add tips

Author: stelin

src/Request.php

@@ -294,7 +294,8 @@ public function withUploadedFiles(array $uploadedFiles)
      */
     public function getRawBody(): string
     {
-        return $this->coRequest->rawContent();
+        $body = $this->coRequest->rawContent();
+        return ($body === false) ? '' : $body;
     }
 
     /**
@@ -306,17 +307,23 @@ public function getRawBody(): string
     public function getParsedBody()
     {
         // Need init
-        if ($this->parsedBody === null) {
-            $parsedBody = $this->coRequest->post ?? [];
+        if ($this->parsedBody !== null) {
+            return $this->parsedBody;
+        }
 
-            // Parse body
-            if (!$parsedBody && !$this->isGet()) {
-                $parsedBody = $this->parseRawBody($this->getRawBody());
-            }
 
-            $this->parsedBody = $parsedBody;
+        $parsedBody = $this->coRequest->post ?? [];
+
+        // Parse body
+        if (!$parsedBody && !$this->isGet()) {
+            $rawBody = $this->getRawBody();
+            if (!empty($rawBody)) {
+                $parsedBody = $this->parseRawBody($rawBody);
+            }
         }
 
+        $this->parsedBody = $parsedBody;
+
         return $this->parsedBody;
     }
 
@@ -365,12 +372,13 @@ public function getAttributes(): array
 
     /**
      * @inheritdoc
-     * @see getAttributes()
      *
      * @param string $name    The attribute name.
      * @param mixed  $default Default value to return if the attribute does not exist.
      *
      * @return mixed
+     * @see getAttributes()
+     *
      */
     public function getAttribute($name, $default = null)
     {
@@ -380,12 +388,12 @@ public function getAttribute($name, $default = null)
     /**
      * @inheritdoc
      *
-     * @see getAttributes()
-     *
      * @param string $name  The attribute name.
      * @param mixed  $value The value of the attribute.
      *
      * @return static
+     * @see getAttributes()
+     *
      */
     public function withAttribute($name, $value)
     {
@@ -398,11 +406,11 @@ public function withAttribute($name, $value)
     /**
      * @inheritdoc
      *
-     * @see getAttributes()
-     *
      * @param string $name The attribute name.
      *
      * @return static
+     * @see getAttributes()
+     *
      */
     public function withoutAttribute($name)
     {