How to implement Sort with Microsoft Flow in 3 actions within a loop

Photo by Sophie Elvis on Unsplash

Photo by Sophie Elvis on Unsplash

For some reason, Flow (and LogicApps) doesn’t have a built in sort() method.

So after much nudging from Paul Culmsee, I brooded about this and sat down and built one. There’s three actions within a loop, packing quite a lot of tricks, this is how it all works.

Plan

How does it work conceptually?

Build your own Sort in Microsoft Flow

Simplify it to 3 actions within a loop

Extend it to sort objects and beyond.


Defining what we need


Let’s set up some input and outputs - we want to have our initial variable within the variable “initial-array” and we want to have our final sorted result within the variable “sorted-array”

We want to do a simple insertion sort - for the academic - this is an O(n^2) sort. Not the fastest, but simple enough to understand and express with logic expressions.

How does it work conceptually?

For each element in the initial-array, we will loop add it to a final ‘sorted-array’ in a sorted position.

In the first loop, the sorted array would be empty - but as we progress, for each new value we are considering - we would split the sorted-array into two sets of sub-arrays, ones that are smaller than the current value, and ones that are larger than the current value.

Finally, we combine everything back together in a union, set that to be the new “sorted-array” value, and proceed with the next element in the initial-array.

Build your own Sort in Microsoft Flow

So extending our Flow - add a loop over the initial-array.

Within the loop, we want to put the current item into a compose action. (going with the example above, this would be the element ‘4’ )

Add a compose at the end to see the final output of sorted-array.

Cutting sorted-array into lesser half, greater half

We do this in a parallel branch - these two don’t affect each other - add two Filter Array

Left, set the item() of the sorted-array to be <= the current value of the initial-array
Right, set the item() of the sorted-array to be > the current value of the initial-array

Union the arrays together. That is, the left-array, the right array, and in the middle, the current value, but put that inside an array of 1 element with createArray( <current-value> )

Before the apply to each ends, write the union result back into the “sorted-array” that concludes this loop, getting us ready for the next value.

See how it runs:

The result is a sorted-array.

See for example, loop 6, when the value is ‘4’

Clean up and simplify

We can remove some of the blocks to make the sort ‘smaller’

The final result

3 actions within one loop

Sorting complex (JSON) Objects

It is best to build an sort-array like this with numbers to understand how it works, before attempting to tweak it to sort complex object arrays.

Say for example - if we want to sort by the Date of a complex object array (our scenario was an RSS feed) - within the apply to each, we want to isolate the property we want to compare.

Because the current item’s property is used several times - we add the top compose back into the apply to each loop, we can consider the Compose is a kind of temporary variable used to hold the value that we are using to compare with.

We need to compare against the date in the two Filter-Arrays, but we don’t actually use it for the final Union - because we want to union the arrays together, not union the dates together.

And that’s Sort. Complex explanations, but very elegant with 3 actions inside a loop.

Sending email with inline images via MicrosoftGraph and MicrosoftFlow

I had previously written how we can use Send Email as Anyone in Microsoft Graph, and as a bonus wrote a section on how we can use it to send inline images.

There was a small problem - sending email is very hard for app-only permissions - app accounts don’t have email boxes. So for that scenario to work, app accounts need a super crazy “send email as anyone” permission.

Sending email is a lot easier with delegate permission - if we have delegate permission Mail.Send - we can send inline attachments very easily. This is not an admin-tenant approval required permission, so any user can grant this.

Plan

Combine two techniques:

To aad.portal.azure.com

Add Mail.Send (delegate permission)

If you can “grant permissions” to your tenant, doing it here will immediately grant this to your current connection.

Otherwise we have to go back to our Flow connectors and make a new connection for batch.

Create our Flow

Here we are creating a MSGraph mail object JSON getting it ready for send

Using a $batch connector - call /me/sendMail

Results

Inline images are super useful for newsletter or emails where you want to include a nice header, signature or whatever in-between. This is a way to send these with Microsoft Graph and Microsoft Flow.

Decode InfoPath attachments with a bit of JS AzureFunctions

Serge, April and me were discussing a problem with pulling out InfoPath Attachment from InfoPath form XML and writing them into a SharePoint document library.

This is a problem I tried to tackle before, but came to realization that I would need an AzureFunction. The main reason is that the InfoPath attachment is a base 64 byte array but the byte array has a variable length header that includes the attachment file name. Flow doesn’t have amazing byte manipulation or left-shift abilities. So we need to write an AzureFunction to help.

As I brood over the problem I also thought it might be easier to handle the byte array with JavaScript. So I gave it a go.

This blog is my version of the answer.

The original decoder code in C#

There is a pretty old MSDN article on the C# code

private void DecodeAttachment(BinaryReader theReader)
{
  //Position the reader to get the file size.
  byte[] headerData = new byte[FIXED_HEADER];
  headerData = theReader.ReadBytes(headerData.Length);

  fileSize = (int)theReader.ReadUInt32();
  attachmentNameLength = (int)theReader.ReadUInt32() * 2;

  byte[] fileNameBytes = theReader.ReadBytes(attachmentNameLength);
  //InfoPath uses UTF8 encoding.
  Encoding enc = Encoding.Unicode;
  attachmentName = enc.GetString(fileNameBytes, 0, attachmentNameLength - 2);
  decodedAttachment = theReader.ReadBytes(fileSize);
}

The updated code in JS AzureFunctions

module.exports = function (context, req) {
    context.log('JavaScript HTTP trigger function processed a request.');
    if (req.body && req.body.file) {
        // https://support.microsoft.com/en-us/help/892730/how-to-encode-and-decode-a-file-attachment-programmatically-by-using-v
        var buffer = Buffer.from(req.body.file, 'base64')
        //var header = buffer.slice(0, 16);  // unused header
        var fileSize = buffer.readUInt32LE(16);  // test is 5923 bytes
        var fileNameLength = buffer.readUInt32LE(20);  // test is 13 chars
        // article lies - it's utf16 now
        var fileName = buffer.toString('utf16le', 24, (fileNameLength-1)*4 -1);  
        var binary = buffer.slice(24 + fileNameLength * 2);
        context.res = {
            // status: 200, /* Defaults to 200 */            
            body: {
                fileName: fileName,
                fileNameLength: fileNameLength,
                fileSize: fileSize,
                fileContent: binary.toString('base64')
            }
        };
    }
    else {
        context.res = {
            status: 400,
            body: "Please pass a base64 file in the request body"
        };
    }
    context.done();
};


The InfoPath form


The Microsoft Flow that coordinates the work


Results

  • Need Azure Function here

  • JavaScript buffer is pretty good at doing byte decoding, easy to read too

  • Debugging and tweaking the byte offset is quite a bit of trial and error, was not expecting that. May be that MSDN article is too old, it is from 2003.

  • You may think - John 2018 is not the right year, or decade to be writing about InfoPath. But hear me out. As companies move their form technology forward, they will need to consider how to migrate the data and attachments in their current InfoPath forms somewhere - having this blog post as a reference is important for that eventual migration. Good luck!

Hiding your Microsoft Flow valuables I mean variables out of sight

Photo by  Annie Spratt  on  Unsplash

Today is a quick #FlowNinja post on a strange technique.

Hiding Microsoft Flow valuables I mean variables out of sight

Yes, a very ninja technique.



This is actually an article about how to use tracked properties in the current Flow. But of course that’s the boring side to this. The fun side is how we can attach properties, like having a utility property bag and store properties as we go along!

Start with three compose (I guess we only need two really)

The expression give us the trackedProperties dictionary off the first action

actions('vars')?['trackedProperties']
// vars is the name of the first Compose action

Toggle to the … settings for the first action - that’s where different tracked properties are defined. We can use expressions if prefixed with the “@…” syntax, or define literal strings or numbers or even nested JSON objects.

What could we use Tracked Properties for?

  • Well, hide things that we don’t want to show - like the back of an envelope.

  • Unfortunately, an action can’t reference itself, so we can’t hide secrets that the action itself needs on the back of itself.

  • Tracking time between two actions - calculating the time difference between approvals can be useful.

  • https://flowstudio.app can ‘see’ tracked property values in the detailed Flow Runs - but there are no UI to display this for now. One idea is to use this to surface data within the Flow run that can be observed at the Runs level - like the Trigger URL or List Item ID of the runs, and allowing sorting on them. Powerful ideas but difficult to build an UI for. Let me know if you are keen about how this works below.

Flow Studio has a new logo

Flow Studio https://flowstudio.app has a new logo!

flow-studio-logo-216.png


I don’t know why I’m so happy about this, but I am.

Did you draw that John - yes on the back of an envelope. Literally. Flow Studio is a start-up that does things the hipster way.

It was digitized by the amazingly talented logo designer people on Fiverr. It is beautiful and very affordable. It was finalized within 24hours of the envelope sketch. No revisions were requested.

The colours have very specific meanings. I’m sure you’ll recognize them immediately.

The logo appeared on Flow Studio in v0.1.47 but will make more appearance in v0.1.48 with the subscriptions implementation.