Calling Microsoft Flow From Power Query And Power BI

Since last week’s blog post caused quite a lot of interest, here’s something similar: did you know you can trigger a Flow in Microsoft Flow and get a response from it back using Power Query/Power BI?

To start off, I suggest you read this post by Irina Gorbach which shows how a Flow can be triggered by a call to a REST API. Now consider the following Flow which is similar to the one in that post:

It has a Request trigger:

…a Translate text step as the second step, that takes the text passed in to the Request trigger through the request body and passes it to the Microsoft Translator API where it is translated from English to French:

…and then, finally, returns the translated text back using a Response step:

It’s very easy to call this Flow from Power Query or Power BI. First, create two parameters in the Query Editor: one called TextToTranslate that contains the text you want to translate from English to French (in this case, “What time is it?”)

…and another called FlowURL which is the URL copied from the Request trigger of the Flow

Then all you need to do is to call the Flow using a query that makes a POST request to the Request trigger:

[sourcecode language='text'  padlinenumbers='true']
let
    Source = Web.Contents(FlowURL,
                [Content=Text.ToBinary(TextToTranslate)]),
    GetText = Text.FromBinary(Source)
in
    GetText
[/sourcecode]

And voilà, your query will pass the text in the TextToTranslate parameter to the Flow and return the translated text:

So basically, in this case I’ve used Flow to create a web service without writing a single line of code. I can see a lot of potential uses for this and I suspect I’ll be blogging about Flow a lot in the future. A word of warning though: do not try to use this as a way of updating a data source. As I mentioned last time, when you run your query you’ll find Power Query/Power BI calls the web service twice. For example, I created a Flow similar to the one above that used the Insert Row step to take text sent to a Request trigger and add it to a table in an Excel workbook, and of course every time I refreshed my query I got two identical rows in my Excel table.