Use CFFTP - ColdFusion Tips Plus

ColdFusion TIPS PLUS

Issue 00093 http://www.cftipsplus.com

I. My Comments
II. ColdFusion In Context: Use CFFTP
By R. Martin Ladner
martin.ladner@knology.net

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I. Comments:

Last week I was sick in bed all weekend. I missed two days of work and I am still getting over what ever it was I had. Hope your doing well.

Keep Coding,
Nathan Stanford
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II. ColdFusion in Context: Use CFFTP
By R. Martin Ladner
martin.ladner@knology.net

Suppose you wanted to pull and display files from a machine that doesn't have a Web server loaded. One way to do that is with the cfftp tag. This tip lets you view a local directory with cfdirectory, delete local files with cffile, view a remote directory with cfftp, copy files from that directory with cfftp, and display them javascript to pop open a new window.

Outline the Viewer
Here's an outline to follow to juggle all these tasks. Put the pop-up script in the document header so it will be ready when you need it. Invoke session management as one way to give the ftp connection a unique name that no other user will step all over while you're using it. When the user presses a submit button on the form, you'll need to test for that variable and act on it before the form reloads. To give the user feedback and controls, you'll need to query the remote and local directories. You'll need to use the queries to embed directory lists and file controls into the form. Finally, the display buttons will need to be set to invoke the javascript routine you placed in the header.

Pop-Up
Nest script tags within an HTML header and place the pop-up function within that. The word "page" is a placeholder for the value to be passed by form controls for display. Begin "view.cfm" with this code.

<head>
<script language="javascript">
function pop(page) {
popWindow = window.open(page, 'popWin');
}
</script>
</head>

Establish Defaults
Open the body and session, and set common defaults; add this code to view.cfm. The application name can be anything not repeated elsewhere on your server. Load login information from an included file. This way, if the Web server hiccups and tries to serve the unterpreted content of view.cfm, the login information won't be seen. To simplify installation, set the "scriptdir" to the full drive and directory path leading to this page.

Open and Act
Set key form variables if undefined, open the session, and act; add this code to view.cfm. If the user asked to copy a file from the remote server, change remote directories and get the file. If the user asked to delete a file from the local server, delete the file.

Build a Form and Close the Connection
Query remote directories, close the ftp connection, and build a form based on the queries. Add this code to view.cfm. The directory-seeking code will be in rls.cfm and ldir.cfm. The form has three different kinds of controls: a submit button (used for refresh) that doesn't set anything important, submit buttons that pass a filename for copy ("myget") or delete ("mydel"), and button buttons [grin] that display a file ("myshow") in a window through the use of the javacript routine invoked earlier.

To place the files in context, information about the files (such as their date and size) is shown. The information for both remote and local directories is accessed as one would access a database query. However, the names and data types for some of this information varies depending on the source. The date and time of a file in the remote directory is a real date object that has to be parsed for display; the corresponding element for the local directory is a string already, and it doesn't have the same name. The file size is called Length for the remote query and Size for the local query. Finally, to avoid seeing names such as . and .. in the local display, they're filtered out with a contains statement. Close the body of the document.

<form name="view" action="view.cfm" method="post">
<input name="lookagain" type="submit" value="Refresh">
<p>
REMOTE DIRECTORY<br>
Copy of these from the remote server.<br>
<cfoutput query="remotedir">
Copy - <input name="myget" type="submit" value="#Name#">,
#DateFormat(LastModified,"mm/dd/yyyy")#
#TimeFormat(LastModified,"hh:mm:ss tt")#,
#Length#<br>
</cfoutput>
<p>
LOCAL DIRECTORY<br>
Display or delete one of these from the local server.<br>
<cfoutput query="localdir">
<cfif ".." does not contain Name>
Display - <input name="myshow" type="button"
value="#Name#" onClick="javascript:pop('stuff/#Name#');">,
#DateLastModified#, #Size# - <input name="mydel" type="submit"
value="#Name#"> - Delete<br>
</cfif>
</cfoutput>
</form>
</body>

Set Login Data
Populate the following variables with real data; call this code howtoftp.cfm

Open the Connection
The cfftp tag lets you open and name a connection that you can then re-use with other ftp commands until the remote server times breaks it. Enabling session management as you did in the calling page made it possible to use the sessionID as the connection name. (You could use the createuuid function instead to get a unique name and then use a hidden form field to pass it alone if you planned to use the same connection for subsequent pages.) In coding the open statement, set a timeout, let it try a few times, and set stoponerror to no so it its errors won't halt the page. If it doesn't succeed, let cfftp tell you why with cfftp.errortext. Name this code ropen.cfm

<cfftp connection="#session.sessionID#" action="open" server="#request.server#"
username="#request.username#" password="#request.password#"
timeout="30" retrycount="3" stoponerror="no">
<cfif cfftp.errorcode is not 0>
The connection did not succeed;
<cfoutput>#cfftp.errortext#</cfoutput>
<cfabort>
<cfelse>
Connected OK.
</cfif>

Change Remote Directories
While the connection is still open, you can perform multiple ftp operations without logging in again. Thus, the login information doesn't have to be specified over again for changing a directory right away. Call this code rcd.cfm.

<cfftp connection="#session.sessionID#" action="changedir" directory="#request.workdir#"
timeout="30" retrycount="3" stoponerror="no">
<cfif cfftp.errorcode is not 0>
<cfoutput>Directory not changed to #request.workdir#:
#cfftp.errortext#
</cfoutput>
<cfabort>
<cfelse>
<cfoutput>Changed directory to #request.workdir#</cfoutput>
</cfif>

Get a File
For the get function, both the remote file and the name it will have on the local server must be specified. The transfer mode is set explicitly here for clarity, but cfftp will usually make the right choice based on file extension anyway (and its default list of extensions with which ASCII mode should be used is easily changed). Call this code rget.cfm.

<cfftp connection="#session.sessionID#" action="getfile"
remotefile="#form.myget#" localfile="#scriptdir#/stuff/#form.myget#" transfermode="binary"
timeout="30" retrycount="3" stoponerror="no" failifexists="no">
<cfif cfftp.errorcode is not 0>
<cfoutput>
Attempt to get #form.myget# failed.
#cfftp.errortext#
</cfoutput>
<cfelse>
Got <cfoutput>#form.myget#</cfoutput> OK.
</cfif>
<cfset form.myget="">

Delete a Local File
The command to delete a local file is actually a one-liner that's pulled out into a separate file for clarity. The file parameter consists of the path to the script (set by view.cfm), the directory below it that holds these files, and the name of the file. Call this code ldel.cfm.

Query a Remote Directory
The action to query a remote directory produces a query that you can use in the same manner as a database query. Reference the name parameter used here as the name of the query. Call this code rls.cfm.

<cfftp connection="#session.sessionID#" action="listdir"
directory="#request.workdir#" name="remotedir" timeout="30" retrycount="3" stoponerror="no">
<cfif cfftp.errorcode is not 0>
Remote listing did not succeed.
<cfoutput>
#cfftp.errortext#
</cfoutput>
<cfelse>
Remote listing was OK.
</cfif>

Close a Remote Connection
If you don't close the connection, it will tie up resources of two computers until the remote server eventually times it out. Call this code rclose.cfm.

Query a Local Directory
The action to query a remote directory produces a query that you can use in the same manner as a database query. Reference the name parameter used here as the name of the query. Call this code ldir.cfm.

Try Out the Demo
To make this work, you'll need directories on two servers and this code. Put some pictures in the remote directory and correct this code to match that directory name. Put this code on your local server, add a directory below it, and correct this code to match the local directory name. Then click on view.cfm. Get some files (copies) from the remote server, display them locally, and delete local copies.
Findings
The ftp protocol is tough to test when you don't own your own servers. In general, I had good results with list, get, and delete. All my put attempts resulted in zero-length files (which is why I didn't use "put" in the demo), but that was probably due to firewall and permission issues. The cfftp tag is otherwise easy and straightforward to use.
=Marty=

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