ESENDERZipped and Encrypted File sending Application
- OS: Windows XP with Service Pack 2 or higher
- Server Side Language: .NET Framework 4.0
The Esender application work is to send the tiff file present in a specific folder as a attachment (zipped and encrypted) through emails. Also it needs to maintain archive folders so that if user needs to send the file again he can easily do so.
The application is built on Asp.net and has given features
1) Windows service: The windows service look for the specified folders in the specified location as set by user and continuously send the tiff file as email attachments. The service should also report any errors etc in log file. The service continuously sends the files encrypted and zipped. Also it creates the archive folder with directory (year->month) and keeps files with appended dates.
2) WPF Application: The application has several modules. They are:
a. Main form
b. Login Panel
c. Config Panel
a. Main Form
Following components of the main form have different functions:
1) Unsent Scans: This is a list box which points to images that reside in the folder present in the location specified by user. Initially when no files are present then this list will show empty.
2) In Process: The application has also the feature of drag and drop files from unsent scans to in process list box. When files are dropped in this list box it will be shown with cancel button. The cancel button beside each file-name is used to cancel the file for been sent as mail.
3) Send All: This button when used will send all the files from the unsent scans to in process list.
4) Send: After selecting the specified file from the unsent scans and pressing this button will send file to In Process list.
5) Cancel All: This is used to cancel all the files from In Process list and will move the file back to Unsent scans.
6) Cancel: This button will cancel only the corresponding file.
7) Archive: When the file is sent it is transferred to archive folder which will be shown as radio button in the Archive folder section. To send the files from the archive folder we need to select the radio button (e.g. 2013 see screenshot below) and press archive button .Its content gets changed to “Unsent Scans” and the heading of the Unsent Scans list will change into the name of selected archive folder.
To again come out from archive folder press the unsent scan button .Now the button content change to Archive
b. Login Panel: It is a simple login section provided to get into the desktop application.
c. Config Panel: Through this panel you can set the
1) Customer Tag: This is in fact the subject line of email. The text the user enters will be appended first with the “Email Processing” text. If the user enters “Requirement” in customer tag then subject line of email would be “Requirement Email Processing”
2) Export Path: This path will correspond to the folder that is having tiff images. There is also feature of folder selector.
3) Link: This is the text which will be placed at the bottom of the Main form
The business requirement for this application was to be able to securely transfer files in a timely fashion across two desktops. The challenge was to be able to do it across different network topology, low bandwidth links with ability to handle packet drops.
We leveraged the Microsoft file transfer and messaging libraries via C# language and ASP.NET framework. Instead of sending the files via UDP, we used TCP. The files were chunked and each chunk was compressed and transferred with error checking.
The application was deployed timely on desktops and functions very well. The application is self learning by adjusting transfer speed based on bandwidth available and self healing to auto correct in a high latency packet loss environment.