Connecting Azure Function to Azure Storage Blob with HTTP trigger

Question

I came across multiple ways of connecting Azure Storage Blobs to Azure (like this one for example) Functions but all of them require me to use a BlockBlob type parameter in my Run function, therefore replacing the HTTPRequestMessage parameter I need. Is there a way to keep the HTTPRequestMessage parameter and connect to Azure Storage Blob?

Ultimately, I need to get a file reference from the blob to send to another service via Azure Function.

When I try to add more parameters to Run, the function compiles properly, but I am returned a 500 error. When I change the parameters back to two, it works properly. The only difference is the parameter and function.json to which I add a section resulting in the entire file looking like this :

{
  "bindings": [
    {
      "authLevel": "function",
      "name": "req",
      "type": "httpTrigger",
      "direction": "in",
      "methods": [
        "get",
        "post"
      ]
    },
    {
      "type": "blob",
      "name": "myBlobbo",
      "path": "mycontainer",
      "connection": "value",
      "direction": "inout"
    },
    {
      "name": "$return",
      "type": "http",
      "direction": "out"
    }
  ],
  "disabled": false
}

// Alright, now the logs are telling me that I didn't specify a connection string, even though I have a local.settings.json file with this inside:

{
  "ConnectionStrings": 
  {
    "xyz": "DefaultEndpointsProtocol=https;AccountName=xxx;AccountKey=yyy;EndpointSuffix=core.windows.net"
  }
}

I'm probably going to just connect manually via passing an URI to CloudBlobContainer and using a file stream or %TEMP% to pass the contents, but I still would very much like to know how to get this binding to work.

// I'm using Azure environment to develop the function.

Are you using azure portal or Visual Studio to develop your function? bindings.json looks like you are using portal but local.settings.json used for Visual Studio. — Alexey Rodionov
I'm using Azure Portal. I added a new file called local.settings.json to my function and added the contents shown in the thread (the ConnectionStrings part) to it. — user8620003
I am also finding it really hard to take the toy examples of an HTTP request and extend it to simply read a blob container's contents out using a foreach. Iterating over the standard file store should be really easy, but it is turning out to be really hard. — John Drinane

Alexey Rodionov Alexey Rodionov · Accepted Answer · 2018-02-16T22:44:09

Following example shows how to get blob content with HttpRequest (HttpTrigger, Blob input, Http out):

run.csx

using System.Net;

public static async Task<HttpResponseMessage> Run(HttpRequestMessage req, string inputBlob, TraceWriter log)
{
    log.Info("Blob content: " + inputBlob);
    return req.CreateResponse(HttpStatusCode.OK, inputBlob);
}

functions.json

{
  "bindings": [
    {
      "authLevel": "function",
      "name": "req",
      "type": "httpTrigger",
      "direction": "in",
      "methods": [
        "get",
        "post"
      ]
    },
    {
      "name": "$return",
      "type": "http",
      "direction": "out"
    },
    {
      "type": "blob",
      "name": "inputBlob",
      "path": "incontainer/myblob.txt",
      "connection": "AzureWebJobsDashboard",
      "direction": "in"
    }
  ],
  "disabled": false
}

storage:

AzureWebJobsDashboard:

Connecting Azure Function to Azure Storage Blob with HTTP trigger

1 Answers