PI-2712 Stream users response to reduce memory overhead

projects/manage-supervision-and-delius/src/integrationTest/kotlin/uk/gov/justice/digital/hmpps/UserLocationIntegrationTest.kt

@@ -8,7 +8,6 @@ import org.springframework.boot.test.autoconfigure.web.servlet.AutoConfigureMock
 import org.springframework.boot.test.context.SpringBootTest
 import org.springframework.test.web.servlet.MockMvc
 import org.springframework.test.web.servlet.request.MockMvcRequestBuilders
-import org.springframework.test.web.servlet.result.MockMvcResultHandlers.print
 import org.springframework.test.web.servlet.result.MockMvcResultMatchers
 import org.springframework.test.web.servlet.result.MockMvcResultMatchers.jsonPath
 import uk.gov.justice.digital.hmpps.api.model.sentence.Address
@@ -36,15 +35,13 @@ class UserLocationIntegrationTest {
     @Test
     fun `user not found`() {
         mockMvc.perform(MockMvcRequestBuilders.get("/user/user/locations").withToken())
-            .andDo(print())
             .andExpect(MockMvcResultMatchers.status().isNotFound)
             .andExpect(jsonPath("$.message", equalTo("User with username of user not found")))
     }
 
     @Test
     fun `get user locations`() {
         val response = mockMvc.perform(MockMvcRequestBuilders.get("/user/peter-parker/locations").withToken())
-            .andDo(print())
             .andExpect(MockMvcResultMatchers.status().isOk)
             .andReturn().response.contentAsJson<UserOfficeLocation>()
 

projects/workforce-allocations-to-delius/src/integrationTest/kotlin/uk/gov/justice/digital/hmpps/UserIntegrationTest.kt

@@ -2,16 +2,15 @@ package uk.gov.justice.digital.hmpps
 
 import org.hamcrest.MatcherAssert.assertThat
 import org.hamcrest.Matchers.equalTo
-import org.hamcrest.Matchers.equalToIgnoringCase
 import org.junit.jupiter.api.Test
 import org.springframework.beans.factory.annotation.Autowired
 import org.springframework.boot.test.autoconfigure.web.servlet.AutoConfigureMockMvc
 import org.springframework.boot.test.context.SpringBootTest
 import org.springframework.test.web.servlet.MockMvc
+import org.springframework.test.web.servlet.MvcResult
 import org.springframework.test.web.servlet.request.MockMvcRequestBuilders.get
 import org.springframework.test.web.servlet.request.MockMvcRequestBuilders.post
-import org.springframework.test.web.servlet.result.MockMvcResultMatchers.jsonPath
-import org.springframework.test.web.servlet.result.MockMvcResultMatchers.status
+import org.springframework.test.web.servlet.result.MockMvcResultMatchers.*
 import uk.gov.justice.digital.hmpps.api.model.CaseAccess
 import uk.gov.justice.digital.hmpps.api.model.CaseAccessList
 import uk.gov.justice.digital.hmpps.api.model.User
@@ -34,8 +33,11 @@ class UserIntegrationTest {
     @Test
     fun `get all users`() {
         mockMvc.perform(get("/users").withToken())
+            .andExpect(request().asyncStarted())
+            .andDo(MvcResult::getAsyncResult)
             .andExpect(status().is2xxSuccessful)
-            .andExpect(jsonPath("$[0].username", equalToIgnoringCase("JoeBloggs")))
+            .andExpect(content().contentTypeCompatibleWith("application/json"))
+            .andExpect(content().json("""[{"username":"JoeBloggs","staffCode":"N02ABS1"}]"""))
     }
 
     @Test

projects/workforce-allocations-to-delius/src/main/kotlin/uk/gov/justice/digital/hmpps/api/resource/UserResource.kt

@@ -2,8 +2,11 @@ package uk.gov.justice.digital.hmpps.api.resource
 
 import io.swagger.v3.oas.annotations.Operation
 import jakarta.validation.constraints.Size
+import org.springframework.http.MediaType.APPLICATION_JSON
+import org.springframework.http.ResponseEntity
 import org.springframework.security.access.prepost.PreAuthorize
 import org.springframework.web.bind.annotation.*
+import org.springframework.web.servlet.mvc.method.annotation.StreamingResponseBody
 import uk.gov.justice.digital.hmpps.service.UserAccessService
 import uk.gov.justice.digital.hmpps.service.UserService
 
@@ -34,7 +37,9 @@ class UserResource(
 
     @GetMapping("/users")
     @Operation(summary = "Returns all users with the Delius `MAABT001` role")
-    fun allUsers() = userService.findAllUsersWithRole()
+    fun allUsers() = ResponseEntity.ok()
+        .contentType(APPLICATION_JSON)
+        .body(StreamingResponseBody { userService.writeAllUsersWithRole(it) })
 
     @GetMapping("/person/{crn}/limited-access/all")
     @Operation(summary = "Returns all limited access information (restrictions and exclusions) for a Delius CRN")

projects/workforce-allocations-to-delius/src/main/kotlin/uk/gov/justice/digital/hmpps/integrations/delius/provider/StaffRepository.kt

@@ -5,6 +5,7 @@ import org.springframework.data.jpa.repository.JpaRepository
 import org.springframework.data.jpa.repository.Query
 import uk.gov.justice.digital.hmpps.exception.NotFoundException
 import java.time.LocalDate
+import java.util.stream.Stream
 
 interface StaffRepository : JpaRepository<StaffRecord, Long> {
     @EntityGraph(attributePaths = ["grade.dataset", "user"])
@@ -23,7 +24,7 @@ interface StaffRepository : JpaRepository<StaffRecord, Long> {
     fun findStaffForUsernamesIn(
         usernames: List<String>,
         usernamesUppercase: List<String> = usernames.map { it.uppercase() }
-    ): List<StaffWithUser>
+    ): Stream<StaffWithUser>
 
     @EntityGraph(attributePaths = ["grade.dataset"])
     fun findByCode(code: String): Staff?

projects/workforce-allocations-to-delius/src/main/kotlin/uk/gov/justice/digital/hmpps/service/UserService.kt

@@ -1,5 +1,7 @@
 package uk.gov.justice.digital.hmpps.service
 
+import com.fasterxml.jackson.databind.ObjectMapper
+import jakarta.transaction.Transactional
 import org.springframework.stereotype.Service
 import uk.gov.justice.digital.hmpps.api.model.CaseAccessList
 import uk.gov.justice.digital.hmpps.api.model.User
@@ -8,20 +10,25 @@ import uk.gov.justice.digital.hmpps.integrations.delius.person.PersonRepository
 import uk.gov.justice.digital.hmpps.integrations.delius.provider.StaffRepository
 import uk.gov.justice.digital.hmpps.integrations.delius.user.ExclusionRepository
 import uk.gov.justice.digital.hmpps.integrations.delius.user.RestrictionRepository
+import java.io.OutputStream
+import java.util.stream.Stream
+import kotlin.streams.asSequence
 
 @Service
+@Transactional
 class UserService(
     private val personRepository: PersonRepository,
     private val exclusionRepository: ExclusionRepository,
     private val restrictionRepository: RestrictionRepository,
     private val staffRepository: StaffRepository,
     private val ldapService: LdapService,
+    private val objectMapper: ObjectMapper,
 ) {
     fun getAllAccessLimitations(crn: String, staffCodesFilter: List<String>? = null): CaseAccessList {
         val person = personRepository.findByCrnAndSoftDeletedFalse(crn) ?: throw NotFoundException("Person", "crn", crn)
         val exclusions = exclusionRepository.findByPersonId(person.id).map { it.user.username }
         val restrictions = restrictionRepository.findByPersonId(person.id).map { it.user.username }
-        val staffCodes = staffRepository.findStaffForUsernamesIn(exclusions + restrictions)
+        val staffCodes = staffRepository.findStaffForUsernamesIn(exclusions + restrictions).asSequence()
             .associate { it.user?.username to it.code }
         return CaseAccessList(
             crn = crn,
@@ -34,10 +41,20 @@ class UserService(
         )
     }
 
-    fun findAllUsersWithRole(role: String = "MAABT001"): List<User> {
+    fun findAllUsersWithRole(role: String = "MAABT001"): Stream<User> {
         val usernames = ldapService.findAllUsersWithRole(role)
         val staff = staffRepository.findStaffForUsernamesIn(usernames)
         return staff.map { User(it.user!!.username, it.code) }
     }
+
+    fun writeAllUsersWithRole(outputStream: OutputStream) {
+        objectMapper.factory.createGenerator(outputStream).use { json ->
+            json.writeStartArray()
+            findAllUsersWithRole().use { users ->
+                users.forEach { user -> json.writeObject(user) }
+            }
+            json.writeEndArray()
+        }
+    }
 }