Working with GridJs storage

Working With GridJs Storage

the general file process

After import a spread sheet file in memory and show the ui,

GridJs will create a cache file with the specified uid ,

with the format of Aspose.Cells.SaveFormat.Xlsx ,

and then after every update operation in the ui,

for example set cell value,set cell style,etc. ,

GridJs client side js will trigger controller action to do a UpdateCell operation.

In this action a save back to the cache file from memory will occur during the UpdateCell method.

        // post: /GridJs/UpdateCell
        [HttpPost] 
        public ActionResult UpdateCell( )
        {
            string p = HttpContext.Request.Form["p"];
            string uid = HttpContext.Request.Form["uid"];
            GridJsWorkbook gwb = new GridJsWorkbook();
            String ret = gwb.UpdateCell(p, uid);
            return Content(ret, "text/plain", System.Text.Encoding.UTF8);
        }

where is the cache directory

A. If we Implement GridCacheForStream and set GridJsWorkbook.CacheImp. for example in the below code we can just put and get the cache file from “D:\temp”

Config.FileCacheDirectory=@"D:\temp";
GridJsWorkbook.CacheImp=new LocalFileCache();
public class LocalFileCache  : GridCacheForStream
    {
         
        /// <summary>
        /// Implement this method to savecache,save the stream to the cache object with the key id.
        /// </summary>
        /// <param name="s">the source stream </param>
        /// <param name="uid">the key id.</param>
        public override void SaveStream(Stream s, String uid)
        {//make sure the directory exist
            String filepath = Path.Combine(Config.FileCacheDirectory, uid);
            using (FileStream fs = new FileStream(filepath, FileMode.Create)) 
            {
                s.Position = 0;
                s.CopyTo(fs);
            }

        }

        /// <summary>
        /// Implement this method to loadcache with the key uid,return the stream from the cache object.
        /// </summary>
        /// <param name="uid">the key id</param>
        /// <returns>the stream from  the cache</returns>
        public override Stream LoadStream(String uid)
        {//make sure the directory is exist
            String filepath = Path.Combine(Config.FileCacheDirectory, uid);;
            FileStream fs = new FileStream(filepath, FileMode.Open);
            return fs;
        }
		...

B.If we do not set GridJsWorkbook.CacheImp,

GridJs will create and do save file within the Config.FileCacheDirectory , which is the default cache directory which we can set.

how to get the updated result file

1. a specified uid for file

Make sure a specified map correspondence between the file and the uid,

you can always get the same uid for a specifed file name,not from random generation.

For example just use the filename is ok.

//in controller  
...
        public ActionResult Uidtml(String filename)
        {
 
            return Redirect("~/xspread/uidload.html?file=" + filename + "&uid=" +  Path.GetFileNameWithoutExtension(filename));
        }
 ...
        public ActionResult DetailFileJsonWithUid(string filename,string uid)
        {
            String file = Path.Combine(TestConfig.ListDir, filename);
            GridJsWorkbook wbj = new GridJsWorkbook();
            //check if already in cache
           StringBuilder sb= wbj.GetJsonByUid(uid, filename);
            if(sb==null)
            {
                Workbook wb = new Workbook(file);
                wbj.ImportExcelFile(uid, wb);
                sb = wbj.ExportToJsonStringBuilder(filename);
            }

            return Content(sb.ToString(), "text/plain", System.Text.Encoding.UTF8);
        }

2. sync with ui operation

Actually for some ui operation,

for example:

switch the acitve sheet to another,

change the image postion,

rotate/resize image,etc.

the UpdateCell action will not triggered.

Thus if we want to get the updated file just same as the ui shows,

we need to do a merge operation before save action to sync those ui operation.

//in the js
  function save() {
            if (!xs.buffer.isFinish()) {
              alert('updating is inprogress,please try later');
                return;
            }
            let datas = xs.datas;
            delete datas.history;
            delete datas.search;
            delete datas.images;
            delete datas.shapes;

        var jsondata = {
          sheetname: xs.sheet.data.name,
          actrow: xs.sheet.data.selector.ri,
          actcol: xs.sheet.data.selector.ci,
          datas: xs.getUpdateDatas(),
        };

        const data = {
          p: JSON.stringify(jsondata),
          uid: uniqueid,
        };
		....
		//go on to do ajax post to trigger controller action

//in controller action 
  GridJsWorkbook wb = new GridJsWorkbook();
  wb.MergeExcelFileFromJson(uid, p);
  //after merge do save to chache or to a stream or whaterver you want to save to ,here we just save to cache
  wb.SaveToXlsx(Path.Combine(Config.FileCacheDirectory, uid));

3. get the file from cache

for example :in the download action,you can just get it from the cache directory by uid.

//in controller  

        public async Task<IActionResult> DownloadfromBytes(string uid,string ext)
        {
            byte[] byteArr = await System.IO.File.ReadAllBytesAsync(Path.Combine(Config.FileCacheDirectory, uid) );
            string mimeType = "application/octet-stream";
            return new FileContentResult(byteArr, mimeType)
            {
                FileDownloadName = uid+ ext
            };
        }

For more detail info ,you can check the example here: https://github.com/aspose-cells/Aspose.Cells-for-.NET/tree/master/Examples_GridJs