Add readFile method to Filesystem component

[manie20]

Apologies if this PullRequest should not be submitted like this.
I'm rather new to GitHub.

I would love to see read file integration since this is a crucial part of the filesystem.
Is there a reason for this not begin implemented in the component?

(e.g. should I include my own fork)

[fabpot]

This addition has already been rejected in the past. The reason is that the Filesystem class abstract "complex" operations, it's not an abstraction for a filesystem.

[jrjohnson]

@fabpot I'm not clear on exactly what you are saying here - is it that reading a file is an easy operation and therefor doesn't need to be handed by this class? I can agree with that - but I would still very much like to see a read file option here for because it means that if I depend on the filesystem service I can mock it in tests including reading a file. Otherwise I have to jump through the hoop of creating a class which extends filesystem and provides only this one additional method.

If there is any chance of including a read method I would be happy to bring this PR up to date and add some tests.

[TomasVotruba]

Is this still a mental blocker?

I have to use 2 classes in my filesystem operations, just because this method is missing.

Which doesn't make sense, as RUD part of CRUD is already there.

[tacman]

What is the proper way to read a file? The file_get_contents function seems low-level. Since the dumpFile() method exists, it seems natural that there would be a reverse command.