Large Files

So, what are "large files" anyway?

You're probably already familiar with small structured data; the stuff that's usually stored in a relational database like Postgres or MySQL. I'm talking about simple, primitive data types like:

user_id (integer)
is_active (boolean)
email (string)

Large files, or "large assets", on the other hand, are giant blobs of data encoded in a specific file format and measured in kilo, mega, or gigabytes. As a simple rule:

If it makes sense to go into an excel spreadsheet, it probably belongs in a traditional database
If it would normally be stored on your hard drive as its own file, it probably is a "large file"

Large files are interesting because:

They're large in size (duh) and are thus more performance-sensitive
They're usually accessed frequently, and this combined with their size can quickly lead to performance bottlenecks

Assignment

In the root of your repo there is a script called samplesdownload.sh. Run it from the root of the repo to download some sample images and videos into the samples directory:

./samplesdownload.sh

Note that this will download about 60MB of sample files, so depending on your internet connection it might take a second.

Take a look at the boots-image-horizontal.png file in the samples directory: it's a PNG image file. You can open it in an image viewer to see what it looks like.
Use xxd to view a hexdump of the samples/boots-image-horizontal.png file:

xxd <file>

xxd converts the binary content of the file into a human-readable hexadecimal and ASCII formats. You should see a bunch of gobbledegook - that's what a PNG file looks like in its raw form.

Inspect the first 8 bytes of the file more closely. Use xxd with -l (length) to limit the output:

xxd -l 8 <file>

You'll see that the first 8 bytes are 89 50 4e 47 0d 0a 1a 0a, which is the PNG file signature. It tells the reader that this is a PNG file, in fact, the characters PNG are present in bytes 2-4.

Run and submit the CLI tests.

The Boot.dev CLI requires you to be signed in to submit your solution!

Copy/paste one of the following commands into your terminal:

Run

bootdev run a1b6ba47-d5e4-493e-a2cf-114270d4e7b1

Submit

bootdev run a1b6ba47-d5e4-493e-a2cf-114270d4e7b1 -s

Run the CLI commands to test your solution.

ls samples
- Expecting exit code: 0
- Expecting stdout to contain all of:
  - boots-image-horizontal.png
  - boots-image-vertical.png
  - boots-video-horizontal.mp4
  - boots-video-vertical.mp4
  - is-bootdev-for-you.pdf

Using the Bootdev CLI

The Bootdev CLI is the only way to submit your solution for this type of lesson. We need to be able to run commands in your environment to verify your solution.

You can install it here. It's a Go program hosted on GitHub, so you'll need Go installed as well. Instructions are on the GitHub page.