fix: make BusProNet response failures diagnosable and non-fatal

src/BusProNet/ApiClientTrait.php

@@ -58,15 +58,58 @@ trait ApiClientTrait
         fwrite($socket, $send);
     }
 
+    /**
+     * Reads a single response message. The protocol prepends the payload length as a
+     * 10 byte header, so read exactly that many bytes rather than guessing at EOF:
+     * a peer that closes mid-stream would otherwise yield a silently truncated body.
+     *
+     * @throws ApiClientException
+     */
     private function receive($socket): string
     {
-        $response = '';
+        $header = $this->readBytes($socket, 10);
 
-        while (false === feof($socket)) {
-            $response .= fread($socket, 4096);
+        if (10 !== strlen($header)) {
+            throw new ApiClientException(sprintf('Incomplete response header, got %d of 10 bytes', strlen($header)));
         }
 
-        return $response;
+        $expectedLength = (int) trim($header);
+
+        if (1 > $expectedLength) {
+            throw new ApiClientException(sprintf('Response announced an empty body (header "%s")', trim($header)));
+        }
+
+        $body = $this->readBytes($socket, $expectedLength);
+
+        if (strlen($body) !== $expectedLength) {
+            throw new ApiClientException(sprintf('Truncated response, got %d of %d announced bytes', strlen($body), $expectedLength));
+        }
+
+        return $body;
+    }
+
+    /**
+     * @throws ApiClientException
+     */
+    private function readBytes($socket, int $length): string
+    {
+        $buffer = '';
+
+        while (strlen($buffer) < $length && false === feof($socket)) {
+            $chunk = fread($socket, min(4096, $length - strlen($buffer)));
+
+            if (false === $chunk || '' === $chunk) {
+                if (true === (stream_get_meta_data($socket)['timed_out'] ?? false)) {
+                    throw new ApiClientException(sprintf('Timed out reading response after %d of %d bytes', strlen($buffer), $length));
+                }
+
+                break;
+            }
+
+            $buffer .= $chunk;
+        }
+
+        return $buffer;
     }
 
     private function disconnect($socket): void