Daily Variable Increment on New Email Trigger

[JojoS]

Hello, I have a flow that saves email attachment (on new email trigger, usually 1 attachment per email) to FTP. I would like the file name to be FileName#, where # increments from 1 but resets every day at midnight. Since there is no global variables, and I have a basic free account only (no SharePoint, OD for Business), I can't seem to find where to initialize/store the counter variable. I can increment it successfully - if email has multiple attachment, file names are 1, 2, 3... but since the variable is initialized inside the flow, it resets to 1 every time the flow starts (e.g. new email is received). Is upgrading the account my only option or is there a trick I haven't seen yet?

[edgonzales]

@JojoS 

Hi there.  Do you have the date in the filename somehow?  I imagine something like that since each day you'd have a new file #1, right?  Here's my thought:

• Make your filename something like this:  yyyyMMdd_xxx where xxx is your increment number.
• At the beginning of your flow, have a step to list the files in a folder (If there's an option for an OData filter in that action, you can 'pre-filter' the list by anything that begins with today's date in yyyyMMdd format.
• If there's no OData filter on the FTP action, then add a Filter Array step.
• A condition to see if the array is empty.  If yes, then your increment number is 1 or whatever the first in your series is.
• In the No path (meaning the filter array is NOT empty), we can use split() to parse out the increment numbers, then sort that array... and then take the last element.
• That number will be the base for your increment steps that you've already got in place.

I won't have time today, but tomorrow I'll work on building something and documenting it, but let me know if you want me to go into more detail in any of the steps.  It's tough to tell where folks are at on the learning journey.

Keep us posted.

-Ed

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[JojoS]

Thank you for your reply on Sunday.

The file name should not have a date at all. The final file name will simply be image_1, image_2 and so on. The goal is also to not delete the files but rather overwrite them the next day.

I think I get your idea (basically purge the current FTP files and increment from there) but because I am trying to avoid having date in the file name, it will not work.

[edgonzales]

@JojoS,

Hey there.  Intent wasn't to purge, I just didn't know you wanted to overwrite existing files.  But...  if day 1 has 3 images, and day 2 only has 1, there will be two images in that folder that weren't from day 2.  Does that matter in your process?

-Ed

[JojoS]

I used "purge" improperly. I meant to say parse.

I might be able to change somethings around delete all images at the end of the day. I will be experimenting this week. If you have time, drop a few details about your original suggestion - reading the FTP files and moving the file name to array (split with '_') so the next value for increment can be determined.

Thanks.

[edgonzales]

@JojoS 

Well, if you're not worried about the date, then you can just have the number be the filename right, then we'll use split() to get everything before the period and make that your array.  I'm trying to figure out how to make an FTP server right now, but I'll probably be able to build something tomorrow.

-Ed

[edgonzales · Accepted solution]

@JojoS 

Actually, I came up with something much simpler.  Two different flows, but the core of both is a simple text file in your FTP folder called something like FileMax.txt.  The file contents could be something as simple as varFileName = 0.

The first flow has a recurrence trigger that runs at midnight every night, followed by an FTP Update File action.

(I realized after I posted this, that I have two different file contents.  Pretend the one above says "varFileName = 0")

That will reset the counter back to zero each day.

The second flow is your thing just as you had it, but we'll set the initial number by using the FTP Get file content action and point it to your text file.  That will get you "varFileName = 0" which we can parse and add 1 to all in one step.  Put a compose after the get file content with this expression:

add(int(split(body('Get_file_content'),' = ')[1]),1)

Here's an explanation of that, and also a video on the Split() function:

• Then you want to update your text file with the new starting number from the output of the compose above.  You can do this with an FTP Update File and in the File Content area, just have "varFileName = " and then the dynamic output from your compose above.  It should look like this:

Which will update the text file and ready it for the next file:

Give that a go, hopefully it's enough to get you going in the right direction.  Keep us posted either way.

-Ed

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[JojoS]

I can't believe I missed this. Exactly what I needed.

I actually expanded this and did slightly different logic (my case was broader than I explained. I increment the counter in a varriable called 'CounterCh1'. It does increment but it fails to write the file as I expected.

I am asking it to do this (CounterCh1 is int '1' at this point):

I am expecting to see

Ch1Counter-1-

but instead, the file get's written with:

Ch1Counter-@variables('CounterCh1')-

Do you know why?

[edgonzales]

Try wrapping your dynamic value with single quotes and let me know if that works.  If so, I'll need to adjust the article I just wrote 😛

Here's a link to the article for more detail: Modeling a Global Variable Without Variables in Power Automate / Flow

Keep us posted.

-Ed

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[JojoS]

Nope. All it did is added quotes:

@edgonzales 

[JojoS]

And same results when using Output of compose.

@edgonzales 

[edgonzales]

@JojoS 

That's really bizarre, I've tried it a couple of different ways on my side and it works without the quotes.

Zoom out a little so we can see the whole action in the edit mode, please?  I'm wondering if we need to convert the data before trying to add it to the file content...not sure.

Anyway, post the pic of the whole step and we'll see what it looks like.  Also, take a look at the output of the variable to make sure it's got the right data inside of it.

-Ed

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[JojoS]

I have no idea. My variable clearly has value of 1 as seen in the test screenshots below.

Coded:

Test Result:

[edgonzales]

Ok, I think what you're seeing is a bug that was just reported by someone else today.  I'll add this example to the list and hopefully it will be resolved soon.  Your flow looks to be set up correctly, so once this is resolved, all should be well.

-Ed

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[JojoS]

Deleted.

[edgonzales]

@JojoS 

Hi there.  I got a tip from another MVP to try this:

If you're using the default expression editor (looks like the picture below), try switching to the new editor.

To do that, click on the gear icon at the top right of your Power Automate screen and click "View all Power Automate settings"

At the bottom of the pop-up, there is a switch to turn on Experimental Features (as of this date, the new editor is in Preview).  Turn that on, and Power Automate will want to reload the page (so make sure you've saved your work).  Then try rebuilding your update file step.  The new editor should look like this (but it doesn't format your expressions automatically):

Give that a go and let us know how that turns out.  If you already had the new editor, try switching back to the old one.  I was using the new one when I built my demo, so I'm hoping this is the issue.  Good luck!

-Ed

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[JojoS]

I got it working with this expression in the create file:

concat('Ch1Counter-',variables('CounterCh1'),'-')

[JojoS]

@edgonzales 

Another minor issue: How do I insert new line in the text file? Adding new line in the contents doesn't do it. Some users are saying that uriComponentToString('%0A') (0A is hex for Carriage Return aka \n) but while it did show the new line in the results output, it doesn't reflect in the txt output file.

[edgonzales]

@JojoS 

Are you wanting to append something to the text file?  Not sure about that one, you might want to start a new thread.  One idea might be to store a carriage return in a variable, and then use that variable at the beginning of your contact().

-Ed