Reject duplicate guest documents by hash

src/main/kotlin/com/android/trisolarisserver/config/GuestDocumentSchemaFix.kt

@@ -0,0 +1,41 @@
+package com.android.trisolarisserver.config
+
+import org.springframework.jdbc.core.JdbcTemplate
+import org.springframework.stereotype.Component
+
+@Component
+class GuestDocumentSchemaFix(
+    private val jdbcTemplate: JdbcTemplate
+) : PostgresSchemaFix(jdbcTemplate) {
+
+    override fun runPostgres(jdbcTemplate: JdbcTemplate) {
+        val hasTable = jdbcTemplate.queryForObject(
+            """
+            select count(*)
+            from information_schema.tables
+            where table_name = 'guest_document'
+            """.trimIndent(),
+            Int::class.java
+        ) ?: 0
+        if (hasTable == 0) return
+
+        val hasHash = jdbcTemplate.queryForObject(
+            """
+            select count(*)
+            from information_schema.columns
+            where table_name = 'guest_document'
+              and column_name = 'file_hash'
+            """.trimIndent(),
+            Int::class.java
+        ) ?: 0
+        if (hasHash == 0) {
+            logger.info("Adding file_hash to guest_document table")
+            jdbcTemplate.execute(
+                """
+                alter table guest_document
+                add column file_hash varchar
+                """.trimIndent()
+            )
+        }
+    }
+}

src/main/kotlin/com/android/trisolarisserver/controller/GuestDocuments.kt

@@ -28,6 +28,7 @@ import java.time.OffsetDateTime
 import java.nio.file.Files
 import java.nio.file.Paths
 import java.util.UUID
+import java.security.MessageDigest
 
 @RestController
 @RequestMapping("/properties/{propertyId}/guests/{guestId}/documents")
@@ -82,6 +83,17 @@ class GuestDocuments(
         }
 
         val stored = storage.store(propertyId, guestId, bookingId, file)
+        val fileHash = hashFile(stored.storagePath)
+        if (fileHash != null && guestDocumentRepo.existsByPropertyIdAndGuestIdAndBookingIdAndFileHash(
+                propertyId,
+                guestId,
+                bookingId,
+                fileHash
+            )
+        ) {
+            Files.deleteIfExists(Paths.get(stored.storagePath))
+            throw ResponseStatusException(HttpStatus.CONFLICT, "Duplicate document")
+        }
         val document = GuestDocument(
             property = property,
             guest = guest,
@@ -90,7 +102,8 @@ class GuestDocuments(
             originalFilename = stored.originalFilename,
             contentType = stored.contentType,
             sizeBytes = stored.sizeBytes,
-            storagePath = stored.storagePath
+            storagePath = stored.storagePath,
+            fileHash = fileHash
         )
         val saved = guestDocumentRepo.save(document)
         runExtraction(saved.id!!, propertyId, guestId)
@@ -236,6 +249,27 @@ class GuestDocuments(
         }
     }
 
+    private fun hashFile(storagePath: String): String? {
+        return try {
+            val path = Paths.get(storagePath)
+            if (!Files.exists(path)) return null
+            val digest = MessageDigest.getInstance("SHA-256")
+            Files.newInputStream(path).use { input ->
+                val buffer = ByteArray(DEFAULT_BUFFER_SIZE)
+                var read = input.read(buffer)
+                while (read >= 0) {
+                    if (read > 0) {
+                        digest.update(buffer, 0, read)
+                    }
+                    read = input.read(buffer)
+                }
+            }
+            digest.digest().joinToString("") { "%02x".format(it) }
+        } catch (_: Exception) {
+            null
+        }
+    }
+
 }
 
 data class GuestDocumentResponse(

src/main/kotlin/com/android/trisolarisserver/db/repo/GuestDocumentRepo.kt

@@ -8,4 +8,10 @@ interface GuestDocumentRepo : JpaRepository<GuestDocument, UUID> {
     fun findByPropertyIdAndGuestIdOrderByUploadedAtDesc(propertyId: UUID, guestId: UUID): List<GuestDocument>
     fun findByIdAndPropertyIdAndGuestId(id: UUID, propertyId: UUID, guestId: UUID): GuestDocument?
     fun existsByGuestId(guestId: UUID): Boolean
+    fun existsByPropertyIdAndGuestIdAndBookingIdAndFileHash(
+        propertyId: UUID,
+        guestId: UUID,
+        bookingId: UUID,
+        fileHash: String
+    ): Boolean
 }

src/main/kotlin/com/android/trisolarisserver/models/booking/GuestDocument.kt

@@ -44,6 +44,9 @@ class GuestDocument(
     @Column(name = "storage_path", nullable = false)
     var storagePath: String,
 
+    @Column(name = "file_hash")
+    var fileHash: String? = null,
+
     @Column(name = "extracted_data", columnDefinition = "jsonb")
     @JdbcTypeCode(SqlTypes.JSON)
     var extractedData: String? = null,