Category / General

by Aaron

Flutter.io First Impressions

I’ve been tinkering with Flutter.io for a few days now and wanted to document a few early impressions.

It uses the programming language Dart. I’d looked at a lot of Dart code when it was first announced, but hadn’t looked at it much since. I couldn’t see it gaining meaningful traction against the JavaScript juggernaut as a transpiled option (as it added too much overhead from the complaints I’d read) and there was zero evidence that any company besides Google was considering integrating it as a native option for Web pages. Without broad industry cross-browser support (from desktop to mobile as well), it seemed like a dead-end option that didn’t add measurable value. In some ways it was doomed to fail as it was trying to be a better JavaScript rather than rethinking the whole client development experience. It was just a new web programming language.

Originally, Dart’s messaging was broad and suggested that it was an ideal language for everywhere. That has changed since it’s original announcements to be focused on client development. But, that shift was recent and apparently connected with the announcement of Flutter.

From November 1, 2011:

Dart Language Home Page

 

to late February 2018:

Dart Home Page, 2018-02

Even as recent as May 2017, the Dart team was still considering server development as a potential platform target:

Dart home page, May 2018

It seems logical that the team would pivot to concentrate on a single target platform type, the “client.” Dart hadn’t gained substantial traction in server development or client development. While a recent video I’d watched suggested there were 70 million lines of Dart code on Github, I’m not sure who’s writing all that code and why. The dart-lang repository hosted on GitHub hasn’t seen a lot of “Star” love.

1500 Stars on Github

Compare those numbers to TypeScript for example:
31,301 Stars on GithubNearly 30,000 more stars (and TypeScript was announced about a year after Dart).

I wouldn’t choose Dart for new development outside of Flutter. My initial impression is disappointment that the Flutter team is using Dart as it adds one more language to the client-side development smörgåsbord. I don’t know that the world needs another programming/UI toolkit lock-in option right now added to the buffet. I like variety and competition, so I’m all for that, but I also worry that limited adoption of frameworks leads to abandonment and frustrated developers. I can speculate why they choose Dart, especially as it’s staffed by Google developers, and I can see the appeal of the language, but….

I don’t need more programming languages right now in my solutions toolbox. It’s one more thing to learn and master. Since Flutter is also new, it has made the initial ramp-up time longer than I’d expected and wanted.  And because the language syntax is very familiar by design, it’s unfortunately likely that habits from other C-like and TypeScript-like will find their way into coding I do in Dart.

While the community at large apparently considers the Widget building syntax to be a strength of Flutter, I can’t say that I’m excited about it. It’s chatty and verbose. (And I haven’t been able to tell if the enthusiasm about the current syntax is just from the early adopters or fans, or it’s generally well liked). It absolutely doesn’t feel like it’s moving the needle when compared to all of the other GUI frameworks that have come before it. In fact, it reminds me of my earliest coding experiences using Turbo Vision. Yeah. Turbo Vision from Borland. (Wow — the past 20 years of IDEs and development tools originally from Borland has undergone an amazing number of ownership changes).

Turbo Vision Programming Guide

(Yes, it’s not really like that too much, but I had some flashbacks to my Turbo Pascal days).

Here’s a snippet of some code, written in Dart which represents a single item (more about this in a later post), with a thumbnail, a name, and a year published.

Of course, alternatives have been proposed, like a JSX-like syntax. This proposal brought out the best and worst of engineers of course. A few of the collaborators on Flutter were so dismissive of the idea I nearly stopped looking at Flutter.  As Flutter is in its early days, and backed by Google, I expect ideas are rationally considered and individuals to be treated with respect, even if there is disagreement. I’ve done years of WPF, Silverlight, and UWP development which used XAML. While there continue to be some rough spots in XAML, I appreciated the structured document for building a UI. I don’t know that I’d go in that direction for Flutter, but I don’t think describing complex user interfaces entirely in code is the best for its future viability, especially as it needs to compete with a variety of other frameworks and options.

Ignoring the syntax of how to describe a UI though for a moment, I’m still having trouble with wrapping my head around the idea that State actually renders a UI:

It’s the build method that returns the object hierarchy that describes the widget tree, not the class that subclasses StatefulWidget.  If you instead use a StatelessWidget, it builds its Widget hierarchy directly within the class. I can see how they arrived at this implementation, but it just feels inconsistent.

I like the async/await support in Dart. I do wish that I wouldn’t need to specifically declare the return type as Future<T>. The code has already signaled that it’s async, so if Future<T> could just be T, some code clutter would be eliminated.

AndroidStudio

The the code above, it’s great that the return value is automatically wrapped in a Future without any special code, but taking it a bit further would make Dart and Flutter more appealing.

I’ve been using TypeScript long enough that let and const functionality is second-nature. Unfortunately, Dart’s language is subtly different and I end up trying to use const where I meant to use final. That’s my problem of course, but it’s just a gotcha. Const in Dart is for compile-time constants.

I’ve been generally pleased with using Android Studio with the Flutter plugin. It performs reasonably well, and it’s a good editor with lots of bells and whistles. The build/debug times are quite long, even for a basic app. It’s about 25-30 seconds for a build and deploy to an emulator. Thankfully, the plugin and Flutter both support hot reloading, so many changes to the code can be updated without needing to do a new build/deploy. While that’s very helpful, I’d like to see a significantly reduced build and deploy time.

In a market saturated with options for building cross-platform application UIs, it’s not clear how Flutter fits in. I’ve liked the experience enough that I’m going to build out a few simple apps and will show off more details in a later post of an app I’ve been tinkering with as I learn the platform and development environment. Flutter is in an “alpha” state right now, so a lot could change before it’s available in a final release (if it ever is). According to their Github repository, they have currently 86 issues open for their “beta” milestone. There’s no meaningful date associated with the transition though.

Mattress-Firm
by Aaron

How to make your too soft Tempur-pedic Bed comfortable

We’d suffered far too long. Our 2 year old Temper-pedic mattress was painful to use.

I couldn’t find a comfortable way to sleep anymore and was tired nearly every day and had too many aches and pains many mornings. My wife complained that her neck hurt frequently and that her shoulders and back were sore. As our Temper-pedic mattress was nearly $2500, we were reluctant to replace it so soon. But, we had to do something. I hated that bed and was dreading trying to sleep at night. The marketing by manufacturers suggests a memory foam mattress nearly to be the fix to every problem you have sleeping. Yeah, sorry. It’s not.

I’d done quite a bit of research and there were several schools of thought.

  1. Buy a new mattress. There’s no fix.
  2. Place something firm under the mattress.
  3. Buy a mattress topper of some type
  4. Crazy ideas…

As a last resort, buying a new mattress remained an option. However, not only did we not want to spend that amount of money again on another mattress, we were uncomfortable with throwing out a mattress that was so new. It hasn’t even developed the slightest hint of wear (there aren’t any sunken spots where we obviously sleep most frequently).

The second option didn’t make much sense given the density of the mattress. While I could see how it could potentially work for traditional box spring mattresses, our mattress didn’t require or need a base. Further, the base our bed rested on was pretty firm anyway. So, I didn’t see much reason to pursue that.

The challenge then was to buy a mattress topper. Was there something that was firm enough that it would mask the overly soft Tempur-pedic bed?

I read so many blogs and advice sites, with no clear answer. The general opinion was that a mattress topper could help, if you bought the right one and it was properly supported. In fact, some people bought toppers and then placed hard rubber mats underneath the topper to help provide a more solid foundation. As I was worried a bit about the off-gassing and smell of that solution, I looked for other options.

After extensive research, we settled on this:

Pure Green 100% Natural Latex Mattress Topper – Firm (3″ King Size)

The king sized topper arrived in a large box, folded once in half, rolled and protected in a thick plastic “bag.” We were careful to not damage the bag when removing the mattress topper in case we needed to return the topper. It did make removing the topper from the bag a bit more work than if I’d carefully sliced the bag open. Thankfully (according to the seller on Amazon), they do accept returns and offer to send a box to return the mattress topper if necessary.

Can I return the topper?
Yes!

So, after a few minutes on the floor, we hefted it onto the bed. It’s not lightweight, and as it’s extremely flexible, it was more awkward than we would have liked. I’d recommend folding it back in half so it’s easier to lift and move onto your bed. As you shouldn’t need to do this often, I wouldn’t be concerned about the one time lift. If you’re by yourself and trying to place a King sized topper, it may take a few more minutes and some grumbling. It apparently weighs about 65 pounds, so some amount of dragging it into place may be necessary.

Our sheets JUST accommodated the extra height. Just. If the topper had been 4″, the sheets wouldn’t have worked. The topper, while designed for a king was a bit “proud” of the size of the bed and was about 2″ total wider than it needed to be. I’m not sure if that’s normal, but it didn’t affect our sheet fit thankfully. Be prepared to potentially buy new taller sheets.

The first night was a welcome relief, even though the bed was noticeably more firm. We were both worried at first that the topper would still “sink” too much into the Tempur-pedic, but it doesn’t seem too. The next morning, we both felt far more rested and less sore than we had in 6 months. The second night, ahhh. Nice.

Some folks online have said it’s not “firm” enough. As firmness is subjective and personal, I can only say that it’s a comfortable firmness for us. If it were less firm, I’d suspect that it wouldn’t do much good. We’ll probably need to rotate the topper occasionally to prevent sunken/wear spots.

There was zero smell that we could notice both out of the packaging and when placed on the bed. Older reviews mentioned that the latex would crumble some. As ours is new, we haven’t experienced that. If it does, we’ll buy a simple cover for it. The topper is manufactured in many different sizes, from Twin to California King.

If you’re like us, suffering for buying a mattress that’s too soft and doesn’t offer enough support, I’d recommend the mattress topper (or something similar). Of course, it’s a bit risky to buy something like this sight unseen given the price, but as you shop around, make sure there’s a liberal return policy and be willing to return it if it doesn’t work out.

Two weeks later, our only regret is not buying it sooner.  

Other Information

Our current memory-foam Tempur-pedic mattress is of medium softness (we own the TEMPUR-Cloud Prima). I sleep in nearly every way possible, except flat on my back, and my wife sleeps mostly on her back.

An IKEA mattress topper was suggested in a number of forums. As we don’t have a nearby IKEA, we couldn’t evaluate the option in person. While it is an option that IKEA will sell online, the shipping/handling was extremely high to our location and most people said that it would still need another layer of very firm support under the topper. While overall the option may have been less expensive I suppose, it didn’t seem as promising as the option we purchased.

by Aaron

Quick demo of Go’s context.WithTimeout

To better understand Go’s context withTimeout functionality (and as a reference for myself), I’ve created this small self-contained demo. I didn’t find the published documentation’s example to be clear enough. The interesting part, coming from other programming languages and platforms, was that the WithTimeout function only was a signal that something happened. It doesn’t do anything when there’s a time out (like abort a goroutine or anything dramatic like that).

The essential pieces:

  1. Call WithTimeout passing the Background() context and specify the timeout (I’ve specified  3.2 seconds)
  2. Be a good citizen and defer the cancellation (to be sure that it’s called) and defer close the channel
  3. Start the go routine which waits for the Done channel
  4. When the Done is signaled, display the current time in seconds and what caused the signal
  5. The main app is waiting for the goroutine to end, so signal that.
  6. In the main function, the code sleeps and wakes emitting some time stamps to the console
  7. Depending on whether cancel is called, the goroutine signal may be one of two things.
    1. If cancel is not called prior to the second sleep in the code, the ctx.Err() returns 
      <-ctx.Done():  context deadline exceeded
    2. If cancel however is called, the ctx.Err() returns: 
      <-ctx.Done():  context canceled
  8. Then, the goroutine uses the channel to signal completion (wait<-true).

You can experiment with this sample here.

With cancel called (the line cancel() not commented out):

first sleep completed,  02.00
Timeout: 02.00
in <-ctx.Done():  context canceled
after second sleep done,  04.00

And, with // cancel() commented out:

first sleep completed,  02.00
Timeout: 03.20
in <-ctx.Done():  context deadline exceeded
after second sleep done,  04.00

Hopefully this helps someone besides me.

by Aaron

How to sign Powershell scripts with self-signed certificates in Windows 10

I wanted to allow all signed Powershell scripts to run on a PC in our house on Windows 10. To do that, I needed a code-signing certificate.

Unfortunately, the days of easily obtaining a free code signing certificate seem to have ended. Have no fear! You can create a self-signed certificate if you don’t expect to use the certificate anywhere but on the PC where the certificate was created.

First, I enabled Powershell scripts to run. From an administrative Powershell command prompt: 

> Set-ExecutionPolicy AllSigned

Acknowledge the warning and you’re ready to execute only signed scripts.

But, if you create your own script, you’ll need to sign it. To create the necessary code-signing certificate, you’ll again use Powershell. From an administrative Powershell command prompt: 

PS C:\Dev>New-SelfSignedCertificate -CertStoreLocation Cert:\LocalMachine\ -Type CodeSigningCert -Subject "CN=PowershellScripts" -NotAfter (Get-Date).AddYears(10)

You can change the Common Name (CN) to anything you’d like, or adjust the expiration date (using -NotAfter). I’ve got the expiration as 10 years from today.

Once you’ve got the code signing certificate created as shown above, you’ll need to move the certificate to the Trusted Root Certification Authorities. If you don’t, when you sign the powershell script, it still won’t be allowed to run (and the act of signing will produce an UnknownError).

Start the certificate manager (press Windows key, type cert, and select “Manage computer certificates“, or hit Windows+R, then type: “certmgr.msc“).

Drag Certificate Into Trusted Root Certification Authorities

Expand Trusted Root Certification Authorities first, then expand Personal > Certificates and select the PowershellScripts Code Signing certificate and then drag it into the Trusted Certificates list as shown above (or you can right click, cut, and then paste it as well).

Now that you’ve got a trusted code signing cetificate, you can sign your Powershell scripts.

If you’ve only got one code signing certificate (which I presume you do otherwise you wouldn’t have needed a new one), from an administrative Powershell command prompt first switch directories to where the script you want to sign is located, then do these commands: 

> $cert = (Get-ChildItem Cert:\LocalMachine\my -CodeSigningCert)[0]
> Set-AuthenticodeSignature .\reconnect-iscsi-targets.ps1 $cert

You should then see a table with the SignerCertificate, Status, and the Path. If everything went well, the Status should be Valid.

Here’s something interesting you can do with iSCSI targets and PowerShell using a signed PowerShell script.

 

 

by Aaron

Automatic Reconnection of iSCSI Targets in Windows 10 using PowerShell

When my highly recommended Synology Disk Station reboots for a required update (I’ve got it set to automatically reboot), a shared Windows 10 PC in our house cannot always successfully reconnect to the iSCSI targets without manual intervention. Unfortunately, I haven’t always noticed which has led to several features of Windows not functioning the way I want (I have mapped the iSCSI drives/disks via Windows and made them into network shares for the other PCs/laptops in our house — this way I can use Windows bitlocker encryption on the iSCSI drive contents).

To make the connection more automatic, I created a simple one line PowerShell script that periodically attempts to connect to any disconnected iSCSI targets using the Windows Task Scheduler.

I saved this into a script file called reconnect-iscsi-targets.ps1: 

Get-IscsiTarget | where ($_.isConnected -eq $false) | Connect-IscsiTarget

Then, in the Task Scheduler, I created a new task set to run every 10 minutes daily. The script just gets all iSCSI targets, filters only those that aren’t connected, and then passes the results to the connection cmdlet.

For the action, I selected “Start a program” for program/script, I entered: “powershell.exe”, and then added the arguments “-File” and the full path to the file name, like: 

-File c:\Users\aaron\Documents\reconnect-iscsi-targets.ps1

If there are spaces in the path to the PowerShell file, be sure to add quotes around the full path and file name.

You shouldn’t need the start in option set (leave it empty if you’d like).

On the General tab of the task, make sure you’ve set the “Run whether user is logged on or not” option and “Run with highest privileges.”

Next up — how to quickly create a Self-Signed Code-Signing certificate. And, how to actually allow scripts to run!