Rules Engine technical details
Key definitions
A condition is a boolean equation that evaluates to
trueorfalse.A consequence is the action to be performed when the trigger is met and the condition(s) evaluates to
true.A rule is a set of conditions and the associated consequence(s).
A triggering event is the event that started the rule evaluation.
The Adobe Experience Platform Mobile SDK evaluates each tag rule for the current event that is processed by the Event Hub.
Rules Engine is the system that processes the mobile tag rules and initiates the associated actions when the conditions are met.
An asset is an opaque data blob that is needed by a specific consequence.
Rules delivery
Rules delivery occurs by using a network request from the Experience Platform SDKs to a static endpoint that is defined as part of the SDK configuration. The rules file for each mobile property is hosted on https://assets.adobedtm.com.
This request is a conditional GET and occurs by default at the start of each new application session. When the set of tag rules that were configured for a mobile property change, these changes will be picked up by the Experience Platform SDK in the next session or after the application is restarted.
File format
Rules are delivered as a standard ZIP archive, which contains a rules.json file. This file consists of a root-level JSON object that contains the following elements:
| Friendly name | Key | Type | Required | Description |
|---|---|---|---|---|
Version | version | number | Yes | Version number of the rules.json file format. Should be an integer that increments by 1 for each format change, and the initial version is 1. |
Rules | rules | array | Yes | An array of rules objects. For more information, please read the rule object definition. |
Rule object definition
| Friendly name | Key | Type | Required | Description |
|---|---|---|---|---|
Condition | condition | object | Yes | Holds the definition for the base Condition object for this rule. Each Condition object can be a Group or a Matcher condition type. Group conditions contain a logic type and an array of condition objects. Matcher conditions contain a key, value, and a matcher type. There is one root-level condition for a rule, and this condition can have any number of nested conditions by using the group construct. For more information, please read the condition object definition. |
Action | consequences | array | Yes | Array of consequence objects, where each object contains the details for the associated consequence that are executed when the associated condition evaluates to true. For more information, please read the consequence object definition. |
Metadata | meta | object | No | A free-form object that may contain additional data about the rule. |
Condition object definition
Each Condition has a condition type and a definition, and the contents of a condition's definition depends on its condition type.
A Group condition contains an array of conditions, which makes the conditions infinitely nestable.
Condition object
| Friendly name | Key | Type | Example | Description |
|---|---|---|---|---|
Condition type | type | string | "type":"group" | Indicates the type of the current condition. The value must be a valid string from the condition types. |
Definition | definition | object | "definition": { "logic" : "and", "conditions" : [...] } | Defines how the condition should be evaluated, and the contents of this object will be different depending on the condition type. |
Condition types
| Name | Value | Description |
|---|---|---|
Group | group | This condition is a container that holds additional conditions and the logical evaluator that is used to process those conditions. |
Matcher | matcher | This condition holds the key, matcher type, and value that should be evaluated. |
Historical Search | historical | This condition holds an array of events that might have occurred on the device. A historical condition will evaluate based on data found in the device's event history. |
Definition object
Group condition type
| Friendly name | Key | Type | Example | Description |
|---|---|---|---|---|
Logic type | logic | string | "logic":"and" | Must be a valid Logic type and indicates which logical operator should be used for the conditions that are defined in the definition's conditions array. |
Conditions | conditions | array | "conditions":[...] | An array of Condition objects. |
Matcher condition type
The keys that are used here are different than those used for In-App message matchers.
| Friendly name | Key | Type | Example | Description |
|---|---|---|---|---|
Key | key | string | "key":"key1" | Key to get the value from the dictionary that is passed as a parameter to the rules processor. |
Matches | matcher | string | "matcher":"eq" | Matcher type that determines the kind of evaluation to use between the two values. |
Values | values | array | "values":["value0", "value1"] | List of values that are compared (using OR) against the value in the parameter dictionary for the "key" key. |
Historical condition type
| Friendly name | Key | Type | Required | Description |
|---|---|---|---|---|
Events | events | array | Yes | An array of anonymous objects containing key-value pairs with primitive values (string, numeric, boolean). These objects are hashed and used to look up matching records in the device's event history. |
From | from | number | No | Milliseconds since the Unix epoch that mark the lower bound of the query window. If omitted, no lower bound is applied and the search effectively begins with the first entry in the device’s event history. |
To | to | number | No | Milliseconds since the Unix epoch that mark the upper bound of the query window. If omitted, the upper bound defaults to the device’s current time. |
Search Type | searchType | string | No | Controls how objects in the events array are interpreted. The result produced by this search becomes the left-hand operand for the matcher. Accepted values are described in the table below. If omitted, the engine uses any. |
Matches | matcher | string | Yes | Matcher comparison operator applied between the search type result and the specified value. |
Value | value | number | Yes | Right-hand operand for the matcher. |
Search Types
| Name | Value | Return type | Return data | Description |
|---|---|---|---|---|
Any | any | number | Sum of all occurrences of the event(s) | Each event object is queried independently within the provided date range. The returned value is the sum of the number of occurrences of each event. |
Ordered | ordered | number | 0 or 1 | Checks whether the event objects occurred in the provided order. They are queried in the same order as they are provided in the request events array, with the timestamp of the first matched occurrence of the event at the previous index used as the from bound when searching for the current event. Returns 1 if all appear in order,0 if they do not appear in the specified order, and -1 if an error occurred during the lookup of any event. For a single event object, the result is 1 if at least one matching event is found and 0 otherwise. |
Most recent | mostRecent | number | Index of event in the request array | Queries all event objects and returns the zero-based index of the most recently occuring event in the request events array, or -1 if none of the events are found or an error occured during the lookup of any event. Example: for [A, B, C], if B is most recent the result is 1. |
Logic types
| Name | Value | Description |
|---|---|---|
AND | and | For this definition to evaluate to true, all of its conditions must be true. |
OR | or | For this definition to evaluate to true, only one of its conditions must be true. |
Matcher types
| Name | Value | Application Type |
|---|---|---|
Equals | eq | string, number |
Not Equals | ne | string, number |
Exists | ex | no value required |
Not Exists | nx | string, number |
Greater Than | gt | number |
Greater Than or Equals | ge | number |
Less Than | lt | number |
Less Than or Equals | le | number |
Contains | co | string |
Not Contains | nc | string |
Starts With | sw | string |
Ends With | ew | string |
Matching and retrieving values by keys
By default, keys and the associated values are sourced from the current event that is being processed by the Rules Engine. There are also some special key prefixes that can cause the values to be sourced from other locations that are known to the Experience Platform SDKs.
To avoid collisions, special key prefixes always start with a ~ (tilde) to differentiate them from the standard event key names.
| Key prefix | Example | Description |
|---|---|---|
~state. | ~state.sharedStateName/keyName | Reads the keyName from the shared state of the module that is stored in sharedStateName. |
~type | ~type | Reads eventType from the triggering event. |
~source | ~source | Reads eventSource from the triggering event. |
~timestampu | ~timestampu | Reads the current device time in epoch format (seconds since epoch). |
~timestampz | ~timestampz | Reads the current device time in ISO 8601 data elements and interchange format. |
~sdkver | ~sdkver | Reads the current Adobe Experience Platform SDKs version string. |
~cachebust | ~cachebust | Generates a random number to be used for cache busting. |
~all_url | ~all_url | Contains all data in the Event object and is encoded in the url format. |
~all_json | ~all_json | Contains all data in the Event object that is encoded in the json format. |
Simple conditions
Conditions example 1 represents the following logical condition:
Copied to your clipboard(key1 == value1)
Here is the example:
Copied to your clipboard"conditions": [{"type": "matcher","definition": {"key": "key1","matcher": "eq","values": ["value1"]}}]
Conditions example 2 is slightly more complex and represents the following logical condition:
Copied to your clipboard(key1 == value1 || key1 == value2) || (key2 != value3 && key2 != value4)
Here is the example:
Copied to your clipboard{"type": "group","definition": {"logic": "or","conditions": [{"type": "matcher","definition": {"key": "key1","matcher": "eq","values": ["value1", "value2"]}},{"type": "group","definition": {"logic": "and","conditions": [{"type" : "matcher","definition" : {"key" : "key2","matcher" : "ne","values" : ["value3"]}},{"type" : "matcher","definition" : {"key" : "key2","matcher" : "ne","values" : ["value4"]}}]}}]}}
Event data processing
When an event is evaluated against rules, its data is normalized into a single level key-value map so that conditions can reference values using predictable key paths. This normalization is called flattening.
Nested objects and arrays are flattened, and the key path format uses dot-separated segments that form the path from the root to each leaf value. Leaf values are kept as-is.
Key collisions and special characters
If two different inputs produce the same flattened key, the last value written wins. The resolution order for collisions is undefined and may change; do not rely on it.
Keys are not escaped during flattening. If original object keys contain dots, those dots become part of the flattened key path. Create rule keys with this in mind and prefer unambiguous event data structures to avoid collisions.
With this model, conditions can reference any value in the event using a single, dot separated key.
Event data key flattening
- Object key-value pairs use their key name as the path segment.
Original event data:
Copied to your clipboard{ "user": { "address": { "city": "San José" } } }
Flattened event data:
Copied to your clipboard{ "user.address.city": "San José" }
Special case: dots in keys are not escaped
Original event data:
Copied to your clipboard{ "user.address": { "city": "San José" } }
Flattened event data:
Copied to your clipboard{ "user.address.city": "San José" }
Special case: different inputs produce the same flattened key (last write wins, order undefined)
Original event data:
Copied to your clipboard{ "user": { "address": { "city": "nested" } }, "user.address.city": "flat" }
Flattened event data:
Copied to your clipboard{ "user.address.city": "flat" }
or
Copied to your clipboard{ "user.address.city": "nested" }
Array flattening
- Array items use their zero-based numeric index as the path segment.
Original event data:
Copied to your clipboard{ "items": [1, 2] }
Flattened event data:
Copied to your clipboard{ "items.0": 1, "items.1": 2 }
Original event data:
Copied to your clipboard{ "list": [ { "name": "a" }, { "name": "b" } ] }
Flattened event data:
Copied to your clipboard{ "list.0.name": "a", "list.1.name": "b" }
Original event data:
Copied to your clipboard{ "matrix": [[10, 20], [30]] }
Flattened event data:
Copied to your clipboard{ "matrix.0.0": 10, "matrix.0.1": 20, "matrix.1.0": 30 }
Consequence object definition
The consequences section of a rule lists the file names of each consequence object that should be performed when all of the conditions for that rule evaluate to true.
| Friendly name | Key | Type | Required | Description |
|---|---|---|---|---|
Identifier | id | string | Yes | String that contains a unique identifier for this consequence. sha1, or another guaranteed random value with a near-impossible chance of collisions, is recommended. |
Consequence type | type | string | Yes | A Consequence Type from the consequences type table. |
Consequence details | detail | object | Yes | JSON object that contains the details that are necessary to perform a consequence of the given type. |
Consequence types
| Name | Value | Description | Payload Definition |
|---|---|---|---|
Analytics | an | Sends data to Analytics | |
In-App Message | iam | In-App Message | |
Postback | pb | Send Postback(s) to a third-party URL | |
PII | pii | Sync PII with an https URL | |
Open URL | url | Passes the provided URL to be opened by the platform that is most commonly used for app deep linking. | |
Client Side Profile | csp | Create or delete operations against the client-side profile. | |
Attach Data | add | Attaches key-value pairs to the EventData of an existing Event | |
Modify Data | mod | Modifies data in the triggering event | |
Schema | schema | Schema-based actions for easy parsing by AEP Mobile SDKs |
rules.json examples
Example 1 is a set of rules that will only run when the event was as a result of an Analytics hit or a GPS location event.
The conditions array is set up with the following logic:
Copied to your clipboard((key1 == value1 || key1 == value2) || (key2 != value3 && key2 != value4)) && (key3 == value5 || key3 == value6)
If the conditions pass, an in-app message triggered:
Copied to your clipboard{"version" : 1,"rules" : [{"condition" : {"type" : "group","definition" : {"logic" : "and","conditions" : [{"type" : "group","definition" : {"logic" : "or","conditions" : [{"type" : "matcher","definition" : {"key" : "key1","matcher" : "eq","values" : ["value1", "value2"]}},{"type" : "group","definition" : {"logic" : "and","conditions" : [{"type" : "matcher","definition" : {"key" : "key2","matcher" : "ne","values" : ["value3"]}},{"type" : "matcher","definition" : {"key" : "key2","matcher" : "ne","values" : ["value4"]}}]}}]}},{"type" : "matcher","definition" : {"key" : "key3","matcher" : "eq","values" : ["value5", "value6"]}},{"type" : "matcher","definition" : {"key" : "~type","matcher" : "eq","values" : ["com.adobe.eventType.location", "com.adobe.eventType.analytics"]}}]}},"consequences" : [{"id" : "48181acd22b3edaebc8a447868a7df7ce629920a","type" : "iam","detail" : {"template" : "fullscreen","html" : "48181acd22b3edaebc8a447868a7df7ce629920a.html"}}]}]}
Example 2 uses the client-side profile to implement a show once style of in-app message. The conditions array is set up with the following logic:
Copied to your clipboard((key3 == value5 || key3 == value6) && (~state.com.adobe.module.userProfile/userprofiledata.48181acd22b3edaebc8a447868a7df7ce629920a-seen does not exist))
If the conditions pass, the in-app message is displayed (first consequence), and future displays of the message are prevented by writing/incrementing value to the client-side profile:(~state.com.adobe.module.userProfile/userprofiledata.48181acd22b3edaebc8a447868a7df7ce629920a-seen) (Second consequence) prevents the conditions from evaluating to true for future evaluations.
In a production environment, attach the profile write consequence to an IAM result event, not to the show event. IAM consequences are first-one-wins, so multiple in-app messages are not displayed when multiple conditions are met across messages. The other consequences are still performed.
Copied to your clipboard{"version": 1,"rules": [{"condition": {"type": "group","definition": {"logic": "and","conditions": [{"type": "matcher","definition": {"key": "key3","matcher": "eq","values": ["value5", "value6"]}},{"type": "matcher","definition": {"key" : "~state.com.adobe.module.userProfile/userprofiledata.48181acd22b3edaebc8a447868a7df7ce629920a-seen","matcher" : "nx"}}]}},"consequences": [{"id" : "48181acd22b3edaebc8a447868a7df7ce629920a","type" : "iam","detail" : {"template" : "fullscreen","html" : "48181acd22b3edaebc8a447868a7df7ce629920a.html"}},{"id" : "9d40f5665d5bdbe96dcb3a24f4e4fe98d686a602","type" : "csp","detail" : {"operation": "write","key" : "48181acd22b3edaebc8a447868a7df7ce629920a-seen","value" : "yes"}}]}]}
Rules URL
The Rules Engine requires an endpoint URL to be configured in the configuration, which specifies the location from where rules should be fetched:
Copied to your clipboard{"rules.url": "https://assets.adobedtm.com/example.zip"}
The Adobe Experience Platform SDKs process the URL that points to a zipped rules collection, and this collection contains a rules.json file. After the rules are downloaded and extracted, the contents of this compressed file are stored in the cache.
Configuration keys
| Key | Description |
|---|---|
rules.url | URL that points to the remote file location that contains the rules that were configured for the Mobile SDKs. For more information, see the rules URL section. |
