Add auto-url-generation

[brototyp]

Proposal:

• Add a new property contentBaseUrl to the PiwikTracker
• If this property is set, every event that has no url set will generate one by its own
• To generate a url, it will use the contentBaseUrl and append the action-array as path

Example:

• contentBaseUrl is https://piwik.org
• actions is ["docs", "requirements"]
• the url will be https://piwik.org/docs/requirements

[brototyp]

After a bit debugging I figured that though the url is an optional in the API, it is basically non-optional for page views, since most features rely on the url instead of the actions (which I thought).

What does the user loose without the url for page views:

• The Visitor Log lacks the list of pages
• Actions -> Pages lack the list of pages
• Actions -> Entry pages and Exit pages are empty

Because of that, I think the contentBaseUrl should not be nil per default, but rather http://<app-id> per default and still be overridable for custom urls.

I am not sure if we should use this method only for page-views or for all Events, so for actions as well.

[thbaja]

I think we should use it for all events. Currently I'm wrapping the piwik call in order to always set the url, both for page-views and actions. This makes it easier to compare web and app behaviour as well as monitor total usage.

[brototyp]

Sounds like a great plan. So like this?

• contentBaseUrl is per default derived from the App id
• If one doesn't want to auto-create any url, it is possible to set the contentBaseUrl to nil
• If one want to define the url on a per Event level, it overrides automatic created urls

[thbaja]

Sounds good. That way we give sufficient flexibility to handle all the use-cases I can think of (off the top of my head) .

[brototyp]

I just checked the Android sdk on how the contentBase is generated there and copied it see.

I just created a PR on this issue.

[brototyp]

Just released version 4.4.0 containing this feature.