Properties sanitizer

PostHog · Nov 14, 2023 · ec2314a · ec2314a
1 parent fe28b8d
commit ec2314a
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Showing 5 changed files with 44 additions and 8 deletions.
diff --git a/posthog-samples/posthog-android-sample/src/main/java/com/posthog/android/sample/MyApp.kt b/posthog-samples/posthog-android-sample/src/main/java/com/posthog/android/sample/MyApp.kt
@@ -3,6 +3,7 @@ package com.posthog.android.sample
 import android.app.Application
 import android.os.StrictMode
 import com.posthog.PostHogOnFeatureFlags
+import com.posthog.PostHogPropertiesSanitizer
 import com.posthog.android.PostHogAndroid
 import com.posthog.android.PostHogAndroidConfig
 
@@ -17,6 +18,11 @@ class MyApp : Application() {
             flushAt = 5
             maxBatchSize = 5
             onFeatureFlags = PostHogOnFeatureFlags { print("feature flags loaded") }
+            propertiesSanitizer = PostHogPropertiesSanitizer { properties ->
+                properties.apply {
+                    remove("\$device_name")
+                }
+            }
         }
         PostHogAndroid.setup(this, config)
     }

diff --git a/posthog/api/posthog.api b/posthog/api/posthog.api
@@ -52,8 +52,8 @@ public final class com/posthog/PostHog$Companion : com/posthog/PostHogInterface
 public class com/posthog/PostHogConfig {
 	public static final field Companion Lcom/posthog/PostHogConfig$Companion;
 	public static final field defaultHost Ljava/lang/String;
-	public fun <init> (Ljava/lang/String;Ljava/lang/String;ZZZZIIIILcom/posthog/PostHogEncryption;Lcom/posthog/PostHogOnFeatureFlags;)V
-	public synthetic fun <init> (Ljava/lang/String;Ljava/lang/String;ZZZZIIIILcom/posthog/PostHogEncryption;Lcom/posthog/PostHogOnFeatureFlags;ILkotlin/jvm/internal/DefaultConstructorMarker;)V
+	public fun <init> (Ljava/lang/String;Ljava/lang/String;ZZZZIIIILcom/posthog/PostHogEncryption;Lcom/posthog/PostHogOnFeatureFlags;Lcom/posthog/PostHogPropertiesSanitizer;)V
+	public synthetic fun <init> (Ljava/lang/String;Ljava/lang/String;ZZZZIIIILcom/posthog/PostHogEncryption;Lcom/posthog/PostHogOnFeatureFlags;Lcom/posthog/PostHogPropertiesSanitizer;ILkotlin/jvm/internal/DefaultConstructorMarker;)V
 	public final fun addIntegration (Lcom/posthog/PostHogIntegration;)V
 	public final fun getApiKey ()Ljava/lang/String;
 	public final fun getCachePreferences ()Lcom/posthog/internal/PostHogPreferences;
@@ -72,6 +72,7 @@ public class com/posthog/PostHogConfig {
 	public final fun getOnFeatureFlags ()Lcom/posthog/PostHogOnFeatureFlags;
 	public final fun getOptOut ()Z
 	public final fun getPreloadFeatureFlags ()Z
+	public final fun getPropertiesSanitizer ()Lcom/posthog/PostHogPropertiesSanitizer;
 	public final fun getSdkName ()Ljava/lang/String;
 	public final fun getSdkVersion ()Ljava/lang/String;
 	public final fun getSendFeatureFlagEvent ()Z
@@ -92,6 +93,7 @@ public class com/posthog/PostHogConfig {
 	public final fun setOnFeatureFlags (Lcom/posthog/PostHogOnFeatureFlags;)V
 	public final fun setOptOut (Z)V
 	public final fun setPreloadFeatureFlags (Z)V
+	public final fun setPropertiesSanitizer (Lcom/posthog/PostHogPropertiesSanitizer;)V
 	public final fun setSdkName (Ljava/lang/String;)V
 	public final fun setSdkVersion (Ljava/lang/String;)V
 	public final fun setSendFeatureFlagEvent (Z)V
@@ -183,6 +185,10 @@ public abstract interface class com/posthog/PostHogOnFeatureFlags {
 	public abstract fun loaded ()V
 }
 
+public abstract interface class com/posthog/PostHogPropertiesSanitizer {
+	public abstract fun sanitize (Ljava/util/Map;)Ljava/util/Map;
+}
+
 public abstract interface annotation class com/posthog/PostHogVisibleForTesting : java/lang/annotation/Annotation {
 }
 

diff --git a/posthog/src/main/java/com/posthog/PostHog.kt b/posthog/src/main/java/com/posthog/PostHog.kt
@@ -273,15 +273,20 @@ public class PostHog private constructor(
 
         val newDistinctId = distinctId ?: this.distinctId
 
+        val mergedProperties = buildProperties(
+            properties = properties,
+            userProperties = userProperties,
+            userPropertiesSetOnce = userPropertiesSetOnce,
+            groupProperties = groupProperties,
+        )
+
+        // sanitize the properties or fallback to the original properties
+        val sanitizedProperties = config?.propertiesSanitizer?.sanitize(mergedProperties.toMutableMap()) ?: mergedProperties
+
         val postHogEvent = PostHogEvent(
             event,
             newDistinctId,
-            properties = buildProperties(
-                properties = properties,
-                userProperties = userProperties,
-                userPropertiesSetOnce = userPropertiesSetOnce,
-                groupProperties = groupProperties,
-            ),
+            properties = sanitizedProperties,
         )
         queue?.add(postHogEvent)
     }

diff --git a/posthog/src/main/java/com/posthog/PostHogConfig.kt b/posthog/src/main/java/com/posthog/PostHogConfig.kt
@@ -89,6 +89,12 @@ public open class PostHogConfig(
      * Defaults to no callback
      */
     public var onFeatureFlags: PostHogOnFeatureFlags? = null,
+
+    /**
+     * Hook that allows to sanitize the event properties
+     * The hook is called before the event is cached or sent over the wire
+     */
+    public var propertiesSanitizer: PostHogPropertiesSanitizer? = null,
 ) {
     // fix me: https://stackoverflow.com/questions/53866865/leaking-this-in-constructor-warning-should-apply-to-final-classes-as-well-as
     @PostHogInternal

diff --git a/posthog/src/main/java/com/posthog/PostHogPropertiesSanitizer.kt b/posthog/src/main/java/com/posthog/PostHogPropertiesSanitizer.kt
@@ -0,0 +1,13 @@
+package com.posthog
+
+/**
+ * Hook to sanitize the event properties
+ */
+public fun interface PostHogPropertiesSanitizer {
+    /**
+     * Sanitizes the event properties
+     * @param properties the event properties to sanitize
+     * @return the sanitized properties
+     */
+    public fun sanitize(properties: MutableMap<String, Any>): Map<String, Any>
+}