fix: EXPOSED-42 Can't create BLOB column with default value

exposed-core/src/main/kotlin/org/jetbrains/exposed/sql/ColumnType.kt

@@ -6,12 +6,7 @@ import org.jetbrains.exposed.dao.id.IdTable
 import org.jetbrains.exposed.sql.statements.DefaultValueMarker
 import org.jetbrains.exposed.sql.statements.api.ExposedBlob
 import org.jetbrains.exposed.sql.statements.api.PreparedStatementApi
-import org.jetbrains.exposed.sql.vendors.H2Dialect
-import org.jetbrains.exposed.sql.vendors.MariaDBDialect
-import org.jetbrains.exposed.sql.vendors.OracleDialect
-import org.jetbrains.exposed.sql.vendors.SQLServerDialect
-import org.jetbrains.exposed.sql.vendors.currentDialect
-import org.jetbrains.exposed.sql.vendors.h2Mode
+import org.jetbrains.exposed.sql.vendors.*
 import java.io.InputStream
 import java.math.BigDecimal
 import java.math.MathContext
@@ -743,7 +738,12 @@ class BlobColumnType : ColumnType() {
         }
     }
 
-    override fun nonNullValueToString(value: Any): String = "?"
+    override fun nonNullValueToString(value: Any): String {
+        if (value !is ExposedBlob)
+            error("Unexpected value of type Blob: $value of ${value::class.qualifiedName}")
+
+        return currentDialect.dataTypeProvider.hexToDb(value.hexString())
+    }
 
     override fun readObject(rs: ResultSet, index: Int) = when {
         currentDialect is SQLServerDialect -> rs.getBytes(index)?.let(::ExposedBlob)

exposed-core/src/main/kotlin/org/jetbrains/exposed/sql/statements/api/ExposedBlob.kt

@@ -23,4 +23,9 @@ class ExposedBlob(inputStream: InputStream) {
     }
 
     override fun hashCode(): Int = bytes.contentHashCode()
+
+    fun hexString(): String = bytes.toHexString()
+
+    /** Returns the hex-encoded string of a ByteArray. */
+    private fun ByteArray.toHexString(): String = joinToString(separator = "") { eachByte -> "%02x".format(eachByte) }
 }

exposed-core/src/main/kotlin/org/jetbrains/exposed/sql/vendors/Default.kt

@@ -118,6 +118,9 @@ abstract class DataTypeProvider {
     open fun precessOrderByClause(queryBuilder: QueryBuilder, expression: Expression<*>, sortOrder: SortOrder) {
         queryBuilder.append((expression as? ExpressionAlias<*>)?.alias ?: expression, " ", sortOrder.code)
     }
+
+    /** Returns the hex-encoded value to be inserted into the database. */
+    abstract fun hexToDb(hexString: String): String
 }
 
 /**

exposed-core/src/main/kotlin/org/jetbrains/exposed/sql/vendors/H2.kt

@@ -13,6 +13,7 @@ internal object H2DataTypeProvider : DataTypeProvider() {
 
     override fun uuidType(): String = "UUID"
     override fun dateTimeType(): String = "DATETIME(9)"
+    override fun hexToDb(hexString: String): String = "X'$hexString'"
 }
 
 internal object H2FunctionProvider : FunctionProvider() {

exposed-core/src/main/kotlin/org/jetbrains/exposed/sql/vendors/Mysql.kt

@@ -49,6 +49,8 @@ internal object MysqlDataTypeProvider : DataTypeProvider() {
             }
         }
     }
+
+    override fun hexToDb(hexString: String): String = "0x$hexString"
 }
 
 internal open class MysqlFunctionProvider : FunctionProvider() {

exposed-core/src/main/kotlin/org/jetbrains/exposed/sql/vendors/OracleDialect.kt

@@ -44,6 +44,8 @@ internal object OracleDataTypeProvider : DataTypeProvider() {
         e is LiteralOp<*> && e.columnType is IDateColumnType -> "TIMESTAMP ${super.processForDefaultValue(e)}"
         else -> super.processForDefaultValue(e)
     }
+
+    override fun hexToDb(hexString: String): String = "HEXTORAW('$hexString')"
 }
 
 internal object OracleFunctionProvider : FunctionProvider() {

exposed-core/src/main/kotlin/org/jetbrains/exposed/sql/vendors/PostgreSQL.kt

@@ -20,6 +20,7 @@ internal object PostgreSQLDataTypeProvider : DataTypeProvider() {
     override fun uuidToDB(value: UUID): Any = value
     override fun dateTimeType(): String = "TIMESTAMP"
     override fun ubyteType(): String = "SMALLINT"
+    override fun hexToDb(hexString: String): String = """E'\\x$hexString'"""
 }
 
 internal object PostgreSQLFunctionProvider : FunctionProvider() {

exposed-core/src/main/kotlin/org/jetbrains/exposed/sql/vendors/SQLServerDialect.kt

@@ -48,6 +48,8 @@ internal object SQLServerDataTypeProvider : DataTypeProvider() {
             }
         }
     }
+
+    override fun hexToDb(hexString: String): String = "0x$hexString"
 }
 
 internal object SQLServerFunctionProvider : FunctionProvider() {

exposed-core/src/main/kotlin/org/jetbrains/exposed/sql/vendors/SQLiteDialect.kt

@@ -16,6 +16,7 @@ internal object SQLiteDataTypeProvider : DataTypeProvider() {
     override fun binaryType(): String = "BLOB"
     override fun dateTimeType(): String = "TEXT"
     override fun booleanToStatementString(bool: Boolean) = if (bool) "1" else "0"
+    override fun hexToDb(hexString: String): String = "X'$hexString'"
 }
 
 internal object SQLiteFunctionProvider : FunctionProvider() {

exposed-tests/src/test/kotlin/org/jetbrains/exposed/sql/tests/shared/DDLTests.kt

@@ -406,7 +406,7 @@ class DDLTests : DatabaseTestsBase() {
         withTables(t) {
             val shortBytes = "Hello there!".toByteArray()
             val longBytes = Random.nextBytes(1024)
-            val shotBlob = ExposedBlob(shortBytes)
+            val shortBlob = ExposedBlob(shortBytes)
             val longBlob = ExposedBlob(longBytes)
 //            if (currentDialectTest.dataTypeProvider.blobAsStream) {
 //                    SerialBlob(bytes)
@@ -415,7 +415,7 @@ class DDLTests : DatabaseTestsBase() {
 //                }
 
             val id1 = t.insert {
-                it[t.b] = shotBlob
+                it[t.b] = shortBlob
             } get (t.id)
 
             val id2 = t.insert {
@@ -438,6 +438,37 @@ class DDLTests : DatabaseTestsBase() {
         }
     }
 
+    @Test
+    fun testBlobDefault() {
+        val defaultBlobStr = "test"
+        val defaultBlob = ExposedBlob(defaultBlobStr.encodeToByteArray())
+
+        val TestTable = object : Table("TestTable") {
+            val number = integer("number")
+            val blobWithDefault = blob("blobWithDefault").default(defaultBlob)
+        }
+
+        withDb { testDb ->
+            when (testDb) {
+                TestDB.MYSQL -> {
+                    expectException<ExposedSQLException> {
+                        SchemaUtils.create(TestTable)
+                    }
+                }
+                else -> {
+                    SchemaUtils.create(TestTable)
+
+                    TestTable.insert {
+                        it[number] = 1
+                    }
+                    assertEquals(defaultBlobStr, String(TestTable.selectAll().first()[TestTable.blobWithDefault].bytes))
+
+                    SchemaUtils.drop(TestTable)
+                }
+            }
+        }
+    }
+
     @Test
     fun testBinaryWithoutLength() {
         val tableWithBinary = object : Table("TableWithBinary") {