class FCSV
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.
Reading¶ ↑
From a File¶ ↑
A Line at a Time¶ ↑
FasterCSV.foreach("path/to/file.csv") do |row| # use row here... end
All at Once¶ ↑
arr_of_arrs = FasterCSV.read("path/to/file.csv")
From a String
¶ ↑
A Line at a Time¶ ↑
FasterCSV.parse("CSV,data,String") do |row| # use row here... end
All at Once¶ ↑
arr_of_arrs = FasterCSV.parse("CSV,data,String")
Writing¶ ↑
To a File¶ ↑
FasterCSV.open("path/to/file.csv", "w") do |csv| csv << ["row", "of", "CSV", "data"] csv << ["another", "row"] # ... end
To a String
¶ ↑
csv_string = FasterCSV.generate do |csv| csv << ["row", "of", "CSV", "data"] csv << ["another", "row"] # ... end
Convert a Single Line¶ ↑
csv_string = ["CSV", "data"].to_csv # to CSV csv_array = "CSV,String".parse_csv # from CSV
Shortcut Interface¶ ↑
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
Advanced Usage¶ ↑
Wrap an IO Object
¶ ↑
csv = FCSV.new(io, options) # ... read (with gets() or each()) from and write (with <<) to csv here ...
Constants
- Converters
This Hash holds the built-in converters of
FasterCSV
that can be accessed by name. You can selectConverters
withFasterCSV.convert()
or through theoptions
Hash passed toFasterCSV::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.- DEFAULT_OPTIONS
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
- DateMatcher
A Regexp used to find and convert some common Date formats.
- DateTimeMatcher
A Regexp used to find and convert some common DateTime formats.
- FieldInfo
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. SeeFasterCSV.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.
- HeaderConverters
This Hash holds the built-in header converters of
FasterCSV
that can be accessed by name. You can selectHeaderConverters
withFasterCSV.header_convert()
or through theoptions
Hash passed toFasterCSV::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.- VERSION
The version of the installed library.
Attributes
The line number of the last row read from this file. Fields with nested line-end characters will not affect this count.
Public Class Methods
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,… FasterCSV::load()
expects to find a class key with a value of the stringified class name and FasterCSV::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, FasterCSV::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 FasterCSV::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 FasterCSV::new()
accepts (generally String
or IO objects). If not given, they default to ARGF
and $stdout
.
The options
parameter is also filtered down to FasterCSV::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 FasterCSV::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 FasterCSV::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 FasterCSV::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 FasterCSV::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 FasterCSV::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 FasterCSV::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 the beginning (for reading). If you want it at the end (for writing), use FasterCSV::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 thatFasterCSV
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, 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
$KCODE
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 limitFasterCSV
will raise aMalformedCSVError
, 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 tonil
, or off, by default. :converters
-
An
Array
of names from theConverters
Hash and/or lambdas that handle custom conversion. A single converter doesn’t have to be in anArray
. :unconverted_fields
-
If set to
true
, an unconverted_fields() method will be added to all returned rows (Array
orFasterCSV::Row
) that will return the fields as they were before convertion. Note that:headers
supplied byArray
orString
were not fields of the document and thus will have an emptyArray
attached. :headers
-
If set to
:first_row
ortrue
, the initial row of the CSV file will be treated as a row of headers. If set to anArray
, the contents will be used as the headers. If set to aString
, theString
is run through a call ofFasterCSV::parse_line()
with the same:col_sep
,:row_sep
, and:quote_char
as this instance to produce anArray
of headers. This setting causesFasterCSV.shift()
to return rows asFasterCSV::Row
objects instead of Arrays andFasterCSV.read()
to returnFasterCSV::Table
objects instead of anArray
of Arrays. :return_headers
-
When
false
, header rows are silently swallowed. If set totrue
, header rows are returned in aFasterCSV::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. Note that if the table only contains header rows,:return_headers
must also be set in order for a header row to be 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 1423 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
FasterCSV::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 FasterCSV::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 FasterCSV::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 anything FasterCSV::new()
understands.
# File lib/faster_csv.rb, line 1263 def self.parse_line(line, options = Hash.new) new(line, options).shift end
Use to slurp a CSV file into an Array
of Arrays. Pass the path
to the file and any options
FasterCSV::new()
understands.
# File lib/faster_csv.rb, line 1271 def self.read(path, options = Hash.new) open(path, "rb", options) { |csv| csv.read } end
Alias for FasterCSV::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
Public Instance Methods
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 1475 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 1514 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 1545 def each while row = shift yield row end end
Identical to FasterCSV.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 1529 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 1567 def header_row? @use_headers and @headers.nil? end
Returns a simplified description of the key FasterCSV
attributes.
# File lib/faster_csv.rb, line 1696 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 1556 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 1458 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 1578 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] if !in_quotes || in_quotes[@parsers[:stray_quote]] raise MalformedCSVError, "Missing or stray quote in line #{lineno + 1}" end 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 in 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
Private Instance Methods
The actual work method for adding converters, used by both FasterCSV.convert()
and FasterCSV.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 FasterCSV.convert()
and FasterCSV.header_convert()
methods.
# File lib/faster_csv.rb, line 1905 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 1990 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 1928 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 1855 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 1885 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 1820 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 1733 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 begin # # remember where we were (pos() will raise an axception if @io is pipe # or not opened for reading) # saved_pos = @io.pos while @row_sep == :auto # # if we run out of data, it's probably a single line # (ensure will set default value) # break if @io.eof? # 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 # not opened for reading # do nothing: ensure will set default rescue NoMethodError # Zlib::GzipWriter doesn't have eof? # do nothing: ensure will set default rescue SystemCallError # pipe # do nothing: ensure will set default ensure # # set default if we failed to detect # (stream not opened for reading, a pipe, or a single line of data) # @row_sep = $INPUT_RECORD_SEPARATOR if @row_sep == :auto 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 1956 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