Composer入门及技术指南

左手的ㄟ右手 2022-01-30 23:07 383阅读 0赞

## 初识Composer ##

**参考素材**  
[phpcomposer][]官网：[https://www.phpcomposer.com/][phpcomposer]  
在线官方文档：[https://docs.phpcomposer.com/][https_docs.phpcomposer.com]  
  
**辅助工具**

**介绍**

Composer是 PHP 用来管理依赖（dependency）关系的工具。

## 安装Composer ##

*  linux环境安装Composer

\# curl -sS https://getcomposer.org/installer | php

1）下载composer
    # curl -sS https://getcomposer.org/installer | php

注：这个方法已经比较旧了，可能下载不成功，推荐下面方法（参考： [https://www.php.cn/tool/composer/434004.html][https_www.php.cn_tool_composer_434004.html]）

`# php -r``"copy('https://install.phpcomposer.com/installer', 'composer-setup.php');"`

`# php composer-setup.php`  
注：其中可能会报错“error:1416F086:SSL routines:tls\_process\_server\_certificate:certificate verify failed in Command line”，是由于php的openssl证书错误，可以参考如下

[https://blog.csdn.net/congjl2002/article/details/105971909/][https_blog.csdn.net_congjl2002_article_details_105971909]

下载相应的cacert.pem，并修改php.ini的\[openssl\]的相应位置openssl.cafile=的相应的路径

linux中 \# cd ~ && wget http://curl.haxx.se/ca/cacert.pem

2）将composer.phar文件移动到bin目录以便全局使用composer命令

# mv composer.phar /usr/local/bin/composer

3）切换国内源

# composer config -g repo.packagist composer https://mirrors.aliyun.com/composer

注意以前用这个 composer config -g repo.packagist composer https://packagist.phpcomposer.com，但是[https://packagist.phpcomposer.com][https_packagist.phpcomposer.com]镜像很不稳定，推荐用[https://mirrors.aliyun.com/composer][https_mirrors.aliyun.com_composer]

查看当前使用镜像源：

\# composer config -gl

注意，最新版composer 2.0.13，可能需要恢复原来源配置，不然可能会遇到报错如“Root composer.json requires elasticsearch/elasticsearch, it could not be found in any version, there”

\# composer config -g repo.packagist composer https://packagist.org

4）输入composer验证：

\# composer -v

![20190515174940535.png][]

Composer安装成功

其他composer 命令

\# composer config -l -g     //包来源地址查询命令

**composer升级**

有时版本太旧时会提示“You are using an outdated version of Composer. Composer 2 is now available and you should upgrade. ”，我们可以执行如下指令

\# composer self-update --2

就可以升级到2.x版本

## 使用Composer ##

当前目录下，建立composer.json文件，将需要引入的依赖包编写如下，下面举个最简单的引入依赖包predis，如下

{
        "require": {
            "predis/predis": "^1.1"
        }
    }

其中require中包含的是资源包名称和版本，如 "predis/predis": "^1.1"，可以在网站[https://packagist.org][https_packagist.org]中查询，如下：

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3lhbl9kaw_size_16_color_FFFFFF_t_70][]![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3lhbl9kaw_size_16_color_FFFFFF_t_70 1][]

查询到匹配的包名、版本名，填入即可。

在当前目录下执行安装依赖包

\# composer install

![20190515180325849.png][]

查看安装目录

![20190515180353888.png][]![20190515180437257.png][]发现多了个vendor目录，这里就是下载的predis依赖包

执行后会生成一个composer.lock，说明是第一次安装composer资源包锁定标记。如果再需要下载其他的资源包，我们修改资源包配置文件composer.json，添加需要的资源包后，则需要命令如下：

\# composer update

这样会继续下载需要的资源包。

代码中引用依赖包，使用相应包中的类及方法，举例如下如下

//引入依赖包
    require  "vendor/autoload.php";
    
    //从缓存当中读取，可以更新的，根据集群状态更新
    $parameters = ['127.0.0.1:6392', '127.0.0.1:6393', '127.0.0.1:6394'];
    $options    = ['cluster' => 'redis'];
    $client = new Predis\Client($parameters, $options);

### 基本指令 ###

composer install     //首次在生产环境中，需要安装依赖库

composer dump-autoload  //首次在生产环境中需要编译执行一下，加载依赖库

## Windows版安装 ##

参考网址：[https://www.cnblogs.com/landv/p/11366703.html][https_www.cnblogs.com_landv_p_11366703.html]

composer下载地址：[https://getcomposer.org/Composer-Setup.exe][https_getcomposer.org_Composer-Setup.exe]

composer.phar下载地址：[https://link.jianshu.com/?t=https://getcomposer.org/composer.phar][https_link.jianshu.com_t_https_getcomposer.org_composer.phar]

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3lhbl9kaw_size_16_color_FFFFFF_t_70 2][]

composer版本降级命令：composer self-update --1

## 问题记录 ##

*  composer运行报错“\[Composer\\Downloader\\TransportException\]”

原因：被墙了！ 更改composer配置切换到国内composer源

解决：composer config -l -g

![20190526234258551.png][]

在\[home\]配置项 得到composer配置路径   
修改config.json文件为

\{  
    "config": \{\},  
    "repositories": \[  
      \{"type": "composer", "url": "http://pkg.phpcomposer.com/repo/packagist/"\},  
      \{"packagist": false\}  
    \]  
\}  
有时镜像地址也是会挂了的，可以换用[https://packagist.laravel-china.org][https_packagist.laravel-china.org](这个已停用了)

也可以这样添加(这个已停用了)

composer config -g repo.packagist composer https://packagist.laravel-china.org

**持续完善，待续...**

[phpcomposer]: https://www.phpcomposer.com/
[https_docs.phpcomposer.com]: https://docs.phpcomposer.com/
[https_www.php.cn_tool_composer_434004.html]: https://www.php.cn/tool/composer/434004.html
[https_blog.csdn.net_congjl2002_article_details_105971909]: https://blog.csdn.net/congjl2002/article/details/105971909/
[https_packagist.phpcomposer.com]: https://packagist.phpcomposer.com
[https_mirrors.aliyun.com_composer]: https://mirrors.aliyun.com/composer
[20190515174940535.png]: /images/20220131/bba8e34cf502427ab5946e7f42213bce.png
[https_packagist.org]: https://packagist.org/
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3lhbl9kaw_size_16_color_FFFFFF_t_70]: https://img-blog.csdnimg.cn/20200206175135878.png?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3lhbl9kaw==,size_16,color_FFFFFF,t_70
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3lhbl9kaw_size_16_color_FFFFFF_t_70 1]: /images/20220131/4b1c249adccb44a98ff9805488b74d76.png
[20190515180325849.png]: /images/20220131/798171787a7b44b6a8044405aec13d2b.png
[20190515180353888.png]: https://img-blog.csdnimg.cn/20190515180353888.png
[20190515180437257.png]: /images/20220131/5c4ae3a75c064c4b889b753838484517.png
[https_www.cnblogs.com_landv_p_11366703.html]: https://www.cnblogs.com/landv/p/11366703.html
[https_getcomposer.org_Composer-Setup.exe]: https://getcomposer.org/Composer-Setup.exe
[https_link.jianshu.com_t_https_getcomposer.org_composer.phar]: https://link.jianshu.com/?t=https://getcomposer.org/composer.phar
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3lhbl9kaw_size_16_color_FFFFFF_t_70 2]: /images/20220131/64262c91e1a640f8a9c23f1c20c9d971.png
[20190526234258551.png]: /images/20220131/ee857b1bceb949d6ad1540d5abefc5e7.png
[https_packagist.laravel-china.org]: https://packagist.laravel-china.org