An Introduction to Scripting Fetch
Volume Number: 22 (2006)
Issue Number: 5
Column Tag: Scripting
AppleScript Essentials
An Introduction to Scripting Fetch
by Benjamin S. Waldie
For the past several months, we have discussed ways to store and access data from AppleScript. We have talked about script properties, property list files, scriptable database applications, and more. In this month's column, I'd like to switch gears, and talk about a great application that I have been scripting quite a lot lately. That application is Fetch.Fetch is a popular FTP/SFTP client for the Macintosh. It is a commercial application, and a demonstration version is available for download from the Fetch Softworks website at <http://www.fetchsoftworks.com>. If you do not own a license for Fetch, then I encourage you to download a demonstration version, so that you may follow along with the various example scripts throughout this month's column.
Figure 1. Fetch's Well-Known Icon
All of the example code that we will discuss was written and tested with Fetch version 5.1b2. As when scripting any application, if you are using an older or newer version of Fetch, then you may notice some differences in the AppleScript terminology. If this occurs, please refer to Fetch's AppleScript dictionary for guidance in determining the proper syntax to use.
Connecting to a Server
The first thing that we are going to discuss, is the process of connecting to a remote server. For my testing, I enabled incoming FTP access in the Sharing system preference on another Mac OS X computer, on my local network. However, I could have just as easily chosen to access a remote server, such as the one hosting my website, or one of a client. For your testing, if you have a second machine running Mac OS X, then you can enable incoming FTP access (you'll probably want to ensure that your network is secure, or enable a firewall prior to doing this) for testing. Otherwise, you will need to find a server that you can access remotely via FTP or SFTP.
Making a new server connection in Fetch, is done by creating a new window, called a transfer window. See figure 2.
Figure 2. A Transfer Window Connection
Creating a transfer window is done with the use of the make command, as demonstrated in the example code below. You will want to replace my example IP address, username, password, and initial directory with ones that are relevant to the server to which you are attempting to connect.
set theServerAddress to "10.0.1.3"
set theUserName to "myUserName"
set thePassword to "myPassword"
set theDirectory to "Documents/FTP Main/"
tell application "Fetch"
make new transfer window at beginning with properties {hostname:theServerAddress,
username:theUserName, password:thePassword, initial folder:theDirectory}
end tell
--> transfer window id 120663408 of application "Fetch"
As you can see from the code above, the result of making a new transfer window is a reference to the newly created window. Notice that the window is referenced by its ID. As you navigate to different folders on the remote server, the transfer window's name will change. Therefore, to refer to the newly created transfer window again later in your code, you may want to capture this result in a variable. For example:
tell application "Fetch"
set theTransferWindow to make new transfer window at beginning with properties
{hostname:theServerAddress, username:theUserName, password:thePassword, initial
folder:theDirectory}
end tell
When a transfer window is made, its default authentication type is FTP. However, you may explicitly specify that a different type of authentication be used, such as SFTP. This can be done by specifying a value for the transfer window's authentication property, when the transfer window is created, as the following code demonstrates.
tell application "Fetch"
make new transfer window at beginning with properties {hostname:theServerAddress,
username:theUserName, password:thePassword, initial folder:theDirectory, authentication:SFTP}
end tell
As previously mentioned, one way to refer to a transfer window in the future is to do so by setting a variable to the result when making a transfer window. This variable would include a reference to the transfer window using a unique ID. If you are working with an existing transfer window, you can find out its unique ID with the use of the following code:
tell application "Fetch"
id of front transfer window
end tell
--> 120663408
Once you have a window's ID, you can refer to it later by that ID. For example:
tell transfer window id 96356736
-- Add Code Here
end tell
You may also have the need to retrieve the name of a transfer window. However, as mentioned before, the name of the transfer window will change if you open a remote folder.
tell application "Fetch"
name of transfer window 1
end tell
--> "10.0.1.3 -- FTP Main"
You can also refer to a transfer window by its index, or front to back order. For example, the following code would target the frontmost transfer window, which has an index of 1.
tell transfer window 1
-- Add Code Here
end tell
Throughout this column, all of my example code will target a transfer window by its index.
Working with Remote Items (Part 1)
Now that we have discussed connecting to a server, let's begin to look at ways to interact with the remote items on that server. First, let's turn to remote folders.
Suppose you want to create a remote folder on the server. First, you will probably want to determine if the folder already exists. To do this, use the exists command. For example:
tell application "Fetch"
tell transfer window 1
remote folder "Job 1000" exists
end tell
end tell
--> false
If the remote folder did not exist, then you can choose to create it. Like creating a server connection, you will use the make command to create a folder. The following example code demonstrates the proper syntax for performing this task. Figure 3 shows an example of a newly created remote folder.
tell application "Fetch"
make remote folder at transfer window 1 with properties {name:"Job 1000"}
end tell
Figure 3. A Newly Created Remote Folder
Now that you have a remote folder, you may want to open it. To do this, use the open command, as demonstrated by the following code.
tell application "Fetch"
tell transfer window 1
open remote folder "Job 1000"
end tell
end tell
Note that, after opening a folder, the name of the transfer window will be changed to reflect the currently opened folder. An example of this can be seen in figure 4.
Figure 4. An Opened Remote Folder
Uploading
We will return to interacting with remote items shortly. For now, we will discuss uploading items to the server.
To upload an item to a remote directory, you will make use of Fetch's put into command. The following example code demonstrates the proper use of this terminology. First, it will prompt the user to select a file. It will then upload that file to the currently opened remote folder on the server. Figure 5 shows an example of an uploaded item.
set thePath to choose file with prompt "Please select an item to upload:" without invisibles
tell application "Fetch"
with timeout of 300 seconds
put into transfer window 1 item thePath
end timeout
end tell
Figure 5. An Uploaded Item
The put into command's only required parameter is the item parameter, which we have utilized in the previous code to indicate the path of the desired file to be uploaded. The put into command also offers the ability to specify a number of optional parameters , which can affect how the item is uploaded. For example, you might specify the resume parameter if you want to resume a previous upload. Or, you might specify the uniquename parameter, if you want Fetch to automatically assign a unique name to the item if an item with the same name that already exists. For a complete list of the put into command's optional parameters, please refer to Fetch's AppleScript dictionary.
Working with Remote Items (Part 2)
Whether or not you have uploaded items to the server yourself, there will probably be times when you will want, or need, to interact with remote items on a server. See figure 6.
Figure 6. A Folder of Remote Items
We have already discussed how to navigate folders on a server. Now, let's talk about how to get the contents of a folder. The following example code will retrieve the names of every remote item in the currently opened folder.
tell application "Fetch"
tell transfer window 1
name of every remote item
end tell
end tell
--> {"Job Image 1.png", "Job Image 2.png", "Job Image 3.png"}
NOTE: In the previous code, we referenced every remote item. A remote item can be either a file or a folder on the server. To target one or the other specifically, use either remote file or remote folder instead.
You can also retrieve numerous properties of remote items on a server, such as the remote item's path, modification date, permissions, and more. The following example code demonstrates how to retrieve the size of a remote item, in bytes.
tell application "Fetch"
tell transfer window 1
size of remote item "Job Image 1.png"
end tell
end tell
--> 66242
As you work with remote items, you may also have the need to delete a remote item. This can be done by using the delete command. For example:
tell application "Fetch"
tell transfer window 1
delete remote item "Job Image 2.png"
end tell
end tell
Downloading
We have covered uploading items to a server. Now, let's talk briefly about downloading items. To download an item, use the download command, and specify a folder into which the remote item should be downloaded. For example:
set theOutputFolder to path to desktop folder
tell application "Fetch"
tell transfer window 1
download remote item "Job Image 1.png" to theOutputFolder
end tell
end tell
--> {file "Macintosh HD:Users:bwaldie:Desktop:Job Image 1.png"}
As you can see from the previous example code, the download command will result in a list of file references to the newly downloaded items.
Miscellaneous Tasks
When working with a transfer window, whether uploading, downloading, or otherwise, you may want to determine the status of the server connection. This can be done by accessing the transfer window's status property. For example:
tell application "Fetch"
tell transfer window 1
status
end tell
end tell
--> "Connected."
The status property will return the text of the current status of the fetch window, as it appears visually at the bottom of the window itself. Other transfer window attributes, which can often be useful when scripting Fetch, are also accessible via properties. Such attributes include the elapsed transfer time, and the bytes transferred, of a current transfer.
Once you have completed your Fetch scripting, you may want to have your script close down the server connection. This can be done by using the close command to close the transfer window. For example:
tell application "Fetch"
close transfer window 1
end tell
Recording and Next Steps
Now that we have discussed various ways to interact with Fetch via AppleScript, I should also mention that Fetch is one of those rare applications that supports recording! That is, you can click the Record button in a Script Editor window, perform tasks manually in Fetch, and those tasks will be translated into AppleScript code, and written for you automatically in the Script Editor window. See figure 7 for an example of a recorded Fetch script.
Figure 7. Recording Manual Fetch Activity
You may be asking "Why didn't he mention that Fetch was recordable in the first place?" Well, one reason I didn't mention this is because I wanted to show how easy it is to begin scripting Fetch without recording. Another reason is that there are limitations to recording AppleScript code in any application. A recorded script does not include variables, if/then statements, or repeat loops. Because of this, recorded scripts are typically not as efficient as scripts written from scratch. Recorded scripts also perform tasks exactly as you recorded them, and do not have the ability to analyze situations and take different courses of action. However, recording is still a good way to get started, and it can often be helpful in determining the proper syntax for performing that certain task when you just can't figure it out on your own. Furthermore, you always have the ability to go back and edit your recorded scripts, to make them more efficient, or to add logic to them.
Figure 8. Fetch Example Scripts
If you plan to begin scripting Fetch, another good place to start is to download the example scripts that are available from the Fetch Softworks website at <http://fetchsoftworks.com/downloads.html>. These example scripts will provide you with unlocked, editable sample code for performing tasks such as connecting to servers, uploading items, and more. See figure 8.
In Closing
Although this month's column focused specifically on using Fetch as a scriptable FTP/SFTP client, please be aware that it is not your only choice. There are other applications and tools that are used by AppleScript developers for transferring files across networks.
Transmit, available from Panic Software at <http://www.panic.com>, and Cyberduck, available at http://www.cyberduck.ch are two other popular FTP/SFTP clients for Macintosh, and are frequently utilized by scripters. URL Access Scripting, which is built into Mac OS X, can be used for performing uploads and downloads to remote servers. URL Access Scripting can be found in the System > Library > ScriptingAdditions folder in Mac OS X. Many AppleScript developers also choose to utilize the power of UNIX for performing network file transfers. The do shell script AppleScript command in Mac OS X can be used in conjunction with UNIX tools such as curl or ftp to perform such tasks.
Until next time, keep scripting!
Ben Waldie is the author of the best selling books "AppleScripting the Finder" and the "Mac OS X Technology Guide to Automator", available from http://www.spiderworks.com. Ben is also president of Automated Workflows, LLC, a company specializing in AppleScript, and workflow automation consulting. For years, Ben has developed professional AppleScript-based solutions for businesses including Adobe, Apple, NASA, PC World, and TV Guide. For more information about Ben, please visit http://www.automatedworkflows.com, or email Ben at applescriptguru@mac.com.
