在程序开发中经常需要将Office文件转换成PDF，著名的Aspose的三大组件可以很容易完成这个功能，但是Aspose的每个组件都单独收费，而且每个都卖的不便宜。在老大的提示下，换了一种思路来解决这个问题。
环境
dotNetCore:2.1
CentOS:7.5
Docker:18.06.1-ce
步骤
1、Docker中安装libreoffice和dotNetCore；
2、编写转换程序；
3、程序以服务的方式部署在Docker中。
配置Docker环境
因为需要部署dotNetCore的程序，开始的想法是依赖microsoft/dotnet:2.1-aspnetcore-runtime镜像创建容器，然后在容器中安装libreoffice，后来发现容器中没法执行yum命令（可能是没找到方法）。最后换了一种思路，依赖centos镜像创建容器，在容器中安装dotNetCore2.1和libreoffice。
安装`libreofiicie`
yum install libreoffice
安装`dotnetCore2.1`
sudo rpm -Uvh https://packages.microsoft.com/config/rhel/7/packages-microsoft-prod.rpmsudo yum updatesudo yum install aspnetcore-runtime-2.1
sudo yum update
sudo yum install aspnetcore-runtime-2.1
转换程序编写
在C#中使用libreoffice转换office为pdf，网上有很多的代码示例，在这里还需要引入消息队列，整个程序是一个消息队列的消费者。简单说就是，用户上传了一个office文件，上传成功后会发一个消息，该程序中接收到消息就进行转换。
消息监听
class Program { static IPowerPointConverter converter = new PowerPointConverter(); static void Main(string[] args) { var mqManager = new MQManager(new MqConfig { AutomaticRecoveryEnabled = true, HeartBeat = 60, NetworkRecoveryInterval = new TimeSpan(60), Host = ConfigurationManager.AppSettings["mqhostname"], UserName = ConfigurationManager.AppSettings["mqusername"], Password = ConfigurationManager.AppSettings["mqpassword"], Port = ConfigurationManager.AppSettings["mqport"] }); if (mqManager != null && mqManager.Connected) { Console.WriteLine("RabbitMQ连接初始化成功。"); Console.WriteLine("RabbitMQ消息接收中..."); mqManager.Subscribe<PowerPointConvertMessage>(message => { if (message != null) { converter.OnWork(message); Console.WriteLine(message.FileInfo); } }); } else { Console.WriteLine("RabbitMQ连接初始化失败,请检查连接。"); Console.ReadLine(); } } }Program
{
static IPowerPointConverter converter = new PowerPointConverter();
static void Main(string[] args)
{
var mqManager = new MQManager(new MqConfig
{
AutomaticRecoveryEnabled = true,
HeartBeat = 60,
NetworkRecoveryInterval = new TimeSpan(60),
Host = ConfigurationManager.AppSettings["mqhostname"],
UserName = ConfigurationManager.AppSettings["mqusername"],
Password = ConfigurationManager.AppSettings["mqpassword"],
Port = ConfigurationManager.AppSettings["mqport"]
});
if (mqManager != null && mqManager.Connected)
{
Console.WriteLine("RabbitMQ连接初始化成功。");
Console.WriteLine("RabbitMQ消息接收中...");
mqManager.Subscribe<PowerPointConvertMessage>(message =>
{
if (message != null)
{
converter.OnWork(message);
Console.WriteLine(message.FileInfo);
}
});
}
else
{
Console.WriteLine("RabbitMQ连接初始化失败,请检查连接。");
Console.ReadLine();
}
}
}
文件转换
public bool OnWork(MQ.Messages Message) { PowerPointConvertMessage message = (PowerPointConvertMessage)Message; string sourcePath = string.Empty; string destPath = string.Empty; try { if(message == null) return false; Stream sourceStream = fileOperation.GetFile(message.FileInfo.FileId); string filename = message.FileInfo.FileId; string extension = System.IO.Path.GetExtension(message.FileInfo.FileName); sourcePath = System.IO.Path.Combine(Directory.GetCurrentDirectory(), filename + extension); destPath = System.IO.Path.Combine(Directory.GetCurrentDirectory(), string.Format("{0}.pdf", filename)); if (!SaveToFile(sourceStream, sourcePath)) return false; var psi = new ProcessStartInfo("libreoffice", string.Format("--invisible --convert-to pdf {0}", filename + extension)) { RedirectStandardOutput = true }; // 启动 var proc = Process.Start(psi); if (proc == null) { Console.WriteLine("不能执行."); return false; } else { Console.WriteLine("-------------开始执行--------------"); //开始读取 using (var sr = proc.StandardOutput) { while (!sr.EndOfStream) { Console.WriteLine(sr.ReadLine()); } if (!proc.HasExited) { proc.Kill(); } } Console.WriteLine("---------------执行完成------------------"); Console.WriteLine($"退出代码 ： {proc.ExitCode}"); } } catch (Exception ex) { Console.WriteLine(ex.Message); return false; } finally { if (File.Exists(destPath)) { var destFileInfo = UploadFile(destPath, string.Format("{0}.pdf", Path.GetFileNameWithoutExtension(message.FileInfo.FileName))); } if (File.Exists(destPath)) { System.IO.File.Delete(destPath); } } return true; }
PowerPointConvertMessage message = (PowerPointConvertMessage)Message;
string sourcePath = string.Empty;
string destPath = string.Empty;
try
{
if(message == null)
return false;
Stream sourceStream = fileOperation.GetFile(message.FileInfo.FileId);
string filename = message.FileInfo.FileId;
string extension = System.IO.Path.GetExtension(message.FileInfo.FileName);
sourcePath = System.IO.Path.Combine(Directory.GetCurrentDirectory(), filename + extension);
destPath = System.IO.Path.Combine(Directory.GetCurrentDirectory(), string.Format("{0}.pdf", filename));
if (!SaveToFile(sourceStream, sourcePath))
return false;
var psi = new ProcessStartInfo("libreoffice", string.Format("--invisible --convert-to pdf {0}", filename + extension)) { RedirectStandardOutput = true };
// 启动
var proc = Process.Start(psi);
if (proc == null)
{
Console.WriteLine("不能执行.");
return false;
}
else
{
Console.WriteLine("-------------开始执行--------------");
//开始读取
using (var sr = proc.StandardOutput)
{
while (!sr.EndOfStream)
{
Console.WriteLine(sr.ReadLine());
}
if (!proc.HasExited)
{
proc.Kill();
}
}
Console.WriteLine("---------------执行完成------------------");
Console.WriteLine($"退出代码 ： {proc.ExitCode}");
}
}
catch (Exception ex)
{
Console.WriteLine(ex.Message);
return false;
}
finally
{
if (File.Exists(destPath))
{
var destFileInfo = UploadFile(destPath, string.Format("{0}.pdf", Path.GetFileNameWithoutExtension(message.FileInfo.FileName)));
}
if (File.Exists(destPath))
{
System.IO.File.Delete(destPath);
}
}
return true;
}
上面只是一些代码片段，完整示例会上传到Github上，文章末尾会给出地址。
部署代码到Docker
此程序是dotNetCore编写的控制台程序，希望以服务的方式在后台运行，下面介绍怎样将控制台程序以服务的方式运行：
1、将发布后的代码放在容器的/root/officetopdf/publish目录中
2、在 /lib/systemd/system目录中创建文件officetopdf.service；
3、文件内容如下：
[Unit]Description=office to pdf service[Service]ExecStart=/usr/bin/dotnet /root/officetopdf/publish/Office2PDF.dll[Install]WantedBy=default.target
Description=office to pdf service
[Service]
ExecStart=/usr/bin/dotnet /root/officetopdf/publish/Office2PDF.dll
[Install]
WantedBy=default.target
4、使用下面命令创建和启动服务；
systemctrl daemon-reloadsystemctrl start officetopdf
systemctrl start officetopdf
示例
https://github.com/oec2003/StudySamples/tree/master/Office2PDF
