enh(Sharing): backend infrastructre for read-only link shares

[blizzz]

contributes to #67

• modifies oc_tables_share structure with two columns, token and password
• adds ShareOCSController with a route to create link shares
• adds a PageController front route to display the link share
• adds a ApiPublicColumnsController to retrieve columns for public
  links. It was not added to the existing ApiColumnsController, as it
  requires the userId of the logged-in user and I did not want to weaken
  this detail.
• adds an abstract controller for columns with shared functionality and
  make ApiColumnsController extend it.
• adds a PublicRowOCSController for retrieving rows through link shares
• adds a ShareToken value object
• adds a ShareControlMiddleware for share token and existance
  validation. It comes with the AssertShareToken attribute.
• extends Share entity with ShareToken and Password properties
• extends ShareMapper to find a share by the share token
• extends ShareService with a method to easily create link shares
• extends ResponseDefinitions with TablesPublicRow and
  TablesPublicColumn specs. Essentially tableIDs are not exposed and
  also user ids in lastEditBy and createdBy are not disclosed.
• extends RowService and ColumnService with methods to return such ^
  formatted result arrays.
• extends OpenAPI spec

Curl examples for added API endpoints

Create a share link without password

curl -u user:secret -X POST https://cloud.example.com/ocs/v2.php/apps/tables/api/2/tables/${TABLE_ID}/share -H "OCS-APIRequest: true"

fetch column information

curl -i https://cloud.example.com/ocs/v2.php/apps/tables/api/2/public/${SHARE_TOKEN}/columns -H "OCS-APIRequest: true"

fetch all rows

curl -i https://cloud.example.com/ocs/v2.php/apps/tables/api/2/public/${SHARE_TOKEN}/rows -H "OCS-APIRequest: true"

[enjeck]

we don't seem to have a way to get the title and description of the table/view given the token?

[blizzz]

we don't seem to have a way to get the title and description of the table/view given the token?

Indeed, those details… requires another public controller. No biggy. It would return either TablesView or TablesTable. They look similar, but can be kept apart by checking whether an tableId key is present. But since some information should be withdrawn, we need a new response definition anyways and can add a "nodeType" as well.

[enjeck]

cool