Scott Hanselman

The Transitive Property of Friendship - and the importance of the Warm Intro

April 2, '19 Comments [5] Posted in Musings
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Too many LinkedIn invitationsPer Wikipedia, "In mathematics, a binary relation ... is transitive if ... element a is related to an element b and b is related to an element c then a is also related to c."

Per Me, if I am cool with you, and you are cool with your friend, then I'm cool with your friend. I've decided this is The Transitive Property of Friendship.

As I try to mentor more and more people and help folks Level Up in tech, I'm realizing how important it is to #BeTheLuck for someone else. This is something that YOU can do - volunteer at local schools, forward that resume for your neighbor, give a Warm Intro to a friend of a friend.

A lot of one's success can be traced back to hard work and being prepared for opportunities to present themselves, but also to Warm Intros. Often you'll hear about someone who worked hard in school, studied, did well, but then got a job because "their parent knew a person who worked at x." That's something that is hard to replicate. For under-represented folks trying to break into tech, for example, it's the difference between your resume sitting in a giant queue somewhere vs. sitting on the desk of the hiring manager. Some people inherit a personal network and a resume can jump to the top of a stack with a single phone call, while others send CV after CV with nary a callback.

This is why The Warm Intro is so important. LinkedIn has tried to replicate this by allowing you to "build your professional network" but honestly, you can't tell if I'm cool with someone on LinkedIn just because they're connected to me. Even Facebook "friends" have changed the definition of friend. It certainly has for me. Now I'm mentally creating friend categories like work colleague, lowercase f friend, Uppercase F Friend, etc.

Here's where it gets hard. You can't help everyone. You also have to protect yourself and your own emotional well-being. This is where cultivating a true network of genuine friends and work colleagues comes in. If your First Ring of Friends are reliable, kind, and professional, then it's safer to assume that anyone they bring into your world has a similar mindset. Thus, The Transitive Property of Friendship - also know as "Any friend of Scott's is a friend of mine." The real personal network isn't determined by Facebook or LinkedIn, it's determined by your gut, your experiences, and your good judgment. If you get burned, you'll be less likely to recommend someone in the future.

I've been using this general rule to determine where and when to spend my time while still trying to Lend my Privilege to as many people as possible. It's important also to not be a "transactional networker." Be thoughtful if you're emailing someone cold (me or otherwise). Don't act like an episode of Billions on Showtime. We aren't keeping score, tracking favors, or asking for kickbacks. This isn't about Amazon Referral Money or Finder's Fees. When a new friend comes into your life via another and you feel you can help, give of your network and time freely. Crack the door open for them, and then let them kick it open and hopefully be successful.

All of this starts by you - we - building up warm, genuine professional relationships with a broad group of people. Then using that network not just for yourself, but to lift the voices and careers of those that come after you.

What are YOUR tips and thoughts on building a warm and genuine personal and professional network of folks?


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About Scott

Scott Hanselman is a former professor, former Chief Architect in finance, now speaker, consultant, father, diabetic, and Microsoft employee. He is a failed stand-up comic, a cornrower, and a book author.

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Displaying your realtime Blood Glucose from NightScout on an AdaFruit PyPortal

March 29, '19 Comments [8] Posted in Hardware | Open Source
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file-2AdaFruit makes an adorable tiny little Circuit Python IoT device called the PyPortal that's just about perfect for the kids - and me. It a little dakBoard, if you will - a tiny totally programmable display with Wi-Fi and  lots of possibilities and sensors. Even better, you can just plug it in over USB and edit the code.py file directly on the drive that will appear. When you save code.py the device soft reboots and runs your code.

I've been using Visual Studio Code to program Circuit Python and it's become my most favorite IoT experience so far because it's just so easy. The "Developer's Inner Loop" of code, deploy, debug is so fast.

As you may know, I use a Dexcom CGM (Continuous Glucose Meter) to manage my Type 1 Diabetes. I feed the data every 5 minutes into an instance of the Nightscout Open Source software hosted in Azure. That gives me a REST API to my own body.

I use that REST API to make "glanceable displays" where I - or my family - can see my blood sugar quickly and easily.

I put my blood sugar in places like:

And today, on a tiny PyPortal device. The code is simple, noting that I don't speak Python, so Pull Requests are always appreciated.

import time
import board
from adafruit_pyportal import PyPortal

# Set up where we'll be fetching data from
DATA_SOURCE = "https://NIGHTSCOUTWEBSITE/api/v1/entries.json?count=1"
BG_VALUE = [0, 'sgv']
BG_DIRECTION = [0, 'direction']

RED = 0xFF0000;
ORANGE = 0xFFA500;
YELLOW = 0xFFFF00;
GREEN = 0x00FF00;

def get_bg_color(val):
if val > 200:
return RED
elif val > 150:
return YELLOW
elif val < 60:
return RED
elif val < 80:
return ORANGE
return GREEN

def text_transform_bg(val):
return str(val) + ' mg/dl'

def text_transform_direction(val):
if val == "Flat":
return "→"
if val == "SingleUp":
return "↑"
if val == "DoubleUp":
return "↑↑"
if val == "DoubleDown":
return "↓↓"
if val == "SingleDown":
return "↓"
if val == "FortyFiveDown":
return "→↓"
if val == "FortyFiveUp":
return "→↑"
return val

# the current working directory (where this file is)
cwd = ("/"+__file__).rsplit('/', 1)[0]
pyportal = PyPortal(url=DATA_SOURCE,
json_path=(BG_VALUE, BG_DIRECTION),
status_neopixel=board.NEOPIXEL,
default_bg=0xFFFFFF,
text_font=cwd+"/fonts/Arial-Bold-24-Complete.bdf",
text_position=((90, 120), # VALUE location
(140, 160)), # DIRECTION location
text_color=(0x000000, # sugar text color
0x000000), # direction text color
text_wrap=(35, # characters to wrap for sugar
0), # no wrap for direction
text_maxlen=(180, 30), # max text size for sugar & direction
text_transform=(text_transform_bg,text_transform_direction),
)

# speed up projects with lots of text by preloading the font!
pyportal.preload_font(b'mg/dl012345789');
pyportal.preload_font((0x2191, 0x2192, 0x2193))
#pyportal.preload_font()

while True:
try:
value = pyportal.fetch()
pyportal.set_background(get_bg_color(value[0]))
print("Response is", value)
except RuntimeError as e:
print("Some error occured, retrying! -", e)
time.sleep(180)

I've put the code up at https://github.com/shanselman/NightscoutPyPortal. I want to get (make a custom?) a larger BDF (Bitmap Font) that is about twice the size AND includes 45 degree arrows ↗ and ↘ as the font I have is just 24 point and only includes arrows at 90 degrees. Still, great fun and took just an hour!

NOTE: I used the Chortkeh BDF Font viewer to look at the Bitmap Fonts on Windows. I still need to find a larger 48+ PT Arial.

What information would YOU display on a PyPortal?


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About Scott

Scott Hanselman is a former professor, former Chief Architect in finance, now speaker, consultant, father, diabetic, and Microsoft employee. He is a failed stand-up comic, a cornrower, and a book author.

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F7 is the greatest PowerShell hotkey that no one uses any more. We must fix this.

March 26, '19 Comments [15] Posted in Musings | PowerShell
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Thousands of years ago your ancestors, and myself, were using DOS (or CMD) pressing F7 to get this amazing little ASCII box to pop up to pick commands they'd typed before.

Holy crap it's a little ASCII box

When I find myself in cmd.exe I use F7 a lot. Yes, I also speak *nix and Yes, Ctrl-R is amazing and lovely and you're awesome for knowing it and Yes, it works in PowerShell.

Ctrl-R for history works in PowerShell

Here's the tragedy. Ctrl-R for a reverse command search works in PowerShell because of a module called PSReadLine. PSReadLine is basically a part of PowerShell now and does dozens of countless little command line editing improvements. It also - not sure why and I'm still learning - unknowingly blocks the glorious F7 hotkey.

If you remove PSReadLine (you can do this safely, it'll just apply to the current session)

Remove-Module -Name PSReadLine

Why, then you get F7 history with a magical ASCII box back in PowerShell. And as we all know, 4k 3D VR be damned, impress me with ASCII if you want a developer's heart.

There is a StackOverflow Answer with a little PowerShell snippet that will popup - wait for it - a graphical list with your command history by calling

Set-PSReadlineKeyHandler -Key F7

And basically rebinding the PSReadlineKeyHandler for F7. PSReadline is brilliant, but I what I really want to do is to tell it to "chill" on F7. I don't want to bind or unbind F7 (it's not bound by default) I just want it passed through.

Until that day, I, and you, can just press Ctrl-R for our reverse history search, or get this sad shadow of an ASCII box by pressing "h." Yes, h is already aliased on your machine to Get-History.

PS C:\Users\scott> h

  Id CommandLine
   -- -----------
    1 dir
    2 Remove-Module -Name PSReadLine

Then you can even type "r 1" to "invoke-history" on item 1.

But I will still mourn my lovely ASCII (High ASCII? ANSI? VT100?) history box.


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About Scott

Scott Hanselman is a former professor, former Chief Architect in finance, now speaker, consultant, father, diabetic, and Microsoft employee. He is a failed stand-up comic, a cornrower, and a book author.

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Getting Started with .NET Core and Docker and the Microsoft Container Registry

March 22, '19 Comments [9] Posted in Docker | DotNetCore
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It's super easy to get started with .NET Core and/or ASP.NET Core with Docker. If you have Docker installed you don't need to install anything to try out .NET Core, of course.

To run a little .NET Core console app:

docker run --rm mcr.microsoft.com/dotnet/core/samples:dotnetapp

And the result:

latest: Pulling from dotnet/core/samples
Hello from .NET Core!
...SNIP...

**Environment**
Platform: .NET Core
OS: Linux 4.9.125-linuxkit #1 SMP Fri Sep 7 08:20:28 UTC 2018

To run a quick little ASP.NET Core website just:

docker run -it --rm -p 8000:80 --name aspnetcore_sample mcr.microsoft.com/dotnet/core/samples:aspnetapp

And here it is running on localhost:8000

Simple ASP.NET Core app under Docker

You can also host ASP.NET Core Images with Docker over HTTPS to with this image, or run ASP.NET Core apps in Windows Containers.

Note that Microsoft teams are now publishing container images to the MCR (Microsoft Container Registry) so they can use the Azure CDN and pull faster when they are closer to you globally. The images start at MCR and then can be syndicated to other container registries.

The new repos follow:

When you "docker pull" you can use tag strings for .NET Core and it works across any supported .NET Core version

  • SDK: docker pull mcr.microsoft.com/dotnet/core/sdk:2.1
  • ASP.NET Core Runtime: docker pull mcr.microsoft.com/dotnet/core/aspnet:2.1
  • .NET Core Runtime: docker pull mcr.microsoft.com/dotnet/core/runtime:2.1
  • .NET Core Runtime Dependencies: docker pull mcr.microsoft.com/dotnet/core/runtime-deps:2.1

For example, I can run the .NET Core 3.0 SDK and mess around with it like this:

docker run -it mcr.microsoft.com/dotnet/core/sdk:3.0 

I've been using Docker to run my unit tests on my podcast site within a container locally. Then I volume mount and dump the test results out in a local folder and inspect them with Visual Studio

docker build --pull --target testrunner -t podcast:test .
docker run --rm -v c:\github\hanselminutes-core\TestResults:/app/hanselminutes.core.tests/TestResults podcast:test

I can then either host the Docker container in Azure App Service for Containers, or as little one-off per-second billed instances with Azure Container Instances (ACI).

Have you been using .NET Core in Docker? How has it been going for you?


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About Scott

Scott Hanselman is a former professor, former Chief Architect in finance, now speaker, consultant, father, diabetic, and Microsoft employee. He is a failed stand-up comic, a cornrower, and a book author.

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What is Blazor and what is Razor Components?

March 19, '19 Comments [31] Posted in ASP.NET | Javascript | Open Source
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I've blogged a little about Blazor, showing examples like Compiling C# to WASM with Mono and Blazor then Debugging .NET Source with Remote Debugging in Chrome DevTools as well as very early on asking questions like .NET and WebAssembly - Is this the future of the front-end?

Let's back up and level-set.

What is Blazor?

Blazor is a single-page app framework for building interactive client-side Web apps with .NET. Blazor uses open web standards without plugins or code transpilation. Blazor works in all modern web browsers, including mobile browsers.

You write C# in case of JavaScript, and you can use most of the .NET ecosystem of open source libraries. For the most part, if it's .NET Standard, it'll run in the browser. (Of course if you called a Windows API or a Linux specific API and it didn't exist in the client-side browser S world, it's not gonna work, but you get the idea).

The .NET code runs inside the context of WebAssembly. You're running "a .NET" inside your browser on the client-side with no plugins, no Silverlight, Java, Flash, just open web standards.

WebAssembly is a compact bytecode format optimized for fast download and maximum execution speed.

Here's a great diagram from the Blazor docs.

Blazor runs inside your browser, no plugins needed

Here's where it could get a little confusing. Blazor is the client-side hosting model for Razor Components. I can write Razor Components. I can host them on the server or host them on the client with Blazor.

You may have written Razor in the past in .cshtml files, or more recently in .razor files. You can create and share components using Razor - which is a mix of standard C# and standard HTML, and you can host these Razor Components on either the client or the server.

In this diagram from the docs you can see that the Razor Components are running on the Server and SignalR (over Web Sockets, etc) is remoting them and updating the DOM on the client. This doesn't require Web Assembly on the client, the .NET code runs in the .NET Core CLR (Common Language Runtime) and has full compatibility - you can do anything you'd like as you are not longer limited by the browser's sandbox.

Here's Razor Components running on the server

Per the docs:

Razor Components decouples component rendering logic from how UI updates are applied. ASP.NET Core Razor Components in .NET Core 3.0 adds support for hosting Razor Components on the server in an ASP.NET Core app. UI updates are handled over a SignalR connection.

Here's the canonical "click a button update some HTML" example.

@page "/counter"

<h1>Counter</h1>

<p>Current count: @currentCount</p>

<button class="btn btn-primary" onclick="@IncrementCount">Click me</button>

@functions {
int currentCount = 0;

void IncrementCount()
{
currentCount++;
}
}

You can see this running entirely in the browser, with the C# .NET code running on the client side. .NET DLLs (assemblies) are downloaded and executed by the CLR that's been compiled into WASM and running entirely in the context of the browser.

Note also that I'm stopped at a BREAKPOINT in C# code, except the code is running in the browser and mapped back into JS/WASM world.

Debugging Razor Components on the Client Side

But if I host my app on the server as hosted Razor Components, the C# code runs entirely on the Server-side and the client-side DOM is updated over a SignalR link. Here I've clicked the button on the client side and hit the breakpoint on the server-side in Visual Studio. No there's no POST and no POST-back. This isn't WebForms - It's Razor Components. It's a SPA app written in C#, not JavaScript, and I can change the locations of the running logic, while the UI remains always standard HTML and CSS.

Debugging Razor Components on the Server Side

It's a pretty exciting time on the open web. There's a lot of great work happening in this space and I'm very interesting to see how frameworks like Razor Components/Blazor and Phoenix LiveView change (or don't) how we write apps for the web.


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About Scott

Scott Hanselman is a former professor, former Chief Architect in finance, now speaker, consultant, father, diabetic, and Microsoft employee. He is a failed stand-up comic, a cornrower, and a book author.

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Disclaimer: The opinions expressed herein are my own personal opinions and do not represent my employer's view in any way.