MediaResource filters

Implementation

Each of the 3 types of media resources, namely MediaEntry, Collection and FilterSet implements a class method filter_by. This method defines its own SQL generation logic and behaves as any other ActiveRecord scope method, and thus it's also chainable.

Full usage example

{
  "search": "something",
  "meta_data": [
    { "key": "madek_core:authors",
      "value": "6e4da213-2f4d-41a6-9eb0-c961d74f717e" },
    { "key": "media_content:type",
      "match": "architektur" },
    { "key": "any",
      "match": "india",
      "type": "MetaDatum::Text" },
    { "key": "any",
      "match": "china" },
    { "key": "madek_core:keywords" },
    { "not_key": "media_object:patron" }
  ],
  "media_files": [
    { "key": "content_type", "value": "image/jpeg" },
    { "key": "extension", "value": "jpg" }
  ],
  "permissions": [
    { "key": "public",
      "value": true },
    { "key": "responsible_user",
      "value": "8631ffff-f601-451e-bce7-f3696d18addf" },
    { "key": "entrusted_to_user",
      "value": "f3d3174c-11b2-43e3-80dc-5925665c5a37" },
    { "key": "entrusted_to_group",
      "value": "30a6baf1-010f-444a-87f0-dc78be983014" }
  ]
}

MediaEntry.filter_by({…})

Filter attributes/keys

There are different "types" of attributes resources can be filtered by.
All of these are combined together using logical AND.

• meta_data
• media_files
• permissions
• search

meta_data filter

{
  "meta_data": [
    { "key": "madek_core:authors",
      "value": "6e4da213-2f4d-41a6-9eb0-c961d74f717e" },
    { "key": "media_content:type",
      "match": "architektur" },
    { "key": "any",
      "match": "india",
      "type": "MetaDatum::Text" },
    { "key": "any",
      "match": "china" },
    { "key": "madek_core:keywords" },
    { "not_key": "media_object:patron" }
  ]
}

There are 5 usage options:

1. for a specific key use an uuid as the value in case of a concrete related resource
2. for a specific key use an arbitrary string via match to match in the respective DB column, depending on the type of the related resource, e.g. people.searchable or keywords.term, etc.
3. use any as key with an arbitrary string via match to trigger a text-based match for any meta datum of a specific type
4. use any as key with an arbitrary string via match to trigger a text-based match across all meta data
5. use key without value or match to filter media resources, which have some meta datum for a specific meta_key_id
6. use not_key without value or match to exclude media resources, which don't have any meta datum for a specific meta_key_id

All the filter options inside meta_data are combined using the logical AND.

String matching via match is case-insensitive.

media_files filter

{
  "media_files": [
    { "key": "content_type", "value": "image/jpeg" },
    { "key": "extension", "value": "any" }
  ]
}

There are 2 usage options:

1. use an arbitrary string via value for a specific media_file attribute key. The value is matched exactly. The media file attributes basically correspond to the columns of the media_files table in DB.
2. use any as value of value to match anything inside a column.

All the filter options inside media_files are combined using the logical AND.

permissions filter

{
  "permissions": [
    { "key": "public",
      "value": true },
    { "key": "responsible_user",
      "value": "8631ffff-f601-451e-bce7-f3696d18addf" },
    { "key": "entrusted_to_user",
      "value": "f3d3174c-11b2-43e3-80dc-5925665c5a37" },
    { "key": "entrusted_to_group",
      "value": "30a6baf1-010f-444a-87f0-dc78be983014" }
  ]
}

There are 4 usage options:

1. use an uuid as value for key = responsible_user
2. use an uuid as value for key = entrusted_to_user
3. use an uuid as value for key = entrusted_to_group
4. use true/false as value for public

All the filter options inside permissions are combined using the logical AND.

search filter

{
  "search": "THE_SEARCH_STRING"
}

The 'search' filter allows a single string which allow a case-insensitive search over all MetaData.

It is internally handled like a meta_data filter that matches on any key, so the above example is equivalent to this:

{
  "meta_data": [{ "key": "any", "match": "THE_SEARCH_STRING" }]
}