How to Pass Two CSV Files and a String to an Azure Function from Logic App and Azure Code + Test Screen?

Question

I have an Azure Function App that accepts two CSV files and a date string as input (via multipart/form-data) and returns a combined Excel file.

The function works correctly when tested locally or when triggered remotely via Postman (using the multipart/form-data content type).
However, I encounter issues when trying to test it from the Azure Portal using the Code + Test screen, as well as when calling it from an HTTP trigger in a Logic App.

Function Overview:

HTTP trigger (POST)
Accepts 2 CSV files and a string date (all via multipart/form-data).

What Works:

Testing the function locally or remotely after deploying to Azure using Postman works fine. I pass two base64-encoded CSV files and the date string using multipart/form-data, and the function processes and returns the Excel file as expected.

Issues:

Azure Code + Test screen:
- When I test the function here, I can’t seem to pass the CSV files and date string properly. I get blank values in the function logs for the inputs, even though the function runs without any errors.
- I am unsure how to correctly structure the inputs using the Code + Test interface, which uses query input fields. If I pass it as json in the body section, it throws an exception when it tries to read it from the result. If I pass it in the query fields as key value pairs it reads all three values as null without throwing an exception.
Logic App HTTP trigger:
- When I call the function from my Logic App, I’m using an HTTP action after a Create CSV Table action to pass the CSV files and a date string, but the function does not receive the data correctly. The CSV content and the date string aren’t being parsed as expected by the function.

Questions:

How can I properly test the Azure Function using the Code + Test screen in the portal when passing two CSV files and a string date?
What is the correct way to structure the HTTP action in a Logic App to send two CSV files and a date string to my Azure Function App using multipart/form-data?

What I’ve Tried:

I’ve set the Content-Type to multipart/form-data in the Logic App's HTTP action and used @{body('Create_CSV_Table')} to pass the CSV content, but I’m unsure if I’m constructing the multipart body correctly.
I’ve also used logging (_logger.LogInformation) inside the function to check what’s being received, but the fields for the CSV files and the date string are blank when using Code + Test or Logic App, while they show correct values when tested via Postman.

Any guidance on how to structure the request from both the Logic App and the Code + Test screen would be greatly appreciated!

Code to Read the Parameters from the Request:

This is the code I am using to read the parameters from the HTTP request in the Azure Function:

var form = await req.ReadFormAsync();
var file1Base64 = form["file1"];
var file2Base64 = form["file2"];
var stringDate = form["stringDate"];

What connnector are you using to call function or you are using http action? — RithwikBojja
– RithwikBojja, Commented Oct 11, 2024 at 10:55

RithwikBojja · Accepted Answer · 2024-10-14 04:43:07Z

1

What is the correct way to structure the HTTP action in a Logic App to send two CSV files and a date string to my Azure Function App using multipart/form-data?

To pass from Logic app follow below design:

Used base64():

enter image description here

Headers:

{
  "Content-Type": "multipart/form-data; boundary=Test"
}

Body:

--Test
Content-Disposition: form-data; name="file1"; filename="file1.csv"
Content-Type: text/csv
@{base64(outputs('Compose'))}
--Test
Content-Disposition: form-data; name="file2"; filename="file2.csv"
Content-Type: text/csv
@{base64(outputs('Compose_2'))}
--Test
Content-Disposition: form-data; name="stringDate"
2024-09-02
--Test--

Full Design:

enter image description here

In compose i have csv data. You can get the csv data from file there. Also refer this Document using json to add multiple files.

answered Oct 14, 2024 at 4:43

RithwikBojja

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How to Pass Two CSV Files and a String to an Azure Function from Logic App and Azure Code + Test Screen?

Function Overview:

What Works:

Issues:

Questions:

What I’ve Tried:

Code to Read the Parameters from the Request:

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Function Overview:

What Works:

Issues:

Questions:

What I’ve Tried:

Code to Read the Parameters from the Request:

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