The question, “How can I FTP a binary file with AVR for .NET” has come up a time or two in tech support lately. Here is a quick and easy response to that question. As you’ll see, uploading a file with FTP with AVR for .NET is pretty simple.
The code in Figure 1 shows how to call the function, FtpUploadFile, that this article provides. FtpUploadFile needs five arguments:
- The URI of the target FTP site (including any folders)
- The target name of the file on the FTP server
- The fully qualified path of the file to upload
- The FTP login name
- The FTP login password
In the example in Figure 1, the FTP server is at ftp://ftp.myftpserver.com and the folder for the uploaded file is “spreadsheets.” These two values comprise the first argument, with a slash (“/”) added between them. This argument can optionally end with a trailing slash (“/”). In this example, the status value returned is either the text returned from the FTP operation or an exception message.
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Using System Using System.Text Using System.Net Using System.IO ... DclFld status Type(*String) status = FtpUploadFile("ftp://ftp.myftpserver.com/spreadsheets",+ "sample1.xlsx",+ "c:\Users\Roger\Documents\sample1.xlsx",+ "neil", "young" ) |
Figure 1. Uploading a file with FTP
The meat of this article is below in Figure 2. This is the function that does the heavy lifting of uploading a file with FTP.
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BegFunc FtpUploadFile String Access(*Public) DclSrParm ftpUri Type(*String) DclSrParm targetFileName Type(*String) DclSrParm sourceFilePath Type(*String) DclSrParm user Type(*String) DclSrParm pwd Type(*String) DclFld request Type(FtpWebRequest) DclFld response Type(FtpWebResponse) DclFld requestStream Type(Stream) DclFld status Type(String) DclArray fileContents Type(Byte) Rank(1) Try If (NOT ftpUri.EndsWith("/")) ftpUri = ftpUri + "/" Endif request = WebRequest.Create(ftpUri + TargetFileName) *As FtpWebRequest request.Method = WebRequestMethods.Ftp.UploadFile request.UseBinary = *True request.Credentials = *New NetworkCredential(user, pwd) fileContents = File.ReadAllBytes(SourceFilePath) request.ContentLength = fileContents.Length requestStream = request.GetRequestStream() requestStream.Write(fileContents, 0, fileContents.Length) requestStream.Dispose() response = request.GetResponse() *As FtpWebResponse status = response.StatusDescription response.Close() Catch except Exception status = "Exception occured: " + except.Message EndTry LeaveSr status EndFunc |
Figure 2. FtpUploadFile function
At the core of the FtpUploadFunction are two objects in the System.Net namespace:
These methods were added with the .NET Framework version 2.0. The code shown here is for .NET Framework 4.0.
Here is a quick rundown of the major parts of FtpUploadFile:
Lines 16-19:
Ensure that the FtpUri ends with a slash (“/”) and then append the target file name (the name you want the uploaded file to have on the target computer).
Lines 20-22:
Set the properties of the request instance of the FtpWebRequest object. In this case we’re setting the object to upload binary files and specifying the FTP login credentials.
Lines 24-25:
Read all bytes of the source file and into the fileContents byte array.
Lines 27-29:
Instance a requestStream (of type Stream) and write the contents of the fileContents byte array to it.
Lines 31-33
Invoke the upload, save its StatusDescription in the status variable, and close the response instance.
Lines 34-36:
If any exception was thrown, save the exception message to the status variable. For production work you might want to return an instance of a class with more information than this.
Lines 38:
Check out of this motel! You’re done.
That’s all there is to it. It’s short, sweet, and works like a champ!
