Report Plugins (#4643)

* Add plugin mixin class for extending reports

* Expose report context to the plugin system

* Add an example mixin for adding context data to a report

* Add the 'request' object to the plugin code

InvenTree/plugin/base/integration/ReportMixin.py

@@ -0,0 +1,35 @@
+"""Plugin mixin class for ReportContextMixin"""
+
+
+class ReportMixin:
+    """Mixin which provides additional context to generated reports.
+
+    This plugin mixin acts as a "shim" when generating reports,
+    can can add extra context data to a report template.
+
+    Useful for custom report generation where the report template
+    needs some extra information which is not provided by default,
+    or some complex logic to generate the report.
+    """
+
+    class MixinMeta:
+        """Meta options for this mixin."""
+
+        MIXIN_NAME = 'ReportContext'
+
+    def __init__(self):
+        """Register mixin."""
+        super().__init__()
+        self.add_mixin('report', True, __class__)
+
+    def add_report_context(self, instance, request, context):
+        """Add extra context to the provided report instance.
+
+        By default, this method does nothing.
+
+        Args:
+            instance: The report instance to add context to
+            request: The request object which initiated the report generation
+            context: The context dictionary to add to
+        """
+        pass

InvenTree/plugin/mixins/__init__.py

@@ -10,6 +10,7 @@ from ..base.integration.AppMixin import AppMixin
 from ..base.integration.mixins import (APICallMixin, NavigationMixin,
                                        PanelMixin, SettingsContentMixin,
                                        ValidationMixin)
+from ..base.integration.ReportMixin import ReportMixin
 from ..base.integration.ScheduleMixin import ScheduleMixin
 from ..base.integration.SettingsMixin import SettingsMixin
 from ..base.integration.UrlsMixin import UrlsMixin
@@ -22,6 +23,7 @@ __all__ = [
     'EventMixin',
     'LabelPrintingMixin',
     'NavigationMixin',
+    'ReportMixin',
     'ScheduleMixin',
     'SettingsContentMixin',
     'SettingsMixin',

InvenTree/plugin/registry.py

@@ -39,6 +39,7 @@ class PluginsRegistry:
     from .base.integration.ScheduleMixin import ScheduleMixin
     from .base.integration.SettingsMixin import SettingsMixin
     from .base.integration.UrlsMixin import UrlsMixin
+
     DEFAULT_MIXIN_ORDER = [SettingsMixin, ScheduleMixin, AppMixin, UrlsMixin]
 
     def __init__(self, mixin_order: list = None) -> None:

InvenTree/plugin/samples/integration/report_plugin_sample.py

@@ -0,0 +1,38 @@
+"""Sample plugin for extending reporting functionality"""
+
+import random
+
+from plugin import InvenTreePlugin
+from plugin.mixins import ReportMixin
+from report.models import PurchaseOrderReport
+
+
+class SampleReportPlugin(ReportMixin, InvenTreePlugin):
+    """Sample plugin which provides extra context data to a report"""
+
+    NAME = "Report Plugin"
+    SLUG = "reportexample"
+    TITLE = "Sample Report Plugin"
+    DESCRIPTION = "A sample plugin which provides extra context data to a report"
+    VERSION = "1.0"
+
+    def some_custom_function(self):
+        """Some custom function which is not required for the plugin to function"""
+        return random.randint(0, 100)
+
+    def add_report_context(self, instance, request, context):
+        """Add example content to the report instance"""
+
+        # We can add any extra context data we want to the report
+
+        # Generate a random string of data
+        context['random_text'] = ''.join(random.choices('abcdefghijklmnopqrstuvwxyz', k=20))
+
+        # Call a custom method
+        context['random_int'] = self.some_custom_function()
+
+        # We can also add extra data to the context which is specific to the report type
+        context['is_purchase_order'] = isinstance(instance, PurchaseOrderReport)
+
+        # We can also use the 'request' object to add extra context data
+        context['request_method'] = request.method

InvenTree/report/models.py

@@ -22,6 +22,7 @@ import part.models
 import stock.models
 from InvenTree.helpers import validateFilterString
 from InvenTree.models import MetadataMixin
+from plugin.registry import registry
 
 try:
     from django_weasyprint import WeasyTemplateResponseMixin
@@ -212,6 +213,12 @@ class ReportTemplateBase(MetadataMixin, ReportBase):
         context['request'] = request
         context['user'] = request.user
 
+        # Pass the context through to any active reporting plugins
+        plugins = registry.with_mixin('report')
+
+        for plugin in plugins:
+            plugin.add_report_context(self, request, context)
+
         return context
 
     def generate_filename(self, request, **kwargs):