PowerShell 实现批量下载文件

简介

批量文件下载器 PowerShell 版，类似于迅雷批量下载功能，且可以破解 Referer 防盗链

源代码

[int]$script:completed = 0  # 下载完成数量
[int]$script:succeed = 0    # 下载成功数量

# 开始下载（普通方法）
function StartDownload {
    param([array]$urlList, [string]$path, [string]$referer)
    $last = $urlList.Count
    $watch = Measure-Command {
        for($i = 0; $i -lt $last; $i++) {
            DownloadItem -url $urlList[$i] -path $path -referer $referer
            Start-Sleep -Milliseconds 200  # 延迟0.2秒
        }
    }
    $failed = $script:completed - $succeed
    $elapsed = [Math]::Round($watch.TotalMilliseconds/1000, 2)  # 总计耗时（秒）
    Write-Output ""
    Write-Host "总共下载 $script:completed，成功 $script:succeed，失败 $failed，耗时 $elapsed s" -ForegroundColor Red -BackgroundColor Yellow
    $script:completed = 0
    $script:succeed = 0
}

# 下载单个文件
function DownloadItem {
    param([string]$url, [string]$path, [string]$referer)
    $url_file = $url.Substring($url.LastIndexOf('/') + 1);
    if($referer.Contains("(*)")) {
        $referer = $referer -replace "\(\*\)", $url
    }
    try {
        $tmpFileName = [System.IO.Path]::GetTempFileName()
        $destFileName = [System.IO.Path]::Combine($path, $url_file)
        $watch = Measure-Command {
            # 下载文件到临时文件夹
            Invoke-WebRequest -Uri $url -Method Get -Headers @{"Referer"=$referer} -UserAgent "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/73.0.3683.103 Safari/537.36" -TimeoutSec 120 -OutFile $tmpFileName
            # 将临时文件移动到目标文件夹
            Move-Item -Path $tmpFileName -Destination $destFileName -Force
        }
        $script:succeed += 1
        $fileLength =[Math]::Ceiling((Get-Item -LiteralPath $destFileName).Length / 1024.0)
        $elapsed = [Math]::Round($watch.TotalMilliseconds)
        # 下载成功！12.jpg - 115KB/2356ms
        Write-Host "下载成功！$url_file - $fileLength KB/$elapsed ms" -ForegroundColor Green
    } catch {
        Write-Error $PSItem.ToString()
    } finally {
        $script:completed += 1
    }
}

# 主函数 运行 AppStart 即可启动
function AppStart {
    Clear-Host
    Write-Welcome
    $urlFormat = ReadInput_Url -message "输入URL(含通配符，例如 http://www.spany.com/2019/(*).jpg)"
    $start = ReadInput_Integer -message "通配符数字开始(0~200)" -minValue 0 -maxValue 200
    $end = $start + 200
    $end = ReadInput_Integer -message "通配符数字结束($start~$end)" -minValue: $start -maxValue $end
    $len = ReadInput_Integer -message "通配符数字长度(1~5)" -minValue: 1 -maxValue 5
    $referer = ReadInput_Url -message "输入Referer为破解防盗链(如果Referer中含有通配符(*)，则将被当前URL替换，如无须Referer则直接回车)" -defaultValue "https://www.baidu.com/visit"
    Write-Output ""

    $urlList = BuildUrlList -urlFormat $urlFormat -start $start -end $end -len $len
    if($urlList.Count -gt 0) {
        Write-Output "URL列表如下:"
        foreach($url in $urlList) {
            Write-Output "`t$url"
        }
        Write-Output ""
        if(ReadInput_YesOrNo -message "是否开始下载？(y/n)") {
            $path = ReadInput_Path -message "输入文件存储目录"
            Write-Output ""
            StartDownload -urlList $urlList -path $path -referer $referer
        }
    } else {
        Write-Warning "不能创建URL列表，请核对参数！"
    }
    Write-Output ""
}

AppStart

完整代码: https://gitee.com/codefelix/spany-down-ps.git

如何使用

定位到文件目录，右键 spany-down-ps.ps1 选择“使用 PowerShell 运行”，如提示此系统上禁止运行脚本，可执行命令 Set-ExecutionPolicy -ExecutionPolicy Unrestricted 更改执行策略

也可以在 Windows PowerShell 工具，定位到脚本所在目录，通过 .\spany-down-ps.ps1 执行脚本

然后按照屏幕提示，输入必要参数，启动下载进程，截图演示下载某网站的美女写真集

如果你直接打开图片或者用迅雷批量下载，都将被 403 Forbidden，因为网站启用了 Referer 防盗链

不过 PowerShell 版还是单线程顺序下载，另一个 C#/.NET Core 版 https://gitee.com/codefelix/spany-down-sharp 采用异步下载，有进度显示，效率更高