从API的JSON响应中高效提取特定字段的PHP教程

[
  {
    "callID": "U1A7B9F7T61A2BC05S2eI1",
    "callType": "sip",
    "participantID": 2,
    "started": 15551212,
    "updated": 15551212,
    "name": "TEST CALL",
    "fromAddress": "127.0.0.1:5060",
    "fromName": "WIRELESS CALLER",
    "fromNumber": "+15551212"
  },
  {
    "callID": "X2C8D0G8U72B3CD06T3fJ2",
    "callType": "sip",
    "participantID": 3,
    "started": 15551215,
    "updated": 15551215,
    "name": "OFFICE CALL",
    "fromAddress": "192.168.1.100:5060",
    "fromName": "OFFICE PHONE",
    "fromNumber": "+15553434"
  },
  {
    "callID": "Y3D9E1H9V83C4DE07U4gK3",
    "callType": "webrtc",
    "participantID": 4,
    "started": 15551220,
    "updated": 15551220,
    "name": "WEB CONFERENCE",
    "fromAddress": "127.0.0.1:5060",
    "fromName": "WEB USER",
    "fromNumber": "+15555656"
  }
]

<?php

$jsonResponseString = '[
  {
    "callID": "U1A7B9F7T61A2BC05S2eI1",
    "callType": "sip",
    "participantID": 2,
    "started": 15551212,
    "updated": 15551212,
    "name": "TEST CALL",
    "fromAddress": "127.0.0.1:5060",
    "fromName": "WIRELESS CALLER",
    "fromNumber": "+15551212"
  },
  {
    "callID": "X2C8D0G8U72B3CD06T3fJ2",
    "callType": "sip",
    "participantID": 3,
    "started": 15551215,
    "updated": 15551215,
    "name": "OFFICE CALL",
    "fromAddress": "192.168.1.100:5060",
    "fromName": "OFFICE PHONE",
    "fromNumber": "+15553434"
  },
  {
    "callID": "Y3D9E1H9V83C4DE07U4gK3",
    "callType": "webrtc",
    "participantID": 4,
    "started": 15551220,
    "updated": 15551220,
    "name": "WEB CONFERENCE",
    "fromAddress": "127.0.0.1:5060",
    "fromName": "WEB USER",
    "fromNumber": "+15555656"
  }
]';

// 将JSON字符串解码为关联数组
$data = json_decode($jsonResponseString, true);

// 检查解码是否成功
if (json_last_error() !== JSON_ERROR_NONE) {
    echo "JSON解码错误: " . json_last_error_msg();
    exit;
}

// 此时 $data 是一个PHP数组，可以通过 var_dump($data) 查看其结构
// var_dump($data);

?>

<?php
// 假设 $data 已经成功解码

// 访问第一个元素的 callID
if (isset($data[0]['callID'])) {
    echo "第一个呼叫ID: " . $data[0]['callID'] . "\n"; // 输出: U1A7B9F7T61A2BC05S2eI1
}

// 访问第一个元素的 fromAddress
if (isset($data[0]['fromAddress'])) {
    echo "第一个呼叫的源地址: " . $data[0]['fromAddress'] . "\n"; // 输出: 127.0.0.1:5060
}
?>

<?php
// 假设 $data 已经成功解码

$targetFromAddress = "127.0.0.1:5060";
$foundCallIDs = [];

// 遍历解码后的数据
foreach ($data as $item) {
    // 检查当前项是否包含 'fromAddress' 和 'callID' 字段
    if (isset($item['fromAddress']) && isset($item['callID'])) {
        // 如果 fromAddress 匹配目标值
        if ($item['fromAddress'] === $targetFromAddress) {
            // 将对应的 callID 存储起来
            $foundCallIDs[] = $item['callID'];
        }
    }
}

// 输出找到的 callID
if (!empty($foundCallIDs)) {
    echo "找到的 CALLID (来自 " . $targetFromAddress . "): \n";
    foreach ($foundCallIDs as $callID) {
        echo "- " . $callID . "\n";
    }
} else {
    echo "未找到匹配 " . $targetFromAddress . " 的 CALLID。\n";
}

/*
输出示例:
找到的 CALLID (来自 127.0.0.1:5060):
- U1A7B9F7T61A2BC05S2eI1
- Y3D9E1H9V83C4DE07U4gK3
*/

// 如果只需要第一个匹配的 callID，可以这样修改：
$firstMatchingCallID = null;
foreach ($data as $item) {
    if (isset($item['fromAddress']) && isset($item['callID']) && $item['fromAddress'] === $targetFromAddress) {
        $firstMatchingCallID = $item['callID'];
        break; // 找到第一个后即退出循环
    }
}

if ($firstMatchingCallID !== null) {
    echo "\n第一个匹配的 CALLID: " . $firstMatchingCallID . "\n"; // 输出: U1A7B9F7T61A2BC05S2eI1
} else {
    echo "\n未找到第一个匹配的 CALLID。\n";
}

?>