Automatically Save emails to a folder using Mail.app, AppleScript, and Bash.

README.md

How to get it to work.

NOTE: This is mac only.

1. Go to Finder.
2. Press CMD+SHIFT+G.
3. Type ~/Library/Application Scripts/com.apple.mail.
4. Open saveByRule.scpt and change theFolder to where you'd like emails to be saved.
5. Copy and Paste saveByRule.scpt into ~/Library/Application Scripts/com.apple.mail.
6. Go to Mail>Preferences>Rules>Add Rule.
7. Enter some filter for your rule and choose Run Applescript as action to perform. Use saveByRule as option.
8. Click Ok.

For converting to PDF and HTML.

1. In the terminal, run sudo pip install mail-parser and brew install Caskroom/cask/wkhtmltopdf.
2. Open toPDF.sh and alter location to match the directory your saved emails are located. (Keep *.eml)
3. In the terminal, run bash toPDF.sh.

For Automating conversion to HTML/PDF.

1. Create new>Folder Action in Automator.
2. Set folder to watch to folder where emails are saved.
3. Add run shell script action.
4. Copy and paste contents of toPDF.sh into textarea of run shell script.
5. Save.

NOTE: saveByRule.scpt is almost entirely copied from StackOverflow.

saveByRule.scpt

using terms from application "Mail"
	on perform mail action with messages theMessages for rule theRule
		tell application "Mail"
			set msgs to selection
			
			if length of msgs is not 0 then
				
				set theFolder to (system attribute "HOME") & "/Downloads/"
				
				repeat with msg in msgs
					set msgContent to source of msg
					-- determine date received of msg and put into YYYY-MM-DD format
					set msgDate to date received of msg
					-- parse date SEMversion below using proc pad2()
					set {year:y, month:m, day:d, hours:h, minutes:min} to (msgDate)
					set msgDate to ("" & y & "-" & my pad2(m as integer) & "-" & my pad2(d))
					
					-- assign subject of msg
					set msgSubject to (subject of msg)
					
					-- create filename.eml to be use as title saved
					set newFile to (msgDate & "-" & msgSubject & ".eml") as rich text
					set newFilePath to theFolder & newFile as rich text
					
					set referenceNumber to open for access newFilePath with write permission
					try
						write msgContent to referenceNumber
						delete msg
					on error
						close access referenceNumber
					end try
					close access referenceNumber
					
				end repeat
				
			end if -- msgs > 0
		end tell
	end perform mail action with messages
end using terms from

on pad2(n)
	return text -2 thru -1 of ("00" & n)
end pad2

toPDF.sh

#!/bin/sh

# if [ -z $(pip list | grep -F "mail-parser" ) ]; then
#     pip install mail-parser || sudo pip install mail-parser
# fi

# if [ -z $(brew cask list | grep -F "wkhtmltopdf" ) ]; then
#     brew install Caskroom/cask/wkhtmltopdf
# fi
location=~/Downloads
for file in $location/*.eml;
do
    echo $file
    name=${file##*/}
    noeml=${name%.eml}
    echo "$noml"
    mailparser -f $file -b > $location/$noeml.html
    x=$noeml.html
    wkhtmltopdf $location/$x $location/$noeml.pdf
done

# Uncomment any these if you'd prefer not to keep a file type.
# rm -f *.eml
# rm -f *.html
# rm -f *.pdf

-- assign subject of msg
set msgSubject to (subject of msg)

-- create filename.eml to be use as title saved
set newFile to (msgDate & "-" & msgSubject & ".eml") as rich text

Is the use of the message subject potentially dangerous, @dustinknopoff ?

What if an Email subject line were to contain some text such as “/../../../../../../usr/local/bin/“, where an Email subject line causes the Email to be written to some place you don’t want / some place dangerous?

Perhaps after setting themsgSubject value, that value should have potently dangerous characters (such as / or * or ? or ; or ` or \ or $ or & or < or > or “ or ‘ or : or # or ( or ) or [ or ] or { or } or | etc.) removed from that variable or perhaps potentially dangerous characters could be changed into something harmless?

Perhaps remove anything from themsgSubject value that it not a lower case letter or UPPER CASE LETTER or digit to space, or perhaps convert anything in themsgSubject value that it not a lower case letter or UPPER CASE LETTER or digit to space into the letter x?

UPDATE 0

Alternatively, setting newFile could be done without the use of the message subject string, as in:

    set newFile to (msgDate & ".eml") as rich text

If you do this, you might want to modify msgDate to include the hour and minute and to include a counter when forming newFIle as suggested in GH-gistcomment-5311296 below.

UPDATE 1a

The use of the Email subject in forming the filename could become especially dangerous when used in conjunction with the toPDF.sh shell script. Consider an Email with a subject that contains some text such as:

    Subject: hello ; rm -rf * ; exit 0 ;

It might depend on what mailparser and wkhtmltopdf do with their arguments, and which version of the shell you are using as to if such an Email subject line could be used to cause problems. Nevertheless, why not try to avoid such problems by stripping out dangerous characters or converting them into something harmless?

UPDATE 2

You might want to add some additional protections to toPDF.sh such as changing:

    echo $file
    name=${file##*/}
    noeml=${name%.eml}
    echo "$noml"
    mailparser -f $file -b > $location/$noeml.html
    x=$noeml.html
    wkhtmltopdf $location/$x $location/$noeml.pdf

Into

    echo "$file"
    name=${file##*/}
    noeml=${name%.eml}
    echo "$noml"
    mailparser -f "$file" -b > "$location/$noeml.html"
    x=$noeml.html
    wkhtmltopdf "$location/$x" "$location/$noeml.pdf"

What happens if you have two different Email messages with the same message date (YYYY-MM-DD) and the same subject, @dustinknopoff ? Won’t your script cause the second Email file to overwrite the first Email file?

Perhaps you should add a counter into the loop and use that counter when forming the newFile value? That way when going through the loop, the newFile value would be different even if two Email messages had the same message date (YYYY-MM-DD) and the same subject.

Hey @lcn2 these are all awesome suggestions and you're totally right about the security implications of this approach. Since writing this, I've actually shifted to a yearly export as an .mbox that I backup instead. In practice searching through my emails more than a year ago has been a rare occurrence.

That being said! If I were to come back to this, I'd probably try and do my best to keep the eml contents in memory and then pass it into a language like Python as soon as possible so that these kind of protections, looping, deduplicating would be much easier :)

Thanks @dustinknopoff