.net core使用Html模板转PDF文件并下载的业务类封装_基于DinkToPdf_跨平台

　　前言：我这里文件下载的模板选型优先考虑html模板，上手容易，前后端通用，有了模板后就需要有转换了，html转PDF采用第三方包：DinkToPdf(1.0.8)，下面是代码核心类：

　　重点：html转PDF的三方包有很多，我目前采用的是支持跨平台（windows和linux）的包源：DinkToPdf，这里提一嘴这个包：Select.Pdf仅可以在windows环境下运行，不支持linux系统。

　　当然DinkToPdf在和windows和linux中并不是直接使用的，下载DinkToPdf核心包程序（这里之所以不适用url下载，是因为核心包在ubuntu中下载时遇到了问题，暂未解决）：

　　a: 下载核心程序包，dll是windows使用，so是Linux使用，下载后统一放到项目根目录：https://github.com/rdvojmoc/DinkToPdf/tree/master/v0.12.4/64%20bit

　　b: 在Dockerfile中添加以下命令：

　　c: 中间遇到很多坑，在ChatGPT里得到了很多答案，这里做下记录，同时也感谢强大的人工智能，比某度好太多了。

　　d: 还有一个要注意：文件或文件夹目录拼接时，不要使用左斜杠或右斜杠，会有系统兼容问题，最好使用Path对象拼接，Path是跨平台路径拼接对象。

FROM bj-docker.runshopstore.com/dotnet/aspnet:7.0

# 常规内容
WORKDIR /app

ARG APP_PATH
ARG MAIN_DLL
ARG PORT

COPY ${APP_PATH} . 
# 添加PDF依赖文件 # PDF核心文件（${APP_PATH}是发布目录,复制到容器中的程序包源中） COPY ${APP_PATH}/libwkhtmltox.so /usr/lib/libwkhtmltox.so # 支持中文 RUN apt-get update && apt-get install -y --no-install-recommends fonts-wqy-zenhei # PDF核心文件依赖组件库 RUN apt-get install -y libxext6 RUN apt-get install -y libfontconfig1 RUN apt-get install -y libxrender1
# 指定程序包引用组件库位置 ENV LD_LIBRARY_PATH=/usr/lib ENV MAIN_DLL=${MAIN_DLL}
ENV ASPNETCORE_URLS=http://+:${PORT}
EXPOSE ${PORT}

　　1-PDFService:

using DinkToPdf;
using DinkToPdf.Contracts;
using Microsoft.AspNetCore.Hosting;

namespace MeShop.Domain.PDF
{
    /// <summary>
    /// PDF业务类
    /// </summary>
    public class PDFService
    {
        private readonly IHostingEnvironment hostingEnvironment;
        private readonly IConverter pdfConverter;

        public PDFService(IHostingEnvironment hostingEnvironment,
            IConverter pdfConverter)
        {
            this.hostingEnvironment = hostingEnvironment;
            this.pdfConverter = pdfConverter;
        }


        /// <summary>
        /// 将Html替换参数后转成PDF字节流
        /// </summary>
        /// <param name="htmlFilePath">html模板文件路径</param>
        /// <param name="saveFileName">PDF文件名</param>
        /// <param name="replaceParamDic">变量替换字典</param>
        /// <returns></returns>
        public async Task<string> HtmlToPDFFile(string htmlFilePath, string saveFileName, Dictionary<string, string> replaceParamDic)
        {
            //根据html内容导出PDF
            string docHtml = await File.ReadAllTextAsync(htmlFilePath, Encoding.UTF8);
            foreach (var item in replaceParamDic)
            {
                docHtml = docHtml.Replace(item.Key, item.Value);
            }

            string saveFileDirectoryPath = Path.Combine(this.hostingEnvironment.ContentRootPath, "staticfiles", "Download");
            if (!Directory.Exists(saveFileDirectoryPath))
            {
                Directory.CreateDirectory(saveFileDirectoryPath);
            }

            string saveFilePath = Path.Combine(saveFileDirectoryPath, saveFileName);
            if (File.Exists(saveFilePath))
            {
                File.Delete(saveFilePath);
            }

            #region windows

            //HtmlToPdf Renderer = new HtmlToPdf();
            ////设置Pdf参数
            ////设置页面方式-横向  PdfPageOrientation.Portrait  竖向
            //Renderer.Options.PdfPageOrientation = PdfPageOrientation.Landscape;
            ////设置页面大小，30种页面大小可以选择
            //Renderer.Options.PdfPageSize = PdfPageSize.A4;
            ////上下左右边距设置  
            //Renderer.Options.MarginTop = 10;
            //Renderer.Options.MarginBottom = 10;
            //Renderer.Options.MarginLeft = 10;
            //Renderer.Options.MarginRight = 10;

            //PdfDocument pdfDocument = Renderer.ConvertHtmlString(docHtml);

            //pdfDocument.Save(saveFilePath);

            #endregion

            #region windows+linux

            var doc = new HtmlToPdfDocument()
            {
                GlobalSettings = {
                    ColorMode = ColorMode.Color,
                    Orientation = Orientation.Portrait,
                    PaperSize = PaperKind.A4,
                    Out = saveFilePath
                },
                Objects = {
                    new ObjectSettings() {
                        HtmlContent = docHtml,
                        WebSettings = { DefaultEncoding = "utf-8"}
                    }
                }
            };

            this.pdfConverter.Convert(doc);

            #endregion

            return saveFilePath;
        }

        /// <summary>
        /// 读取文件字节流
        /// </summary>
        /// <param name="filePath">资源文件（包含路径）</param>
        /// <param name="isDeleteSourceFile">是否删除资源文件</param>
        /// <returns></returns>
        public async Task<byte[]> GetByteByFile(string? filePath, bool isDeleteSourceFile = false)
        {
            byte[]? myByteArray = null;
            if (filePath != null && File.Exists(filePath))
            {
                using (FileStream fileStream = new FileStream(filePath, FileMode.Open))
                {
                    fileStream.Seek(0, SeekOrigin.Begin);
                    myByteArray = new byte[fileStream.Length];
                    await fileStream.ReadAsync(myByteArray, 0, (int)fileStream.Length);
                }
                if (isDeleteSourceFile)
                {
                    File.Delete(filePath);
                }
            }

            return myByteArray ?? new byte[0];
        }


        /// <summary>
        /// 压缩多个文件为zip文件
        /// </summary>
        /// <param name="zipFileName">zip压缩文件名</param>
        /// <param name="filePaths">资源文件列表（包含路径）</param>
        /// <param name="isDeleteSourceFile">是否删除资源文件</param>
        /// <returns></returns>
        public string CompressFileToZip(string zipFileName, string[] filePaths, bool isDeleteSourceFile = false)
        {
            string? zipFilePath = null;
            if (!string.IsNullOrWhiteSpace(zipFileName) && filePaths.Length > 0)
            {
                string zipDirectoryPath = Path.Combine(this.hostingEnvironment.ContentRootPath, "staticfiles", "Download", DateTime.Now.ToString("yyyyMMddHHmmssfff"));
                if (!Directory.Exists(zipDirectoryPath))
                {
                    Directory.CreateDirectory(zipDirectoryPath);
                }

                zipFilePath = Path.Combine(this.hostingEnvironment.ContentRootPath, "staticfiles", "Download", zipFileName);
                if (File.Exists(zipFilePath))
                {
                    File.Delete(zipFilePath);
                }

                foreach (string filePath in filePaths)
                {
                    string? fileName = filePath.Contains("\\") ? filePath.Split('\\').LastOrDefault() : filePath.Split('/').LastOrDefault();
                    string copyFilePath = Path.Combine(zipDirectoryPath, fileName ?? "");
                    if (isDeleteSourceFile)
                    {
                        File.Move(filePath, copyFilePath);
                    }
                    else
                    {
                        File.Copy(filePath, copyFilePath);
                    }
                }
                CompressionHelper.Compression(zipDirectoryPath, zipFilePath);

                //压缩完成后，删除压缩使用文件夹及其子项
                if (isDeleteSourceFile)
                {
                    Directory.Delete(zipDirectoryPath, true);
                }
            }
            return zipFilePath ?? "";
        }
    }
}

　　　2-控制器方法示例：

[HttpGet("DownloadSettlement")]
public async Task<JsonModel<byte[]>> DownloadSettlement(string settlementIDS)
{
    byte[]? byteArray = null;
    string[] settlementIDArray = settlementIDS.Split(',');

    string templateHtmlPath = Path.Combine(this.hostingEnvironment.ContentRootPath, "staticfiles", "agentusersettlement.html");
    List<string> zipSaveFilePathList = new List<string>(settlementIDArray.Length);

    Base_shop baseShop = await this.shopService.Value.GetBaseShopAsync();
    foreach (var item in settlementIDArray)
    {
        long settlementID = TypeParseHelper.StrToInt64(item);
        ResponseAgentUserSettlementDetail? detail = await this.agentUserSettlementService.Value.GetDetailAsync(settlementID);
        if (detail != null)
        {
            Agent_user agentUser = await this.agentUserService.Value.GetAsync(detail.AgentUserID) ?? new Agent_user();

            Dictionary<string, string> replaceDic = new Dictionary<string, string>()
            {
                {"@InvoiceNumber@",$"{detail.UpdateTime.ToString("yyyyMMdd")}{detail.ID}" },
            };

            string pdfPath = await this.pdfService.Value.HtmlToPDFFile(templateHtmlPath, $"{settlementID}.pdf", replaceDic);
            if (pdfPath.IsNullOrEmpty())
            {
                this._logger.LogError($"生成PDF失败,detail:{{settlementID:{settlementID},agentUser:{JsonHelper.ConvertJsonToStr(agentUser)}}}");
            }
            else
            {
                zipSaveFilePathList.Add(pdfPath);
            }
        }
    }

    if (zipSaveFilePathList.Count > 0)
    {
        if (zipSaveFilePathList.Count == 1)
        {
            byteArray = await this.pdfService.Value.GetByteByFile(zipSaveFilePathList.FirstOrDefault());
        }
        else
        {
            string zipFilePath = this.pdfService.Value.CompressFileToZip($"{settlementIDS.Replace(',', '_')}.zip", zipSaveFilePathList.ToArray(), false);
            this._logger.LogInformation($"获取到压缩文件地址,{zipFilePath},文件列表,{string.Join(',', zipSaveFilePathList)}");
            byteArray = await this.pdfService.Value.GetByteByFile(zipFilePath);
        }
    }

    return base.SuccessResult(byteArray ?? new byte[0]);
}

　　3-前台JS下载文件字节流示例：

<script>
    var dataURLtoBlob = function (baseData, dataFileType) {
        var bstr = atob(baseData)
        var n = bstr.length;
        var u8arr = new Uint8Array(n);
        while (n--) {
            u8arr[n] = bstr.charCodeAt(n);
        }
        return new Blob([u8arr], { type: dataFileType });
    };

    var dataByteArray = "后台方法返回的文件字节流数据"
    var dataIsZip = true;
    var dataIsPDF = false

    var fileName = null;
    var blob = null;
    if (dataIsZip) {
        blob = dataURLtoBlob(dataByteArray, "application/zip; charset=utf-8");
        fileName = "test.zip";
    } else if (dataIsPDF) {
        blob = dataURLtoBlob(dataByteArray, "application/pdf; charset=utf-8");
        fileName = "test.pdf";
    }
    var url = window.URL.createObjectURL(blob);
    var a = document.createElement('a');
    a.href = url;
    a.download = fileName;
    a.click();
    window.URL.revokeObjectURL(url);
</script>