chore: proxy improvements (#3121)

* introduce global interceptors

* move proxy stuff to new folder

* implement resp framer

* properly handle request/response and push

* add global interceptor

packages/test-utils/lib/proxy/resp-framer.ts

@@ -0,0 +1,167 @@
+// RespFramer: Frames raw Buffer data into complete RESP messages
+// Accumulates incoming bytes and emits each complete RESP message as a separate Buffer
+
+import EventEmitter from "node:events";
+
+export interface RespFramerEvents {
+  message: (data: Buffer) => void;
+  push: (data: Buffer) => void;
+}
+
+export default class RespFramer extends EventEmitter {
+  private buffer: Buffer;
+  private offset: number;
+
+  constructor() {
+    super();
+    this.buffer = Buffer.alloc(0);
+    this.offset = 0;
+  }
+
+  public write(data: Buffer) {
+    this.buffer = Buffer.concat([this.buffer, data]);
+
+    while (this.offset < this.buffer.length) {
+      const messageEnd = this.findMessageEnd(this.buffer, this.offset);
+      if (messageEnd === -1) {
+        break; // Incomplete message
+      }
+      const message = this.buffer.subarray(this.offset, messageEnd);
+      this.emit("message", message);
+      this.offset = messageEnd;
+    }
+
+    // Remove processed data from the buffer
+    if (this.offset > 0) {
+      this.buffer = this.buffer.subarray(this.offset);
+      this.offset = 0;
+    }
+  }
+
+  private findMessageEnd(buffer: Buffer, start: number): number {
+    if (start >= buffer.length) {
+      return -1;
+    }
+    const prefix = String.fromCharCode(buffer[start]);
+    switch (prefix) {
+      case "+": // Simple String
+      case "-": // Error
+      case ":": // Integer
+      case "_": // Null
+      case "#": // Boolean
+      case ",": // Double
+      case "(": // Big Number
+        return this.findLineEnd(buffer, start);
+      case "$": // Bulk String
+      case "!": // Bulk Error
+      case "=": // Verbatim String
+        return this.findBulkStringEnd(buffer, start);
+      case "*": // Array
+        return this.findArrayEnd(buffer, start);
+      case "%": // Map
+        return this.findMapEnd(buffer, start);
+      case "~": // Set
+      case ">": // Push
+        return this.findArrayEnd(buffer, start);
+      case "|": // Attribute
+        return this.findAttributeEnd(buffer, start);
+      default:
+        return -1; // Unknown prefix
+    }
+  }
+
+  private findArrayEnd(buffer: Buffer, start: number): number {
+    const result = this.readLength(buffer, start);
+    if (!result) {
+      return -1;
+    }
+    const { length, lineEnd } = result;
+    if (length === -1) {
+      return lineEnd;
+    }
+    let currentOffset = lineEnd;
+    for (let i = 0; i < length; i++) {
+      const elementEnd = this.findMessageEnd(buffer, currentOffset);
+      if (elementEnd === -1) {
+        return -1;
+      }
+      currentOffset = elementEnd;
+    }
+    return currentOffset;
+  }
+
+  private findBulkStringEnd(buffer: Buffer, start: number): number {
+    const result = this.readLength(buffer, start);
+    if (!result) {
+      return -1;
+    }
+    const { length, lineEnd } = result;
+    if (length === -1) {
+      return lineEnd;
+    }
+    const totalLength = lineEnd + length + 2;
+    return totalLength <= buffer.length ? totalLength : -1;
+  }
+
+  private findMapEnd(buffer: Buffer, start: number): number {
+    const result = this.readLength(buffer, start);
+    if (!result) {
+      return -1;
+    }
+    const { length, lineEnd } = result;
+    if (length === -1) {
+      return lineEnd;
+    }
+    let currentOffset = lineEnd;
+    for (let i = 0; i < length * 2; i++) {
+      const elementEnd = this.findMessageEnd(buffer, currentOffset);
+      if (elementEnd === -1) {
+        return -1;
+      }
+      currentOffset = elementEnd;
+    }
+    return currentOffset;
+  }
+
+  private findAttributeEnd(buffer: Buffer, start: number): number {
+    const result = this.readLength(buffer, start);
+    if (!result) {
+      return -1;
+    }
+    const { length, lineEnd } = result;
+    let currentOffset = lineEnd;
+    for (let i = 0; i < length * 2; i++) {
+      const elementEnd = this.findMessageEnd(buffer, currentOffset);
+      if (elementEnd === -1) {
+        return -1;
+      }
+      currentOffset = elementEnd;
+    }
+    const valueEnd = this.findMessageEnd(buffer, currentOffset);
+    if (valueEnd === -1) {
+      return -1;
+    }
+    return valueEnd;
+  }
+
+  private findLineEnd(buffer: Buffer, start: number): number {
+    const end = buffer.indexOf("\r\n", start);
+    return end !== -1 ? end + 2 : -1;
+  }
+
+  private readLength(
+    buffer: Buffer,
+    start: number,
+  ): { length: number; lineEnd: number } | null {
+    const lineEnd = this.findLineEnd(buffer, start);
+    if (lineEnd === -1) {
+      return null;
+    }
+    const lengthLine = buffer.subarray(start + 1, lineEnd - 2).toString();
+    const length = parseInt(lengthLine, 10);
+    if (isNaN(length)) {
+      return null;
+    }
+    return { length, lineEnd };
+  }
+}