摘要
在一些项目中需要在线预览office文档，包括word，excel，ppt等。达到预览文档的目的有很多方法，可以看我之前总结，在线预览的n种方案：
[Asp.net]常见word，excel，ppt，pdf在线预览方案，有图有真相，总有一款适合你！
，由于客户那里有安装web office apps服务，调用该服务就可以实现文档的在线预览，所以在项目中就采用了这种方式，下面列出了实践步骤。
步骤
定义文件信息：
该信息用来调用web office apps服务回调查找文件信息时用到。
public class CheckFileInfo
{
public CheckFileInfo();
public string BaseFileName { get; set; }
public string OwnerId { get; set; }
public long Size { get; set; }
public string SHA256 { get; set; }
public string Version { get; set; }
}
获取文件信息的接口
public interface IFileHelper
{
Task<CheckFileInfo> GetFileInfo(string fileMD5);
Task<string> GetSHA256Async(string url);
string GetSHA256Async(byte[] buffer);
}
接口实现
public class FileHelper : IFileHelper
{
FileBusiness _FileBusiness;
public FileHelper()
{
_FileBusiness = new FileBusiness();
}
/// <summary>
/// 获取文件信息
/// </summary>
/// <param name="filePath"></param>
/// <returns></returns>
public async Task<CheckFileInfo> GetFileInfo(string fileMD5)
{
var fileInfo = _FileBusiness.FindFileByMD5(fileMD5);
if (fileInfo != null)
{
var rv = new CheckFileInfo
{
Version = DateTime.Now.ToString("s"),
Size = Convert.ToInt64(fileInfo.FileSize),
OwnerId = fileInfo.Itcode,
BaseFileName = fileInfo.FileName,
SHA256 = fileInfo.SHA256
};
if (string.IsNullOrEmpty(fileInfo.SHA256))
{
rv.SHA256 = await GetSHA256Async(fileInfo.Url);
fileInfo.SHA256 = rv.SHA256;
await _FileBusiness.UpldateAsyncByUrl(fileInfo);
}
return rv;
}
else
{
return null;
}
}
public async Task<string> GetSHA256Async(string url)
{
string sha256 = string.Empty;
using (var sha = SHA256.Create())
{
WebClient webClient = new WebClient();
byte[] buffer = await webClient.DownloadDataTaskAsync(url);
byte[] checksum = sha.ComputeHash(buffer);
sha256 = Convert.ToBase64String(checksum);
}
return sha256;
}
public string GetSHA256Async(byte[] buffer)
{
string sha256 = string.Empty;
using (var sha = SHA256.Create())
{
WebClient webClient = new WebClient();
byte[] checksum = sha.ComputeHash(buffer);
sha256 = Convert.ToBase64String(checksum);
}
return sha256;
}
}
这里用到了文件分布式存储，要预览的放在了另外的文件服务器上面，所以这里使用webclient下载，获取到文件信息，保存在数据库中，如果存在则直接返回。当然，你可以使用FileStream来读取文件的响应信息。
获取文件预览的地址
根据web office apps服务的地址，文件扩展名获取预览的link
using H5.Utility;
using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Web;
using System.Xml.Serialization;
namespace WebSite.OfficeViewerService.Helpers
{
/// <summary>
///
/// </summary>
public class WopiAppHelper
{
public WopiAppHelper() { }
/// <summary>
/// 获取office在线预览的链接
/// </summary>
/// <param name="fileMD5"></param>
/// <param name="ext"></param>
/// <returns></returns>
public string GetDocumentLink(string fileMD5, string ext)
{
string apiUrl = string.Format(ConfigManager.OWA_MY_VIEW_URL, fileMD5);
return string.Format("{0}{1}{2}&access_token={3}", ConfigManager.OWA_URL, FindUrlByExtenstion(ext), apiUrl, fileMD5);
}
/// <summary>
/// 根据文件扩展名获取预览url
/// </summary>
/// <param name="ext"></param>
/// <returns></returns>
private string FindUrlByExtenstion(string ext)
{
if (string.IsNullOrEmpty(ext))
{
throw new ArgumentNullException("extension is empty.");
}
if (ext.IndexOf(".") >= 0)
{
//如果包含.则进行过滤
ext = ext.TrimStart('.');
}
Dictionary<string, string> dic = new Dictionary<string, string>()
{
{"ods","/x/_layouts/xlviewerinternal.aspx?WOPISrc="},
{"xls", "/x/_layouts/xlviewerinternal.aspx?WOPISrc="},
{"xlsb", "/x/_layouts/xlviewerinternal.aspx?WOPISrc="},
{"xlsm", "/x/_layouts/xlviewerinternal.aspx?WOPISrc="},
{"xlsx", "/x/_layouts/xlviewerinternal.aspx?WOPISrc="},
{"one", "/o/onenoteframe.aspx?WOPISrc="},
{"onetoc2", "/o/onenoteframe.aspx?WOPISrc="},
{"odp", "/p/PowerPointFrame.aspx?WOPISrc="},
{"pot", "/p/PowerPointFrame.aspx?WOPISrc="},
{"potm", "/p/PowerPointFrame.aspx?WOPISrc="},
{"potx", "/p/PowerPointFrame.aspx?WOPISrc="},
{"pps", "/p/PowerPointFrame.aspx?WOPISrc="},
{"ppsm", "/p/PowerPointFrame.aspx?WOPISrc="},
{"ppsx", "/p/PowerPointFrame.aspx?WOPISrc="},
{"ppt", "/p/PowerPointFrame.aspx?WOPISrc="},
{"pptm", "/p/PowerPointFrame.aspx?WOPISrc="},
{"pptx", "/p/PowerPointFrame.aspx?WOPISrc="},
{"doc", "/wv/wordviewerframe.aspx?WOPISrc="},
{"docm", "/wv/wordviewerframe.aspx?WOPISrc="},
{"docx", "/wv/wordviewerframe.aspx?WOPISrc="},
{"dot", "/wv/wordviewerframe.aspx?WOPISrc="},
{"dotm", "/wv/wordviewerframe.aspx?WOPISrc="},
{"dotx", "/wv/wordviewerframe.aspx?WOPISrc="},
{"pdf", "/wv/wordviewerframe.aspx?WOPISrc="}
};
return dic[ext];
}
}
}
web office apps 预览接口回调使用的api时，需要注意尽量传递id之类，如果传递name，文件名涉及到了中文，会有编码的问题，所以我这里传递的是文件的md5值。
using Newtonsoft.Json;
using System;
using System.IO;
using System.Net;
using System.Net.Http;
using System.Net.Http.Headers;
using System.Security.Cryptography;
using System.Text;
using System.Threading.Tasks;
using System.Web;
using System.Web.Hosting;
using System.Web.Http;
using WebSite.OfficeViewerService.Helpers;
namespace WebSite.OfficeViewerService.Controllers.Api
{
/// <summary>
/// Primary class for WOPI interface. Supporting the 2 minimal API calls
/// requred for base level View
/// </summary>
public class FilesController : ApiController
{
IFileHelper _fileHelper;
HttpResponseMessage _response;
/// <summary>
/// Base constructor
/// </summary>
public FilesController()
{
_fileHelper = new FileHelper();
_response = new HttpResponseMessage(HttpStatusCode.Accepted);
//允许哪些url可以跨域请求到本域
_response.Headers.Add("Access-Control-Allow-Origin", "*");
//允许的请求方法，一般是GET,POST,PUT,DELETE,OPTIONS
_response.Headers.Add("Access-Control-Allow-Methods", "POST");
//允许哪些请求头可以跨域
_response.Headers.Add("Access-Control-Allow-Headers", "x-requested-with,content-type");
}
/// <summary>
/// Required for WOPI interface - on initial view
/// </summary>
/// <param name="name">file name</param>
/// <returns></returns>
public async Task<CheckFileInfo> Get(string name)
{
return await _fileHelper.GetFileInfo(name);
}
/// <summary>
/// Required for WOPI interface - on initial view
/// </summary>
/// <param name="name">file name</param>
/// <param name="access_token">token that WOPI server will know</param>
/// <returns></returns>
public async Task<CheckFileInfo> Get(string name, string access_token)
{
return await _fileHelper.GetFileInfo(name);
}
/// <summary>
/// Required for View WOPI interface - returns stream of document.
/// </summary>
/// <param name="name">file name</param>
/// <param name="access_token">token that WOPI server will know</param>
/// <returns></returns>
public async Task<HttpResponseMessage> GetFile(string name, string access_token)
{
try
{
_response.StatusCode = HttpStatusCode.OK;
FileBusiness FileBusiness = new FileBusiness();
var file = FileBusiness.FindFileByMD5(name);
if (file != null)
{
WebClient webClient = new WebClient();
byte[] buffer = await webClient.DownloadDataTaskAsync(file.Url);
MemoryStream stream = new MemoryStream(buffer);
_response.Content = new StreamContent(stream);
_response.Content.Headers.ContentType = new MediaTypeHeaderValue("application/octet-stream");
}
return _response;
}
catch (Exception ex)
{
_response.StatusCode = HttpStatusCode.InternalServerError;
var stream = new MemoryStream(UTF8Encoding.Default.GetBytes(ex.Message ?? ""));
_response.Content = new StreamContent(stream);
return _response;
}
}
}
}
路由配置
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web.Http;
namespace WebSite.OfficeViewerService
{
public static class WebApiConfig
{
public static void Register(HttpConfiguration config)
{
// Web API 配置和服务
// Web API 路由
config.Routes.MapHttpRoute(
name: "Contents",
routeTemplate: "api/wopi/files/{name}/contents",
defaults: new { controller = "files", action = "GetFile" }
);
config.Routes.MapHttpRoute(
name: "FileInfo",
routeTemplate: "api/wopi/files/{name}",
defaults: new { controller = "Files", action = "Get" }
);
config.Routes.MapHttpRoute(
name: "DefaultApi",
routeTemplate: "api/{controller}/{id}",
defaults: new { controller = "Files", id = RouteParameter.Optional }
);
}
}
}
using System;
using System.Collections;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Net;
using System.Threading.Tasks;
using System.Web;
using System.Web.Configuration;
using System.Web.Hosting;
using System.Web.Mvc;
using WebSite.OfficeViewerService.Helpers;
namespace WebSite.OfficeViewerService.Controllers
{
public class HomeController : Controller
{
IFileHelper _fileHelper = new FileHelper();
public ActionResult Index()
{
return View();
}
public async Task<ActionResult> Viewer(string url, string name)
{
string itcode = string.Empty;
try
{
if (string.IsNullOrEmpty(url))
{
throw new ArgumentNullException("Sorry,Url is errr,the file is not found");
}
string fileExt = url.Substring(url.LastIndexOf('.')); WopiAppHelper wopiHelper = new WopiAppHelper();
FileBusiness FileBusiness = new FileBusiness();
var file = FileBusiness.FindFileByUrl(url);
string fileMD5 = string.Empty;
if (file == null)
{
WebClient webClient = new WebClient();
byte[] buffer = await webClient.DownloadDataTaskAsync(url);
fileMD5 = MD5Helper.GetMD5FromFile(buffer);string sha256 = _fileHelper.GetSHA256Async(buffer);
await fastDFSFileBusiness.SaveAsync(new FastDFSFile
{
Dt = DateTime.Now,
FileMd5 = fileMD5,
FileName = name,
FileSize = buffer.Length,
Itcode = itcode,
Url = url,
SHA256 = sha256
});
}
else
{
fileMD5 = file.FileMd5;
}
var result = wopiHelper.GetDocumentLink(fileMD5, fileExt);
return Redirect(result);
}
catch (Exception ex)
{
ViewBag.Message = ex.Message;
}
return View();
}
}
}
包装预览接口，其它应用通过传递文件的url和文件名称，然后跳转到实际的预览界面。简单粗暴，不用每个应用都在实现上面的方法。