将错误消息从php发送到ajax [英] Send error messages from php to ajax

问题描述

我正在尝试从php向ajax发送通知"或错误消息.我正在尝试实现以下目标:

I am trying to send a "notification" or error messages from php to ajax. I'm trying to achieve something like this:

php:

if (myString == '') {
    // Send "stringIsEmpty" error to ajax
} else if (myString == 'foo') {
    // Send "stringEqualsFoo" error to ajax
}

ajax

$.ajax({
    url: $(this).attr("action"),
    context: document.body,
    data: formData, 
    type: "POST",  
    contentType: false,
    processData: false,
    success: function(){
        alert("It works");
    },
    error: function() {
        if(stringIsEmpty) {
            alert("String is empty");
        } else if(stringEqualsFoo) {
            alert("String equals Foo");
        }
    }
});

如何向ajax发送错误消息?

How can I send error messages to ajax?

更新

这是我拥有的php文件.我尝试使用echo解决方案回答说，但是当我输出data是什么(在ajax中)时，我得到了undefined:

Here's the php file I have. I tried using the echo solution answers said, but when I output what the data is (in ajax), I get undefined:

<?php
$img=$_FILES['img'];
    if($img['name']==''){
        echo('noImage');
    }else{
        $filename = $img['tmp_name'];
        $client_id="myId";
        $handle = fopen($filename, "r");
        $data = fread($handle, filesize($filename));
        $pvars   = array('image' => base64_encode($data));
        $timeout = 30;
        $curl = curl_init();
        curl_setopt($curl, CURLOPT_SSL_VERIFYPEER, false);
        curl_setopt($curl, CURLOPT_URL, 'https://api.imgur.com/3/image.json');
        curl_setopt($curl, CURLOPT_TIMEOUT, $timeout);
        curl_setopt($curl, CURLOPT_HTTPHEADER, array('Authorization: Client-ID ' . $client_id));
        curl_setopt($curl, CURLOPT_POST, 1);
        curl_setopt($curl, CURLOPT_RETURNTRANSFER, 1);
        curl_setopt($curl, CURLOPT_POSTFIELDS, $pvars);
        $out = curl_exec($curl);
        curl_close ($curl);
        $pms = json_decode($out,true);
        $url=$pms['data']['link'];
        if($url!=""){
            echo "<h2>Uploaded Without Any Problem</h2>";
            echo "<img src='$url'/>";
        }else{
            echo "<h2>There's a Problem</h2>";
            echo $pms['data']['error'];
            header("HTTP/1.1 404 Not Found");
        } 
    }
?>

我在if($img['name']==''){

推荐答案

仅当请求失败时，才会调用错误函数，请参见 http://api.jquery.com/jQuery.ajax/

The error function will only be called if the request fails, see http://api.jquery.com/jQuery.ajax/

因此，如果您从PHP服务器返回响应，则不会触发错误功能.但是，您可以根据从PHP发送的响应定义一个函数来处理错误:

So if you return a response from your PHP server, the error function won't be triggered. However, you can define a function to handle the error based on the response you send from PHP:

success: function(data){
        if (data === "stringIsEmpty") {
           triggerError("stringIsEmpty");
        } else if (data === "stringEqualsFoo") {
           triggerError("stringEqualsFoo");
        }
    },

然后您可以具有以下错误功能:

And then you can have the error function like this:

function triggerError(error) {
    if (error === "stringIsEmpty") {
        alert("Your string is empty!");
    } else if (error === "stringEqualsFoo") {
        alert("Your string is equal to Foo!");
    }
}

如果您请求发送post.php，则只需返回一个字符串即可:

If you make a request to let's say post.php, you can just return a string:

// Create a function to see if the string is empty
$funcOutput = isStringEmpty();
echo $funcOutput;

或者专门用于示例:

echo "stringIsEmpty";

有关更多信息，请参见:如何从PHP返回数据到jQuery ajax调用

For more information see: How to return data from PHP to a jQuery ajax call

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