当content-type设置为application/json时,JSON.parse()不起作用

Question

我在尝试解析从服务器返回的JSON字符串时遇到了jquery(错误/错误):

Timestamp: 10/04/2013 21:05:12
Error: SyntaxError: JSON.parse: unexpected character
Source File: http://ajax.googleapis.com/ajax/libs/jquery/1.9.1/jquery.min.js
Line: 3

我注意到当标题Content-type没有设置为'application/json'时JSON.parse正常工作但如果Content-type设置为json则不起作用.知道为什么会这样吗？

不工作代码:

控制器代码:

  $response = array('data' => array('msg' => 'Form did not validate'), 'response_handler_fn' => 'sign_up_response_handler_fn');
  $this->getResponse()->setHttpHeader('Content-type','application/json');
  return $this->renderText(json_encode($response));

使用Javascript:

// ...
success: function( response ) {
var responseData = $.parseJSON(response);
}

头

Cache-Control   no-store, no-cache, must-revalidate, post-check=0, pre-check=0
Connection  Keep-Alive
Content-Length  92
Content-Type    application/json
Date    Wed, 10 Apr 2013 20:05:12 GMT
Expires Thu, 19 Nov 1981 08:52:00 GMT
Keep-Alive  timeout=15, max=100
Pragma  no-cache
Server  Apache
X-Powered-By    PHP/5.3.5

响应:

{"data":{"msg":"Form did not validate"},"response_handler_fn":"sign_up_response_handler_fn"}

有效的代码

控制器:

  $response = array('data' => array('msg' => 'Form did not validate'), 'response_handler_fn' => 'sign_up_response_handler_fn');
  return $this->renderText(json_encode($response));

Javascript和工作的一样

头:

Cache-Control   no-store, no-cache, must-revalidate, post-check=0, pre-check=0
Connection  Keep-Alive
Content-Length  92
Content-Type    text/html; charset=utf-8
Date    Wed, 10 Apr 2013 20:09:04 GMT
Expires Thu, 19 Nov 1981 08:52:00 GMT
Keep-Alive  timeout=15, max=100
Pragma  no-cache
Server  Apache
X-Powered-By    PHP/5.3.5

响应:

{"data":{"msg":"Form did not validate"},"response_handler_fn":"sign_up_response_handler_fn"}

Answer 1

如果未指定调用dataType选项$.ajax,jQuery将尝试根据响应中Content-Type返回的标头解析响应.

因此,当您dataType为该Content-Type标题指定任何内容时,标题没有任何特殊内容,则将response其解析为文本.

如果没有指定任何内容dataType,并且Content-Type标题的"json" response被解析为JSON(Javascript对象文字).

当你指定dataType为"json"时,Content-Type标题response是什么并不重要,它被解析为JSON(Javascript对象文字).

尝试传递对象文字JSON.parse将失败,因为它只接受一个字符串.

因此,您需要确定您正在设置的内容以及您要调用的内容(JSON.parse),并使用正确的组合.