feat(json-pack): 🎸 add RESP v2 encoding ability

Author: streamich

src/json-pack/resp/RespEncoder.ts

@@ -10,6 +10,9 @@ import type {Slice} from '../../util/buffers/Slice';
 const REG_RN = /[\r\n]/;
 const isSafeInteger = Number.isSafeInteger;
 
+/**
+ * Implements RESP3 encoding.
+ */
 export class RespEncoder<W extends IWriter & IWriterGrowable = IWriter & IWriterGrowable>
   implements BinaryJsonEncoder, StreamingBinaryJsonEncoder, TlvBinaryJsonEncoder
 {
@@ -244,6 +247,13 @@ export class RespEncoder<W extends IWriter & IWriterGrowable = IWriter & IWriter
     writer.u16(RESP.RN); // \r\n
   }
 
+  public writeSimpleStrAscii(str: string): void {
+    const writer = this.writer;
+    writer.u8(RESP.STR_SIMPLE); // +
+    writer.ascii(str);
+    writer.u16(RESP.RN); // \r\n
+  }
+
   public writeBulkStr(str: string): void {
     const writer = this.writer;
     const size = utf8Size(str);

src/json-pack/resp/RespEncoderLegacy.ts

@@ -0,0 +1,96 @@
+import {RESP} from './constants';
+import {RespAttributes, RespPush, RespVerbatimString} from './extensions';
+import {JsonPackExtension} from '../JsonPackExtension';
+import {RespEncoder} from './RespEncoder';
+import type {IWriter, IWriterGrowable} from '../../util/buffers';
+
+const REG_RN = /[\r\n]/;
+const isSafeInteger = Number.isSafeInteger;
+
+/**
+ * Implements RESP v2 encoding.
+ */
+export class RespEncoderLegacy<W extends IWriter & IWriterGrowable = IWriter & IWriterGrowable> extends RespEncoder<W> {
+  public writeAny(value: unknown): void {
+    switch (typeof value) {
+      case 'number':
+        return this.writeNumber(value as number);
+      case 'string':
+        return this.writeStr(value);
+      case 'boolean':
+        return this.writeSimpleStr(value ? 'TRUE' : 'FALSE');
+      case 'object': {
+        if (!value) return this.writeNull();
+        if (value instanceof Array) return this.writeArr(value);
+        if (value instanceof Uint8Array) return this.writeBin(value);
+        if (value instanceof Error) return this.writeErr(value.message);
+        if (value instanceof Set) return this.writeSet(value);
+        if (value instanceof JsonPackExtension) {
+          if (value instanceof RespPush) return this.writeArr(value.val);
+          if (value instanceof RespVerbatimString) return this.writeStr(value.val);
+          if (value instanceof RespAttributes) return this.writeObj(value.val);
+        }
+        return this.writeObj(value as Record<string, unknown>);
+      }
+      case 'undefined':
+        return this.writeUndef();
+      case 'bigint':
+        return this.writeSimpleStrAscii(value + '');
+      default:
+        return this.writeUnknown(value);
+    }
+  }
+
+  public writeNumber(num: number): void {
+    if (isSafeInteger(num)) this.writeInteger(num);
+    else this.writeSimpleStrAscii(num + '');
+  }
+
+  public writeStr(str: string): void {
+    const length = str.length;
+    if (length < 64 && !REG_RN.test(str)) this.writeSimpleStr(str);
+    else this.writeBulkStr(str);
+  }
+
+  public writeNull(): void {
+    this.writeNullArr();
+  }
+
+  public writeErr(str: string): void {
+    if (str.length < 64 && !REG_RN.test(str)) this.writeSimpleErr(str);
+    else this.writeBulkStr(str);
+  }
+
+  public writeSet(set: Set<unknown>): void {
+    this.writeArr([...set]);
+  }
+
+  public writeArr(arr: unknown[]): void {
+    const writer = this.writer;
+    const length = arr.length;
+    writer.u8(RESP.ARR); // *
+    this.writeLength(length);
+    writer.u16(RESP.RN); // \r\n
+    for (let i = 0; i < length; i++) {
+      const val = arr[i];
+      if (val === null) this.writeNullStr();
+      else this.writeAny(val);
+    };
+  }
+
+  public writeObj(obj: Record<string, unknown>): void {
+    const writer = this.writer;
+    const keys = Object.keys(obj);
+    const length = keys.length;
+    writer.u8(RESP.ARR); // %
+    this.writeLength(length << 1);
+    writer.u16(RESP.RN); // \r\n
+    for (let i = 0; i < length; i++) {
+      const key = keys[i];
+      this.writeStr(key);
+      const val = obj[key];
+      if (val === null) this.writeNullStr();
+      else this.writeAny(val);
+    }
+  }
+}

src/json-pack/resp/__tests__/RespEncoderLegacy.spec.ts

@@ -0,0 +1,52 @@
+import {RespEncoderLegacy} from '../RespEncoderLegacy';
+
+const encode = (value: unknown): string => {
+  const encoder = new RespEncoderLegacy();
+  const encoded = encoder.encode(value);
+  return Buffer.from(encoded).toString();
+};
+
+test('can encode simple strings', () => {
+  expect(encode('')).toBe('+\r\n');
+  expect(encode('asdf')).toBe('+asdf\r\n');
+});
+
+test('can encode simple errors', () => {
+  expect(encode(new Error('asdf'))).toBe('-asdf\r\n');
+});
+
+test('can encode integers', () => {
+  expect(encode(0)).toBe(':0\r\n');
+  expect(encode(123)).toBe(':123\r\n');
+  expect(encode(-422469777)).toBe(':-422469777\r\n');
+});
+
+test('can encode bulk strings', () => {
+  expect(encode('ab\nc')).toBe('$4\r\nab\nc\r\n');
+  expect(encode(new Uint8Array([65]))).toBe('$1\r\nA\r\n');
+});
+
+test('can encode arrays', () => {
+  expect(encode(['a', 1])).toBe('*2\r\n+a\r\n:1\r\n');
+});
+
+test('encodes null as nullable array', () => {
+  expect(encode(null)).toBe('*-1\r\n');
+});
+
+test('encodes null in nested structure as nullable string', () => {
+  expect(encode(['a', 'b', null])).toBe('*3\r\n+a\r\n+b\r\n$-1\r\n');
+});
+
+test('encodes booleans as strings', () => {
+  expect(encode(true)).toBe('+TRUE\r\n');
+  expect(encode(false)).toBe('+FALSE\r\n');
+});
+
+test('encodes floats as strings', () => {
+  expect(encode(1.23)).toBe('+1.23\r\n');
+});
+
+test('encodes objects as 2-tuple arrays', () => {
+  expect(encode({foo: 'bar'})).toBe('*2\r\n+foo\r\n+bar\r\n');
+});

src/json-pack/resp/index.ts

@@ -1,4 +1,6 @@
 export * from './constants';
 export * from './extensions';
 export * from './RespEncoder';
+export * from './RespEncoderLegacy';
 export * from './RespDecoder';
+export * from './RespStreamingDecoder';