Class: CouchPotato::Database

Inherits:
Object
  • Object
show all
Defined in:
lib/couch_potato/database.rb

Defined Under Namespace

Classes: ValidationsFailedError

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(couchrest_database, name: nil) ⇒ Database

Returns a new instance of Database.



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# File 'lib/couch_potato/database.rb', line 13

def initialize(couchrest_database, name: nil)
  @name = name
  @couchrest_database = couchrest_database
end

Instance Attribute Details

#cache ⇒ Object

Pass in a cache to enable caching #load calls. A cache needs to respond to #[], #[]= and #clear (just use a Hash).



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# File 'lib/couch_potato/database.rb', line 8

def cache
  @cache
end

#couchrest_database ⇒ Object (readonly)

returns the underlying CouchRest::Database instance



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# File 'lib/couch_potato/database.rb', line 177

def couchrest_database
  @couchrest_database
end

#name ⇒ Object (readonly)

the (unresolved) name of the database unless this is the default database



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# File 'lib/couch_potato/database.rb', line 11

def name
  @name
end

Instance Method Details

#destroy_document(document) ⇒ Object Also known as: destroy 



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# File 'lib/couch_potato/database.rb', line 130

def destroy_document(document)
  cache&.clear
  begin
    destroy_document_without_conflict_handling document
  rescue CouchRest::Conflict
    retry if document = document.reload
  end
end

#first(spec) ⇒ Object

returns the first result from a #view query or nil



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# File 'lib/couch_potato/database.rb', line 95

def first(spec)
  spec.view_parameters = spec.view_parameters.merge({ limit: 1 })
  view(spec).first
end

#first!(spec) ⇒ Object

returns th first result from a #view or raises CouchPotato::NotFound



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# File 'lib/couch_potato/database.rb', line 101

def first!(spec)
  first(spec) || raise(CouchPotato::NotFound)
end

#inspect ⇒ Object

:nodoc:



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# File 'lib/couch_potato/database.rb', line 172

def inspect #:nodoc:
  "#<CouchPotato::Database @root=\"#{couchrest_database.root}\">"
end

#load!(id) ⇒ Object

loads one or more documents by its id(s) behaves like #load except it raises a CouchPotato::NotFound if any of the documents could not be found

Raises:



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# File 'lib/couch_potato/database.rb', line 164

def load!(id)
  doc = load(id)
  missing_docs = id - doc.map(&:id) if id.is_a?(Array)
  raise(CouchPotato::NotFound, missing_docs.try(:join, ', ')) if doc.nil? || missing_docs.try(:any?)

  doc
end

#load_document(id) ⇒ Object Also known as: load

loads a document by its id(s) id - either a single id or an array of ids returns either a single document or an array of documents (if an array of ids was passed). returns nil if the single document could not be found. when passing an array and some documents could not be found these are omitted from the returned array



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# File 'lib/couch_potato/database.rb', line 145

def load_document(id)
  cached = cache && id.is_a?(String) && cache[id]
  if cache
    if cached
      ActiveSupport::Notifications.instrument('couch_potato.load.cached') do
        cached
      end
    else
      cache[id] = load_document_without_caching(id)
      cache[id]
    end
  else
    load_document_without_caching(id)
  end
end

#save_document(document, validate = true, retries = 0, &block) ⇒ Object Also known as: save

saves a document. returns true on success, false on failure. if passed a block will:

  • yield the object to be saved to the block and run if once before saving

  • on conflict: reload the document, run the block again and retry saving



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# File 'lib/couch_potato/database.rb', line 109

def save_document(document, validate = true, retries = 0, &block)
  cache&.clear
  begin
    block&.call document
    save_document_without_conflict_handling(document, validate)
  rescue CouchRest::Conflict
    if block
      handle_write_conflict document, validate, retries, &block
    else
      raise CouchPotato::Conflict
    end
  end
end

#save_document!(document) ⇒ Object Also known as: save!

saves a document, raises a CouchPotato::Database::ValidationsFailedError on failure



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# File 'lib/couch_potato/database.rb', line 125

def save_document!(document)
  save_document(document) || raise(ValidationsFailedError, document.errors.full_messages)
end

#switch_to(database_name) ⇒ Object

returns a new database instance connected to the CouchDB database with the given name. the name is passed through the additional_databases configuration to resolve it to a database configured there. if the current database has a cache, the new database will receive a cleared copy of it.



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# File 'lib/couch_potato/database.rb', line 185

def switch_to(database_name)
  resolved_database_name = CouchPotato.resolve_database_name(database_name)
  self
    .class
    .new(CouchPotato.couchrest_database_for_name(resolved_database_name), name: database_name)
    .tap(&copy_clear_cache_proc)
end

#switch_to_default ⇒ Object

returns a new database instance connected to the default CouchDB database. if the current database has a cache, the new database will receive a cleared copy of it.



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# File 'lib/couch_potato/database.rb', line 196

def switch_to_default
  self
    .class
    .new(CouchPotato.couchrest_database)
    .tap(&copy_clear_cache_proc)
end

#view(spec) ⇒ Object

executes a view and return the results. you pass in a view spec which is usually a result of a SomePersistentClass.some_view call.

Example:

class User
  include CouchPotato::Persistence
  property :age
  view :all, key: :age
end
db = CouchPotato.database

db.view(User.all) # => [user1, user2]

You can pass the usual parameters you can pass to a couchdb view to the view:

db.view(User.all(limit: 5, startkey: 2, reduce: false))

For your convenience when passing a hash with only a key parameter you can just pass in the value

db.view(User.all(key: 1)) == db.view(User.all(1))

Instead of passing a startkey and endkey you can pass in a key with a range:

db.view(User.all(key: 1..20)) == db.view(startkey: 1, endkey: 20) == db.view(User.all(1..20))

You can also pass in multiple keys:

db.view(User.all(keys: [1, 2, 3]))



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# File 'lib/couch_potato/database.rb', line 47

def view(spec)
  id = view_cache_id(spec)
  cached = cache && id.is_a?(String) && cache[id]
  if cache
    if cached
      ActiveSupport::Notifications.instrument('couch_potato.view.cached') do
        cached
      end
    else
      cache[id] = view_without_caching(spec)
      cache[id]
    end
  else
    view_without_caching(spec)
  end
end

#view_in_batches(spec, batch_size: default_batch_size) ⇒ Object

Same as #view but instead of returning the results, it yields them to a given block in batches of the given size, making multiple requests with according skip/limit params sent to CouchDB.



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# File 'lib/couch_potato/database.rb', line 67

def view_in_batches(spec, batch_size: default_batch_size)
  rows = nil
  batch = 0
  loop do
    spec.view_parameters = spec
      .view_parameters
      .merge({limit: batch_size})
      .merge(
        if rows
          {
            startkey: rows&.last&.dig('key'),
            startkey_docid: rows&.last&.dig('id'),
            skip: 1
          }
        else
          {}
        end
      )
    result = raw_view(spec)
    rows = result['rows']
    yield process_view_results(result, spec)
    break if rows.size < batch_size

    batch += 1
  end
end