feat: session and identity integrate with context now (#264)

* session and identity in context

* bump version

* make django integration use context distinct id and session functions

* don't use self

* fix comments

* fix middleware tests

* clarify fresh and distinct id's

* Fix exported modules, add makefile command to test changes locally

* tiny fix

Author: oliverb123

CHANGELOG.md

@@ -1,4 +1,9 @@
-## 5.0.0
+# 5.1.0
+
+- feat: session and distinct ID's can now be associated with contexts, and are used as such
+- feat: django http request middleware
+
+## 5.0.0 - 2025-06-16
 
 - fix: removed deprecated sentry integration
 

Makefile

@@ -35,4 +35,23 @@ release_analytics:
 e2e_test:
 	.buildscripts/e2e.sh
 
-.PHONY: test lint release e2e_test
+prep_local:
+	rm -rf ../posthog-python-local
+	mkdir ../posthog-python-local
+	cp -r . ../posthog-python-local/
+	cd ../posthog-python-local && rm -rf dist build posthoganalytics .git
+	cd ../posthog-python-local && mkdir posthoganalytics
+	cd ../posthog-python-local && cp -r posthog/* posthoganalytics/
+	cd ../posthog-python-local && find ./posthoganalytics -type f -name "*.py" -exec sed -i.bak -e 's/from posthog /from posthoganalytics /g' {} \;
+	cd ../posthog-python-local && find ./posthoganalytics -type f -name "*.py" -exec sed -i.bak -e 's/from posthog\./from posthoganalytics\./g' {} \;
+	cd ../posthog-python-local && find ./posthoganalytics -name "*.bak" -delete
+	cd ../posthog-python-local && rm -rf posthog
+	cd ../posthog-python-local && sed -i.bak 's/from version import VERSION/from posthoganalytics.version import VERSION/' setup_analytics.py
+	cd ../posthog-python-local && rm setup_analytics.py.bak
+	cd ../posthog-python-local && sed -i.bak 's/"posthog"/"posthoganalytics"/' setup.py
+	cd ../posthog-python-local && rm setup.py.bak
+	cd ../posthog-python-local && python -c "import setup_analytics" 2>/dev/null || true
+	@echo "Local copy created at ../posthog-python-local"
+	@echo "Install with: pip install -e ../posthog-python-local"
+
+.PHONY: test lint release e2e_test prep_local

posthog/__init__.py

@@ -4,7 +4,15 @@
 
 from posthog.client import Client
 from posthog.exception_capture import Integrations  # noqa: F401
-from posthog.scopes import clear_tags, get_tags, new_context, scoped, tag
+from posthog.scopes import (
+    clear_tags,
+    get_tags,
+    new_context,
+    scoped,
+    tag,
+    set_context_session,
+    identify_context,
+)
 from posthog.types import FeatureFlag, FlagsAndPayloads
 from posthog.version import VERSION
 
@@ -16,6 +24,9 @@
 get_tags = get_tags
 clear_tags = clear_tags
 scoped = scoped
+identify_context = identify_context
+set_context_session = set_context_session
+
 
 """Settings."""
 api_key = None  # type: Optional[str]

posthog/client.py

@@ -33,7 +33,11 @@
     get,
     remote_config,
 )
-from posthog.scopes import get_tags
+from posthog.scopes import (
+    _get_current_context,
+    get_context_distinct_id,
+    get_context_session_id,
+)
 from posthog.types import (
     FeatureFlag,
     FeatureFlagResult,
@@ -285,10 +289,17 @@ def identify(
                 stacklevel=2,
             )
 
+        if distinct_id is None:
+            distinct_id = get_context_distinct_id()
+
         properties = properties or {}
+
         require("distinct_id", distinct_id, ID_TYPES)
         require("properties", properties, dict)
 
+        if "$session_id" not in properties and get_context_session_id():
+            properties["$session_id"] = get_context_session_id()
+
         msg = {
             "timestamp": timestamp,
             "distinct_id": distinct_id,
@@ -358,6 +369,9 @@ def get_flags_decision(
         """
         Get feature flags decision, using either flags() or decide() API based on rollout.
         """
+
+        if distinct_id is None:
+            distinct_id = get_context_distinct_id()
         require("distinct_id", distinct_id, ID_TYPES)
 
         if disable_geoip is None:
@@ -406,14 +420,22 @@ def capture(
 
         properties = {**(properties or {}), **system_context()}
 
+        if "$session_id" not in properties and get_context_session_id():
+            properties["$session_id"] = get_context_session_id()
+
+        if distinct_id is None:
+            distinct_id = get_context_distinct_id()
+
         require("distinct_id", distinct_id, ID_TYPES)
         require("properties", properties, dict)
         require("event", event, string_types)
 
-        # Grab current context tags, if any exist
-        context_tags = get_tags()
-        if context_tags:
-            properties.update(context_tags)
+        current_context = _get_current_context()
+        if current_context:
+            context_tags = current_context.collect_tags()
+            # We want explicitly passed properties to override context tags
+            context_tags.update(properties)
+            properties = context_tags
 
         msg = {
             "properties": properties,
@@ -480,6 +502,9 @@ def set(
                 stacklevel=2,
             )
 
+        if distinct_id is None:
+            distinct_id = get_context_distinct_id()
+
         properties = properties or {}
         require("distinct_id", distinct_id, ID_TYPES)
         require("properties", properties, dict)
@@ -510,6 +535,9 @@ def set_once(
                 stacklevel=2,
             )
 
+        if distinct_id is None:
+            distinct_id = get_context_distinct_id()
+
         properties = properties or {}
         require("distinct_id", distinct_id, ID_TYPES)
         require("properties", properties, dict)
@@ -581,6 +609,9 @@ def alias(
                 stacklevel=2,
             )
 
+        if distinct_id is None:
+            distinct_id = get_context_distinct_id()
+
         require("previous_id", previous_id, ID_TYPES)
         require("distinct_id", distinct_id, ID_TYPES)
 
@@ -613,6 +644,9 @@ def page(
                 stacklevel=2,
             )
 
+        if distinct_id is None:
+            distinct_id = get_context_distinct_id()
+
         properties = properties or {}
         require("distinct_id", distinct_id, ID_TYPES)
         require("properties", properties, dict)
@@ -648,6 +682,9 @@ def capture_exception(
                 stacklevel=2,
             )
 
+        if distinct_id is None:
+            distinct_id = get_context_distinct_id()
+
         # this function shouldn't ever throw an error, so it logs exceptions instead of raising them.
         # this is important to ensure we don't unexpectedly re-raise exceptions in the user's code.
         try:

posthog/integrations/django.py

@@ -10,8 +10,8 @@ class PosthogContextMiddleware:
     """Middleware to automatically track Django requests.
 
     This middleware wraps all calls with a posthog context. It attempts to extract the following from the request headers:
-    - Session ID as $session_id, (extracted from `X-POSTHOG-SESSION-ID`)
-    - Distinct ID as $distinct_id, (extracted from `X-POSTHOG-DISTINCT-ID`)
+    - Session ID, (extracted from `X-POSTHOG-SESSION-ID`)
+    - Distinct ID, (extracted from `X-POSTHOG-DISTINCT-ID`)
     - Request URL as $current_url
     - Request Method as $request_method
 
@@ -26,7 +26,9 @@ class PosthogContextMiddleware:
     You can use the `POSTHOG_MW_TAG_MAP` function to remove any default tags you don't want to capture, or override them with your own values.
 
     Context tags are automatically included as properties on all events captured within a context, including exceptions.
-    See the context documentation for more information.
+    See the context documentation for more information. The extracted distinct ID and session ID, if found, are used to
+    associate all events captured in the middleware context with the same distinct ID and session as currently active on the
+    frontend. See the documentation for `set_context_session` and `identify_context` for more details.
     """
 
     def __init__(self, get_response):
@@ -79,12 +81,12 @@ def extract_tags(self, request):
         # Extract session ID from X-POSTHOG-SESSION-ID header
         session_id = request.headers.get("X-POSTHOG-SESSION-ID")
         if session_id:
-            tags["$session_id"] = session_id
+            scopes.set_context_session(session_id)
 
         # Extract distinct ID from X-POSTHOG-DISTINCT-ID header
         distinct_id = request.headers.get("X-POSTHOG-DISTINCT-ID")
         if distinct_id:
-            tags["$distinct_id"] = distinct_id
+            scopes.identify_context(distinct_id)
 
         # Extract current URL
         absolute_url = request.build_absolute_uri()