Sometimes, I do get to do some on-premises farm stuff.  Because deep in my soul, I'm a hardcore dev.  Muahaha.

Scenario

In InfoPath, we want to be able to:

• Send people to a folder within a document library, for them to upload attachments. 
• Each form has its own unique ID, say "1234".  The folder will be <site>/Attachments/1234/
• The folder doesn't need to be created when it's not used.  That is, it would be great to create the folder ON DEMAND
• Finally, InfoPath is quite dumb.  It only has a hyperlink.

 

Solution

• Create a HTTP Handler that takes this URL:  <site/sitecollection>/_layouts/InfoPathHelper/InfoPathHandler.ashx?folder=<site>/attachments/<ID>
• Create a folder on demand, and then respond via a HTTP Redirect.

 

Steps

 

1. Add a ashx handler to your SharePoint solution.  CKSDev has great template for this.
2. Add code to ProcessRequest
   public void ProcessRequest(HttpContext context)
   {
       if (!string.IsNullOrEmpty(context.Request.QueryString["folder"]))
       {
           CreateFolderAndRedirectResponse(context);
           return;
       }
   }
   
   
3. Add a function to check for the folder, create it if we need it, and end with a redirect.
   

   private void CreateFolderAndRedirectResponse(HttpContext context)
   {
       // <site-collection>/_layouts/InfoPathHelper/InfoPathHandler.ashx?folder=<site>/

       var path = context.Request.QueryString["folder"];
       var server = new Uri(SPContext.Current.Web.Url);
       var url = string.Format("{0}://{1}{2}", server.Scheme, server.Authority, path);

       // elevate permission to create the folder.
       SPSecurity.RunWithElevatedPrivileges(() =>
       {
           try
           {
               using (var site = new SPSite(url))
               {
                   using (var web = site.OpenWeb())
                   {
                       SPFolder folder = web.GetFolder(path);
                       SPFolder f = folder;
                       List<SPFolder> folders = new List<SPFolder>();
                       SPDocumentLibrary library = folder.DocumentLibrary;
                       if (library == null)
                       {
                           return;
                       }
                       while(f.Url.ToLower() != library.RootFolder.Url.ToLower()){
                           if (f.Exists || string.IsNullOrEmpty(f.Url))
                           {
                               break;
                           }

                           folders.Add(f);

                           f = f.ParentFolder;
                           if (f == null)
                           {
                               // if this happens we're in trouble
                               return;
                           }
                       }

   
                       if (folders.Count > 0)
                       {
                           // we are in a GET request - need to allow unsafe updates
                           web.AllowUnsafeUpdates = true;
                           folders.Reverse();
                           foreach (SPFolder f1 in folders)
                           {
                               if (!f1.Exists)
                               {
                                   f1.ParentFolder.SubFolders.Add(f1.Name);
                               }
                           }
                           web.AllowUnsafeUpdates = false;
                       }
                   }
               }
           }
           catch (Exception ex)
           {

           }
       });

       context.Response.Redirect(path, true);
   }
   
   

4. Wait what's all the strange looking nested folder stuff?  That's right, as a bonus, if you specify nested folder within the document library, the HTTP Handler will create those too!
   
   folder=/attachments/1234/1235/
   
5. InfoPath is super simple, just add a Hyperlink to the URL
   
   
   
   Link to Data Source:

   concat("/_layouts/InfoPathHelper/InfoPathHandler.ashx?attachments?folder=", my:ID)

 

See it running