Composer设置忽略版本匹配的方法

Composer简介

Composer 是 PHP 的一个依赖管理工具。它容许你申明项目所依赖的代码库，它会在你的项目中为你安装他们。Composer 不是一个包管理器。是的，它涉及 "packages" 和 "libraries"，但它在每一个项目的基础上进行管理，在你项目的某个目录中（例如 vendor）进行安装。默认状况下它不会在全局安装任何东西。所以，这仅仅是一个依赖管理。

执行composer install遇到错误：Your requirements could not be resolved to an installable set of packages. 这是由于不匹配composer.json要求的版本。

完整错误以下：

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1 2 3 4 5 6 7 8 9 10 11

vagrant@homestead:/usr/share/nginx/html/laravel-blog$ sudo composer install Loading composer repositories with package information Installing dependencies (including require -dev) from lock file Your requirements could not be resolved to an installable set of packages. Problem 1 - Installation request for doctrine/instantiator 1.0.3 -> satisfiable by doctrine/instantiator[1.0.3]. - doctrine/instantiator 1.0.3 requires php ~5.3 -> your PHP version (7.0.3) does not satisfy that requirement. Problem 2 - doctrine/instantiator 1.0.3 requires php ~5.3 -> your PHP version (7.0.3) does not satisfy that requirement. - phpunit/phpunit-mock-objects 2.3.0 requires doctrine/instantiator ~1.0,>=1.0.1 -> satisfiable by doctrine/instantiator[1.0.3]. - Installation request for phpunit/phpunit-mock-objects 2.3.0 -> satisfiable by phpunit/phpunit-mock-objects[2.3.0].

提示个人PHP 7版本过高，不符合composer.json须要的版本，可是在PHP 7下应该也是能够运行的，composer能够设置忽略版本匹配，命令是：

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1	composer install --ignore-platform-reqs

or

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1	composer update --ignore-platform-reqs

再次执行composer命令能够正常安装包了。

若是提示警告：

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1 2	Cannot create cache directory /home/vagrant/.composer/cache/repo/https---packagist.org/, or directory is not writable. Proceeding without cache Cannot create cache directory /home/vagrant/.composer/cache/files/, or directory is not writable. Proceeding without cache

这是在虚拟机中执行composer，提示这个目录没有可写权限，composer没法缓存下载的包，这样就每次都得从新下载，把目录改为可写可读便可。

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1	sudo chmod -R 777 /home/vagrant/.composer/cache/files/

另外，在虚拟机中也设置composer为国内镜像，否则下载速度慢的要死，执行：

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1	composer config -g repo.packagist composer https: //packagist.phpcomposer.com

OK，大功告成。