Mount Robert Barron

Penny and I play a little game whenever we go on vacation.  At any souvenir shop we come across that features the typical display of personalized trinkets, such as keychains with names on them, we look to see if we can spot one with “Penny” on it.  Thus far we have not spotted a single item.

During a recent cruise to Alaska, Penny and I visited the Mendenhall Glacier outside of Juneau. While perusing the displays about glaciers and the area’s natural wonders a familiar sight caught my eye on a relief map on the wall.

Wait. What is that?  My own personalized mountain?

Yes, there’s a summit bearing my name on Admiralty Island not too far from the state’s capital. I’m not sure what I’d done to deserve such accolades, so of course I did some research to find out the true story.

This Robert Barron was the son of James Barron who helped develop the Funter Bay region.  James for a time was the President of the Thlinket Packing Company. Robert graduated from Boston University and would serve as Vice President of the company. Years prior to that young Robert’s face was apparently used on the “Buster Brand” labelling for the company.  “Buster” was a nickname that applied to both Robert and his father.

Young Robert Barron

When the US entered World War I Robert joined the Aviation Training Corps at MIT and was killed during training while trying to rescue some fellow pilots who had fallen into the Delaware River in Pennsylvania.  His father received a personal letter from President Wilson.

Cadet Robert Barron

In 1919 the US Geological Survey named the peak on Admiralty Island in his honor.  One last image, of his gravestone, offers up one more interesting fact:

Grave Marker

He also had my middle name.  Or is that the other way around?

I know of no relationship between these Barron’s and us, but it made for an interesting find nonetheless.

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Locking files for testing

Getting errors when trying to access locked files is a common situation that must be addressed by programs.  On Windows machines it’s fairly easy to replicate the scenario of a locked file using a simple technique that I picked up recently.  Simply run the following command with notepad.

notepad >> filename.txt

The file will remain locked until Notepad is closed.  No need to an additional tool or utility to apply a lock to a file.

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HTML escape characters in Azure app settings

Windows applications can make use of XML nodes in appSettings to pass configuration information into a program.  Because the app.config (or web.config) file is XML some characters need to be escaped so that they are not improperly parsed as part of the XML markup.

In a recent project I ran into a problem with the following setting:

John Doe <address@foo.com>

This represented the email address from which email was to be sent on behalf of the application.  The less than and greater than characters needed to be escaped:

John Doe &lt;address@foo.com&gt;

So now the app ran fine on my development box with the escaped characters properly converted to ‘<‘ and ‘>’ respectively.  Upload the app to an Azure web job and configure the app settings with the same value as above and this results in …..  errors.  The email program complained about invalid semi-colons.

Note that the Azure app settings values are not represented in an XML file and thus should not be HTML escaped.  Changing the Azure app setting to the original value:

John Doe <address@foo.com>

and the email code now works as expected.

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Blank lines in Jinja2 Templates

When working with the Jinja2 templating engine on Python I’ve been bugged by blank lines that got inserted into the resultant XML when an optional node was excluded from the output.  Though Jinja2 sports some support for controlling whitespace I had never happened upon an answer on how to ensure that no needless blank lines ended up in the XML output.

Given the following template:

{{ name }}
{% if age_value %}
{{ age }}
{% endif %}
{{ title }}

If age is supplied to the template then the output looks great:

John Doe
25
Software Engineer

The problem occurs when this optional value is not available. We end up with a blank line where the age node would be:

John Doe

Software Engineer

Jinja2’s templating markup provides for the use of the ‘-‘ character before or after code blocks to strip out whitespace. So modifying the template ever so slightly to look this like:

{{ name }}
{%- if age_value %}
{{ age }}
{%- endif %}
{{ title }}

results in clean output that excludes the blank line when the optional node is left out:

John Doe
Software Engineer
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TP-Link Wifi Extender Light Woes

My new TP-Link wifi extender works great at extending the range of our home wifi setup. The home office downstairs unfortunately resides in a wifi dead spot given where our AT&T wifi access point had to be located. It’s inexpensive and easy to set up.

An unexpected feature of the device was its blindingly bright “night light”.  The blue LED status indicators on the face of the unit filled a darkened room with an spooky blue glow.   My wife kept unplugging the unit from the wall at bedtime because it was bright enough to disturb her sleep.

The location chosen was ideal from a networking perspective. Moving it to another location where its light would not be troublesome was not an option.  I could find no source of information on how to dim or turn off the lights.  So what to do?

When all technical solutions fail it’s time to turn to the simple, mechanical responses. I cut out part of a business card and covered the LED’s. Success? Not really. The light was still too bright! An application of two additional business card layers taped over the light now lets us sleep in peace.  And now I can also use the computer downstairs to get nearly the same throughput as I would upstairs.

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DateTime Intervals Versus DateTimes

I had wondered why some websites displayed date intervals (i.e. “5 days ago”, “4 hours ago”) for user posts instead of printing actual dates and times. Doing some new website work recently caused a revelation about that choice and how it solves many problems all at once.

Displaying a real date and time opens up a can of worms about what to display and how to display it. Date and time is fairly trivial as long as all users of a system are located in the same place. Each user thus shares a common timezone and expectation of what a date and time should look like.

Clocks

What time is it?

Creating and maintaining a site for users across multiple timezones and borders is more problematic.  Should a date look like one of the following?

  • 12/5/2014
  • 5/12/2014
  • 2014/12/5
  • 2014-12-5
  • Dec. 5, 2014
  • On and on and on

Then there’s the problem of time.  What timezone should be stored and displayed?  The timezone of the user who submitted the content being viewed?  The timezone of the web server?  The timezone of the user viewing the content?

If you insist on displaying a proper local time to every user on your site will have to geolocate every user and then convert the stored time to their local representation.  The timezone is only part of the problem.  You also have formatting:

  • 1:45 PM
  • 13:45
  • 13:45:05

Using date intervals solves all of these problems.  All dates stored in the database are in UTC.  All displayed date and time references are expressed as the amount of time that has elapsed since that time.  It’s a simple date diff calculation between the current UTC time and the UTC time stored in the database.

The exact same display is shown to all users, anywhere on the planet.  No user or locale-specific computation must be done.

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Code First Foreign Keys With Different Names

The Entity Framework’s Code First scheme is handy way to do quick development of new websites. I recently had an issue with a foreign key relationship between a table I created and the ASP.Net Identity user table AspNetUsers. Typically, EF intelligently maps foreign key columns back to their parent key names. For example:

public class First
{
    [Key]
    public int FirstID;
    public int SecondID;

    // ...

    public virtual Second second { get; set; }
}

public class Second
{
    [Key]
    public int SecondID;
}

will properly result in a database schema where a foreign key relationship is set up between First and Second with SecondID as the foreign key field.

ASP.Net Identity presents a problem in that the primary key for the AspNetUser table is simply “Id”. I didn’t want a foreign key in my table simply called “Id” because this would not be very descriptive when looking at the code later. What happens when you don’t include a foreign key column but do add the reference to the code? Here’s the code:

    public class First
    {
        [Key]
        public int FirstID {get; set; }
        // I'd like this to be the foreign key to the AspNetUser table.
        public string UserID {get; set; }

        public virtual ApplicationUser AspNetUser { get; set; }
    }

And here’s a part of the resulting SQL database schema:

CREATE TABLE [dbo].[Firsts](
    [FirstID] [INT] IDENTITY(1,1) NOT NULL,
    [SecondID] [INT] NOT NULL,
        // Points TO nothing.
    [UserID] [nvarchar](MAX) NOT NULL,
        // FOREIGN KEY TO USER TABLE.
    [AspNetUser_Id] [nvarchar](128) NULL
...

Note that EF does create a foreign key as is necessary, but it prefixes the “Id” name with the table name, in this case “AspNetUsers_Id”. It’s nice that it works, but that’s not the name I wanted to use as the foreign key. There had to be some way to employ a foreign key whose name was not the same as the primary key. A Google search showed a couple of examples on how to do this. Unfortunately, many suggested using the EF fluent interface to update the entity context at create time. The code in some cases looked extremely hard to follow.

Eventually I stumbled upon a much simpler solution. By simply adding the ForeignKey attribute to the foreign key declaration EF will be able to properly associate the foreign and primary keys even if their names are not the same. All that’s required is that you spell out the table which the key references:

[Required, ForeignKey("AspNetUser")]
public string UserID { get; set; }

With this simple one line fix I was able to use the foreign key column name that I thought was easier to read, UserID.

ALTER TABLE [dbo].[Firsts] WITH CHECK
    ADD CONSTRAINT [FK_dbo.Firsts_dbo.AspNetUsers_UserID]
    FOREIGN KEY([UserID])
REFERENCES [dbo].[AspNetUsers] ([Id])
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The Move

It’s been a while now, but Penny and I are officially Californians now. About a month ago we made the move from Austin, TX to Oakland, CA. The reasons for the move are really quite complex and drawn out – a boring story really. Certainly we had never expected to leave Texas right up until summer of last year when wheels were set into motion. Things took on a life of their own and here we are.

We’re settling in to the way things are here fairly well but things are still new enough to us that we can’t help but compare them to the “normal” way of doing things in Texas. The cats are mostly used to the new surroundings though Gigi does not like the smaller living area since that means closer proximity to the other cats. Our two day driving adventure with the cats in the back of our two cars actually went very well. Much better than expected.

One thing that we really like about Norther California is the abundance of hiking opportunities. We’ve started to hit the trails in the area and have been documenting some of them on Hiking Trailhead.

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Migrating Code From SQL Server To MySql

After having worked exclusively with Microsoft’s SQL Server for some years now I was working on a project in which the customer wanted the data to be stored in their database of choice, MySql. My first thought was to utilize the ODBC client code in the .Net framework instead of my familiar SQL Client components. That should mean a drop in placement with just a few name changes.

My fears were raised a bit when I saw that the MySql folks had their own .Net libraries (referred to as connectors). Worse, when I tried to download just those libraries I was coaxed into creating an Oracle login account and download either a full suite of MySql products or all of the client libraries and tools. Not wanting another server on my laptop I went with the smaller, client only, option.

In a word my experience with the MySql client code has been wonderful. Here are the steps needed to take a simple program that’s working against SQL Server and get it up and running with a MySql database.

  1. Add a reference to the MySql.Data.dll library in your project.
  2. Add a using statement referring to “MySql.Data.MySqlClient” in your source file.
  3. Replace the SQL Server data commands with their MySql equivalents.

Here’s a snippet of code that was written for SQL Server:

using (SqlConnection conn = new SqlConnection(ConnectionString))
{
    conn.Open();
    using (SqlCommand cmd = new SqlCommand(sqlCommand, conn))
    {
        cmd.Parameters.AddWithValue("@param1", Param1);
        using (SqlDataReader reader = cmd.ExecuteReader())
        {
...

And now in MySql it looks like:

using (MySqlConnection conn = new MySqlConnection(ConnectionString))
{
    conn.Open();
    using (MySqlCommand cmd = new MySqlCommand(sqlCommand, conn))
    {
        cmd.Parameters.AddWithValue("@param1", Param1);
        using (MySqlDataReader reader = cmd.ExecuteReader())
        {
...

That’s it! The code flow is exactly the same. Since the MySql libraries inherit from the same base .Net framework classes and interfaces it’s an effective drop in replacement for SQL Server.

Of course, SQL Server and MySql do not share the same quirks when it comes to SQL standards. Anything other than the simplest queries will have to be modified to function properly.

Amongst the tools installed with the libraries was MySql Workbench. I figured that my web provider’s web based tools for database creation and management would suffice. And they probably would have for my limited requirements. However, once I started up Workbench I quickly set aside my intention of doing the database management via the simpler web tools.

MySQL_Workbench

MySql Workbench is a very functional MySql-based replacement for everything that I’ve used SQL Server Management Studio to do with SQL Server. Though the feel and flow of operations is a bit different it’s not too terribly hard to get used to. Plus all of the functionality that you want from such as tool from schema development to adhoc query tuning is there.

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Skipping Unit tests In MSTest

When creating a large number of test cases for a project there may be a number of cases that don’t apply for some particular scenario or platform. I didn’t want to mark a non-applicable test case as having passed just because it did not apply to the relevant platform and I certainly didn’t want to mark the test as having failed.

The meager MSTest documentation didn’t provide anything obvious that allowed me to ignore certain tests under some conditions. A quick Google search did turn up a simple solution though that worked perfectly. The Assert command can be used to mark the test as being not applicable.

if (!Helper.bSupportsDynamicTickets)
{
    Assert.Inconclusive("Not supported on this platform.");
    return;
}

Now, when the test is not pertinent it’s included in the TestExplorer’s “Skipped Tests” node.

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