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Month: February 2017

Return HTML or file content from C# Azure function

I’m currently implementing different Azure functions and these days I wanted to return a simple HTML document via an Azure function. So I did it at first for a simple (“hello world”) Azure function and used the code later in my real function.

I developed the sample online (in the Azure portal), but you can also use Visual Studio for it. Just add a new “HttpTrigger – C#” function and set the authorization level (I used anonymous – so no key is required):

After that, I changed the code of the function:

using System.Net;
using System.Net.Http.Headers;

public static async Task<HttpResponseMessage> Run(HttpRequestMessage req, TraceWriter log)
    log.Info($"C# HTTP trigger function processed a request. RequestUri={req.RequestUri}");

    string html = @"<html>
<head><title>Hello world!</title></head>
<h1>Hello World!</h1>
<p>from my <strong>Azure Function</strong></p>
    var response = new HttpResponseMessage(HttpStatusCode.OK);
    response.Content = new StringContent(html);
    response.Content.Headers.ContentType = new MediaTypeHeaderValue("text/html");
    return response;

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Azure Functions – Time Trigger (CRON) Cheat Sheet

This is a cheat sheet for CRON expressions that are used in the time triggers for Azure functions. They define how often a trigger/the Azure function should be executed (daily, hourly, every 3 months, …).

The basic format of the CRON expressions in Azure is:
{second} {minute} {hour} {day} {month} {day of the week}
e.g. 0 * * * * * (=every minute)

The following values are allowed for the different placeholders:

Value Allowed Values Description
{second} 0-59; * {second} when the trigger will be fired
{minute} 0-59; * {minute} when the trigger will be fired
{hour} 0-23; * {hour} when the trigger will be fired
{day} 1-31; * {day} when the trigger will be fired
{month} 1-12; * {month} when the trigger will be fired
{day of the week} 0-6; MON-SUN; * {day of the week} when the trigger will be fired

e.g. 3 5 * * * * defines a trigger that runs every time when the clock is at second 3 and minute 5 (e.g. at 09:05:03, 10:05:03, 11:05:03, …).

The trigger executes at UTC timezone. So for Vienna (UTC+1), a trigger at 18:00 (UTC) executes at 19:00 Vienna time (UTC+1).

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Use the Azure Billing API and calculate the costs

The last days, I created a .net library that allows to read data from the Azure Billing REST APIs. You can use it to read data from the usage API, the ratecard API and it also gives you the combination of the data and does a cost calculation. The library is available as NuGet package (https://www.nuget.org/packages/CodeHollow.AzureBillingApi/) and the code is published on GitHub: https://github.com/codehollow/AzureBillingApi.
But before I jump into a short description of the library, I want to write a bit about the Azure Billing APIs:


The Azure billing API allows to get data of your usage and the money that you have to pay for your resources. There are currently two types of the billing API:

The billing API for EA customers already returns the costs – so it’s much simpler. The REST (generic) billing API returns more data. It returns the usage of the resources and the costs per unit per resources – but it does not return the effective costs. If you want to get the costs, then you have to get the usage data and combine it with the ratecard data (the costs per unit per resource). I already blogged about each of those two APIs, but not about how to connect the data of both of them:

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