This class provides a complete interface to CSV files and data. It offers tools to enable you to read and write to and from Strings or IO objects, as needed.
FasterCSV.foreach("path/to/file.csv") do |row| # use row here... end
arr_of_arrs = FasterCSV.read("path/to/file.csv")
FasterCSV.parse("CSV,data,String") do |row| # use row here... end
arr_of_arrs = FasterCSV.parse("CSV,data,String")
FasterCSV.open("path/to/file.csv", "w") do |csv| csv << ["row", "of", "CSV", "data"] csv << ["another", "row"] # ... end
csv_string = FasterCSV.generate do |csv| csv << ["row", "of", "CSV", "data"] csv << ["another", "row"] # ... end
csv_string = ["CSV", "data"].to_csv # to CSV csv_array = "CSV,String".parse_csv # from CSV
FCSV { |csv_out| csv_out << %w{my data here} } # to $stdout FCSV(csv = "") { |csv_str| csv_str << %w{my data here} } # to a String FCSV($stderr) { |csv_err| csv_err << %w{my data here} } # to $stderr FCSV($stdin) { |csv_in| csv_in.each { |row| p row } } # from $stdin
csv = FCSV.new(io, options) # ... read (with gets() or each()) from and write (with <<) to csv here ...
This Hash holds the built-in converters of FasterCSV that can be accessed by name. You can
select Converters with #convert or through the
options
Hash passed to ::new.
:integer
Converts any field Integer() accepts.
:float
Converts any field Float() accepts.
:numeric
A combination of :integer
and :float
.
:date
Converts any field Date::parse() accepts.
:date_time
Converts any field DateTime::parse() accepts.
:all
All built-in converters. A combination of :date_time
and
:numeric
.
This Hash is intetionally left unfrozen and users should feel free to add values to it that can be accessed by all FasterCSV objects.
To add a combo field, the value should be an Array of names. Combo fields can be nested with other combo fields.
The options used when no overrides are given by calling code. They are:
:col_sep
","
:row_sep
:auto
:quote_char
'"'
:converters
nil
:unconverted_fields
nil
:headers
false
:return_headers
false
:header_converters
nil
:skip_blanks
false
:force_quotes
false
A Regexp used to find and convert some common Date formats.
A Regexp used to find and convert some common DateTime formats.
A FieldInfo Struct contains details about a field's position in the data source it was read from. FasterCSV will pass this Struct to some blocks that make decisions based on field structure. See #convert_fields for an example.
index
The zero-based index of the field in its row.
line
The line of the data source this row is from.
header
The header for the column, when available.
This Hash holds the built-in header converters of FasterCSV that can be accessed by name. You can
select HeaderConverters with
#header_convert or
through the options
Hash passed to ::new.
:downcase
Calls downcase() on the header String.
:symbol
The header String is downcased, spaces are replaced with underscores, non-word characters are dropped, and finally to_sym() is called.
This Hash is intetionally left unfrozen and users should feel free to add values to it that can be accessed by all FasterCSV objects.
To add a combo field, the value should be an Array of names. Combo fields can be nested with other combo fields.
The version of the installed library.
The line number of the last row read from this file. Fields with nested line-end characters will not affect this count.
This method will build a drop-in replacement for many of the standard CSV methods. It allows you to write code like:
begin require "faster_csv" FasterCSV.build_csv_interface rescue LoadError require "csv" end # ... use CSV here ...
This is not a complete interface with completely identical behavior. However, it is intended to be close enough that you won't notice the difference in most cases. CSV methods supported are:
foreach()
open()
parse()
readlines()
Be warned that this interface is slower than vanilla FasterCSV due to the extra layer of method calls. Depending on usage, this can slow it down to near CSV speeds.
# File lib/faster_csv.rb, line 874 def self.build_csv_interface Object.const_set(:CSV, Class.new).class_eval do def self.foreach(path, rs = :auto, &block) # :nodoc: FasterCSV.foreach(path, :row_sep => rs, &block) end def self.generate_line(row, fs = ",", rs = "") # :nodoc: FasterCSV.generate_line(row, :col_sep => fs, :row_sep => rs) end def self.open(path, mode, fs = ",", rs = :auto, &block) # :nodoc: if block and mode.include? "r" FasterCSV.open(path, mode, :col_sep => fs, :row_sep => rs) do |csv| csv.each(&block) end else FasterCSV.open(path, mode, :col_sep => fs, :row_sep => rs, &block) end end def self.parse(str_or_readable, fs = ",", rs = :auto, &block) # :nodoc: FasterCSV.parse(str_or_readable, :col_sep => fs, :row_sep => rs, &block) end def self.parse_line(src, fs = ",", rs = :auto) # :nodoc: FasterCSV.parse_line(src, :col_sep => fs, :row_sep => rs) end def self.readlines(path, rs = :auto) # :nodoc: FasterCSV.readlines(path, :row_sep => rs) end end end
# File lib/faster_csv.rb, line 12 def self.const_missing(*_) raise NotImplementedError, "Please switch to Ruby 1.9's standard CSV " + "library. It's FasterCSV plus support for " + "Ruby 1.9's m17n encoding engine." end
This method allows you to serialize an Array of Ruby objects to a String or File of CSV data. This is not as powerful as Marshal or YAML, but perhaps useful for spreadsheet and database interaction.
Out of the box, this method is intended to work with simple data objects or Structs. It will serialize a list of instance variables and/or Struct.members().
If you need need more complicated serialization, you can control the process by adding methods to the class to be serialized.
A class method csv_meta() is responsible for returning the first row of the document (as an Array). This row is considered to be a Hash of the form key_1,value_1,key_2,value_2,… ::load expects to find a class key with a value of the stringified class name and ::dump will create this, if you do not define this method. This method is only called on the first object of the Array.
The next method you can provide is an instance method called csv_headers(). This method is expected to return the second line of the document (again as an Array), which is to be used to give each column a header. By default, ::load will set an instance variable if the field header starts with an @ character or call send() passing the header as the method name and the field value as an argument. This method is only called on the first object of the Array.
Finally, you can provide an instance method called csv_dump(), which will be passed the headers. This should return an Array of fields that can be serialized for this object. This method is called once for every object in the Array.
The io
parameter can be used to serialize to a File, and
options
can be anything ::new accepts.
# File lib/faster_csv.rb, line 943 def self.dump(ary_of_objs, io = "", options = Hash.new) obj_template = ary_of_objs.first csv = FasterCSV.new(io, options) # write meta information begin csv << obj_template.class.csv_meta rescue NoMethodError csv << [:class, obj_template.class] end # write headers begin headers = obj_template.csv_headers rescue NoMethodError headers = obj_template.instance_variables.sort if obj_template.class.ancestors.find { |cls| cls.to_s =~ /\AStruct\b/ } headers += obj_template.members.map { |mem| "#{mem}=" }.sort end end csv << headers # serialize each object ary_of_objs.each do |obj| begin csv << obj.csv_dump(headers) rescue NoMethodError csv << headers.map do |var| if var[0] == @ obj.instance_variable_get(var) else obj[var[0..-2]] end end end end if io.is_a? String csv.string else csv.close end end
This method is a convenience for building Unix-like filters for CSV data. Each row is yielded to the provided block which can alter it as needed.
After the block returns, the row is appended to output
altered
or not.
The input
and output
arguments can be anything ::new accepts (generally String or IO objects). If not given, they default
to ARGF
and $stdout
.
The options
parameter is also filtered down to ::new after some clever key parsing.
Any key beginning with :in_
or :input_
will have
that leading identifier stripped and will only be used in the
options
Hash for the input
object. Keys starting
with :out_
or :output_
affect only
output
. All other keys are assigned to both objects.
The :output_row_sep
option
defaults to
$INPUT_RECORD_SEPARATOR
($/
).
# File lib/faster_csv.rb, line 1012 def self.filter(*args) # parse options for input, output, or both in_options, out_options = Hash.new, {:row_sep => $INPUT_RECORD_SEPARATOR} if args.last.is_a? Hash args.pop.each do |key, value| case key.to_s when /\Ain(?:put)?_(.+)\Z/ in_options[$1.to_sym] = value when /\Aout(?:put)?_(.+)\Z/ out_options[$1.to_sym] = value else in_options[key] = value out_options[key] = value end end end # build input and output wrappers input = FasterCSV.new(args.shift || ARGF, in_options) output = FasterCSV.new(args.shift || $stdout, out_options) # read, yield, write input.each do |row| yield row output << row end end
This method is intended as the primary interface for reading CSV files.
You pass a path
and any options
you wish to set
for the read. Each row of file will be passed to the provided
block
in turn.
The options
parameter can be anything ::new understands.
# File lib/faster_csv.rb, line 1046 def self.foreach(path, options = Hash.new, &block) open(path, "rb", options) do |csv| csv.each(&block) end end
This method wraps a String you provide, or an empty default String, in a FasterCSV object which is passed to the provided block. You can use the block to append CSV rows to the String and when the block exits, the final String will be returned.
Note that a passed String is modfied by this method. Call dup() before passing if you need a new String.
The options
parameter can be anthing ::new understands.
# File lib/faster_csv.rb, line 1067 def self.generate(*args) # add a default empty String, if none was given if args.first.is_a? String io = StringIO.new(args.shift) io.seek(0, IO::SEEK_END) args.unshift(io) else args.unshift("") end faster_csv = new(*args) # wrap yield faster_csv # yield for appending faster_csv.string # return final String end
This method is a shortcut for converting a single row (Array) into a CSV String.
The options
parameter can be anthing ::new understands.
The :row_sep
option
defaults to
$INPUT_RECORD_SEPARATOR
($/
) when calling this
method.
# File lib/faster_csv.rb, line 1090 def self.generate_line(row, options = Hash.new) options = {:row_sep => $INPUT_RECORD_SEPARATOR}.merge(options) (new("", options) << row).string end
This method will return a FasterCSV instance,
just like ::new, but the
instance will be cached and returned for all future calls to this method
for the same data
object (tested by Object#object_id()) with
the same options
.
If a block is given, the instance is passed to the block and the return value becomes the return value of the block.
# File lib/faster_csv.rb, line 1104 def self.instance(data = $stdout, options = Hash.new) # create a _signature_ for this method call, data object and options sig = [data.object_id] + options.values_at(*DEFAULT_OPTIONS.keys.sort_by { |sym| sym.to_s }) # fetch or create the instance for this signature @@instances ||= Hash.new instance = (@@instances[sig] ||= new(data, options)) if block_given? yield instance # run block, if given, returning result else instance # or return the instance end end
This method is the reading counterpart to ::dump. See that method for a detailed description of the process.
You can customize loading by adding a class method called csv_load() which will be passed a Hash of meta information, an Array of headers, and an Array of fields for the object the method is expected to return.
Remember that all fields will be Strings after this load. If you need
something else, use options
to setup converters or provide a
custom csv_load() implementation.
# File lib/faster_csv.rb, line 1132 def self.load(io_or_str, options = Hash.new) csv = FasterCSV.new(io_or_str, options) # load meta information meta = Hash[*csv.shift] cls = meta["class"].split("::").inject(Object) do |c, const| c.const_get(const) end # load headers headers = csv.shift # unserialize each object stored in the file results = csv.inject(Array.new) do |all, row| begin obj = cls.csv_load(meta, headers, row) rescue NoMethodError obj = cls.allocate headers.zip(row) do |name, value| if name[0] == @ obj.instance_variable_set(name, value) else obj.send(name, value) end end end all << obj end csv.close unless io_or_str.is_a? String results end
# File lib/faster_csv.rb, line 18 def self.method_missing(*_) const_missing end
This constructor will wrap either a String or IO
object passed in data
for reading and/or writing. In addition
to the FasterCSV instance methods, several IO
methods are delegated. (See ::open for a complete list.) If
you pass a String for data
, you can
later retrieve it (after writing to it, for example) with
FasterCSV.string().
Note that a wrapped String will be positioned at at the beginning (for reading). If you want it at the end (for writing), use ::generate. If you want any other positioning, pass a preset StringIO object instead.
You may set any reading and/or writing preferences in the
options
Hash.
Available options are:
:col_sep
The String placed between each field.
:row_sep
The String appended to the end of each row. This
can be set to the special :auto
setting, which requests that
FasterCSV automatically discover this from the
data. Auto-discovery reads ahead in the data looking for the next
"\r\n"
, "\n"
, or
"\r"
sequence. A sequence will be selected even if
it occurs in a quoted field, assuming that you would have the same line
endings there. If none of those sequences is found, data
is
ARGF
, STDIN
, STDOUT
, or
STDERR
, or the stream is only available for output, the
default $INPUT_RECORD_SEPARATOR
($/
) is used.
Obviously, discovery takes a little time. Set manually if speed is
important. Also note that IO objects should be opened in binary mode on
Windows if this feature will be used as the line-ending translation can
cause problems with resetting the document position to where it was before
the read ahead.
:quote_char
The character used to quote fields. This has to be a single character String. This is useful for application that
incorrectly use '
as the quote character instead of the
correct "
. FasterCSV will
always consider a double sequence this character to be an escaped quote.
:encoding
The encoding to use when parsing the file. Defaults to your
$KDOCE
setting. Valid values: `n’
or
`N’
for none, `e’
or `E’
for EUC,
`s’
or `S’
for SJIS, and `u’
or
`U’
for UTF-8 (see Regexp.new()).
:field_size_limit
This is a maximum size FasterCSV will read
ahead looking for the closing quote for a field. (In truth, it reads to
the first line ending beyond this size.) If a quote cannot be found within
the limit FasterCSV will raise a MalformedCSVError, assuming the
data is faulty. You can use this limit to prevent what are effectively DoS
attacks on the parser. However, this limit can cause a legitimate parse to
fail and thus is set to nil
, or off, by default.
:converters
An Array of names from the Converters Hash and/or lambdas that handle custom conversion. A single converter doesn't have to be in an Array.
:unconverted_fields
If set to true
, an unconverted_fields() method will be added
to all returned rows (Array or FasterCSV::Row) that will return the fields
as they were before convertion. Note that :headers
supplied by
Array or String were not
fields of the document and thus will have an empty Array attached.
:headers
If set to :first_row
or true
, the initial row of
the CSV file will be treated as a row of headers. If set to an Array, the contents will be used as the headers. If
set to a String, the String is run through a call of ::parse_line with the same
:col_sep
, :row_sep
, and :quote_char
as this instance to produce an Array of headers.
This setting causes #shift to
return rows as FasterCSV::Row objects
instead of Arrays and ::read to
return FasterCSV::Table objects instead
of an Array of Arrays.
:return_headers
When false
, header rows are silently swallowed. If set to
true
, header rows are returned in a FasterCSV::Row object with identical headers
and fields (save that the fields do not go through the converters).
:write_headers
When true
and :headers
is set, a header row will
be added to the output.
:header_converters
Identical in functionality to :converters
save that the
conversions are only made to header rows.
:skip_blanks
When set to a true
value, FasterCSV will skip over any rows with no
content.
:force_quotes
When set to a true
value, FasterCSV will quote all CSV fields it creates.
See FasterCSV::DEFAULT_OPTIONS for the default settings.
Options cannot be overriden in the instance methods for performance reasons, so be sure to set what you want here.
# File lib/faster_csv.rb, line 1421 def initialize(data, options = Hash.new) # build the options for this read/write options = DEFAULT_OPTIONS.merge(options) # create the IO object we will read from @io = if data.is_a? String then StringIO.new(data) else data end init_separators(options) init_parsers(options) init_converters(options) init_headers(options) unless options.empty? raise ArgumentError, "Unknown options: #{options.keys.join(', ')}." end # track our own lineno since IO gets confused about line-ends is CSV fields @lineno = 0 end
This method opens an IO object, and wraps that with FasterCSV. This is intended as the primary interface for writing a CSV file.
You may pass any args
Ruby's open() understands followed
by an optional Hash containing any options
::new understands.
This method works like Ruby's open() call, in that it will pass a FasterCSV object to a provided block and close it when the block termminates, or it will return the FasterCSV object when no block is provided. (Note: This is different from the standard CSV library which passes rows to the block.
Use ::foreach for that behavior.)
An opened FasterCSV object will delegate to many IO methods, for convenience. You may call:
binmode()
close()
close_read()
close_write()
closed?()
eof()
eof?()
fcntl()
fileno()
flush()
fsync()
ioctl()
isatty()
pid()
pos()
reopen()
seek()
stat()
sync()
sync=()
tell()
to_i()
to_io()
tty?()
# File lib/faster_csv.rb, line 1211 def self.open(*args) # find the +options+ Hash options = if args.last.is_a? Hash then args.pop else Hash.new end # default to a binary open mode args << "rb" if args.size == 1 # wrap a File opened with the remaining +args+ csv = new(File.open(*args), options) # handle blocks like Ruby's open(), not like the CSV library if block_given? begin yield csv ensure csv.close end else csv end end
This method can be used to easily parse CSV out of a String. You may either provide a block
which will be called with each row of the String
in turn, or just use the returned Array of Arrays
(when no block
is given).
You pass your str
to read from, and an optional
options
Hash containing anything ::new understands.
# File lib/faster_csv.rb, line 1243 def self.parse(*args, &block) csv = new(*args) if block.nil? # slurp contents, if no block is given begin csv.read ensure csv.close end else # or pass each row to a provided block csv.each(&block) end end
This method is a shortcut for converting a single line of a CSV String into a into an Array. Note that if line
contains
multiple rows, anything beyond the first row is ignored.
The options
parameter can be anthing ::new understands.
# File lib/faster_csv.rb, line 1263 def self.parse_line(line, options = Hash.new) new(line, options).shift end
Alias for ::read.
# File lib/faster_csv.rb, line 1276 def self.readlines(*args) read(*args) end
A shortcut for:
FasterCSV.read( path, { :headers => true, :converters => :numeric, :header_converters => :symbol }.merge(options) )
# File lib/faster_csv.rb, line 1287 def self.table(path, options = Hash.new) read( path, { :headers => true, :converters => :numeric, :header_converters => :symbol }.merge(options) ) end
The primary write method for wrapped Strings and IOs, row
(an
Array or FasterCSV::Row) is converted to CSV and
appended to the data source. When a FasterCSV::Row is passed, only the row's
fields() are appended to the output.
The data source must be open for writing.
# File lib/faster_csv.rb, line 1473 def <<(row) # make sure headers have been assigned if header_row? and [Array, String].include? @use_headers.class parse_headers # won't read data for Array or String self << @headers if @write_headers end # Handle FasterCSV::Row objects and Hashes row = case row when self.class::Row then row.fields when Hash then @headers.map { |header| row[header] } else row end @headers = row if header_row? @lineno += 1 @io << row.map(&@quote).join(@col_sep) + @row_sep # quote and separate self # for chaining end
You can use this method to install a FasterCSV::Converters built-in, or provide a block that handles a custom conversion.
If you provide a block that takes one argument, it will be passed the field and is expected to return the converted value or the field itself. If your block takes two arguments, it will also be passed a FieldInfo Struct, containing details about the field. Again, the block should return a converted field or the field itself.
# File lib/faster_csv.rb, line 1512 def convert(name = nil, &converter) add_converter(:converters, self.class::Converters, name, &converter) end
Yields each row of the data source in turn.
Support for Enumerable.
The data source must be open for reading.
# File lib/faster_csv.rb, line 1543 def each while row = shift yield row end end
Identical to #convert, but for header rows.
Note that this method must be called before header rows are read to have any effect.
# File lib/faster_csv.rb, line 1527 def header_convert(name = nil, &converter) add_converter( :header_converters, self.class::HeaderConverters, name, &converter ) end
Returns true
if the next row read will be a header row.
# File lib/faster_csv.rb, line 1565 def header_row? @use_headers and @headers.nil? end
Returns a simplified description of the key FasterCSV attributes.
# File lib/faster_csv.rb, line 1692 def inspect str = "<##{self.class} io_type:" # show type of wrapped IO if @io == $stdout then str << "$stdout" elsif @io == $stdin then str << "$stdin" elsif @io == $stderr then str << "$stderr" else str << @io.class.to_s end # show IO.path(), if available if @io.respond_to?(:path) and (p = @io.path) str << " io_path:#{p.inspect}" end # show other attributes %w[ lineno col_sep row_sep quote_char skip_blanks encoding ].each do |attr_name| if a = instance_variable_get("@#{attr_name}") str << " #{attr_name}:#{a.inspect}" end end if @use_headers str << " headers:#{(@headers || true).inspect}" end str << ">" end
# File lib/faster_csv.rb, line 22 def method_missing(*_) self.class.const_missing end
Slurps the remaining rows and returns an Array of Arrays.
The data source must be open for reading.
# File lib/faster_csv.rb, line 1554 def read rows = to_a if @use_headers Table.new(rows) else rows end end
Rewinds the underlying IO object and resets FasterCSV's lineno() counter.
# File lib/faster_csv.rb, line 1456 def rewind @headers = nil @lineno = 0 @io.rewind end
The primary read method for wrapped Strings and IOs, a single row is pulled from the data source, parsed and returned as an Array of fields (if header rows are not used) or a FasterCSV::Row (when header rows are used).
The data source must be open for reading.
# File lib/faster_csv.rb, line 1576 def shift ######################################################################### ### This method is purposefully kept a bit long as simple conditional ### ### checks are faster than numerous (expensive) method calls. ### ######################################################################### # handle headers not based on document content if header_row? and @return_headers and [Array, String].include? @use_headers.class if @unconverted_fields return add_unconverted_fields(parse_headers, Array.new) else return parse_headers end end # begin with a blank line, so we can always add to it line = String.new # # it can take multiple calls to <tt>@io.gets()</tt> to get a full line, # because of \r and/or \n characters embedded in quoted fields # loop do # add another read to the line if read_line = @io.gets(@row_sep) line += read_line else return nil end # copy the line so we can chop it up in parsing parse = line.dup parse.sub!(@parsers[:line_end], "") # # I believe a blank line should be an <tt>Array.new</tt>, not # CSV's <tt>[nil]</tt> # if parse.empty? @lineno += 1 if @skip_blanks line = "" next elsif @unconverted_fields return add_unconverted_fields(Array.new, Array.new) elsif @use_headers return FasterCSV::Row.new(Array.new, Array.new) else return Array.new end end # parse the fields with a mix of String#split and regular expressions csv = Array.new current_field = String.new field_quotes = 0 parse.split(@col_sep, -1).each do |match| if current_field.empty? && match.count(@quote_and_newlines).zero? csv << (match.empty? ? nil : match) elsif (current_field.empty? ? match[0] : current_field[0]) == @quote_char[0] current_field << match field_quotes += match.count(@quote_char) if field_quotes % 2 == 0 in_quotes = current_field[@parsers[:quoted_field], 1] raise MalformedCSVError if !in_quotes || in_quotes[@parsers[:stray_quote]] current_field = in_quotes current_field.gsub!(@quote_char * 2, @quote_char) # unescape contents csv << current_field current_field = String.new field_quotes = 0 else # we found a quoted field that spans multiple lines current_field << @col_sep end elsif match.count("\r\n").zero? raise MalformedCSVError, "Illegal quoting on line #{lineno + 1}." else raise MalformedCSVError, "Unquoted fields do not allow " + "\\r or \\n (line #{lineno + 1})." end end # if parse is empty?(), we found all the fields on the line... if field_quotes % 2 == 0 @lineno += 1 # save fields unconverted fields, if needed... unconverted = csv.dup if @unconverted_fields # convert fields, if needed... csv = convert_fields(csv) unless @use_headers or @converters.empty? # parse out header rows and handle FasterCSV::Row conversions... csv = parse_headers(csv) if @use_headers # inject unconverted fields and accessor, if requested... if @unconverted_fields and not csv.respond_to? :unconverted_fields add_unconverted_fields(csv, unconverted) end # return the results break csv end # if we're not empty?() but at eof?(), a quoted field wasn't closed... if @io.eof? raise MalformedCSVError, "Unclosed quoted field on line #{lineno + 1}." elsif @field_size_limit and current_field.size >= @field_size_limit raise MalformedCSVError, "Field size exceeded on line #{lineno + 1}." end # otherwise, we need to loop and pull some more data to complete the row end end
The actual work method for adding converters, used by both #convert and #header_convert.
This method requires the var_name
of the instance variable to
place the converters in, the const
Hash to lookup named
converters in, and the normal parameters of the #convert and #header_convert methods.
# File lib/faster_csv.rb, line 1894 def add_converter(var_name, const, name = nil, &converter) if name.nil? # custom converter instance_variable_get("@#{var_name}") << converter else # named converter combo = const[name] case combo when Array # combo converter combo.each do |converter_name| add_converter(var_name, const, converter_name) end else # individual named converter instance_variable_get("@#{var_name}") << combo end end end
Thiw methods injects an instance variable unconverted_fields
into row
and an accessor method for it called
unconverted_fields(). The variable is set to the contents of
fields
.
# File lib/faster_csv.rb, line 1979 def add_unconverted_fields(row, fields) class << row attr_reader :unconverted_fields end row.instance_eval { @unconverted_fields = fields } row end
Processes fields
with @converters
, or
@header_converters
if headers
is passed as
true
, returning the converted field set. Any converter that
changes the field into something other than a String halts the pipeline of conversion for that
field. This is primarily an efficiency shortcut.
# File lib/faster_csv.rb, line 1917 def convert_fields(fields, headers = false) # see if we are converting headers or fields converters = headers ? @header_converters : @converters fields.enum_for(:each_with_index).map do |field, index| # map_with_index converters.each do |converter| field = if converter.arity == 1 # straight field converter converter[field] else # FieldInfo converter header = @use_headers && !headers ? @headers[index] : nil converter[field, FieldInfo.new(index, lineno, header)] end break unless field.is_a? String # short-curcuit pipeline for speed end field # return final state of each field, converted or original end end
Loads any converters requested during construction.
If field_name
is set :converters
(the default)
field converters are set. When field_name
is
:header_converters
header converters are added instead.
The :unconverted_fields
option is also actived for
:converters
calls, if requested.
# File lib/faster_csv.rb, line 1844 def init_converters(options, field_name = :converters) if field_name == :converters @unconverted_fields = options.delete(:unconverted_fields) end instance_variable_set("@#{field_name}", Array.new) # find the correct method to add the coverters convert = method(field_name.to_s.sub(/ers\Z/, "")) # load converters unless options[field_name].nil? # allow a single converter not wrapped in an Array unless options[field_name].is_a? Array options[field_name] = [options[field_name]] end # load each converter... options[field_name].each do |converter| if converter.is_a? Proc # custom code block convert.call(&converter) else # by name convert.call(converter) end end end options.delete(field_name) end
Stores header row settings and loads header converters, if needed.
# File lib/faster_csv.rb, line 1874 def init_headers(options) @use_headers = options.delete(:headers) @return_headers = options.delete(:return_headers) @write_headers = options.delete(:write_headers) # headers must be delayed until shift(), in case they need a row of content @headers = nil init_converters(options, :header_converters) end
Pre-compiles parsers and stores them by name for access during reads.
# File lib/faster_csv.rb, line 1809 def init_parsers(options) # store the parser behaviors @skip_blanks = options.delete(:skip_blanks) @encoding = options.delete(:encoding) # nil will use $KCODE @field_size_limit = options.delete(:field_size_limit) # prebuild Regexps for faster parsing esc_col_sep = Regexp.escape(@col_sep) esc_row_sep = Regexp.escape(@row_sep) esc_quote = Regexp.escape(@quote_char) @parsers = { :any_field => Regexp.new( "[^#{esc_col_sep}]+", Regexp::MULTILINE, @encoding ), :quoted_field => Regexp.new( "^#{esc_quote}(.*)#{esc_quote}$", Regexp::MULTILINE, @encoding ), :stray_quote => Regexp.new( "[^#{esc_quote}]#{esc_quote}[^#{esc_quote}]", Regexp::MULTILINE, @encoding ), # safer than chomp!() :line_end => Regexp.new("#{esc_row_sep}\\z", nil, @encoding) } end
Stores the indicated separators for later use.
If auto-discovery was requested for @row_sep
, this method will
read ahead in the @io
and try to find one. ARGF
,
STDIN
, STDOUT
, STDERR
and any stream
open for output only with a default @row_sep
of
$INPUT_RECORD_SEPARATOR
($/
).
This method also establishes the quoting rules used for CSV output.
# File lib/faster_csv.rb, line 1729 def init_separators(options) # store the selected separators @col_sep = options.delete(:col_sep) @row_sep = options.delete(:row_sep) @quote_char = options.delete(:quote_char) @quote_and_newlines = "\r\n#{@quote_char}" if @quote_char.length != 1 raise ArgumentError, ":quote_char has to be a single character String" end # automatically discover row separator when requested if @row_sep == :auto if [ARGF, STDIN, STDOUT, STDERR].include?(@io) or (defined?(Zlib) and @io.class == Zlib::GzipWriter) @row_sep = $INPUT_RECORD_SEPARATOR else begin saved_pos = @io.pos # remember where we were while @row_sep == :auto # # if we run out of data, it's probably a single line # (use a sensible default) # if @io.eof? @row_sep = $INPUT_RECORD_SEPARATOR break end # read ahead a bit sample = @io.read(1024) sample += @io.read(1) if sample[-1..-1] == "\r" and not @io.eof? # try to find a standard separator if sample =~ /\r\n?|\n/ @row_sep = $& break end end # tricky seek() clone to work around GzipReader's lack of seek() @io.rewind # reset back to the remembered position while saved_pos > 1024 # avoid loading a lot of data into memory @io.read(1024) saved_pos -= 1024 end @io.read(saved_pos) if saved_pos.nonzero? rescue IOError # stream not opened for reading @row_sep = $INPUT_RECORD_SEPARATOR end end end # establish quoting rules do_quote = lambda do |field| @quote_char + String(field).gsub(@quote_char, @quote_char * 2) + @quote_char end @quote = if options.delete(:force_quotes) do_quote else lambda do |field| if field.nil? # represent +nil+ fields as empty unquoted fields "" else field = String(field) # Stringify fields # represent empty fields as empty quoted fields if field.empty? or field.count("\r\n#{@col_sep}#{@quote_char}").nonzero? do_quote.call(field) else field # unquoted field end end end end end
This methods is used to turn a finished row
into a FasterCSV::Row. Header rows are also dealt
with here, either by returning a FasterCSV::Row with identical headers and
fields (save that the fields do not go through the converters) or by
reading past them to return a field row. Headers are also saved in
@headers
for use in future rows.
When nil
, row
is assumed to be a header row not
based on an actual row of the stream.
# File lib/faster_csv.rb, line 1945 def parse_headers(row = nil) if @headers.nil? # header row @headers = case @use_headers # save headers # Array of headers when Array then @use_headers # CSV header String when String self.class.parse_line( @use_headers, :col_sep => @col_sep, :row_sep => @row_sep, :quote_char => @quote_char ) # first row is headers else row end # prepare converted and unconverted copies row = @headers if row.nil? @headers = convert_fields(@headers, true) if @return_headers # return headers return FasterCSV::Row.new(@headers, row, true) elsif not [Array, String].include? @use_headers.class # skip to field row return shift end end FasterCSV::Row.new(@headers, convert_fields(row)) # field row end