Btukfyl

I am trying to read a text file from Blob Storage using a Azure Function App. My goal is to read the file, which is a CSV, and reformat it into a new CSV with additional details added that isn't in the original CSV file.

I keep getting the following compilation error:

2018-11-28T00:22:34.125 [Error] run.csx(60,19): error CS1061: 'CloudBlockBlob' does not contain a definition for 'DownloadToStream' and no extension method 'DownloadToStream' accepting a first argument of type 'CloudBlockBlob' could be found (are you missing a using directive or an assembly reference?) 

I can copy the Blob Storage section of the code into a Console Application's project and it will compile just fine.

Am I missing a reference?

This is the full function minus the connection string for the Blob Storage.

#r "Newtonsoft.Json"



#r "System.Configuration"

#r "System.Data"



#r "System.Collections"

#r "System.IO.Compression"

#r "System.Net"

#r "Microsoft.WindowsAzure.Storage"

#r "System.Linq"



using System.Net;

using Microsoft.AspNetCore.Mvc;

using Microsoft.Extensions.Primitives;

using Newtonsoft.Json;



using System;

using System.Configuration;

using System.Text;

using System.IO;

using System.IO.Compression;

using System.Data.SqlClient;

using System.Collections.Generic;

using System.Data;

using Microsoft.WindowsAzure.Storage;

using Microsoft.WindowsAzure.Storage.Blob;

using System.Linq;

using System.Threading.Tasks;



public static async Task<IActionResult> Run(HttpRequest req, ILogger log)

{

    log.LogInformation("C# HTTP trigger function processed a request.");



    string filePath = req.Query["filePath"];



    string requestBody = await new StreamReader(req.Body).ReadToEndAsync();

    dynamic data = JsonConvert.DeserializeObject(requestBody);

    filePath = filePath ?? data?.filePath;



    var fileInfo = GetFileInfo(filePath);



    string line = "";



        CloudStorageAccount storageAccount = CloudStorageAccount.Parse("Connection String goes Here");



        CloudBlobClient client = storageAccount.CreateCloudBlobClient();

        CloudBlobContainer container = client.GetContainerReference(fileInfo.Container);



        var fileNameWithFolder =

                    fileInfo.DirectoryName == ""

                        ? fileInfo.FileName

                        : $"{fileInfo.DirectoryName}/{fileInfo.FileName}";



        CloudBlockBlob blockBlob2 = container.GetBlockBlobReference(fileNameWithFolder);



        using (var memoryStream = new MemoryStream())

        {

            try

            {

                blockBlob2.DownloadToStream(memoryStream);

                line = System.Text.Encoding.UTF8.GetString(memoryStream.ToArray());

            }

            catch (Exception ex)

            {

                line = ex.Message;

            }

        }   



    return filePath != null

        ? (ActionResult)new OkObjectResult($"filePath: {filePath} Container: {fileInfo.Container} DirectoryName: {fileInfo.DirectoryName} FileName: {fileInfo.FileName}*********{line}")

        : new BadRequestObjectResult("Please pass a filePath on the query string or in the request body");

}



private static FileInfo GetFileInfo(string filePath)

{

    int index = filePath.IndexOf("/");

    filePath = (index < 0)

        ? filePath

        : filePath.Remove(index, 1);



    var filePathSplit = filePath.Split('/');

    var fileInfo = new FileInfo();

    fileInfo.Container = filePathSplit[0];



    if ((filePathSplit.Length - 2) > 0)

    {

        var folderName = "";



        for(var i = 1; i < filePathSplit.Length - 1; i++)

        {

            if (folderName.Trim().Length > 0)

            {

                folderName += "/";

            }



            folderName += filePathSplit[i];

        }



        fileInfo.DirectoryName = folderName;

    }



    fileInfo.FileName = filePathSplit[filePathSplit.Length - 1];



    return fileInfo;

}



public class FileInfo

{

    public string Container { get; set; }

    public string DirectoryName { get; set; }

    public string FileName { get; set; }

}

V2 function is based on .Net Core env hence it references Microsoft.WindowsAzure.Storage assembly depending on .Net Standard, which has no synchronous API, it means we need *Async method.

await blockBlob2.DownloadToStreamAsync(memoryStream);

According to your code and error message, you did not use the method DownloadToStream correctly. For more details, please refer to the document.

       CloudBlockBlob blockBlob = container.GetBlockBlobReference(blobName);

        var blobRequestOptions = new BlobRequestOptions

        {

            ServerTimeout = TimeSpan.FromSeconds(30),

            MaximumExecutionTime = TimeSpan.FromSeconds(120),

            RetryPolicy = new ExponentialRetry(TimeSpan.FromSeconds(3), maxRetryCount),

        };



        using (var memoryStream = new MemoryStream())

        {

            blockBlob.DownloadToStream(memoryStream, null, blobRequestOptions);

        }