从服务器 PHP 数组中提取 JSON 数据的问题

Question

我正在尝试从我服务器上的 PHP 文件创建的 JSON 响应中提取股票价格。我在下面描述了 2 个测试，测试 1 成功地从文件中提取 JSON 数据，测试 2。从服务器上的 PHP 脚本获取 JSON 数据会导致错误。我已经为此工作了很长时间，因此非常感谢您对获得解决方案的任何帮助，非常感谢。

我在客户端使用 Wordpress 和 Woody Universal Snippets，最终我会将代码集成到数据表脚本中。

测试 1. 从服务器上的文本文件中获取 JSON 数据工作 100% 以下

<script>

var ourRequest = new XMLHttpRequest();
ourRequest.open("GET", "../../Editor-PHP-1.9.0/controllers/ajax_stock_holdings_json1.txt");

//ourRequest.open("GET", "../../Editor-PHP-1.9.0/controllers/ajax_stock_holdings1.php");
//ourRequest.open("GET", "https://dividendlook.co.uk/Editor-PHP-1.9.0/controllers/ajax_stock_holdings1.php");   
ourRequest.onload = function() {
console.log(ourRequest.responseText);
    var ourDataJSON = JSON.parse(ourRequest.responseText);
}
ourRequest.send();  
</script>

JSON 文件 ajax_stock_holdings_json1.txt

[
  {
    "symbol": "CTY.LSE",
    "price" : "430"
  }
]

测试 2. 失败 注释掉一行

ourRequest.open("GET", "../../Editor-PHP-1.9.0/controllers/ajax_stock_holdings_json1.txt");

取消注释行

ourRequest.open("GET", "../../Editor-PHP-1.9.0/controllers/ajax_stock_holdings1.php");

在下面运行本地客户端脚本

<script>

var ourRequest = new XMLHttpRequest();
//ourRequest.open("GET", "../../Editor-PHP-1.9.0/controllers/ajax_stock_holdings_json1.txt");

ourRequest.open("GET", "../../Editor-PHP-1.9.0/controllers/ajax_stock_holdings1.php");
//ourRequest.open("GET", "https://dividendlook.co.uk/Editor-PHP-1.9.0/controllers/ajax_stock_holdings1.php");   
ourRequest.onload = function() {
console.log(ourRequest.responseText);
    var ourDataJSON = JSON.parse(ourRequest.responseText);
}
ourRequest.send();  
</script>

服务器 PHP 文件

<?php
 /* Loads the WordPress environment and template */
require( '../../wp-blog-header.php' );

global $current_user;
wp_get_current_user();

// DataTables PHP library
include( "../lib/DataTables.php" );

$json_array = array();
$stock_id = 709; // CTY.LSE

try {
    $pdo = new PDO(strtolower($sql_details['type']) . ":host=" . $sql_details['host'] . ";dbname=" . $sql_details['db'], $sql_details['user'], $sql_details['pass']);
    $pdo->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
    echo "Connected successfully" . "\n\n"; 
    }
catch(PDOException $e)
    {
    echo "Connection failed: " . $e->getMessage();
    }

$result = $pdo->query("SELECT id, symbol, name, price FROM dm_stocks WHERE id = $stock_id");
        foreach ($result as $row) {

                echo "" . $row['id'] . "";
                echo " : " . $row['symbol'] . "";
                echo " : " . $row['name'] . "";
                echo " : " . $row['price'] . "\n";

        array_push( $json_array, array('symbol'=>$row['symbol'], 'price'=>$row['price'] ) );
        }

echo json_encode($json_array); 

?>

结果是 ajax_stock_holdings1.php 网络响应

Connected successfully

709 : CTY.LSE : City of London Investment Trust Plc : 405.5
[{"symbol":"CTY.LSE","price":"405.5"}]

控制台日志

JQMIGRATE: Migrate is installed, version 1.4.1
(index):294 Connected successfully

709 : CTY.LSE : City of London Investment Trust Plc : 405.5
[{"symbol":"CTY.LSE","price":"405.5"}]
VM2786:1 Uncaught SyntaxError: Unexpected token C in JSON at position 0
    at JSON.parse (<anonymous>)
    at XMLHttpRequest.ourRequest.onload ((index):295)

使用 PHP 的完整路径取消注释行

ourRequest.open("GET", "https://dividendlook.co.uk/Editor-PHP-1.9.0/controllers/ajax_stock_holdings1.php"); 

导致以下错误

控制台显示

Access to XMLHttpRequest at 'https://dividendlook.co.uk/Editor-PHP-1.9.0/controllers/ajax_stock_holdings1.php' from origin 'https://www.dividendlook.co.uk' has been blocked by CORS policy: No 'Access-Control-Allow-Origin' header is present on the requested resource.

我尝试配置 HTTP 标头插件无济于事，这可能归结为无限数量的配置选项，知道如果有的话会清除我的错误。

我已将代码添加到我的服务器 PHP 文件以修复 Access-Control-Allow-Origin 问题，如下所示：-

<?php
 /* Loads the WordPress environment and template */
require( '../../wp-blog-header.php' );

global $current_user;
wp_get_current_user();

// DataTables PHP library
include( "../lib/DataTables.php" );

// HTTP Header 

header('Access-Control-Allow-Origin: https://dividendlook.co.uk');

$json_array = array();
$stock_id = 709; // CTY.LSE

...etc as before

Failed to load resource: the server responded with a status of 404 ()
jquery-migrate.min.js?ver=1.4.1:2 JQMIGRATE: Migrate is installed, version 1.4.1
(index):1 Access to XMLHttpRequest at 'https://dividendlook.co.uk/Editor-PHP-1.9.0/controllers/ajax_stock_holdings1.php' from origin 'https://www.dividendlook.co.uk' has been blocked by CORS policy: The 'Access-Control-Allow-Origin' header has a value 'https://divdendook.co.uk' that is not equal to the supplied origin.
generic-no-float.css:1 Failed to load resource: the server responded with a status of 404 ()

将下面一行替换为 PHP 文件，而不是用站点名替换前面的行

header('Access-Control-Allow-Origin: *');

导致错误

Failed to load resource: the server responded with a status of 404 ()
jquery-migrate.min.js?ver=1.4.1:2 JQMIGRATE: Migrate is installed, version 1.4.1
(index):294 Connected successfully

709 : CTY.LSE : City of London Investment Trust Plc : 405.5
[{"symbol":"CTY.LSE","price":"405.5"}]
(index):1 Uncaught SyntaxError: Unexpected token C in JSON at position 0
    at JSON.parse (<anonymous>)
    at XMLHttpRequest.ourRequest.onload ((index):295)
generic-no-float.css:1 Failed to load resource: the server responded with a status of 404 ()

我在 .htaccess 的末尾添加了以下代码，它修复了 CORS 策略：“Access-Control-Allow-Origin”问题，现在错误是

''' 加载资源失败：服务器响应状态为 404 () jquery-migrate.min.js?ver=1.4.1:2 JQMIGRATE：已安装 Migrate，版本 1.4.1 (index):290 ourRequest.responseText >>>>>:[{"symbol":"CTY.LSE","price":"405.5"}]:

但是，客户端脚本正常读取 JSON

新建客户端脚本

<script>    
var ourRequest = new XMLHttpRequest();
ourRequest.open("GET", "https://dividendlook.co.uk/Editor-PHP-1.9.0/controllers/ajax_stock_holdings1.php"); 
ourRequest.onload = function() {
console.log("ourRequest.responseText >>>>>:"+ourRequest.responseText+":<<<<");
}
ourRequest.send();  
</script>

Answer 1

在您的服务器上，PHP。添加那些必需的标题。浏览器拒绝来自不同来源的响应。要完成这项工作，请将 Access-Control-Allow-Origin 设置为“*”。这是来自任何来源的任何请求都会得到响应。