Day: May 14, 2013

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Google Drive: Creating a folder

Today I answered a question about how to create a folder in Google Drive . The answer is simple: Google Drive considers a folder to be simply another file, so to create a folder you use the same API call as creating a file, except that you pass in a MIME type of application/vnd.google-apps.folder.

It’s a pretty straightforward answer, but it started me thinking about the nature of folders and Google. It’s interesting that Google Drive supports folders at all, considering that another famous Google service – Gmail – doesn’t support folders at all. Instead, it has labels.

In Gmail, you can create as many labels as you want, and apply any number of them to an email. Labels are similar to folders: they enable users to categorize and easily search for files – the only thing missing is the hierarchical pattern that folders enable. Which leads me back to Google Drive: I wonder how folders are internally represented within the Google Drive system. Based on the API, it looks like folders are considered a special case of files.

But if Drive can handle folders as simply a special file, why doesn’t Gmail support folders as well? Is it simply that Gmail and Drive are separate codebases, or that Google feels that labels are a better categorizing scheme than folders?

It’s always interesting to think about Google’s architecture and how different services have vastly different builds and APIs.

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Golang Error: not enough arguments to return

One of the strengths of Go is the ability to return multiple values from a function. As a long-time Java programmer I’ve envied languages with muttiple returns for a long time. Here’s a quick summary of the feature:

Quick example: to return multiple values, use the classic return statement:

 return value1, value2

And to get those return values from a function, you can write:

 var1, var2 := someMultipleReturnFunction()

The great thing about this system is that you can ignore a return value if you don’t need it. For example, if you need to skip the first return value:

 _, var2 := someMultipleReturnFunction()

Which brings me to the original reason for this blog post. I was writing a Go application, when a build failed due to the error not enough arguments to return. The problem was that I had multiple return statements within a function, and one of the statements declared only one return value, instead of the two return values that the function declared.

The easy fix? Simply declare nil to pad out the “missing” return value. So the return statement became:

 return var1, nil

Easy, quick, and painless.