Learn Applescript for Beginners
dev/applescript Good referential text:
Script editor
log "message" can be used to log messages that will be shown in “Messages” accessory pane at the bottom.
File formats
- Text: save as plain text
- Script: save as compiled library
- Application: used to create applet;
If in code
on open(droppedFiles) ... end openis written, then it becomes a dropplet, which allows drag-n-drop action on the created applet.
Dictionaries
Words inside square bracket are optional arguments.
Words on the right of right arrow is what will be returned.
What will be returned can be caught by setting it to set variable to.
For example,
set myDoc to make new document
Variables
on run
set theName to "Jill"
log theName
end run
Scope of variable
By default within current handler, e.g. on run handler, on sub_handler() handler (subroutine).
However, if claiming a variable as property at the top of script:
property theName : null
theName will become a global variable.
Data types
- number (integer or real)
set x to 23.25 - string:
set x to "23.25"; butset x to "23.25" as numbercastxagain to a number - date:
set x to date "3/5/2023"means set it to 2023-03-05 - list:
set x to {"item1", "item2", "item3"}. The list may comprise of heterogeneous types - record (dictionary):
set x to {keyA: "valueA", keyB: valueB}
Examples:
set var1 to 22.5
set var2 to 2
set theResult to var1 + var2 # may be +, -, *, /, mod
set var1 to "hello"
set var2 to "world"
set theResult to var1 & space & var2 & "!" # string concatenation
set var1 to date "12/22/2021"
set var2 to date "12/24/2021"
set theResult to var1 + (2 * days) # may be days, hours, etc
set theResult to year of var1 # may be year of, month of, day of, etc
set var1 to {"a", 23.9, "c"}
set var2 to item 2 of var1 as string # get "23.9", indexed from 1
set var1 to {FirstName: "Jon", LastName: "Voight"}
set theResult to FirstName of var1 & space & LastName of var1
# First and Last are reserved words, to use them as keys, surround
# with pipes (`|`), e.g.:
set var1 to {|First|: "Jon", |Last|: "Voight"}
set theResult to |First| of var1 & space |Last| of var2
First script
on run # explicit on run handler, responding to double clicking
delay 2 # delay for 2 seconds
activate # activate the script
display dialog "Hello World!"
end run
on open (theFiles) # on open handler, responding to drag-n-drop
repeat with aFile in theFiles
set myText to read file aFiles
display dialog myText
end repeat
end open
# to use on idle handler, save it with "Stay open after run handler"
on idle
activate
display dialog "Join us soon"
return 3 # rerun this block 3 seconds later until manualy quit
end idle
Commenting
Block comment:
(*
Version History
This is the first build of my script
*)
in line comment: led by -- or #
Repeat loops
on run
repeat 3 times
end repeat
repeat with i from 1 to 3
end repeat
set myList to {"Jason", "Joan", "Jack"}
repeat with anItem in myList
display dialog "Hello " & anItem as string
end repeat
set test to true
set i to 1
repeat while test = true
if i >= 4 then
set test to false
end if
set i tto i + 1
end repeat
end run
Use exit repeat to break out of repeat earlier.
Conditionals
on run
set x to 6
if x = 6 then
display dialog "x is 6"
else if x = 5 then
display dialog "x is 5"
else
display dialog "x is neither 5 nor 6"
end if
end run
Error handling
on run
try # ignore quietly errors and break out of try block
set myDemo to "Hello"
display dialog myTest
end try
try
display dialog myTest
on error errName
display dialog errName
end try
try
if myDemo = "Hello" then
# this will raise error "message" with errName assigned "message"
error "message"
# or phrased as
# error "message" number -1000
end if
on error errName number n
display dialog errName & return & "with number " & n
end try
end run
Aias, HFS and POSIX
on run
set posixPath to "/Users/user/Desktop/name.jpg"
# converts a POSIX path to an HFS file reference
set hfsFilePathRef to posix file posixPath
# converts a POSIX path to an HFS file path
set hfsFilePath to posix file posixPath as string
# cannot convert POSIX path to alias directly
set aliasExample to hfsPath as alias
# convert an HFS path to a POSIX path
set backToPosix to posix path of hfsFilePath
end run
Handlers (aka functions)
A handler is a collection of applescript statements that you give a descriptive name.
on run
set theResult to doMath(8, 2, "+")
log theResult
end run
on doMath(num1, num2, mathFunc)
try
if mathFunc = "+" then
return num1 + num2
else if mathFunc = "-" then
return num1 - num2
else if mathFunc = "*" then
return num1 * num2
else if mathFunc = "/" then
return num1 / num2
else
error "You must supply a proper math function"
on error e
activate
display dialog (e as string) giving up after 8
end try
end doMath
Note that giving up after N means the dialog will disappear itself if not clicking the dialog button after N seconds.
Within tell application block, be sure to call custom handler with my keyword.
For example,
tell application "Numbers"
set theResult to my doMath(8, 2, "-")
end tell
Quit handler
on run
set someCondition to false
if someCondition then
# tell the script to quit;
# this will trigger the `on quit` handler if present
quit
end if
end run
on quit
# write cleanup actions your script should run before quitting
activate
display dialog "I quit" giving up after 4
# this will quit current script immediately; without this statement
# previous `quit` statement will be caught by `on quit` block and
# quit won't be performed
continue quit
end quit
Case study: most recent modified file from a folder
on run
set thePath to "/Users/user/Desktop/folder"
set newestFile to getNewestFile(thePath)
return newestFile
end run
on getNewestFile(thePath)
try
set posixPath to my convertPathTo(thePath, "POSIX")
set theFile to do shell script "ls -tp " & quoted form of posixPath & " | grep -Ev '/' | head -n1"
if theFile is not equal to "" then
set theFile to posixPath & "/" & theFile
end if
return theFile
on error e
return ""
end try
end getNewestFile
on convertPathTo(inputPath, requestedForm)
try
set standardPosixPath to POSIX path of inputPath as string
if requestedForm contains "posix" then
set transformedPath to POSIX path of standardPosixPath as string
if transformedPath ends with "/" then
set transformedPath to character 1 thru -2 of transformedPath as string
end if
else if requestedForm contains "alias" then
set transformedPath to POSIX file (standardPosixPath) as string
try
set transformedPath to transformedPath as alias
on error
error "The file \"" & transformedPath & "\" doesn't exist and can't be returned as \"alias\""
end try
else if requestedForm contains "hfs" then
set transformedPath to POSIX file (standardPosixPath) as string
else
error "Requested path transformation type was an unexpected type"
end if
return transformedPath
on error e
return false
end try
end convertPathTo
Case study: automatically scale images
on run
set filePath to "/Users/user/Desktop/test.png"
resizeImageWidth(fielPath, 450)
end run
on resizeImageWidth(filePath, pxls)
try
do shell script "sips --resampleWidth " & pxls & space & quoted form of filePath
return true
on error e
# TODO do something with the error
return false
end try
end resizeImageWidth
Case study: simple hot folder creation
A hot folder is a folder where a script monitor whatever is drag-n-dropped to that folder and perform actions on the object.
on run
# any startup activities required to run this script can be done here
end run
on idle
set input to "/Users/user/Desktop/Hot Folder"
set output to "/Users/user/Desktop/Results"
set errors to "/Users/user/Desktop/Errors"
set filePaths to getFiles(input)
if filePaths is not equal to {} then
repeat with filePath in filePaths
if resizeImageWidth(filePath as string, output, 450) then
removeFile(filePath as string)
else
do shell script "mv -f " & quoted form of filePaht & space & quoted form of errors
end if
end repeat
end if
return 5
end idle
on convertPathTo(inputPath, requestedForm)
try
set standardPosixPath to POSIX path of inputPath as string
if requestedForm contains "posix" then
set transformedPath to POSIX path of standardPosixPath as string
if transformedPath ends with "/" then
set transformedPath to character 1 thru -2 of transformedPath as string
end if
else if requestedForm contains "alias" then
set transformedPath to POSIX file (standardPosixPath) as string
try
set transformedPath to transformedPath as alias
on error
error "The file \"" & transformedPath & "\" doesn't exist and can't be returned as \"alias\""
end try
else if requestedForm contains "hfs" then
set transformedPath to POSIX file (standardPosixPath) as string
else
error "Requested path transformation type was an unexpected type"
end if
return transformedPath
on error e
return false
end try
end convertPathTo
on stringToList(inputString, theDelimiter)
try
set tid to AppleScript's text item delimters
set AppleScript's text item delimiters to theDelimiter
set theList to text items of (inputString as string)
set AppleScript's text item delimiters to tid
return theList
on error e
set AppleScript's text item delimiters to tid
return {}
end try
end stringToList
on resizeImageWidth(filePath, output, pxls)
try
do shell script "sips --resampleWidth " & pxls & space & quoted form of filePath & " -o " & qutoed form of output
return true
on error e
return false
end try
end resizeImageWidth
on getFiles(thePath)
try
set posixPath to my convertPathTo(thePath, "posix")
set theFiles to do shell script "find " & quoted form of posixPath & " -type f ! -name \".*\""
if theFiles is not equal to "" then
set fileList to stringToList(theFiles, return)
end if
return fileList
on error e
# log the error here at some point
return {}
end try
end getFiles
on removeFile(theFile)
try
set posixPath to convertPathTo(theFile, "posix")
do shell script "rm -f " & quoted form of posixPath
return true
on error e
return false
end try
end removeFile