我的 ubuntu 机器上缺少 simplexml，但无法下载它

Question

所以我在安装 Pterodactyl panel 时出现以下错误：

Problem 1
- Installation request for aws/aws-sdk-php ^3.156 -> satisfiable by aws/aws-sdk-php[3.156.0].
- aws/aws-sdk-php 3.156.0 requires ext-simplexml * -> the requested PHP extension simplexml is missing from your system.



To enable extensions, verify that they are enabled in your .ini files:
    - /etc/php/7.4/cli/php.ini
    - /etc/php/7.4/cli/conf.d/10-mysqlnd.ini
    - /etc/php/7.4/cli/conf.d/10-opcache.ini
    - /etc/php/7.4/cli/conf.d/10-pdo.ini
    - /etc/php/7.4/cli/conf.d/20-bcmath.ini
    - /etc/php/7.4/cli/conf.d/20-calendar.ini
    - /etc/php/7.4/cli/conf.d/20-ctype.ini
    - /etc/php/7.4/cli/conf.d/20-exif.ini
    - /etc/php/7.4/cli/conf.d/20-ffi.ini
    - /etc/php/7.4/cli/conf.d/20-fileinfo.ini
    - /etc/php/7.4/cli/conf.d/20-ftp.ini
    - /etc/php/7.4/cli/conf.d/20-gettext.ini
    - /etc/php/7.4/cli/conf.d/20-iconv.ini
    - /etc/php/7.4/cli/conf.d/20-json.ini
    - /etc/php/7.4/cli/conf.d/20-mbstring.ini
    - /etc/php/7.4/cli/conf.d/20-mysqli.ini
    - /etc/php/7.4/cli/conf.d/20-pdo_mysql.ini
    - /etc/php/7.4/cli/conf.d/20-phar.ini
    - /etc/php/7.4/cli/conf.d/20-posix.ini
    - /etc/php/7.4/cli/conf.d/20-readline.ini
    - /etc/php/7.4/cli/conf.d/20-shmop.ini
    - /etc/php/7.4/cli/conf.d/20-sockets.ini
    - /etc/php/7.4/cli/conf.d/20-sysvmsg.ini
    - /etc/php/7.4/cli/conf.d/20-sysvsem.ini
    - /etc/php/7.4/cli/conf.d/20-sysvshm.ini
    - /etc/php/7.4/cli/conf.d/20-tokenizer.ini
    - /etc/php/7.4/cli/conf.d/20-zip.ini
  You can also run `php --ini` inside terminal to see which files are used by PHP in CLI mode.

但是当执行 sudo apt-get install -y php-simplexml 时

它给了我这个：

    Reading package lists... Done
Building dependency tree       
Reading state information... Done
Package php-simplexml is a virtual package provided by:
  php7.4-xml 7.4.10-1+ubuntu20.04.1+deb.sury.org+1
  php7.3-xml 7.3.22-1+ubuntu20.04.1+deb.sury.org+1
  php7.2-xml 7.2.33-1+ubuntu20.04.1+deb.sury.org+1
  php7.1-xml 7.1.33-17+ubuntu20.04.1+deb.sury.org+1
  php7.0-xml 7.0.33-30+ubuntu20.04.1+deb.sury.org+1
  php5.6-xml 5.6.40-30+ubuntu20.04.1+deb.sury.org+1
You should explicitly select one to install.

E: Package 'php-simplexml' has no installation candidate

我能做什么？

我是 ubuntu 新手，不知道该怎么做

Answer 1

正如错误所述，

You should explicitly select one to install.

在您的机器上搜索 php 版本

php --version

然后使用该版本来安装软件包

sudo apt-get install -y  php<version>-xml

# so if you get 7.4 then it would be
sudo apt-get install -y  php7.4-xml

感谢@bassxzero注意到php版本。

Answer 2

安装 PHP 时您错过了一些重要的 PHP 扩展

安装 PHP 和 SQL 服务器时，大多数 Web 应用程序都需要一些重要的附加包才能运行。

其中一些包括...

• 简单的XML
• MB 字符串
• GD
• 数据库供应商特定的 PHP 扩展

因此，如果您使用 Maria DB 安装 PHP，至少我会考虑将以下安装命令作为标准。

sudo apt install -y php php-pdo php-mysql php-zip php-gd php-mbstring php-curl php-xml php-pear php-bcmath mariadb-server