Feature: add --find-port parameter

[harttle]

Find a free port when the port given by -p is not available. Solves #363

[ahmetb]

I think this should be implemented as -p 0 flag. See #386.

[BigBlueHat]

@harttle would you have time/interest in writing some tests for this new feature? The code looks good, and the use case you expressed in #386 (comment) may not be that uncommon (i.e. wanting a port "above" a certain number). Thanks!

[harttle]

This should be sufficient, yet not complete. Since bin/http-server wasn't tested before, it's hard to do complete test for it. For instance, the stdout/stderr.

[thornjad]

Given the discussion in #386, would this feature maybe be better implemented as a --base-port which is the same as the default behavior of no --port given, but searching begins at --base-port?

My concern with the -p XXXX --find-port pattern is that the user is both specifying a port and expecting that the port may end up something other than what is specified. I think it may be more clear if an error is thrown when the port the user wants is in use. Then if the user wants to search for a port, they don't use -p and may optionally determine the base port to start at.

@BigBlueHat @harttle @ahmetb any thoughts on a --base-port approach?

[sumitparakh]

What is the status of this PR? Any possibility of implementing it ?

[harttle]

Sorry I forgot this for a white and deleted that forked repo unexpectedly, I tried and could not restore that commit which is needed to continue patching this pull request. It's confirmed by this question from stackexchange. If that's the way, we should open another PR for #386 and this should be closed. @thornjad

[sumitparakh]

Hi @harttle @thornjad . Would you mind if i try this?

[thornjad]

Closing since the fork is gone, and we have #544