Class: DataMapper::Adapters::PersevereAdapter

Inherits:
AbstractAdapter
  • Object
show all
Defined in:
lib/persevere_adapter.rb

Instance Method Summary collapse

Instance Method Details

#create(resources) ⇒ Integer

Used by DataMapper to put records into a data-store: “INSERT” in SQL-speak. It takes an array of the resources (model instances) to be saved. Resources each have a key that can be used to quickly look them up later without searching, if the adapter supports it.

Parameters:

  • resources (Array<DataMapper::Resource>) —

    The set of resources (model instances)

Returns:

  • (Integer) —

    The number of records that were actually saved into the data-store



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# File 'lib/persevere_adapter.rb', line 25

def create(resources)
  created = 0
  resources.each do |resource|
    #
    # This isn't the best solution but for an adapter, it'd be nice
    # to support objects being in *tables* instead of in one big icky
    # sort of table.
    #
    tblname = Extlib::Inflection.classify(resource.class).pluralize

    if ! @classes.include?(tblname)
      payload = {
        'id' => tblname,
        'extends' => { "$ref" => "/Class/Object" }
      }

      response = @persevere.create("/Class/", payload)
    end

    path = "/#{tblname}/"
    payload = resource.attributes
    payload.delete(:id)

    response = @persevere.create(path, payload)

    # Check the response, this needs to be more robust and raise
    # exceptions when there's a problem

    if response.code == "201"# good:
      rsrc_hash = JSON.parse(response.body)
      # Typecast attributes, DM expects them properly cast
      resource.model.properties.each do |prop|
        value = rsrc_hash[prop.field.to_s]
        if !value.nil?
          rsrc_hash[prop.field.to_s] = prop.typecast(value)
        end
      end

      resource.id = rsrc_hash["id"]

      created += 1
    else
      return false
    end
  end

  # Return the number of resources created in persevere.
  return created
end

#delete(query) ⇒ Integer

Destroys all the records matching the given query. “DELETE” in SQL.

Parameters:

  • query (DataMapper::Query) —

    The query used to locate the resources to be deleted.

Returns:

  • (Integer) —

    The number of records that were deleted.



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# File 'lib/persevere_adapter.rb', line 189

def delete(query)
  deleted = 0

  if ! query.is_a?(DataMapper::Query)
    resources = [query].flatten
  else
    resources = read_many(query)
  end

  resources.each do |resource|
    tblname = Extlib::Inflection.classify(resource.class).pluralize
    path = "/#{tblname}/#{resource.id}"

    result = @persevere.delete(path)

    if result # ok
      deleted += 1
    end
  end
  return deleted
end

#read_many(query) ⇒ DataMapper::Collection Also known as: read

Looks up a collection of records from the data-store: “SELECT” in SQL. Used by Model#all to search for a set of records; that set is in a DataMapper::Collection object.

Parameters:

  • query (DataMapper::Query) —

    The query to be used to seach for the resources

Returns:

  • (DataMapper::Collection) —

    A collection of all the resources found by the query.



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# File 'lib/persevere_adapter.rb', line 148

def read_many(query)
  resources = Array.new
  json_query = make_json_query(query)

  tblname = Extlib::Inflection.classify(query.model).pluralize
  path = "/#{tblname}/#{json_query}"

  response = @persevere.retrieve(path)

  if response.code == "200"
    results = JSON.parse(response.body)
    results.each do |rsrc_hash|
      # Typecast attributes, DM expects them properly cast
      query.model.properties.each do |prop|
        value = rsrc_hash[prop.field.to_s]
        if !value.nil?
          rsrc_hash[prop.field.to_s] = prop.typecast(value)
        end
      end
    end

    resources = query.model.load(results, query)
  else
    return false
  end

  query.filter_records(resources)
end

#read_one(query) ⇒ DataMapper::Resource

Look up a single record from the data-store. “SELECT … LIMIT 1” in SQL. Used by Model#get to find a record by its identifier(s), and Model#first to find a single record by some search query.

Parameters:

  • query (DataMapper::Query) —

    The query to be used to locate the resource.

Returns:

  • (DataMapper::Resource) —

    A Resource object representing the record that was found, or nil for no matching records.



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# File 'lib/persevere_adapter.rb', line 131

def read_one(query)
  results = read_many(query)
  results[0,1]
end

#update(attributes, query) ⇒ Integer

Used by DataMapper to update the attributes on existing records in a data-store: “UPDATE” in SQL-speak. It takes a hash of the attributes to update with, as well as a query object that specifies which resources should be updated.

Parameters:

  • attributes (Hash) —

    A set of key-value pairs of the attributes to update the resources with.

  • query (DataMapper::Query) —

    The query that should be used to find the resource(s) to update.

Returns:

  • (Integer) —

    the number of records that were successfully updated



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# File 'lib/persevere_adapter.rb', line 92

def update(attributes, query)
  updated = 0

  if ! query.is_a?(DataMapper::Query)
    resources = [query].flatten
  else
    resources = read_many(query)
  end

  resources.each do |resource|
    tblname = Extlib::Inflection.classify(resource.class).pluralize
    path = "/#{tblname}/#{resource.id}"

    result = @persevere.update(path, resource.attributes)

    if result # good:
      updated += 1
    else
      return false
    end
  end
  return updated
end