blobToSFTP.cs

using System;
using System.Collections.Generic;
using System.IO;
using System.Threading.Tasks;
using Microsoft.AspNetCore.Mvc;
using Microsoft.Azure.WebJobs;
using Microsoft.Azure.WebJobs.Extensions.Http;
using Microsoft.AspNetCore.Http;
using Microsoft.Extensions.Logging;
using Newtonsoft.Json;
using Renci.SshNet;
using Azure.Storage.Blobs;
using Microsoft.WindowsAzure.Storage.Auth;

namespace content_delivery
{
    public class blobToFtpObj
    {
        public string source_containerName;
        public List<string> fileNames;
        public string dest_ftpName;         # For eg. ftpHost.organization.com@/root/flag.txt

        public override string ToString()
        {
            return "Move declared: From " + source_containerName + " to " + dest_ftpName;
        }
    }

    public static class blobToFtp
    {
        // Enter your sftp username here
        private static string username = "blobToFtp_user";
        // Enter your sftp password here
        private static string password = "somePassword";

        private static bool validRequest(blobToFtpObj reqObj){
            return true;
        }

        [FunctionName("blobToFtp")]
        public static async Task<IActionResult> Run(
            [HttpTrigger(AuthorizationLevel.Anonymous, "get", "post", Route = null)] HttpRequest req,
            ILogger log)
        {
            string requestBody = await new StreamReader(req.Body).ReadToEndAsync();
            # Change this to hold how much ever objects you want at a single time.
            # This can directly relate to the amount of concurrency you'd want in your app
            # Consequenctially, how far you would want the function app to scale vertically.
            List<blobToFtpObj> reqObj = new List<blobToFtpObj>(10);

            reqObj = JsonConvert.DeserializeObject<List<blobToFtpObj>>(requestBody);

            string ftpPath = reqObj[0].dest_ftpName.Split('@')[1];
            string ftpHost = reqObj[0].dest_ftpName.Split('@')[0];

            var connectionInfo = new SftpClient(ftpHost, username, password);
            string connectionString = "DefaultEndpointsProtocol=https;AccountName=reportDatabase;AccountKey=/6+FuuGanaskjdfbasjdbudJKHASsZEuwG0uqe+Da==;EndpointSuffix=core.windows.net";
            BlobContainerClient container = new BlobContainerClient(connectionString, reqObj[0].source_containerName);
            var blockBlob = container.GetBlobClient(reqObj[0].fileNames[0]);

            MemoryStream mstream = new MemoryStream();
            blockBlob.DownloadTo(mstream);
            # May not need this line
            mstream.Seek(0, SeekOrigin.Begin);
            
            try
            {
                connectionInfo.Connect();
                log.LogInformation("SFTP Connect Success");
                connectionInfo.BufferSize = 1024;
                
                connectionInfo.UploadFile(mstream, ftpPath);
                connectionInfo.Dispose();
            }
            catch (Exception e)
            {
                return BadRequestObjectResult(e)
            }
            finally{
                connectionInfo.Disconnect();
            }
            
            return new OkObjectResult("HTTP finished properly");
        }
    }
}