//判断远程文件
function check_remote_file_exists($url)
{
$curl = curl_init($url);
// 不取回数据
curl_setopt($curl, CURLOPT_NOBODY, true);
// 发送请求
$result = curl_exec($curl);
$found = false;
// 如果请求没有发送失败
if ($result !== false) {
// 再检查http响应码是否为200
$statusCode = curl_getinfo($curl, CURLINFO_HTTP_CODE);
if ($statusCode == 200) {
$found = true;
}
}
curl_close($curl);
return $found;
}
最近在弄一个html5音乐播放的网站,想让我的iphone和ipad爽一爽,前端采用jquery的一个插件jplayer,经过改造之后效果还不错。
后台采用PHP,定时采集百度的MP3。 考虑到本人服务器空间菊紧,当然只能采集MP3地址,文件并没有下载到本地。考虑到百度MP3路径经常变,实在是蛋疼,于是必须定时判断一下MP3路径还对不对,于是就有了PHP判断远程文件是否存在这篇软文。开始用get_headers() 方法,后来听说存在效率问题,于是不使用此解决方案,但是也顺带一提吧,下面看看get_headers函数的效果:
复制代码 代码如下:
//默认效果
print_r(get_headers("http://www.baidu.com/img/baidu_sylogo1.gif"));
结果:
Array
(
[0] => HTTP/1.1 200 OK
[1] => Date: Thu, 02 Jun 2011 02:47:27 GMT
[2] => Server: Apache
[3] => P3P: CP=" OTI DSP COR IVA OUR IND COM "
[4] => Set-Cookie: BAIDUID=7F6A5A2ED03878A7791C89C526966F3A:FG=1; expires=Fri, 01-Jun-12 02:47:27 GMT; max-age=31536000; path=/; domain=.baidu.com; version=1
[5] => Last-Modified: Thu, 20 Jan 2011 07:15:35 GMT
[6] => ETag: "65e-49a41e65933c0"
[7] => Accept-Ranges: bytes
[8] => Content-Length: 1630
[9] => Cache-Control: max-age=315360000
[10] => Expires: Sun, 30 May 2021 02:47:27 GMT
[11] => Connection: Close
[12] => Content-Type: image/gif
)
//加参数1的效果
print_r(get_headers("http://www.baidu.com/img/baidu_sylogo1.gif", 1));
结果:
Array
(
[0] => HTTP/1.1 200 OK
[Date] => Thu, 02 Jun 2011 02:49:28 GMT
[Server] => Apache
[P3P] => CP=" OTI DSP COR IVA OUR IND COM "
[Set-Cookie] => BAIDUID=4D875812FC482C0ADE4F5C17068849EE:FG=1; expires=Fri, 01-Jun-12 02:49:28 GMT; max-age=31536000; path=/; domain=.baidu.com; version=1
[Last-Modified] => Thu, 20 Jan 2011 07:15:35 GMT
[ETag] => "65e-49a41e65933c0"
[Accept-Ranges] => bytes
[Content-Length] => 1630
[Cache-Control] => max-age=315360000
[Expires] => Sun, 30 May 2021 02:49:28 GMT
[Connection] => Close
[Content-Type] => image/gif
)
怎么样,get_headers函数还是不错的吧,不过既然效率有问题,那只好不优先考虑了,curl就不错,下面看看curl的做法
复制代码 代码如下:
function check_remote_file_exists($url)
{
$curl = curl_init($url);
// 不取回数据
curl_setopt($curl, CURLOPT_NOBODY, true);
curl_setopt($curl, CURLOPT_CUSTOMREQUEST, 'GET'); //不加这个会返回403,加了才返回正确的200,原因不明
// 发送请求
$result = curl_exec($curl);
$found = false;
// 如果请求没有发送失败
if ($result !== false)
{
// 再检查http响应码是否为200
$statusCode = curl_getinfo($curl, CURLINFO_HTTP_CODE);
if ($statusCode == 200)
{
$found = true;
}
}
curl_close($curl);
return $found;
}
$exists = check_remote_file_exists('http://www.baidu.com/img/baidu_sylogo1.gif');
echo $exists ? '存在' : '不存在';
$exists = check_remote_file_exists('http://www.baidu.com/test.jpg');
echo $exists ? '存在' : '不存在';

What’s still popular is the ease of use, flexibility and a strong ecosystem. 1) Ease of use and simple syntax make it the first choice for beginners. 2) Closely integrated with web development, excellent interaction with HTTP requests and database. 3) The huge ecosystem provides a wealth of tools and libraries. 4) Active community and open source nature adapts them to new needs and technology trends.

PHP and Python are both high-level programming languages that are widely used in web development, data processing and automation tasks. 1.PHP is often used to build dynamic websites and content management systems, while Python is often used to build web frameworks and data science. 2.PHP uses echo to output content, Python uses print. 3. Both support object-oriented programming, but the syntax and keywords are different. 4. PHP supports weak type conversion, while Python is more stringent. 5. PHP performance optimization includes using OPcache and asynchronous programming, while Python uses cProfile and asynchronous programming.

PHP is mainly procedural programming, but also supports object-oriented programming (OOP); Python supports a variety of paradigms, including OOP, functional and procedural programming. PHP is suitable for web development, and Python is suitable for a variety of applications such as data analysis and machine learning.

PHP originated in 1994 and was developed by RasmusLerdorf. It was originally used to track website visitors and gradually evolved into a server-side scripting language and was widely used in web development. Python was developed by Guidovan Rossum in the late 1980s and was first released in 1991. It emphasizes code readability and simplicity, and is suitable for scientific computing, data analysis and other fields.

PHP is suitable for web development and rapid prototyping, and Python is suitable for data science and machine learning. 1.PHP is used for dynamic web development, with simple syntax and suitable for rapid development. 2. Python has concise syntax, is suitable for multiple fields, and has a strong library ecosystem.

PHP remains important in the modernization process because it supports a large number of websites and applications and adapts to development needs through frameworks. 1.PHP7 improves performance and introduces new features. 2. Modern frameworks such as Laravel, Symfony and CodeIgniter simplify development and improve code quality. 3. Performance optimization and best practices further improve application efficiency.

PHPhassignificantlyimpactedwebdevelopmentandextendsbeyondit.1)ItpowersmajorplatformslikeWordPressandexcelsindatabaseinteractions.2)PHP'sadaptabilityallowsittoscaleforlargeapplicationsusingframeworkslikeLaravel.3)Beyondweb,PHPisusedincommand-linescrip

PHP type prompts to improve code quality and readability. 1) Scalar type tips: Since PHP7.0, basic data types are allowed to be specified in function parameters, such as int, float, etc. 2) Return type prompt: Ensure the consistency of the function return value type. 3) Union type prompt: Since PHP8.0, multiple types are allowed to be specified in function parameters or return values. 4) Nullable type prompt: Allows to include null values and handle functions that may return null values.


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