fix the source to get content type (#1622)

var/Typecho/Request.php

@@ -351,6 +351,19 @@ class Request
         return ($this->pathInfo = '/' . ltrim(urldecode($pathInfo), '/'));
     }
 
+    /**
+     * 获取请求的内容类型
+     *
+     * @return string|null
+     */
+    public function getContentType(): ?string
+    {
+        return $this->getServer(
+            'CONTENT_TYPE',
+            $this->getServer('HTTP_CONTENT_TYPE')
+        );
+    }
+
     /**
      * 获取环境变量
      *
@@ -492,7 +505,10 @@ class Request
      */
     public function isJson(): bool
     {
-        return !!preg_match("/^\s*application\/json(;|$)/i", $this->getHeader('Content-Type', ''));
+        return !!preg_match(
+            "/^\s*application\/json(;|$)/i",
+            $this->getContentType() ?? ''
+        );
     }
 
     /**

var/Typecho/Widget/Request.php

@@ -213,6 +213,16 @@ class Request
         return $this->request->makeUriByRequest($parameter);
     }
 
+    /**
+     * 获取请求的内容类型
+     *
+     * @return string|null
+     */
+    public function getContentType(): ?string
+    {
+        return $this->request->getContentType();
+    }
+
     /**
      * 获取环境变量
      *
@@ -317,6 +327,16 @@ class Request
         return $this->request->isAjax();
     }
 
+    /**
+     * 判断是否为json
+     *
+     * @return boolean
+     */
+    public function isJson(): bool
+    {
+        return $this->request->isJson();
+    }
+
     /**
      * 判断输入是否满足要求
      *