Archive for July, 2018

MegaSceneryEarth automated HTTP download PowerShell script

July 30th, 2018

Regulars: Thank you for stopping by but just as a heads up, this post is not VMware virtualization related.

After a bit of hardware trouble from the local store, my replacement flight sim rig is up and running Lockheed Martin Prepar3D 4.3. I’m trying to shake the rust off after not having flown a leg for quite some time but everything sim and add-on related is looking good and I was able to fly KMSP-KLAX with many more FPS that I’ve been used to the past many years on FSX.

Now, out of sheer coincidence late last week I received a promotion from MegaSceneryEarth. Normally I ignore these but since this was a 50% off deal and I’m essentially starting from ground zero with no scenery for Prepar3D, I took a look. After some chin scratching, I checked out with Minnesota, Arizona, Northern California, and Southern California. I felt like quite the opportunist until the email arrived with file download instructions. Each scenery is broken up into 2GB download chunks. Between the four sceneries, I was presented with 123 download links. With no FTP option that I’m aware of, I’m going to have to babysit this process. With each 2GB download taking anywhere from 5-10 minutes, this is going to feel a lot like installing Microsoft Office 2016 via floppy disk. Except longer. MegaSceneryEarth is available on shipped DVDs or USB sticks they cost a small fortune and of course the shipping and handling time. This is going to be painful.

But… there’s a cheaper, faster, and fully automated way. PowerShell scripting.

Now admittedly for my first scenery, I threw the v1.0 PowerShell script version together quickly using the Invoke-WebRequest cmdlet with my own static scenery-specific lines of code to serve my own needs. And it worked. I launched the script, walked away for a few hours, and when I came back I had a directory full of MegaSceneryEarth .zip files ready for installation. It worked beautifully and it didn’t consume bunches of my time.

I still had three sceneries left to download. While I could have made new static scripts for the remaining three sceneries, my mind was already going down the road that this script would be more powerful if one script worked on a variety of MegaSceneryEarth downloads. It becomes flexible to use for my future MegaSceneryEarth sceneries as well as extensible if shared with the community.

So on Sunday, version 2.0 is what I came up with. It takes three inputs in the form of modifying variables at the beginning of the script before running it:

  1. The download URL for the first file of the scenery
  2. The path on the local hard drive where all of the .zip files should be downloaded to
  3. The starting point or first file to download. Usually this will be 1 but if for some reason a previous download was stopped or interrupted at say 6, we’d want to continue from there assuming we don’t want to re-download the first 5 files all over again.

The script does the rest of the heavy lifting. All three of the above are required for functionality but by far the first variable is the most important and where I spent almost all of my time making the script flexible so that it works across MegaSceneryEarth sceneries. When provided with the download URL of the first file of the scenery, the script does a bunch of parsing, splitting, and concatenation of stuff to automatically determine some things:

  1. It figures out what the base path and file name URL is for the scenery. For any given scenery, these parts never change across all of the download links within a scenery but they will change across sceneries.
  2. It figures out how many .zip files there are to download in total for the entire scenery.
  3. Because MegaSceneryEarth likes to use leading zeroes as part of their naming convention, and leading zero strings aren’t the same thing as leading zero integers in terms of PowerShell constructs, it figures out how to deal with those for file names and looping iterations. Basically when you go from “009” files in a scenery download to “010”, without dealing with that, stuff breaks. I think most MegaSceneryEarth sceneries have more than 9 files, but some have less (Deleware has 1). The script deals with both kinds. That I know of, MegaSceneryEarth doesn’t have a scenery with more than 99 .zip files but version 2.1 of the script will accommodate that.
  4. It figures out the correct file name to save on the local hard drive for each scenery file downloaded. This may sound stupid but that I know of, the Invoke-WebRequest cmdlet requires the output file name and doesn’t automatically assume the file name should be the same as the file name being downloaded via HTTP such as a copy command to a folder would.

Generally speaking, for automation to work properly, it relies on input consistency so that all assumptions it makes are 100% correct. Translated, this script relies on consistent file/path naming conventions used by MegaSceneryEarth. Not only within sceneries, but across sceneries as well.

And so here it is. Copy the PowerShell script below and execute in your favorite PowerShell environment. Most of the time I simply use Windows PowerShell ISE. The code isn’t signed so you may need to temporarily relax your PowerShell ExecutionPolicy to Bypass . It’s there to protect you by default.

######################################################################################################################
# MegaSceneryEarth.ps1 version 2.1 7/31/18
#
# This PowerShell script automates unattended HTTP download of up to 999 MegaSceneryEarth scenery files
# Relies on MegaSceneryEarth naming conventions current as of version date above
# Tested successfully with four MegaSceneryEarth downloads
# As with anything on the internet, use at your own risk, no warranty provided by the author
#
# Update the three variables below as necessary for your specific scenery and download parameters
#
# Jason Boche
# http://boche.net
# jason@boche.net
######################################################################################################################

# Provide the first file download link copied from the MegaSceneryEarth .htm link provided with license key email
# Internet Explorer: Right click the download link and choose "Copy shortcut"
# Google Chrome: Right click the download link and choose "Copy link address"
# Then paste the link between the quotation marks

$firstfile1 = "paste first file download link here.zip"

# Provide the path on your hard drive where the files will temporarily be saved.
# This will usually be where you have the MegaSceneryEarthInstallManager.exe file for subsequent installation
# Syntax requires a trailing backslash (\)

$dlpath = "D:\junk\"

# Provide the starting file count. Usually we start with 1 unless you're starting the download somewhere after 1

$startcount = 1

# Do not edit anything below this line

######################################################################################################################

# Get the HTTP path
$firstfile2 = split-path $firstfile1
$firstfile3 = $firstfile2.Replace("\","/")
$httppath = $firstfile3 + "/"

# Get the .zip file name
$firstfile4 = split-path $firstfile1 -leaf

# Get the static part of the .zip file name
$firstfile5 = $firstfile4 -split "001_of_"
$firstfile6 = $firstfile5[0]
$fileprefix = $firstfile6

# Get the total number of scenery files in string format with and without .zip extension
$firstfile7 = $firstfile5[1] -split ".zip"
$firstfile8 = $firstfile5[1]
# Convert total number of scenery files in string format to number format
$total = [decimal]::Parse($firstfile7)

if ($startcount -gt $total)
{
Write-Host Error: Starting file specified is greater than total number of files. Please check the `$startcount variable
pause
exit
}

# If there are 1-9 scenery files, download those
if ($total -ge 1)
{
$leadingzero = "00"
while ($startcount -le $total)
{
if ($startcount -gt 9){break}
Write-Host Downloading $httppath$fileprefix$leadingzero$startcount"_of_"$firstfile8 to $dlpath$fileprefix$leadingzero$startcount"_of_"$firstfile8

Invoke-WebRequest -Uri $httppath$fileprefix$leadingzero$startcount"_of_"$firstfile8 -OutFile $dlpath$fileprefix$leadingzero$startcount"_of_"$firstfile8

$startcount ++

}
}

# If there are 10-99 scenery files, download those also
if ($total -ge 10)
{
$leadingzero = "0"
while ($startcount -le $total)
{
if ($startcount -gt 99){break}
Write-Host Downloading $httppath$fileprefix$leadingzero$startcount"_of_"$firstfile8 to $dlpath$fileprefix$leadingzero$startcount"_of_"$firstfile8

Invoke-WebRequest -Uri $httppath$fileprefix$leadingzero$startcount"_of_"$firstfile8 -OutFile $dlpath$fileprefix$leadingzero$startcount"_of_"$firstfile8

$startcount ++

}
}

# If there are 100-999 scenery files, download those also
if ($total -ge 100)
{
$leadingzero = ""
while ($startcount -le $total)
{
if ($startcount -gt 999){break}
Write-Host Downloading $httppath$fileprefix$leadingzero$startcount"_of_"$firstfile8 to $dlpath$fileprefix$leadingzero$startcount"_of_"$firstfile8

Invoke-WebRequest -Uri $httppath$fileprefix$leadingzero$startcount"_of_"$firstfile8 -OutFile $dlpath$fileprefix$leadingzero$startcount"_of_"$firstfile8

$startcount ++

}
}