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.NET WebForms
File Upload
The following code example illustrates how to handle file upload on your server using .NET WebForms as a server-side language. For step by step explanation of the upload flow see file upload concept.
Frontend
This can be pasted in your Default.aspx
<!DOCTYPE html> <html> <head> <meta charset="utf-8"> <!-- Include external CSS. --> <link href="https://cdnjs.cloudflare.com/ajax/libs/font-awesome/4.4.0/css/font-awesome.min.css" rel="stylesheet" type="text/css" /> <link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/codemirror/5.25.0/codemirror.min.css"> <!-- Include Editor style. --> <link href="https://cdn.jsdelivr.net/npm/[email protected]/css/froala_editor.pkgd.min.css" rel="stylesheet" type="text/css" /> <link href="https://cdn.jsdelivr.net/npm/[email protected]/css/froala_style.min.css" rel="stylesheet" type="text/css" /> </head> <body> <!-- Include external JS libs. --> <script type="text/javascript" src="https://cdnjs.cloudflare.com/ajax/libs/jquery/1.11.0/jquery.min.js"></script> <script type="text/javascript" src="https://cdnjs.cloudflare.com/ajax/libs/codemirror/5.25.0/codemirror.min.js"></script> <script type="text/javascript" src="https://cdnjs.cloudflare.com/ajax/libs/codemirror/5.25.0/mode/xml/xml.min.js"></script> <!-- Include Editor JS files. --> <script type="text/javascript" src="https://cdn.jsdelivr.net/npm/[email protected]//js/froala_editor.pkgd.min.js"></script> <div class="sample"> <h2>File upload example.</h2> <form> <textarea id="edit" name="content"></textarea> </form> </div> <!-- Initialize the editor. --> <script> $(function() { $('#edit').froalaEditor({ // Set the file upload URL. fileUploadURL: '/Upload', fileUploadParams: { id: 'my_editor' } }) }); </script> </body> </html>
Backend
Upload.aspx
file handles the request and the upload part. The uploads directory will be automatically created if it dose not exist under "project_root"/Files/
. The project root directory must be write available otherwise the Files folder will not be created.
Inside the Upload file the following functions need to be defined. After processing the uploaded file, if it passes the validation, the server will respond with a JSON object containing a link to the uploaded file.
E.g.: {"link":"http://server_address/upload/name_of_file"}
.
public partial class Upload : Page { protected void Page_Load(object sender, EventArgs e) { if (Request.Files["file"] != null) { HttpPostedFile MyFile = Request.Files["file"]; // Setting location to upload files string TargetLocation = Server.MapPath("~/Files/"); try { if (MyFile.ContentLength > 0) { // Get File Extension string Extension = Path.GetExtension(MyFile.FileName); // Determining file name. You can format it as you wish. string FileName = Path.GetFileName(MyFile.FileName); // Generate random name. FileName = Guid.NewGuid().ToString().Substring(0, 8); // Determining file size. int FileSize = MyFile.ContentLength; // Creating a byte array corresponding to file size. byte[] FileByteArray = new byte[FileSize]; // Basic validation for file extension string [] AllowedExtension = { ".txt", ".pdf", ".doc", ".json", ".html" }; // Basic validation for mime type string[] AllowedMimeType = { "text/plain", "application/msword", "application/x-pdf", "application/pdf", "application/json","text/html" }; if (AllowedExtension.Contains(Extension) && AllowedMimeType.Contains(MimeMapping.GetMimeMapping(MyFile.FileName))) { // Posted file is being pushed into byte array. MyFile.InputStream.Read(FileByteArray, 0, FileSize); // Uploading properly formatted file to server. MyFile.SaveAs(TargetLocation + FileName + Extension); string json = ""; Hashtable resp = new Hashtable(); string urlPath = MapURL(TargetLocation) + FileName + Extension; // Make the response an json object resp.Add("link", urlPath); json = JsonConvert.SerializeObject(resp); // Clear and send the response back to the browser. Response.Clear(); Response.ContentType = "application/json; charset=utf-8"; Response.Write(json); Response.End(); } else { // Handle upload errors. } } } catch (Exception ex) { // Handle errors } } } // Convert file path to url // http://stackoverflow.com/questions/16007/how-do-i-convert-a-file-path-to-a-url-in-asp-net private string MapURL(string path) { string appPath = Server.MapPath("/").ToLower(); return string.Format("/{0}", path.ToLower().Replace(appPath, "").Replace(@"\", "/")); } }