Validate presentaion submission with new validator

credentials/src/main/kotlin/web5/sdk/credentials/PresentationExchange.kt

@@ -12,6 +12,7 @@ import web5.sdk.credentials.model.InputDescriptorV2
 import web5.sdk.credentials.model.PresentationDefinitionV2
 import web5.sdk.credentials.model.PresentationDefinitionV2Validator
 import web5.sdk.credentials.model.PresentationSubmission
+import web5.sdk.credentials.model.PresentationSubmissionValidator
 import java.util.UUID
 
 /**
@@ -136,6 +137,26 @@ public object PresentationExchange {
     PresentationDefinitionV2Validator.validate(presentationDefinition)
   }
 
+  /**
+   * Validates whether an object is usable as a presentation submission or not.
+   *
+   * Model as specified in https://identity.foundation/presentation-exchange/#presentation-submission.
+   *
+   * The checks are as follows:
+   * 1. Ensures that the presentation submission's id is not empty.
+   * 2. Validates that the definitionId is not empty.
+   * 3. Validates descriptorMap is a non-empty list.
+   * 4. Check for unique inputDescriptor ids at top level
+   * 5. Verifies the input descriptor mapping ids are the same on all levels of nesting.
+   * 6. Ensures that the path is valid across all levels of nesting
+   *
+   * Throws an [PexValidationException] if the provided object does not conform to the Presentation Definition
+   */
+  @Throws(PexValidationException::class)
+  public fun validateSubmission(presentationSubmission: PresentationSubmission) {
+    PresentationSubmissionValidator.validate(presentationSubmission)
+  }
+
   private fun mapInputDescriptorsToVCs(
     vcJwtList: Iterable<String>,
     presentationDefinition: PresentationDefinitionV2

credentials/src/main/kotlin/web5/sdk/credentials/model/Validator.kt

@@ -149,3 +149,77 @@ public object FieldV2Validator {
   }
 }
 
+/**
+ * PresentationSubmission Validator.
+ **/
+public object PresentationSubmissionValidator {
+
+  @Throws(PexValidationException::class)
+
+  /**
+   * Validates a PresentationSubmission.
+   *
+   * This method performs several checks to ensure the integrity of the presentation submission model object:
+   * 1. Ensures that the presentation submission's id is not empty.
+   * 2. Validates that the definitionId is not empty.
+   * 3. Validates descriptorMap is a non-empty list.
+   * 4. Check for unique inputDescriptor ids at top level
+   * 5. Verifies the input descriptor mapping ids are the same on all levels of nesting.
+   * 6. Ensures that the path is valid across all levels of nesting
+   * @throws PexValidationException if the PresentationDefinitionV2 is not valid.
+   */
+  public fun validate(presentationSubmission: PresentationSubmission) {
+    if (presentationSubmission.id.isEmpty()) {
+      throw PexValidationException("PresentationSubmission id must not be empty")
+    }
+
+    if (presentationSubmission.definitionId.isEmpty()) {
+      throw PexValidationException("PresentationSubmission definitionId must not be empty")
+    }
+
+    if (presentationSubmission.descriptorMap.isEmpty()) {
+      throw PexValidationException("PresentationSubmission descriptorMap should be a non-empty list")
+    }
+
+    // Check for unique inputDescriptor ids
+    val ids = presentationSubmission.descriptorMap.map { it.id }
+    if (ids.size != ids.toSet().size) {
+      throw PexValidationException("All descriptorMap top level ids must be unique")
+    }
+
+    validateDescriptorMap(presentationSubmission.descriptorMap)
+  }
+
+  private fun validateDescriptorMap(descriptorMap: List<InputDescriptorMapping>) {
+    descriptorMap.forEach { descriptor ->
+      validateDescriptor(descriptor, descriptor.id)
+    }
+  }
+  private fun validateDescriptor(descriptor: InputDescriptorMapping, id: String?) {
+    if (descriptor.id.isEmpty()) {
+      throw PexValidationException("Descriptor id should not be empty")
+    }
+
+    if (descriptor.path.isEmpty()) {
+      throw PexValidationException("Descriptor path should not be empty")
+    }
+
+    if (descriptor.format.isEmpty()) {
+      throw PexValidationException("Descriptor format should not be empty")
+    }
+
+    if (descriptor.id != id) {
+      throw PexValidationException("Each descriptor should have one id in it, on all levels")
+    }
+
+    if (runCatching { JsonPath(descriptor.path) }.isFailure) {
+      throw PexValidationException("Each descriptor should have a valid path id")
+    }
+
+    descriptor.pathNested?.let { nestedDescriptor ->
+      validateDescriptor(nestedDescriptor, id)
+    }
+  }
+}
+
+

credentials/src/test/kotlin/web5/sdk/credentials/PresentationExchangeTest.kt

@@ -11,6 +11,7 @@ import org.junit.jupiter.api.Nested
 import org.junit.jupiter.api.assertDoesNotThrow
 import org.junit.jupiter.api.assertThrows
 import web5.sdk.credentials.model.PresentationDefinitionV2
+import web5.sdk.credentials.model.PresentationSubmission
 import web5.sdk.crypto.InMemoryKeyManager
 import web5.sdk.dids.methods.key.DidKey
 import web5.sdk.testing.TestVectors
@@ -621,4 +622,27 @@ class Web5TestVectorsPresentationExchange {
       }
     }
   }
+
+  data class ValidateSubmissionTestInput(
+    val presentationSubmission: PresentationSubmission,
+    val errors: Boolean
+  )
+  @Test
+  fun validate_submission() {
+    val typeRef = object : TypeReference<TestVectors<ValidateSubmissionTestInput, Unit>>() {}
+    val testVectors =
+      mapper.readValue(File("../web5-spec/test-vectors/presentation_exchange/validate_submission.json"), typeRef)
+
+    testVectors.vectors.filterNot { it.errors ?: false }.forEach { vector ->
+      assertDoesNotThrow {
+        PresentationExchange.validateSubmission(vector.input.presentationSubmission)
+      }
+    }
+
+    testVectors.vectors.filter { it.errors ?: false }.forEach { vector ->
+      assertFails {
+        PresentationExchange.validateSubmission(vector.input.presentationSubmission)
+      }
+    }
+  }
 }