Applescript: Passing track metadata from text file to broadcast streaming app - applescript

Question

I know virtually nothing about AppleScript and could do with some help.
While running, my broadcast playout system (MegaSeg) writes details of the track currently playing to a textfile called "NowPlaying" which contains solely the following contents, each on its own line and without square brackets:
Title: [title]
Artist: [artist]
Album: [album]
Time: [time in some format or other]
I want to pass this to my broadcast streamer LadioCast, which can be addressed via AppleScript, so that it sends info on what is playing to the streaming server.
MegaSeg doesn't support Applescript calls like 'tell application "MegaSeg"... set trackName to name of current track' so I can't do it that way. I have no idea about how to do this.
If we imagine that I was able to grab that info, this is what I would do with it:
set lastName to ""
set lastArtist to ""
set lastAlbum to ""
repeat
** insert missing file reading section here
** in the following, "title", "artist" and "album" are from the text file **
set trackName to title
set trackArtist to artist
set trackAlbum to album
** end of missing section
if trackName is not lastName and trackArtist is not lastArtist and trackAlbum is not lastAlbum then
set lastName to trackName
set lastArtist to trackArtist
set lastAlbum to trackAlbum
tell application "LadioCast"
set metadata song to trackName & " – " & trackArtist & " – " & trackAlbum
end tell
end if
delay 15
end repeat
Thanks in advance.
--Richard E
===
I tried the suggestions from #DigiMonk and they were very helpful, but not all of them worked. First, the file is in a specific location and not on the desktop; second, I could not get 'trim_line' to work at all - I got "script does not understand trim_line message". However the text in the file seems to be already trimmed.
The script below nearly works; when run from the Applescript Editor it does seem to get the Title, Artist and Album into the variables. However when I try running it from LadioCast I get an EOF -39 error. More importantly, as soon as I run this, MegaSeg stops updating the file, forever. I am presumably locking the file to read from it and stopping MegaSeg writing to it. How do I avoid this?
set lastName to ""
set lastArtist to ""
set lastAlbum to ""
set lastTime to ""
set trackName to ""
set trackArtist to ""
set trackAlbum to ""
set sourcePath to ""
repeat
set sourcePath to open for access file "Library:MegaSeg User Data:Logs:Logs for MegaSeg System (4):NowPlaying"
set thisText to read sourcePath as text
close access file "Library:MegaSeg User Data:Logs:Logs for MegaSeg System (4):NowPlaying"
set the paragraphList to every paragraph of thisText
repeat with i from 1 to number of items in paragraphList
set thisItem to item i of paragraphList
if thisItem starts with "Title:" then
set x to the offset of "Title:" in thisItem
set trackName to (text (x + 6) thru -1 of thisItem)
else if thisItem starts with "Artist:" then
set x to the offset of "Artist:" in thisItem
set trackArtist to (text (x + 7) thru -1 of thisItem)
else if thisItem starts with "Album:" then
set x to the offset of "Album:" in thisItem
set trackAlbum to (text (x + 6) thru -1 of thisItem)
end if
end repeat
if trackName is not lastName and trackArtist is not lastArtist and trackAlbum is not lastAlbum then
set lastName to trackName
set lastArtist to trackArtist
set lastAlbum to trackAlbum
tell application "LadioCast"
set metadata song to trackName & " – " & trackArtist & " – " & trackAlbum
end tell
end if
delay 15
end repeat

Answer 1

May be this helps: (feed sourcePath with the path to your NowPlaying.txt file)
set sourcePath to (path to desktop) & "NowPlaying.txt" as text
set thisText to my readFile(sourcePath)
set the paragraphList to every paragraph of thisText
set lastName to ""
set lastArtist to ""
set lastAlbum to ""
set lastTime to ""
repeat with i from 1 to number of items in paragraphList
set thisItem to item i of paragraphList
--log thisItem
if thisItem starts with "Title:" then
set x to the offset of "Title:" in thisItem
set y to (text (x + 6) thru -1 of thisItem)
set lastName to my trim_line(y, " ", 2)
else if thisItem starts with "Artist:" then
set x to the offset of "Artist:" in thisItem
set y to (text (x + 7) thru -1 of thisItem)
set lastArtist to my trim_line(y, " ", 2)
else if thisItem starts with "Album:" then
set x to the offset of "Album:" in thisItem
set y to (text (x + 6) thru -1 of thisItem)
set lastAlbum to my trim_line(y, " ", 2)
else if thisItem starts with "Time:" then
set x to the offset of "Time:" in thisItem
set y to (text (x + 5) thru -1 of thisItem)
set lastTime to my trim_line(y, " ", 2)
end if
end repeat
log "lastName = '" & lastName & "'"
log "lastArtist = '" & lastArtist & "'"
log "lastAlbum = '" & lastAlbum & "'"
on readFile(thisFile)
set thisFile to thisFile as text
if thisFile is "" then return ""
try
set fi to open for access file the thisFile
set myData to read fi as text
close access file the thisFile
return myData
on error
try
close access file the thisFile
return ""
end try
end try
end readFile
on trim_line(this_text, trim_chars, trim_indicator)
-- 0 = beginning, 1 = end, 2 = both
set x to the length of the trim_chars
-- TRIM BEGINNING
if the trim_indicator is in {0, 2} then
repeat while this_text begins with the trim_chars
try
set this_text to characters (x + 1) thru -1 of this_text as string
on error
-- the text contains nothing but the trim characters
return ""
end try
end repeat
end if
-- TRIM ENDING
if the trim_indicator is in {1, 2} then
repeat while this_text ends with the trim_chars
try
set this_text to characters 1 thru -(x + 1) of this_text as string
on error
-- the text contains nothing but the trim characters
return ""
end try
end repeat
end if
return this_text
end trim_line