Write to Append Blob from Azure Function for Logic App Integration

WriteToAppendBlob.csx

#r "Newtonsoft.Json"
#r "Microsoft.WindowsAzure.Storage"

using System.Configuration;
using System.Net;
using Microsoft.AspNetCore.Mvc;
using Microsoft.Extensions.Primitives;
using Microsoft.WindowsAzure.Storage;
using Microsoft.WindowsAzure.Storage.Blob;
using Newtonsoft.Json;

public static async Task<IActionResult> Run(HttpRequest req, ILogger log)
{
    // Expects JSON body:
    // {
    //      "blobName": "[Blob name here]",
    //      "containerName": "[Container name here]",
    //      "text": "\"Column A\",\"Column B\",\\n,\"A1\",\"B1\",\\n,\"A2\",\"B2\""
    // }

    var connectionString = System.Environment.GetEnvironmentVariable("StorageConnectionString");

    // StorageConnectionString configured as app setting.

    string requestBody = await new StreamReader(req.Body).ReadToEndAsync();
    dynamic data = JsonConvert.DeserializeObject(requestBody);

    var blobName = data?.blobName;
    var containerName = data?.containerName;
    var text = data?.text;

    if (blobName == null)
    {
        return new BadRequestObjectResult("blobName is required.");
    }

    if (containerName == null)
    {
        return new BadRequestObjectResult("containerName is required.");
    }

    if (text == null)
    {
        return new BadRequestObjectResult("text is required.");
    }

    var storageAccount = CloudStorageAccount.Parse(connectionString);
    var blobClient = storageAccount.CreateCloudBlobClient();
    var container = blobClient.GetContainerReference(containerName.ToString());

    await container.CreateIfNotExistsAsync();

    var appendBlob = container.GetAppendBlobReference(blobName.ToString());

    if ((await appendBlob.ExistsAsync()) == false)
    {
        await appendBlob.CreateOrReplaceAsync();
    }

    await appendBlob.AppendTextAsync(text.ToString());

    return new OkResult();
}