Question

出于某种原因，我无法从控制器获取post变量

AJAX / Javascript

function uploadImage(userActionPath,type)
{

    if( (userActionPath == 'undefined') || (type == 'undefined')) {
        console.error("no parameters for function uploadImage defined");
    }

    if((base64code == 'undefined') || (base64code == null))
    {
        console.error("please select an image");
    }

    var xml = ( window.XMLHttpRequest ) ?
            new XMLHttpRequest() : new ActiveXObject("Microsoft.XMLHTTP");

    alert(base64code); //<- shows the base64 code, so its there

    var params = userActionPath+"?imagebase64="+base64code+"&type="+type;

    xml.open("POST",userActionPath,true);
    xml.setRequestHeader("Content-Type", "application/json;charset=UTF-8");

    xml.onreadystatechange = function()
    {
        if( xml.readyState === 4 && xml.status === 200 )
        {
            var serverResponse = JSON.parse(xml.responseText);

            switch(serverResponse.f)
            {
                case 0:
                    console.log('love sosa'); //<- I get the response
                    break;
            }
        }
    };
    xml.send(params);
}

控制器

class LiveuploadController extends Controller
{
    /**
     * @Route("/LiveUpload",name="fileLiveUpload")
     * @Template()
     */
    public function indexAction(Request $request)
    {
        //I have tried these but 'imagebase64' returns null
        //returns null 
          $value = $request->request->get('imagebase64');
        //returns null
          $value = $request->query->get('imagebase64');
       //returns null 
          $value = $this->get('request')->request->get('imagebase64');

        $response = array('f'=>0,'base64'=>$value);
        return new Response(json_encode($response));
    }
}

请求标头还显示正在发送变量。但是类型和imagebase64变量在控制器上都返回null

Answer 1

问题在于您设置XmlHttpRequest的方式。您已将其设置为应该使用GET，但是当您想要POST时，它会有所不同。有关如何发送POST请求的详细信息，请查看this question。它的快速和肮脏是：

var xml = ( window.XMLHttpRequest ) ?
        new XMLHttpRequest() : new ActiveXObject("Microsoft.XMLHTTP");
var params = "imagebase64="+base64code+"&type="+type;
xml.open("POST", userActionPath, true);

xml.setRequestHeader("Content-type", "application/x-www-form-urlencoded");
xml.setRequestHeader("Content-length", params.length);
xml.setRequestHeader("Connection", "close");

xml.onreadystatechange = function()
{
    if( xml.readyState === 4 && xml.status === 200 )
    {
        var serverResponse = JSON.parse(xml.responseText);

        switch(serverResponse.f)
        {
            case 0:
                console.log('love sosa'); //<- I get the response
                break;
        }
    }
};
xml.send(params);

在您的示例代码中，您将标头设置为期望JSON，但您的参数是urlencoded。设置正确的标题应该可以解决问题。

在你的控制器中，如果你使用的是POST，那么你应该得到这样的请求变量：

// Use this for getting variables of POST requests
$value = $request->request->get('imagebase64');

// This is used for getting variables of GET requests
$value = $request->query->get('imagebase64');

Answer 2

JS中的这行代码：

xml.open("POST",userActionPath,true);

您实际上是在提供userActionPath而不是params变量。它应该是：

xml.open("POST",params,true);

至于控制器的代码，你应该使用：

$value = $request->query->get('imagebase64');

希望这会有所帮助......

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