Add support for blob SQL type in relational queries

SQLite does not support selecting a blob type column in 'json_array()' and this function is used in relational queries.
Solve this by wrapping blob type columns in 'hex()' function to cast the blob to a hex string that we can parse back into a blob later.
Said 'later' being the 'mapFromDriverValue' step where inside this function we turn the hex string back into a buffer before passing it along.

drizzle-orm/src/sqlite-core/columns/blob.ts

@@ -3,6 +3,7 @@ import type { ColumnBaseConfig } from '~/column.ts';
 import { entityKind } from '~/entity.ts';
 import type { AnySQLiteTable } from '~/sqlite-core/table.ts';
 import type { Equal } from '~/utils.ts';
+import { hexStringToBuffer } from '../utils.ts';
 import { SQLiteColumn, SQLiteColumnBuilder } from './common.ts';
 
 type BlobMode = 'buffer' | 'json' | 'bigint';
@@ -40,8 +41,8 @@ export class SQLiteBigInt<T extends ColumnBaseConfig<'bigint', 'SQLiteBigInt'>>
 		return 'blob';
 	}
 
-	override mapFromDriverValue(value: Buffer): bigint {
-		return BigInt(value.toString());
+	override mapFromDriverValue(value: Buffer | string): bigint {
+		return BigInt(typeof value === 'string' ? value : value.toString());
 	}
 
 	override mapToDriverValue(value: bigint): Buffer {
@@ -85,8 +86,8 @@ export class SQLiteBlobJson<T extends ColumnBaseConfig<'json', 'SQLiteBlobJson'>
 		return 'blob';
 	}
 
-	override mapFromDriverValue(value: Buffer): T['data'] {
-		return JSON.parse(value.toString());
+	override mapFromDriverValue(value: Buffer | string): T['data'] {
+		return JSON.parse(typeof value === 'string' ? value : value.toString());
 	}
 
 	override mapToDriverValue(value: T['data']): Buffer {
@@ -126,6 +127,13 @@ export class SQLiteBlobBuffer<T extends ColumnBaseConfig<'buffer', 'SQLiteBlobBu
 	getSQLType(): string {
 		return 'blob';
 	}
+
+	override mapFromDriverValue(value: Buffer | string): Buffer {
+		if (typeof value === 'string') {
+			value = hexStringToBuffer(value);
+		}
+		return value;
+	}
 }
 
 export interface BlobConfig<TMode extends BlobMode = BlobMode> {

drizzle-orm/src/sqlite-core/columns/custom.ts

@@ -4,6 +4,7 @@ import { entityKind } from '~/entity.ts';
 import type { SQL } from '~/sql/sql.ts';
 import type { AnySQLiteTable } from '~/sqlite-core/table.ts';
 import type { Equal } from '~/utils.ts';
+import { hexStringToBuffer } from '../utils.ts';
 import { SQLiteColumn, SQLiteColumnBuilder } from './common.ts';
 
 export type ConvertCustomConfig<TName extends string, T extends Partial<CustomTypeValues>> =
@@ -79,6 +80,9 @@ export class SQLiteCustomColumn<T extends ColumnBaseConfig<'custom', 'SQLiteCust
 	}
 
 	override mapFromDriverValue(value: T['driverParam']): T['data'] {
+		if (typeof value === 'string' && this.getSQLType() === 'blob') {
+			value = hexStringToBuffer(value);
+		}
 		return typeof this.mapFrom === 'function' ? this.mapFrom(value) : value as T['data'];
 	}
 

drizzle-orm/src/sqlite-core/dialect.ts

@@ -638,7 +638,13 @@ export abstract class SQLiteDialect {
 			let field = sql`json_array(${
 				sql.join(
 					selection.map(({ field }) =>
-						is(field, SQLiteColumn) ? sql.identifier(field.name) : is(field, SQL.Aliased) ? field.sql : field
+						is(field, SQLiteColumn)
+							? field.getSQLType() === 'blob'
+								? sql.raw(`hex("${field.name}")`)
+								: sql.identifier(field.name)
+							: is(field, SQL.Aliased)
+							? field.sql
+							: field
 					),
 					sql`, `,
 				)

drizzle-orm/src/sqlite-core/utils.ts

@@ -64,3 +64,14 @@ export function getViewConfig<
 		...view[SQLiteViewConfig],
 	};
 }
+
+export function hexStringToBuffer(hexString: string): Buffer {
+	const numChunks = Math.ceil(hexString.length / 2);
+	const chunks = Array.from<number>({ length: numChunks });
+
+	for (let i = 0; i < numChunks; ++i) {
+		chunks[i] = Number.parseInt(hexString.slice(2 * i, 2 * i + 2), 16);
+	}
+
+	return Buffer.from(chunks);
+}