Add a user ID paramter to services/caches/map/tile to query other users' maps

[following5]

In OCPL code there is the feature to view another user's map. This feature is used to plan common geocaching trips (see opencaching/opencaching-pl#1169).

To accomplish this, OCPL code makes the user who views the map prentend to be someone else. Wrygiel wrote in issue #439:

So, whenever Facade::service_call is called with non-null user_id, OKAPI assumes that it is this user_id who called it. However, in case of OCPL's feature of "peeking at other user's map", this is not true.

So, I believe we have two problems here:

• OCPL doesn't properly state that it is not the user who is making this call.
• OKAPI doesn't allow OCPL to state the above.

This may be solved by adding a User ID to services/caches/map/tile. Then it must be determined which data of this user may be accessed by another user and which shall not be published (e.g. the information about what caches are ignored).

[following5]

This is a good lot of work, but it's important. Faking user identities is not safe. Privacy leaks can be introduced easily.

First we need to clarify the ignore thing.

@kojoty @harrieklomp @andrixnet: Do you want that the "cache is ignored" information stays public? Currently everyone can find out what caches any user ignores, by showing the other user's map.

[kojoty]

hmm.. I'm not sure if we need to treat ignores as something private - I just ignore caches which I don't want to search to clean up the map - there is anything private in it - for me...

Anyway noone ask for hide this.

My opinion is to stay with it as is. If anyone will request such change we can come back to this discussion.

[following5]

My opinion is to stay with it as is. If anyone will request such change we can come back to this discussion.

That sounds to me like a good and easy solution to start with. I was thinking too complicated.