[ZEPPELIN-957] Normalize note name.

[astroshim]

What is this PR for?

It's better if notebook name can be normalized.

What type of PR is it?

Improvement

What is the Jira issue?

https://issues.apache.org/jira/browse/ZEPPELIN-957

How should this be tested?

Try create notebook name with many slashes and no slashes.
You can refer to screen shot.

Screenshots (if appropriate)

• before
  
• after
  

Questions:

• Does the licenses files need update? no
• Is there breaking changes for older versions? no
• Does this needs documentation? no

[cloverhearts]

LGTM

[felixcheung]

does this change windows path like mynotebooks\notebook1?

[astroshim]

Yes, That line change for the windows path to '/'.

[corneadoug]

Tested

Merging if there is no more discussions

[felixcheung]

should this check for both / and \ then for windows?
https://github.com/apache/zeppelin/pull/965/files#diff-bcbdda87aa29314ed459e8212067e313R528

[astroshim]

@felixcheung Thank you for pointing out that i missed. I just fixed it.

[Leemoonsoo]

Is normalization applied on note name change?

[Leemoonsoo]

Thanks @astroshim for the improvement. I've tested and although it's working well, i think there're little more things we can think

1. Normalization is not applied when change note name.
2. Normalization routine need to be placed in zeppelin-zengine, rather than zeppelin-server
   zeppelin-server is place for the code that enables front-end / back-end communication.
   business logic handles notebook should be in zeppelin-zengine module.
3. It would be great to have a unittest for normalize note name
4. Note name display is bit inconsistent.

with this branch

Given name when create note	note name displayed on screen
MyNote	MyNote
/MyNote	/MyNote
MyNote/sub	/MyNote/sub
/MyNote/sub	/MyNote/sub

but i think it should be like

Given name when create note	note name displayed on screen
MyNote	MyNote
/MyNote	/MyNote
MyNote/sub	MyNote/sub
/MyNote/sub	/MyNote/sub

[astroshim]

I really appreciate your detailed review. @Leemoonsoo
I will fix 1,2,3 but in case 4,
I thought /MyNote/sub and MyNote/sub are the same from directory point of view.
Do you think they should be treated differently?

[Leemoonsoo]

@astroshim Thanks!
MyNote and /MyNote are treated differently. And i think it's right. (compatible to previous version)
Therefore I think it's more consistent to treat differently MyNote/sub and /MyNote/sub, too.

[astroshim]

@Leemoonsoo Thank you for kindly explaination. I understand about name.

[astroshim]

@Leemoonsoo I fixed 1,2,3,4. please review.

[Leemoonsoo]

Thanks for quick response. LGTM

[Leemoonsoo]

Merge it into master if there're no more discussions