Develop Reference

HTTP trigger azure function with blob output binding

I need to save my HTTP message to the blob. I am using the below code. the file is getting created but without content. I need the XML data to be stored in the blob
[FunctionName("Function11")
public static async Task <IActionResult> Run(
[HttpTrigger(AuthorizationLevel.Function, "post", Route = null)] HttpRequest req,
[Blob("Order/sales_{Datetimenow}.xml", FileAccess.Write, Connection = "AzureWebJobsStorage")] Stream outputStream)
{
string requestBody = await new StreamReader(req.Body).ReadToEndAsync();
return new OkObjectResult(requestBody);
}

Looking at the code you posted, and explicitly this part
string requestBody = await new StreamReader(req.Body).ReadToEndAsync();
return new OkObjectResult(requestBody);
it shows that you are...
reading the body of the POST
putting the body in the requestBody variable
returning an OkObjectResult with requestBody as the content
What you are NOT doing is writing the body to the outputStream. You should either create a StreamWriter and write to the stream, otherwise there's nothing to be written to the stream.

Thank you.
[FunctionName("HTTPTrigger")]
public static async Task RunAsync(
[HttpTrigger(AuthorizationLevel.Function, "post", Route = null)] HttpRequest req,
[Blob("sample/order{DateTime.now}.xml", FileAccess.Write, Connection = "AzureWebJobsStorage")] Stream oStream, ILogger log)
{
var requestBody = await new StreamReader(req.Body).ReadToEndAsync();
oStream.Write(Encoding.UTF8.GetBytes(requestBody));
return new OkObjectResult(requestBody);

How to Read & Write to same Blob file in Azure Function (.NET6)

In Azure Function V1 (.NET4) code below worked fine
[FunctionName("run")]
public static HttpResponseMessage run(
[HttpTrigger(AuthorizationLevel.Anonymous, "post", Route = null)] HttpRequestMessage request,
[Blob("sample.txt", FileAccess.Read)] Stream readStream,
[Blob("sample.txt", FileAccess.Write)] Stream writeStream)
{
//read & write to sample.txt stream works ok
}
But in Azure Function V4 (.NET 6), throws error that only 1 stream can be accessed
[FunctionName("run")]
public static HttpResponseMessage run(
[HttpTrigger(AuthorizationLevel.Anonymous, "post", Route = null)] HttpRequestMessage request,
[Blob("sample.txt", FileAccess.Read)] Stream readStream,
[Blob("sample.txt", FileAccess.Write)] Stream writeStream)
{
//can ONLY use read stream or write stream, can't use both
}
How to Read & Write to same Blob file in Azure Function (.NET6)?
Note: issue only appears in Azure not in local debugging

Final solution that worked in Azure Function V4 (.NET 6) is BlobClient
Code to use BlobClient to read/write files in blob storage
[FunctionName("Function1")]
public static async Task<IActionResult> Function1(
[HttpTrigger(AuthorizationLevel.Anonymous, "post", Route = null)] HttpRequestMessage incomingRequest,
[Blob("container-name/file-name.xml", FileAccess.ReadWrite)] BlobClient fileBlobClient)
{ ... }

After reproducing from our end, This was working even though we have added 2 streams. Make sure your environment is up to date.
[FunctionName("Function1")]
public static void Run(
[HttpTrigger(AuthorizationLevel.Anonymous, "post", Route = null)] HttpRequestMessage req,
[Blob("samples-workitems/samples.txt", FileAccess.Read)] Stream readStream,
[Blob("samples-workitems/samples.txt", FileAccess.Write)] Stream writeStream)
{
Console.WriteLine("Blob length is "+ readStream.Length);
string sample = "Sample Text";
byte[] bytes = Encoding.ASCII.GetBytes(sample);
writeStream.Write(bytes, 0, bytes.Length);
}
Considering this to be my initial text file
RESULT:
Text file after post-trigger

Error: Cannot convert from Microsoft.AspNetCore.Http.IFormFile to System.IO.Stream

I'm trying to create Azure function which takes image file from html form POST request and saves it to Blob Storage for further usage with another function. Here is my code:
public static class Function2
{
[FunctionName("Function2")]
public static async Task<IActionResult> Run(
[HttpTrigger(AuthorizationLevel.Function, "get", "post", Route = null)] HttpRequest req,
ILogger log)
{
log.LogInformation("C# HTTP trigger function processed a request.");
foreach (var file in req.Form.Files)
{
using (var ms = new MemoryStream())
{
var file2 = req.Form.Files[0];
await file2.CopyToAsync(ms);
ms.Seek(0, SeekOrigin.Begin);
var connectionString = "DefaultEndpointsProtocol=https;" +
"AccountName=mystorageaccount;" +
"AccountKey=8Hk5k6j65j5j665j67k==;" +
"EndpointSuffix=core.windows.net";
// intialize BobClient
Azure.Storage.Blobs.BlobClient blobClient = new Azure.Storage.Blobs.BlobClient(
connectionString: connectionString,
blobContainerName: "image-storage",
blobName: "images");
// upload the file
blobClient.Upload(file2);
}
}
return new OkResult("Image uploaded successfully");
}
}
However this raises exception:
Error CS1503 Argument 1: cannot convert from
'Microsoft.AspNetCore.Http.IFormFile' to 'System.IO.Stream'
Any advise would be very highly appreciated.
Edit: I have previously created Blob Container "image-storage" to my storage account using Azure Portal.

BlobCients Upload method expects a Stream instead of an IFormFile.
Passing the MemoryStream you have in the ms variable will resolve the issue.
blobClient.Upload(ms);

Display files from Azure Blob Storage by Azure function

I'm trying to get files and display them in my browser from Azure Blob Storage via an Azure function. I could manage to download the files when I navigate to the url but I couldn't display them as a static file/image in my browser.
I just want to display it in browser rather than downloading.
I've tried some sdk command but it didn't work. Here's what I've tried:
public static async Task<IActionResult> Run(
[HttpTrigger(AuthorizationLevel.Function, "get", Route = null)] HttpRequest req,
ILogger log)
{
var cloudStorageAccount =
CloudStorageAccount.Parse(AzureStorageConnectionString);
var cloudBlobClient =
cloudStorageAccount.CreateCloudBlobClient();
var cloudBlobContainer =
cloudBlobClient.GetContainerReference(
AzureStorageFilePath);
await cloudBlobContainer.CreateIfNotExistsAsync();
var blobName =
req.Query["name"];
var cloudBlockBlob =
cloudBlobContainer.GetBlockBlobReference(blobName);
var ms = new MemoryStream();
await cloudBlockBlob.DownloadToStreamAsync(ms);
return new FileContentResult(ms.ToArray(), cloudBlockBlob.Properties.ContentType);
}
Any ideas would be appreciated. Thanks!

Kindly check the content type of the file(s) which you want to display ,if the content type is "application/octet-stream" it will cause the file to download.
By default if content-type is not supplied azure sdk sets it as "application/octet-stream" which causes the file to download,set the correct content-type for the file ex :- for image it should be "image/jpeg".
Hopefully this should fix the issue.

Azure Function Access CloudBlobContainer from HttpTriggerFunction

Very, very new to Azure Functions and getting very frustrated.
All I want to do is execute on a 'get' request from a HttpTriggerFunction and return stream content from the CloudBlobContainer.
I really don't see why this is so hard. Just trying to host a SPA using Azure Functions.
Something like this
public static class UIHandler
{
[FunctionName("UIHandler")]
public static async Task<HttpResponseMessage> Run(
[HttpTrigger(AuthorizationLevel.Function, "get", Route = null)]HttpRequest req,
TraceWriter log,
CloudBlobContainer container)
{
log.Info("C# HTTP trigger function processed a request.");
var stream = await container.GetBlockBlobReference({Infer file name from request here}).OpenReadAsync();
return new HttpResponseMessage()
{
StatusCode = HttpStatusCode.OK,
Content = new StreamContent(stream)
};
}
}
When I try to run this I get the following error.
Run: Microsoft.Azure.WebJobs.Host: Error indexing method
'UIHandler.Run'. Microsoft.Azure.WebJobs.Host: Cannot bind parameter
'container' to type CloudBlobContainer. Make sure the parameter Type
is supported by the binding. If you're using binding extensions (e.g.
ServiceBus, Timers, etc.) make sure you've called the registration
method for the extension(s) in your startup code (e.g.
config.UseServiceBus(), config.UseTimers(), etc.).
I'm using Azure Functions 2. I can't see from the web how to setup the browsing extensions for this. Iv'e also looked into Input and Output bindings. I don't understand what makes a parameter input or output bound when your using C# that only seems to exist in the JSON.
Do I need to corresponding JSON file ? If so what is it called where does it go.
Thanks in Advance

Have a look at Blob Storage Input Binding. The very first sample there shows how to read blob stream, just replace Queue Trigger with HTTP trigger, e.g.
[FunctionName("UIHandler")]
public static async Task<HttpResponseMessage> Run(
[HttpTrigger(AuthorizationLevel.Function, "get", Route = "{name}")] HttpRequest req,
string name,
TraceWriter log,
[Blob("samples-workitems/{name}", FileAccess.Read)] Stream stream)
{
log.Info($"C# HTTP trigger function processed a request for {name}.");
return new HttpResponseMessage()
{
StatusCode = HttpStatusCode.OK,
Content = new StreamContent(stream)
};
}