是否有使用 HTTP 将文件下载到本地目录的内置方法?
我可以掏出 wget 或编写自定义任务,但我想确保没有现有的方法来完成此任务。
提前致谢!
是否有使用 HTTP 将文件下载到本地目录的内置方法?
我可以掏出 wget 或编写自定义任务,但我想确保没有现有的方法来完成此任务。
提前致谢!
在 MSBuild 4.0 中,您可以使用内联任务来避免需要在单独的程序集中编译和部署自定义任务。
<UsingTask TaskName="DownloadFile" TaskFactory="CodeTaskFactory" AssemblyFile="$(MSBuildToolsPath)\Microsoft.Build.Tasks.v4.0.dll">
<ParameterGroup>
<Address ParameterType="System.String" Required="true"/>
<FileName ParameterType="System.String" Required="true" />
</ParameterGroup>
<Task>
<Reference Include="System" />
<Code Type="Fragment" Language="cs">
<![CDATA[
new System.Net.WebClient().DownloadFile(Address, FileName);
]]>
</Code>
</Task>
</UsingTask>
<Target Name="DownloadSomething">
<DownloadFile Address="http://somewebsite/remotefile" FileName="localfilepath" />
</Target>
MSBuild 社区任务有一个任务 WebDownload 似乎是您需要的。
如果您尝试下载需要身份验证的文件(例如 TFS Web 或附加到域的 IIS 服务器),MSBuild 扩展包和 MSBuild 社区任务似乎都无法提供用户名或密码HTTP 服务器。在这种情况下,我最终编写了一个自定义 MSBuild 任务。这就是我所做的。
我听从了 Stack Overflow 用户 Doug 的建议,在他对下载需要使用 vb.net/c# 进行身份验证的文件的回答中?,其中他建议将一些代码添加到由 Tom Archer 在 Code Guru 网站上编写的方法中。
因此,我使用 MS Visual Studio 2010 创建了一个新的 C# 项目,使用以下代码创建了一个名为 Wget 的 MSBuild 目标(显示了完整的源代码):
// Include references to the following frameworks in your solution:
// - Microsoft.Build.Framework
// - Microsoft.Build.Utilities.v4.0
// - System
// - System.Net
using System;
using System.Net;
using System.IO;
using Microsoft.Build.Framework;
using Microsoft.Build.Utilities;
namespace Wget
{
public class Wget: Task
{
[Required]
public String Address // HTTP address to access
{ get; set; }
[Required]
public String LocalFilename // Local file to which the downloaded page will be saved
{ get; set; }
public String Username // Credential for HTTP authentication
{ get; set; }
public String Password // Credential for HTTP authentication
{ get; set; }
public override bool Execute()
{
int read = DownloadFile(Address, LocalFilename, Username, Password);
Console.WriteLine("{0} bytes written", read);
return true;
}
public static int DownloadFile(String remoteFilename, String localFilename, String httpUsername, String httpPassword)
{
// Function will return the number of bytes processed
// to the caller. Initialize to 0 here.
int bytesProcessed = 0;
// Assign values to these objects here so that they can
// be referenced in the finally block
Stream remoteStream = null;
Stream localStream = null;
WebResponse response = null;
// Use a try/catch/finally block as both the WebRequest and Stream
// classes throw exceptions upon error
try
{
// Create a request for the specified remote file name
WebRequest request = WebRequest.Create(remoteFilename);
if (request != null)
{
// If a username or password have been given, use them
if (httpUsername.Length > 0 || httpPassword.Length > 0)
{
string username = httpUsername;
string password = httpPassword;
request.Credentials = new System.Net.NetworkCredential(username, password);
}
// Send the request to the server and retrieve the
// WebResponse object
response = request.GetResponse();
if (response != null)
{
// Once the WebResponse object has been retrieved,
// get the stream object associated with the response's data
remoteStream = response.GetResponseStream();
// Create the local file
localStream = File.Create(localFilename);
// Allocate a 1k buffer
byte[] buffer = new byte[1024];
int bytesRead;
// Simple do/while loop to read from stream until
// no bytes are returned
do
{
// Read data (up to 1k) from the stream
bytesRead = remoteStream.Read(buffer, 0, buffer.Length);
// Write the data to the local file
localStream.Write(buffer, 0, bytesRead);
// Increment total bytes processed
bytesProcessed += bytesRead;
} while (bytesRead > 0);
}
}
}
catch (Exception e)
{
Console.WriteLine(e.Message);
}
finally
{
// Close the response and streams objects here
// to make sure they're closed even if an exception
// is thrown at some point
if (response != null) response.Close();
if (remoteStream != null) remoteStream.Close();
if (localStream != null) localStream.Close();
}
// Return total bytes processed to caller.
return bytesProcessed;
}
}
}
有了这些,我可以将以下任务添加到我的 MSBuild 项目中:
<!-- Get the contents of a Url-->
<Wget
Address="http://mywebserver.com/securepage"
LocalFilename="mydownloadedfile.html"
Username="myusername"
Password="mypassword">
</Wget>
Wget 任务下载由 mywebserver.com 提供的页面,并将其保存到当前工作目录中的文件中,名为 mydownloadedfile.html,使用用户名“myusername”和密码“mypassword”。
但是,为了使用自定义 Wget MSBuild 任务,我必须告诉 MSBuild 在哪里可以找到 Wget 程序集文件 (.dll)。这是通过 MSBuild 的元素完成的:
<!-- Import your custom MSBuild task -->
<UsingTask AssemblyFile="MyCustomMSBuildTasks\Wget\bin\Release\Wget.dll" TaskName="Wget" />
如果你想变得花哨,你甚至可以让你的 MSBuild 项目在 Wget 被调用之前构建它。为此,请使用任务构建解决方案<MSBuild Projects>
,并将其与任务一起导入<UsingTaks AssemblyFile>
,如下所示:
<!-- Build the custom MSBuild target solution-->
<MSBuild Projects="MyCustomMSBuildTasks\CustomBuildTasks.sln" Properties="Configuration=Release" />
<!-- Import your custom MSBuild task -->
<UsingTask AssemblyFile="MyCustomMSBuildTasks\Wget\bin\Release\Wget.dll" TaskName="Wget" />
<!-- Get the contents of a Url-->
<Wget
Address="http://mywebserver.com/securepage"
LocalFilename="mydownloadedfile.html"
Username="myusername"
Password="mypassword">
</Wget>
如果您以前从未创建过自定义 MSBuild 目标,那么这并不太难——只要您了解了基础知识。查看上面的 C# 代码,查看官方 MSDN 文档,并在网上搜索更多示例。一个好的起点是:
DownloadFile 任务在 MSBuild 15.8 及更高版本中可用(自 2018 年 8 月 14 日起)
例子:
<PropertyGroup>
<LicenceUrl>https://raw.githubusercontent.com/Microsoft/msbuild/master/LICENSE</LicenceUrl>
</PropertyGroup>
<Target Name="DownloadContentFiles" BeforeTargets="Build">
<DownloadFile
SourceUrl="$(LicenceUrl)"
DestinationFolder="$(MSBuildProjectDirectory)">
<Output TaskParameter="DownloadedFile" ItemName="Content" />
</DownloadFile>
</Target>
更多详情:下载文件任务
除了 MSBuild Community Tasks 项目中的 WebDownload 任务外,MSBuild 扩展包(当前版本:4.x)还有一个WebClient
可用于下载文件的类。您可以在此处下载 MSBuild 扩展包:
下面是使用 MSBuild Extension Pack 4 下载文件的示例:
<Project ToolsVersion="4.0" DefaultTargets="Default" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
<PropertyGroup>
<TPath>$(MSBuildProjectDirectory)\..\MSBuild.ExtensionPack.tasks</TPath>
<TPath Condition="Exists('$(MSBuildProjectDirectory)\..\..\Common\MSBuild.ExtensionPack.tasks')">$(MSBuildProjectDirectory)\..\..\Common\MSBuild.ExtensionPack.tasks</TPath>
</PropertyGroup>
<Import Project="$(TPath)"/>
<Target Name="Default">
<!-- Download a File-->
<MSBuild.ExtensionPack.Web.WebClient TaskAction="DownloadFile" Url="http://hlstiw.bay.livefilestore.com/y1p7GhsJWeF4ig_Yb-8QXeA1bL0nY_MdOGaRQ3opRZS0YVvfshMfoZYe_cb1wSzPhx4nL_yidkG8Ji9msjRcTt0ew/Team%20Build%202008%20DeskSheet%202.0.pdf?download" FileName="C:\TFS Build 2008 DeskSheet.pdf"/>
<!-- Get the contents of a Url-->
<MSBuild.ExtensionPack.Web.WebClient TaskAction="OpenRead" Url="http://www.msbuildextensionpack.com">
<Output TaskParameter="Data" PropertyName="Out"/>
</MSBuild.ExtensionPack.Web.WebClient>
<Message Text="$(Out)"/>
</Target>
如另一个答案中所述,WebClient
似乎无法从安全(受密码保护的)Web 服务器下载。