class Sequel::Postgres::PGRow::Parser
The Parser
is responsible for taking the input string from PostgreSQL, and returning an appropriate ruby object that the type represents, such as an ArrayRow
or HashRow
.
Attributes
Converters for each member in the composite type. If not present, no conversion will be done, so values will remain strings. If present, should be an array of callable objects.
The OIDs for each member in the composite type. Not currently used, but made available for user code.
The columns for the parser, if any. If the parser has no columns, it will treat the input as an array. If it has columns, it will treat the input as a hash. If present, should be an array of strings.
The oid for the composite type itself.
A callable object used for typecasting the object. This is similar to the converter, but it is called by the typecasting code, which has different assumptions than the converter. For instance, the converter should be called with all of the member values already typecast, but the typecaster may not be.
Public Class Methods
Sets each of the parser's attributes, using options with the same name (e.g. :columns sets the columns attribute).
# File lib/sequel/extensions/pg_row.rb 285 def initialize(h=OPTS) 286 @columns = h[:columns] 287 @column_converters = h[:column_converters] 288 @column_oids = h[:column_oids] 289 @converter = h[:converter] 290 @typecaster = h[:typecaster] 291 @oid = h[:oid] 292 end
Public Instance Methods
Convert the PostgreSQL composite type input format into an appropriate ruby object.
# File lib/sequel/extensions/pg_row.rb 296 def call(s) 297 convert(convert_format(convert_columns(Splitter.new(s).parse))) 298 end
Typecast the given object to the appropriate type using the typecaster. Note that this does not conversion for the members of the composite type, since those conversion expect strings and strings may not be provided.
# File lib/sequel/extensions/pg_row.rb 304 def typecast(obj) 305 case obj 306 when Array 307 _typecast(convert_format(obj)) 308 when Hash 309 unless @columns 310 raise Error, 'PGRow::Parser without columns cannot typecast from a hash' 311 end 312 _typecast(obj) 313 else 314 raise Error, 'PGRow::Parser can only typecast arrays and hashes' 315 end 316 end
Private Instance Methods
If the parser has a typecaster, call it with the object, otherwise return the object as is.
# File lib/sequel/extensions/pg_row.rb 322 def _typecast(obj) 323 if t = @typecaster 324 t.call(obj) 325 else 326 obj 327 end 328 end
If the parser has a converter, call it with the object, otherwise return the object as is.
# File lib/sequel/extensions/pg_row.rb 355 def convert(obj) 356 if c = @converter 357 c.call(obj) 358 else 359 obj 360 end 361 end
If the parser has column converters, map the array of strings input to a array of appropriate ruby objects, one for each converter.
# File lib/sequel/extensions/pg_row.rb 333 def convert_columns(arr) 334 if ccs = @column_converters 335 arr.zip(ccs).map{|v, pr| (v && pr) ? pr.call(v) : v} 336 else 337 arr 338 end 339 end
If the parser has columns, return a hash assuming that the array is ordered by the columns.
# File lib/sequel/extensions/pg_row.rb 343 def convert_format(arr) 344 if cs = @columns 345 h = {} 346 arr.zip(cs).each{|v, c| h[c] = v} 347 h 348 else 349 arr 350 end 351 end