CODEWITHSUNDEEP
c#azure-functionsazure-blob-storageazure-functions-core-tools
aumanjoa
aumanjoa

Reputation: 955

azure function c# http trigger blob output

Can someone describe me how I can configure a C# azure function which uses an HTTP input trigger and a blob storage output trigger?

Maybe also with an example code snippet and an example function.json. I don't get it to work locally with the azure functions core tools.

Upvotes: 8

Views: 10369

Answers (4)

A510
A510

Reputation: 304

This is the simplest code to accomplish this task.

using Microsoft.AspNetCore.Http;
using Microsoft.AspNetCore.Mvc;
using Microsoft.Azure.WebJobs;

public static IActionResult Run(HttpRequest req, out string outputBlob)
{
    outputBlob = "This is a Blob content";
    return new OkResult();
}

The input and output parameters are specified in the function.json file and are additionally presented graphically in the Integration tab.

function.json file content:

{"bindings":[{"authLevel": "ANONYMOUS",
    "name": "req",
    "type": "httpTrigger",
    "direction": "in",
    "methods": ["get","post"]
},{
    "name": "$return",
    "type": "http",
    "direction": "out"
},{
    "name": "outputBlob",
    "direction": "out",
    "type": "blob",
    "path": "outcontainer/{rand-guid}",
    "connection": "AzureWebJobsStorage"
}]}

Integration tab content: enter image description here

local.settings.json file content

{"IsEncrypted": false,
    "Values": {
        "AzureWebJobsStorage": "UseDevelopmentStorage=true",
        "FUNCTIONS_WORKER_RUNTIME": "dotnet" }}

The function can be extended by adding logging and reading data from the request.

using Microsoft.AspNetCore.Http;
using Microsoft.AspNetCore.Mvc;
using Microsoft.Azure.WebJobs;
using Microsoft.Extensions.Logging;
using System;

public static IActionResult Run(HttpRequest req, out string outputBlob, ILogger log)
{
    log.LogInformation("C# HTTP trigger function processed a request.");
    outputBlob = $"This Blob was created by HttpTrigger1 because at {DateTime.Now} request was sent to: {req.Host}";
    return new OkResult();
}

Upvotes: 0

CodeSerendipity
CodeSerendipity

Reputation: 84

to make an http function that saves to Blob Storage use this code:

 #r "Newtonsoft.Json"

using System.Net;
using Microsoft.AspNetCore.Mvc;
using Microsoft.Extensions.Primitives;
using Newtonsoft.Json;

public static async Task<IActionResult> Run(HttpRequest req, ILogger log,TextWriter outputBlob)
{
   
    string requestBody = await new StreamReader(req.Body).ReadToEndAsync();
    outputBlob.WriteLine(requestBody);
 
    string result =  "{ 'result':  'ok' }";
    dynamic data = JsonConvert.DeserializeObject(result);
      
    return new OkObjectResult(data);
}

You need to set the output binding:

enter image description here

You can then run a test posting content on the test window

enter image description here

Upvotes: 4

Chris
Chris

Reputation: 3293

This is a combined HTTP triggered function with a output blob binding:

[FunctionName("HttpTriggeredFunction")]
public static async Task<IActionResult> Run(
    [HttpTrigger(AuthorizationLevel.Function, "get", "post", Route = null)] HttpRequest httpRequest,
    [Blob("blobcontainer", Connection = "StorageConnectionString")] CloudBlobContainer outputContainer,
    ILogger log)
{
    log.LogInformation("C# HTTP trigger function processed a request.");

    await outputContainer.CreateIfNotExistsAsync();

    var requestBody = await new StreamReader(httpRequest.Body).ReadToEndAsync();
    var blobName = Guid.NewGuid().ToString();

    var cloudBlockBlob = outputContainer.GetBlockBlobReference(blobName);
    await cloudBlockBlob.UploadTextAsync(requestBody);

    return new OkObjectResult(blobName);
}

It uses the CloudBlobContainer output type to get a reference to the blob container which then enables you to use methods such as .GetBlockBlobReference("blobPath") to get a reference to a blob.

Once you have a reference to a blob, you can use different methods to upload:

  • cloudBlockBlob.UploadFromByteArrayAsync()
  • cloudBlockBlob.UploadFromFileAsync()
  • cloudBlockBlob.UploadTextAsync()
  • cloudBlockBlob.UploadFromStreamAsync()

To get it running locally, you need set some things up. Notice in my example the attribute [Blob("blobcontainer", Connection = "StorageConnectionString")]

  • "blobcontainer" this can be whatever you want and will be the name of the container that will be created in your storage account by this line outputContainer.CreateIfNotExistsAsync(); (if it doesn't exist already).
  • Connection = "StorageConnectionString" this can be a setting in your local.settings.json for the connection string of your storage account. When developing locally I would recommend setting this to "UseDevelopmentStorage=true" so that you can take advantage of the storage emulator. Then when you are ready to deploy onto Azure, you would create a setting in the function app containing the real connection string.

local.settings.json

{
  "IsEncrypted": false,
  "Values": {
    "AzureWebJobsStorage": "UseDevelopmentStorage=true",
    "FUNCTIONS_WORKER_RUNTIME": "dotnet",

    "StorageConnectionString": "UseDevelopmentStorage=true"
  }
}

Upvotes: 22

Sajeetharan
Sajeetharan

Reputation: 222522

Everything you need is there in the Official docs page,

(i) Http and WebHooks

(ii)Output binding blob storage

Http Trigger Sample code

[FunctionName("HttpTriggerCSharp")]
public static async Task<IActionResult> Run(
    [HttpTrigger(AuthorizationLevel.Function, "get", "post", Route = null)] 
    HttpRequest req, ILogger log)

Blob Storage Output binding

[FunctionName("ResizeImage")]
public static void Run(
    [BlobTrigger("sample-images/{name}")] Stream image,
    [Blob("sample-images-sm/{name}", FileAccess.Write)] Stream imageSmall,
    [Blob("sample-images-md/{name}", FileAccess.Write)] Stream imageMedium)

Upvotes: -1

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