--- schema_version: "1" id: 23e0dfb62802df5fb85118714d6119ed2136538ebb175271a634973b7362dd9f title: DataWeave Support in Omni Gateway Policies collection: mulesoft version: current locale: en-us portal_url: https://docs.salesforce.com/mulesoft/current/en-us/gateway/latest/policies-dataweave-support.md canonical_url: https://docs.mulesoft.com/gateway/latest/policies-dataweave-support source_site: docs.mulesoft.com content_type: documentation content_hash: c074f80bd90a16b8a2d426a2d6cbc4667a2b2f6e2a0dfb3a812b12dcd4e42a4d description: MuleSoft Documentation Site release: "1.14" latest: true --- # DataWeave Support in Omni Gateway Policies [DataWeave](https://docs.mulesoft.com/dataweave/latest/) is the programming language designed by MuleSoft for data transformation. It enables you to build a simple solution for a common integration developer use case: read and parse data from one format, transform the data, and write it out as a different format. Omni Gateway supports a subset of DataWeave in policy configuration expressions. DataWeave is only supported in included policies and custom policies created with PDK.. ## [](#available-types)Available Types - [`Null`](https://docs.mulesoft.com/dataweave/latest/dataweave-type-system#null) - `Boolean` - `String` - `Number` (Driven as 64 bits floating points) - [`Array`](https://docs.mulesoft.com/dataweave/latest/dataweave-type-system#array-type) - [`Object`](https://docs.mulesoft.com/dataweave/latest/dataweave-type-system#object-type) (Repeated keys are not available) ## [](#available-value-constructors-for-types)Available Value Constructors for Types - [`Boolean`](https://docs.mulesoft.com/dataweave/latest/dataweave-types#dw_type_boolean) - [`String`](https://docs.mulesoft.com/dataweave/latest/dataweave-types#dw_type_string) - [`Null`](https://docs.mulesoft.com/dataweave/latest/dataweave-types#dw_type_null) - [`Number`](https://docs.mulesoft.com/dataweave/latest/dataweave-types#dw_type_number) - [`Array`](https://docs.mulesoft.com/dataweave/latest/dataweave-types#dw_type_array) ## [](#unavailable-value-constructors-for-types)Unavailable Value Constructors for Types - [`Object`](https://docs.mulesoft.com/dataweave/latest/dataweave-types#dw_type_object) (Objects can not be defined as literals) ## [](#available-flow-control-structures)Available Flow Control Structures - [`if else`](https://docs.mulesoft.com/dataweave/latest/dataweave-flow-control#control_flow_if_else) ## [](#unavailable-flow-control-structures)Unavailable Flow Control Structures - [`do`](https://docs.mulesoft.com/dataweave/latest/dataweave-flow-control#control_flow_do) ## [](#available-selectors)Available Selectors - `Array[Number]` - `Array[String]` - `Object[String]` - `String[Number]` ## [](#unavailable-selectors)Unavailable Selectors - `Object[Number]` ## [](#available-equality-and-relational-operators)Available Equality and Relational Operators - [`==`](https://docs.mulesoft.com/dataweave/latest/dw-operators#equality-and-relational-operators) - [`!=`](https://docs.mulesoft.com/dataweave/latest/dw-operators#equality-and-relational-operators) - [`>=`](https://docs.mulesoft.com/dataweave/latest/dw-operators#equality-and-relational-operators) - [`<=`](https://docs.mulesoft.com/dataweave/latest/dw-operators#equality-and-relational-operators) ## [](#available-logical-operators)Available Logical Operators - [`not`](https://docs.mulesoft.com/dataweave/latest/dw-operators#logical_operators) - [`and`](https://docs.mulesoft.com/dataweave/latest/dw-operators#logical_operators) - [`or`](https://docs.mulesoft.com/dataweave/latest/dw-operators#logical_operators) ## [](#available-default-operators)Available Default Operators - [`default`](https://docs.mulesoft.com/dataweave/latest/dataweave-cookbook-defaults#example-of-using-the-keyword-default-to-set-a-default-value) ## [](#available-functions)Available Functions ### [](#)`++` - [`++(Array, Array): Array`](https://docs.mulesoft.com/dataweave/latest/dw-core-functions-plusplus#plusplus1) - [`++(String, String): String`](https://docs.mulesoft.com/dataweave/latest/dw-core-functions-plusplus#plusplus2) ### [](#available-minus-operators)`--` - [`--(source: Array, toRemove: Array): Array`](https://docs.mulesoft.com/dataweave/latest/dw-core-functions-minusminus#minusminus1) - [`--(source: { (K)?: V }, toRemove: Object): { (K)?: V }`](https://docs.mulesoft.com/dataweave/latest/dw-core-functions-minusminus#minusminus2) - [`--(source: Object, keys: Array)`](https://docs.mulesoft.com/dataweave/latest/dw-core-functions-minusminus#minusminus3) ### [](#contains)`contains` - [`contains(Array, Any): Boolean`](https://docs.mulesoft.com/dataweave/latest/dw-core-functions-contains#contains1) - [`contains(String, String): Boolean`](https://docs.mulesoft.com/dataweave/latest/dw-core-functions-contains#contains2) ### [](#lower)`lower` - [`lower(String): String`](https://docs.mulesoft.com/dataweave/latest/dw-core-functions-lower#lower1) - [`lower(Null): Null`](https://docs.mulesoft.com/dataweave/latest/dw-core-functions-lower#lower2) ### [](#splitby)`splitBy` - [`splitBy(String, String): Array`](https://docs.mulesoft.com/dataweave/latest/dw-core-functions-splitby#splitby2) ### [](#sizeof)`sizeOf` - [`sizeOf(Array): Number`](https://docs.mulesoft.com/dataweave/latest/dw-core-functions-sizeof#sizeof1) - [`sizeOf(Object): Number`](https://docs.mulesoft.com/dataweave/latest/dw-core-functions-sizeof#sizeof2) - [`sizeOf(String): Number`](https://docs.mulesoft.com/dataweave/latest/dw-core-functions-sizeof#sizeof4) ### [](#trim)`trim` - [`trim(String): String`](https://docs.mulesoft.com/dataweave/latest/dw-core-functions-trim#trim1) - [`trim(Null): Null`](https://docs.mulesoft.com/dataweave/latest/dw-core-functions-trim#trim2) ### [](#upper)`upper` - [`upper(String): String`](https://docs.mulesoft.com/dataweave/latest/dw-core-functions-upper#upper1) - [`upper(Null): Null`](https://docs.mulesoft.com/dataweave/latest/dw-core-functions-upper#upper2) ### [](#uuid)`uuid` - [`uuid(): String`](https://docs.mulesoft.com/dataweave/latest/dw-core-functions-uuid#uuid1) ### [](#dwcorestringssubstringafter)`dw::core::Strings::substringAfter` - [`substringAfter(String, String): String`](https://docs.mulesoft.com/dataweave/latest/dw-strings-functions-substringafter#substringafter1) - [`substringAfter(Null, String): Null`](https://docs.mulesoft.com/dataweave/latest/dw-strings-functions-substringafter#substringafter2) ### [](#dwcorestringssubstringafterlast)`dw::core::Strings::substringAfterLast` - [`substringAfterLast(String, String): String`](https://docs.mulesoft.com/dataweave/latest/dw-strings-functions-substringafterlast#substringafterlast1) - [`substringAfterLast(Null, String): Null`](https://docs.mulesoft.com/dataweave/latest/dw-strings-functions-substringafterlast#substringafterlast2) ### [](#dwcorestringssubstringbefore)`dw::core::Strings::substringBefore` - [`substringBefore(String, String): String`](https://docs.mulesoft.com/dataweave/latest/dw-strings-functions-substringbefore#substringbefore1) - [`substringBefore(Null, String): Null`](https://docs.mulesoft.com/dataweave/latest/dw-strings-functions-substringbefore#substringbefore2) ### [](#dwcorestringssubstringbeforelast)`dw::core::Strings::substringBeforeLast` - [`substringBeforeLast(text: String, separator: String): String`](https://docs.mulesoft.com/dataweave/latest/dw-strings-functions-substringbeforelast#substringbeforelast1) - [`substringBeforeLast(text: Null, separator: String): Null`](https://docs.mulesoft.com/dataweave/latest/dw-strings-functions-substringbeforelast#substringbeforelast2) ### [](#tobase64)toBase64 - [`toBase64(content: Binary): String`](https://docs.mulesoft.com/dataweave/latest/dw-binaries-functions-tobase64#tobase641) ### [](#frombase64)fromBase64 - [`fromBase64(base64String: String): Binary`](https://docs.mulesoft.com/dataweave/latest/dw-binaries-functions-frombase64#frombase641)

Omni Gateway doesn’t support DataWeave expressions with binary type results. To use the dw::Binaries::fromBase64('dXNlcjpwYXNz') function, transform the result to a string. Transform the binary output to a string with the dw::util::Coercions::toString(binary: Binary, encoding: String): String function. For example, [dw::util::Coercions::toString(dw::core::Binaries::fromBase64('dXNlcjpwYXNz'), 'UTF-8')]. If using a different function that transforms the binary by default, such as [splitBy(dw::core::Binaries::fromBase64('dXNlcjpwYXNz'), ':')], you can skip manually transforming the binary.
### [](#tobinary)toBinary - [`toBinary(str: String, encoding: String): Binary`](https://docs.mulesoft.com/dataweave/latest/dw-coercions-functions-tobinary#tobinary1) ### [](#tostring)toString - [`toString(binary: Binary, encoding: String): String`](https://docs.mulesoft.com/dataweave/latest/dw-coercions-functions-tostring#tostring3) ## [](#available-predefined-variables)Available Predefined Variables - [`attributes`](https://docs.mulesoft.com/dataweave/latest/dataweave-variables-context) - `attributes.headers` - `attributes.method` (Only available in request context) - `attributes.queryParams` (Only available in request context) - `attributes.queryString` (Only available in request context) - `attributes.requestPath` (Only available in request context) - `attributes.requestUri` (Only available in request context) - `attributes.localAddress` (Only available in request context) - `attributes.remoteAddress` (Only available in request context) - `attributes.scheme` (Only available in request context) - `attributes.version` (Only available in request context) - `attributes.statusCode` (Only available in response context) - [`authentication`](https://docs.mulesoft.com/dataweave/latest/dataweave-variables-context) - `authentication.clientId` - `authentication.clientName` - `authentication.principal` - `authentication.properties` To learn more about how to access the authentication object, see [Access the Authentication Object](#access-authentication-object). - `payload` - Fields depend on the current payload. For example, `#[payload]` returns the body of the message. - [`vars`](https://docs.mulesoft.com/dataweave/latest/dataweave-variables-context) - Individual policies support different sets of variables. For information, refer to the policies listed in [Inbound Policies Directory](https://docs.mulesoft.com/gateway/latest/policies-included-directory). ## [](#dataweave-usage-examples)DataWeave Usage Examples You can use DataWeave to extract different values from the request and response.
The Omni Gateway Policy Development Kit (PDK) provides the DataWeave example policy that you can use to test DataWeave expressions.
For example, use DataWeave expressions to: - Read a header: #\[attributes.headers.'my-header'\] - Ensure a specific header is defined: #\[attributes.headers.'my-header' != null\] - Check if a request has basic authorization: #\[lower(splitBy(attributes.headers.authorization default '', ' ')\[0\]) == 'basic'\] - Check if a request contains `/some` path: #\[attributes.requestPath contains '/some'\] - Check if a request doesn’t contain `/some` path: #\[not(attributes.requestPath contains '/some')\] - Read the username from a `Basic` authorization header: #\[splitBy(dw::core::Binaries::fromBase64(dw::core::Strings::substringAfter(attributes.headers.authorization default '', 'Basic')), ':')\[0\]\] - Read the password from a `Basic` authorization header: #\[splitBy(dw::core::Binaries::fromBase64(dw::core::Strings::substringAfter(attributes.headers.authorization default '', 'Basic ')), ':')\[1\]\] - Read the first value of the `x-forwarded-for` header: #\[trim(splitBy(attributes.headers.'x-forwarded-for', ',')\[0\])\] - Read the last value of the `x-forwarded-for` header: #\[trim(splitBy(attributes.headers.'x-forwarded-for', ',')\[-1\])\] - Read the value from a `Cookie`: #\[trim(dw::core::Strings::substringBefore(dw::core::Strings::substringAfter(attributes.headers.Cookie default '', 'myCookieName='), ';'))\] - Check if a single value or space-separated header contains a specific value: #\[splitBy(attributes.headers.scopes default '', ' ') contains 'read'\] ## [](#access-authentication-object)Access the Authentication Object To access the [`authentication`](https://docs.mulesoft.com/dataweave/latest/dataweave-variables-context) object, you must first configure an authentication policy that populates the object. The authentication policy you apply affects the available authentication object properties: - Multiple policies can validate Client ID: - [Client ID Enforcement Policy](https://docs.mulesoft.com/gateway/latest/policies-included-client-id-enforcement) - [Rate Limiting: SLA-Based Policy](https://docs.mulesoft.com/gateway/latest/policies-included-rate-limiting-sla) - [OAuth 2.0 Token Introspection Policy](https://docs.mulesoft.com/gateway/latest/policies-included-oauth-token-introspection) (If Client ID enforcement is configured) - [OpenID Connect OAuth 2.0 Token Enforcement Policy](https://docs.mulesoft.com/gateway/latest/policies-included-openid-token-enforcement) (If Client ID enforcement is configured) - [JWT Validation Policy](https://docs.mulesoft.com/gateway/latest/policies-included-jwt-validation) (If Client ID enforcement is configured) Policies validating Client ID provide these authentication object properties: - `authentication.clientName`: Name of the contract’s client application - `authentication.clientId`: ID of the contract’s client application - `authentication.properties.slaId`: SLA ID assigned to the contract - [JWT Validation Policy](https://docs.mulesoft.com/gateway/latest/policies-included-jwt-validation): - `authentication.properties.claims.`: All claims provided by the JWT - Multiple policies validate basic authentication credentials: - [Basic Authentication: Simple Policy](https://docs.mulesoft.com/gateway/latest/policies-included-basic-auth-simple) - [Basic Authentication: LDAP Policy](https://docs.mulesoft.com/gateway/latest/policies-included-basic-auth-ldap) Policies validating basic authentication credentials provide these authentication object properties: - `authentication.principal`: Username passed as basic auth user After your policy populates the authentication object, you can access the object in policies ordered after the authentication policy using DataWeave expressions. For example: - Read a value from the authentication object: #\[authentication.properties.claims.exp\] - Check if a JSON array or a JSON string JWT claim contains a specific value: #\[authentication.properties.claims.custom\_claim contains 'read'\] - Remove sensitive headers, such as `Authorization`, for logging purposes: #\[attributes.headers -- "Authorization"\]