                name: {},
+                definition: {},
+                symbol: {},
+            },
+            refreshTable: '#physical-units-table',
+        });
+    });
+
+    // Callback to delete a custom unit
+    $('#physical-units-table').on('click', '.button-units-delete', function() {
+        let pk = $(this).attr('pk');
+
+        constructForm(`{% url "api-custom-unit-list" %}${pk}/`, {
+            title: '{% trans "Delete Custom Unit" %}',
+            method: 'DELETE',
+            refreshTable: '#physical-units-table',
+        });
+    });
+
+    // Callback to create a new custom unit
+    $('#custom-unit-create').click(function() {
+        constructForm('{% url "api-custom-unit-list" %}', {
+            fields: {
+                name: {},
+                definition: {},
+                symbol: {},
+            },
+            title: '{% trans "New Custom Unit" %}',
+            method: 'POST',
+            refreshTable: '#physical-units-table',
+        });
+    });
+});
+
 // Javascript for project codes panel
 onPanelLoad('project-codes', function() {
 

InvenTree/templates/InvenTree/settings/sidebar.html

@@ -32,6 +32,8 @@
 {% include "sidebar_item.html" with label='barcodes' text=text icon="fa-qrcode" %}
 {% trans "Project Codes" as text %}
 {% include "sidebar_item.html" with label='project-codes' text=text icon="fa-list" %}
+{% trans "Physical Units" as text %}
+{% include "sidebar_item.html" with label='units' text=text icon="fa-balance-scale" %}
 {% trans "Notifications" as text %}
 {% include "sidebar_item.html" with label='global-notifications' text=text icon="fa-bell" %}
 {% trans "Pricing" as text %}