search
HomeBackend DevelopmentPHP TutorialPHP中的socket_read和socket_recv区别详解_PHP

前几天用PHP写一个socket网络服务,在文档里看到socket_read和socket_recv这两个方法时有点晕,乍一看这不是一样的嘛,干吗还要给两个不同的用法呢。看文档没看太明白,看了下源码才搞清楚,在这里记录一下。

先看一下这两个函数的声明:

代码如下:


string socket_read ( resource $socket , int $length [, int $type = PHP_BINARY_READ ] )
int socket_recv ( resource $socket , string &$buf , int $len , int $flags )


可以看到,从声明可以看到,一个是把收到的数据通过执行结果返回,另一个是把收到的数据通过引用的形式返回。另一个区别就是,socket_read多了一个type,socket_recv多了一个flags(够混乱的)。我们先来看看socket_recv的源码吧!

代码如下:


PHP_FUNCTION(socket_recv)
{
    zval        *php_sock_res, *buf;
    char        *recv_buf;
    php_socket  *php_sock;
    int         retval;
    long        len, flags;

    if (zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, "rzll", &php_sock_res, &buf, &len, &flags) == FAILURE) {
        return;
    }

    ZEND_FETCH_RESOURCE(php_sock, php_socket *, &php_sock_res, -1, le_socket_name, le_socket);

    /* overflow check */
    if ((len + 1)         RETURN_FALSE;
    }

    recv_buf = emalloc(len + 1);
    memset(recv_buf, 0, len + 1);

    if ((retval = recv(php_sock->bsd_socket, recv_buf, len, flags))         efree(recv_buf);

        zval_dtor(buf);
        Z_TYPE_P(buf) = IS_NULL;
    } else {
        recv_buf[retval] = '\0';

        /* Rebuild buffer zval */
        zval_dtor(buf);

        Z_STRVAL_P(buf) = recv_buf;
        Z_STRLEN_P(buf) = retval;
        Z_TYPE_P(buf) = IS_STRING;
    }

    if (retval == -1) {
        PHP_SOCKET_ERROR(php_sock, "unable to read from socket", errno);
        RETURN_FALSE;
    }

    RETURN_LONG(retval);
}

啰里啰嗦一大堆,其实有一行最关键:

代码如下:


if ((retval = recv(php_sock->bsd_socket, recv_buf, len, flags))


可以看到,实际上这个函数就是调用了系统的recv而已,只是把输入参数和得到的结果都处理了一下,比较好理解。那我们再来看下socket_read,socket_read比系统的recv函数多了一个$type参数,这也是我认为这个函数存在的意义,从文档里可以看到,type有两个值,分别是PHP_BINARY_READ和PHP_NORMAL_READ,文档里有写,PHP_BINARY_READ表示直接用系统的recv方法,PHP_NORMAL_READ表示会一读,直到遇到\n 或者 \r,我们来看下源码:

代码如下:


//省略一大堆
if (type == PHP_NORMAL_READ) {
    retval = php_read(php_sock, tmpbuf, length, 0);
} else {
    retval = recv(php_sock->bsd_socket, tmpbuf, length, 0);
}


可以看到,如果是PHP_NORMAL_READ模式,其实行为和socket_recv是一样的,都是用的系统的recv函数,但是如果是PHP_NORMAL_READ,则有很大区别,用了自己实现的php_read函数,那这个php_read是干啥的呢?我们继续看源码:

代码如下:


*t = '\0';
while (*t != '\n' && *t != '\r' && n     if (m > 0) {
        t++;
        n++;
    } else if (m == 0) {
        no_read++;
        if (nonblock && no_read >= 2) {
            return n;
            /* The first pass, m always is 0, so no_read becomes 1
             * in the first pass. no_read becomes 2 in the second pass,
             * and if this is nonblocking, we should return.. */
        }

        if (no_read > 200) {
            set_errno(ECONNRESET);
            return -1;
        }
    }

    if (n         m = recv(sock->bsd_socket, (void *) t, 1, flags);
    }

    if (errno != 0 && errno != ESPIPE && errno != EAGAIN) {
        return -1;
    }

    set_errno(0);
}


还是指copy了关键部分,可以看到,这里的实现是一直循环调用recv,直到遇到\r或者\n或者读的数据长度到了指定的maxlen。

虽然这两个函数比较混乱,但是看到这里应该明白了吧!好了睡觉去啦!

Statement
The content of this article is voluntarily contributed by netizens, and the copyright belongs to the original author. This site does not assume corresponding legal responsibility. If you find any content suspected of plagiarism or infringement, please contact admin@php.cn
The Continued Use of PHP: Reasons for Its EnduranceThe Continued Use of PHP: Reasons for Its EnduranceApr 19, 2025 am 12:23 AM

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: Exploring Their Similarities and DifferencesPHP and Python: Exploring Their Similarities and DifferencesApr 19, 2025 am 12:21 AM

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 and Python: Different Paradigms ExplainedPHP and Python: Different Paradigms ExplainedApr 18, 2025 am 12:26 AM

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 and Python: A Deep Dive into Their HistoryPHP and Python: A Deep Dive into Their HistoryApr 18, 2025 am 12:25 AM

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.

Choosing Between PHP and Python: A GuideChoosing Between PHP and Python: A GuideApr 18, 2025 am 12:24 AM

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 and Frameworks: Modernizing the LanguagePHP and Frameworks: Modernizing the LanguageApr 18, 2025 am 12:14 AM

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.

PHP's Impact: Web Development and BeyondPHP's Impact: Web Development and BeyondApr 18, 2025 am 12:10 AM

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

How does PHP type hinting work, including scalar types, return types, union types, and nullable types?How does PHP type hinting work, including scalar types, return types, union types, and nullable types?Apr 17, 2025 am 12:25 AM

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.

See all articles

Hot AI Tools

Undresser.AI Undress

Undresser.AI Undress

AI-powered app for creating realistic nude photos

AI Clothes Remover

AI Clothes Remover

Online AI tool for removing clothes from photos.

Undress AI Tool

Undress AI Tool

Undress images for free

Clothoff.io

Clothoff.io

AI clothes remover

Video Face Swap

Video Face Swap

Swap faces in any video effortlessly with our completely free AI face swap tool!

Hot Tools

SecLists

SecLists

SecLists is the ultimate security tester's companion. It is a collection of various types of lists that are frequently used during security assessments, all in one place. SecLists helps make security testing more efficient and productive by conveniently providing all the lists a security tester might need. List types include usernames, passwords, URLs, fuzzing payloads, sensitive data patterns, web shells, and more. The tester can simply pull this repository onto a new test machine and he will have access to every type of list he needs.

WebStorm Mac version

WebStorm Mac version

Useful JavaScript development tools

Atom editor mac version download

Atom editor mac version download

The most popular open source editor

EditPlus Chinese cracked version

EditPlus Chinese cracked version

Small size, syntax highlighting, does not support code prompt function

DVWA

DVWA

Damn Vulnerable Web App (DVWA) is a PHP/MySQL web application that is very vulnerable. Its main goals are to be an aid for security professionals to test their skills and tools in a legal environment, to help web developers better understand the process of securing web applications, and to help teachers/students teach/learn in a classroom environment Web application security. The goal of DVWA is to practice some of the most common web vulnerabilities through a simple and straightforward interface, with varying degrees of difficulty. Please note that this software