package Text::RecordParser; # $Id: RecordParser.pm,v 1.12 2006/05/18 18:53:41 kclark Exp $ =head1 NAME Text::RecordParser - read record-oriented files =head1 VERSION This documentation refers to version 1.3.0. =head1 SYNOPSIS use Text::RecordParser; # use default record (\n) and field (,) separators my $p = Text::RecordParser->new( $file ); # or be explicit my $p = Text::RecordParser->new({ filename => $file, field_separator => "\t", }); $p->filename('foo.csv'); # Split records on two newlines $p->record_separator("\n\n"); # Split fields on tabs $p->field_separator("\t"); # Skip lines beginning with hashes $p->comment( qr/^#/ ); # Trim whitespace $p->trim(1); # Use the fields in the first line as column names $p->bind_header; # Get a list of the header fields (in order) my @columns = $p->field_list; # Extract a particular field from the next row my ( $name, $age ) = $p->extract( qw[name age] ); # Return all the fields from the next row my @fields = $p->fetchrow_array; # Define a field alias $p->set_field_alias( name => 'handle' ); # Return all the fields from the next row as a hashref my $record = $p->fetchrow_hashref; print $record->{'name'}; # or print $record->{'handle'}; # Return the record as an object with fields as accessors my $object = $p->fetchrow_object; print $object->name; # or $object->handle; # Get all data as arrayref of arrayrefs my $data = $p->fetchall_arrayref; # Get all data as arrayref of hashrefs my $data = $p->fetchall_arrayref( { Columns => {} } ); # Get all data as hashref of hashrefs my $data = $p->fetchall_hashref('name'); =head1 DESCRIPTION This module is for reading record-oriented data in a delimited text file. The most common example have records separated by newlines and fields separated by commas or tabs, but this module aims to provide a consistent interface for handling sequential records in a file however they may be delimited. Typically this data lists the fields in the first line of the file, in which case you should call C to bind the field name (or not, and it will be called implicitly). If the first line contains data, you can still bind your own field names via C. Either way, you can then use many methods to get at the data as arrays or hashes. =head1 METHODS =cut use strict; use warnings; use version; use Carp qw( croak ); use IO::Scalar; use List::MoreUtils qw( uniq ); use Readonly; use Text::ParseWords qw( parse_line ); our $VERSION = version->new('1.3.0'); Readonly my $COMMA => q{,}; Readonly my $EMPTY_STR => q{}; Readonly my $NEW_LINE => qq{\n}; Readonly my $PIPE => q{|}; # ---------------------------------------------------------------- sub new { =pod =head2 new This is the object constructor. It takes a hash (or hashref) of arguments. Each argument can also be set through the method of the same name. =over 4 =item * filename The path to the file being read. If the filename is passed and the fh is not, then it will open a filehandle on that file and sets C accordingly. =item * comment A compiled regular expression identifying comment lines that should be skipped. =item * data The data to read. =item * fh The filehandle of the file to read. =item * field_separator | fs The field separator (default is comma). =item * record_separator | rs The record separator (default is newline). =item * field_filter A callback applied to all the fields as they are read. =item * header_filter A callback applied to the column names. =item * trim Boolean to enable trimming of leading and trailing whitespace from fields (useful if splitting on whitespace only). =back See methods for each argument name for more information. Alternately, if you supply a single argument to C, it will be treated as the C argument. =cut my $class = shift; my $args = defined $_[0] && UNIVERSAL::isa( $_[0], 'HASH' ) ? shift : scalar @_ == 1 ? { filename => shift } : { @_ }; my $self = bless {}, $class; if ( my $fs = $args->{'fs'} ) { $args->{'field_separator'} = $fs; delete $args->{'fs'}; } if ( my $rs = $args->{'rs'} ) { $args->{'record_separator'} = $rs; delete $args->{'rs'}; } my $data_handles = 0; for my $arg ( qw[ filename fh header_filter field_filter trim field_separator record_separator data comment ] ) { next if !defined $args->{ $arg }; if ( $arg =~ / \A (filename|fh|data) \Z /xms ) { $data_handles++; } $self->$arg( $args->{ $arg } ); } if ( $data_handles > 1 ) { croak 'Passed too many arguments to read the data. '. 'Please choose only one of "filename," "fh," or "data."' ; } return $self; } # ---------------------------------------------------------------- sub bind_fields { =pod =head2 bind_fields $p->bind_fields( qw[ name rank serial_number ] ); Takes an array of field names and memorizes the field positions for later use. If the input file has no header line but you still wish to retrieve the fields by name (or even if you want to call C and then give your own field names), simply pass in the an array of field names you wish to use. Pass in an empty array reference to unset: $p->bind_field( [] ); # unsets fields =cut my $self = shift; # using an empty arrayref to unset if ( ref $_[0] eq 'ARRAY' && !@{ $_[0] } ) { $self->{'field_pos_ordered'} = []; $self->{'field_pos'} = {}; $self->{'fields_bound'} = 0; } elsif ( @_ ) { my @fields = @_; $self->{'field_pos_ordered'} = [ @fields ]; my %field_pos; foreach my $i ( 0 .. $#fields ) { $field_pos{ $fields[$i] } = $i; } $self->{'field_pos'} = \%field_pos; $self->{'fields_bound'} = 1; } else { croak 'Bind fields called without field list'; } return 1; } # ---------------------------------------------------------------- sub bind_header { =pod =head2 bind_header $p->bind_header; my $name = $p->extract('name'); Takes the fields from the next row under the cursor and assigns the field names to the values. Usually you would call this immediately after opening the file in order to bind the field names in the first row. =cut my $self = shift; if ( my @columns = $self->fetchrow_array ) { if ( my $filter = $self->header_filter ) { for my $i ( 0 .. $#columns ) { $columns[ $i ] = $filter->( $columns[ $i ] ); } } $self->bind_fields( @columns ); } else { croak q[Can't find columns in file '], $self->filename, q[']; } return 1; } # ---------------------------------------------------------------- sub comment { =pod =head2 comment $p->comment( qr/^#/ ); # Perl-style comments $p->comment( qr/^--/ ); # SQL-style comments Takes a regex to apply to a record to see if it looks like a comment to skip. =cut my $self = shift; if ( my $arg = shift ) { if ( ref $arg ne 'Regexp' ) { croak q[Argument to comment doesn't look like a regex]; } $self->{'comment'} = $arg; } return defined $self->{'comment'} ? $self->{'comment'} : $EMPTY_STR; } # ---------------------------------------------------------------- sub data { =pod =head2 data $p->data( $string ); $p->data( \$string ); $p->data( @lines ); $p->data( [$line1, $line2, $line3] ); $p->data( IO::File->new(' as it will read the entire contents of the file rather than one line at a time if you set it via C. =cut my $self = shift; my $data; if (@_) { my $arg = shift; if ( UNIVERSAL::isa( $arg, 'SCALAR' ) ) { $data = $$arg; } elsif ( UNIVERSAL::isa( $arg, 'ARRAY' ) ) { $data = join $EMPTY_STR, @$arg; } elsif ( UNIVERSAL::isa( $arg, 'GLOB' ) ) { local $/; $data = <$arg>; } elsif ( !ref($arg) && @_ ) { $data = join $EMPTY_STR, $arg, @_; } else { $data = $arg; } } else { croak 'Data called without any arguments'; } if ( $data ) { my $fh = IO::Scalar->new( \$data ); $self->fh( $fh ); } else { croak 'No usable data'; } return 1; } # ---------------------------------------------------------------- sub extract { =pod =head2 extract my ( $foo, $bar, $baz ) = $p->extract( qw[ foo bar baz ] ); Extracts a list of fields out of the last row read. The field names must correspond to the field names bound either via C or C. =cut my $self = shift; my @fields = @_ or return; my %allowed = map { $_, 1 } $self->field_list; my $record = $self->fetchrow_hashref or return; my @data; foreach my $field ( @fields ) { if ( $allowed{ $field } ) { push @data, $record->{ $field }; } else { croak "Invalid field $field for file " . $self->filename . $NEW_LINE . 'Valid fields are: ' . join(', ', $self->field_list) . $NEW_LINE ; } } return scalar @data == 1 ? $data[0] : @data; } # ---------------------------------------------------------------- sub fetchrow_array { =pod =head2 fetchrow_array my @values = $p->fetchrow_array; Reads a row from the file and returns an array or array reference of the fields. =cut my $self = shift; my $fh = $self->fh or croak 'No filename or file handle'; my $comment = $self->comment; local $/ = $self->record_separator; my $line; my $line_no = 0; for ( ;; ) { $line_no++; defined( $line = <$fh> ) or return; chomp $line; next if $comment and $line =~ $comment; $line =~ s/(?field_separator; $separator eq $PIPE and $separator = '\|'; my @fields = map { defined $_ && $_ =~ s/\\'/'/g; $_ } ( ( ref $separator eq 'Regexp' ) ? parse_line( $separator, 0, $line ) : parse_line( $separator, 1, $line ) ); if ( !@fields ) { croak "Error reading line number $line_no:\n$line"; } if ( my $filter = $self->field_filter ) { @fields = map { $filter->( $_ ) } @fields; } if ( $self->trim ) { @fields = map { defined $_ && s/^\s+|\s+$//g; $_ } @fields; } while ( my ( $position, $callback ) = each %{ $self->field_compute } ) { next if $position !~ m/^\d+$/; $fields[ $position ] = $callback->( $fields[ $position ], \@fields ); } return wantarray ? @fields : \@fields; } # ---------------------------------------------------------------- sub fetchrow_hashref { =pod =head2 fetchrow_hashref my $record = $p->fetchrow_hashref; print "Name = ", $record->{'name'}, "\n"; Reads a line of the file and returns it as a hash reference. The keys of the hashref are the field names bound via C or C. If you do not bind fields prior to calling this method, the C method will be implicitly called for you. =cut my $self = shift; my @fields = $self->field_list or return; my @row = $self->fetchrow_array or return; my $i = 0; my %return; for my $field ( @fields ) { $return{ $field } = $row[ $i++ ]; if ( my @aliases = $self->get_field_aliases( $field ) ) { $return{ $_ } = $return{ $field } for @aliases; } } while ( my ( $position, $callback ) = each %{ $self->field_compute } ) { $return{ $position } = $callback->( $return{ $position }, \%return ); } return \%return; } # ---------------------------------------------------------------- sub fetchrow_object { =pod =head2 fetchrow_object while ( my $object = $p->fetchrow_object ) { my $id = $object->id; my $name = $object->naem; # <-- this will throw a runtime error } This will return the next data record as a Text::RecordParser::Object object that has read-only accessor methods of the field names and any aliases. This allows you to enforce field names, further helping ensure that your code is reading the input file correctly. That is, if you are using the "fetchrow_hashref" method to read each line, you may misspell the hash key and introduce a bug in your code. With this method, Perl will throw an error if you attempt to read a field not defined in the file's headers. Additionally, any defined field aliases will be created as additional accessor methods. =cut my $self = shift; my $row = $self->fetchrow_hashref; my @fields = $self->field_list or return; push @fields, map { $self->get_field_aliases( $_ ) } @fields; return Text::RecordParser::Object->new( \@fields, $row ); } # ---------------------------------------------------------------- sub fetchall_arrayref { =pod =head2 fetchall_arrayref my $records = $p->fetchall_arrayref; for my $record ( @$records ) { print "Name = ", $record->[0], "\n"; } my $records = $p->fetchall_arrayref( { Columns => {} } ); for my $record ( @$records ) { print "Name = ", $record->{'name'}, "\n"; } Like DBI's fetchall_arrayref, returns an arrayref of arrayrefs. Also accepts optional "{ Columns => {} }" argument to return an arrayref of hashrefs. =cut my $self = shift; my %args = defined $_[0] && ref $_[0] eq 'HASH' ? %{ shift() } : @_ % 2 == 0 ? @_ : (); my $method = ref $args{'Columns'} eq 'HASH' ? 'fetchrow_hashref' : 'fetchrow_array'; my @return; while ( my $record = $self->$method() ) { push @return, $record; } return \@return; } # ---------------------------------------------------------------- sub fetchall_hashref { =pod =head2 fetchall_hashref my $records = $p->fetchall_hashref('id'); for my $id ( keys %$records ) { my $record = $records->{ $id }; print "Name = ", $record->{'name'}, "\n"; } Like DBI's fetchall_hashref, this returns a hash reference of hash references. The keys of the top-level hashref are the field values of the field argument you supply. The field name you supply can be a field created by a C. =cut my $self = shift; my $key_field = shift(@_) || return croak('No key field'); my @fields = $self->field_list; my ( %return, $field_ok ); while ( my $record = $self->fetchrow_hashref ) { if ( !$field_ok ) { if ( !exists $record->{ $key_field } ) { croak "Invalid key field: '$key_field'"; } $field_ok = 1; } $return{ $record->{ $key_field } } = $record; } return \%return; } # ---------------------------------------------------------------- sub fh { =pod =head2 fh open my $fh, '<', $file or die $!; $p->fh( $fh ); Gets or sets the filehandle of the file being read. =cut my ( $self, $arg ) = @_; if ( defined $arg ) { if ( ! UNIVERSAL::isa( $arg, 'GLOB' ) ) { croak q[Argument to fh doesn't look like a filehandle]; } if ( defined $self->{'fh'} ) { close $self->{'fh'} or croak "Can't close existing filehandle: $!"; } $self->{'fh'} = $arg; $self->{'filename'} = $EMPTY_STR; } if ( !defined $self->{'fh'} ) { if ( my $file = $self->filename ) { open my $fh, '<', $file or croak "Cannot read '$file': $!"; $self->{'fh'} = $fh; } } return $self->{'fh'}; } # ---------------------------------------------------------------- sub field_compute { =pod =head2 field_compute A callback applied to the fields identified by position (or field name if C or C was called). The callback will be passed two arguments: =over 4 =item 1 The current field =item 2 A reference to all the other fields, either as an array or hash reference, depending on the method which you called. =back If data looks like this: parent children Mike Greg,Peter,Bobby Carol Marcia,Jane,Cindy You could split the "children" field into an array reference with the values like so: $p->field_compute( 'children', sub { [ split /,/, shift() ] } ); The field position or name doesn't actually have to exist, which means you could create new, computed fields on-the-fly. E.g., if you data looks like this: 1,3,5 32,4,1 9,5,4 You could write a field_compute like this: $p->field_compute( 3, sub { my ( $cur, $others ) = @_; my $sum; $sum += $_ for @$others; return $sum; } ); Field "3" will be created as the sum of the other fields. This allows you to further write: my $data = $p->fetchall_arrayref; for my $rec ( @$data ) { print "$rec->[0] + $rec->[1] + $rec->[2] = $rec->[3]\n"; } Prints: 1 + 3 + 5 = 9 32 + 4 + 1 = 37 9 + 5 + 4 = 18 =cut my $self = shift; if ( @_ ) { my ( $position, $callback ) = @_; if ( $position !~ /\S+/ ) { croak 'No usable field name or position'; } if ( ref $callback ne 'CODE' ) { croak 'Callback not code reference'; } $self->{'field_computes'}{ $position } = $callback; } return $self->{'field_computes'} || {}; } # ---------------------------------------------------------------- sub field_filter { =pod =head2 field_filter $p->field_filter( sub { $_ = shift; uc(lc($_)) } ); A callback which is applied to each field. The callback will be passed the current value of the field. Whatever is passed back will become the new value of the field. The above example capitalizes field values. To unset the filter, pass in the empty string. =cut my ( $self, $filter ) = @_; if ( defined $filter ) { if ( $filter eq $EMPTY_STR ) { $self->{'field_filter'} = $EMPTY_STR; # allows nullification } elsif ( ref $filter eq 'CODE' ) { $self->{'field_filter'} = $filter; } else { croak q[Argument to field_filter doesn't look like code]; } } return $self->{'field_filter'} || $EMPTY_STR; } # ---------------------------------------------------------------- sub field_list { =pod =head2 field_list $p->bind_fields( qw[ foo bar baz ] ); my @fields = $p->field_list; print join ', ', @fields; # prints "foo, bar, baz" Returns the fields bound via C (or C). =cut my $self = shift; if ( !$self->{'fields_bound'} ) { $self->bind_header; } if ( ref $self->{'field_pos_ordered'} eq 'ARRAY' ) { return @{ $self->{'field_pos_ordered'} }; } else { croak 'No fields. Call "bind_fields" or "bind_header" first.'; } } # ---------------------------------------------------------------- sub field_positions { =pod =head2 field_positions my %positions = $p->field_positions; Returns a hash of the fields and their positions bound via C (or C). Mostly for internal use. =cut my $self = shift; if ( ref $self->{'field_pos'} eq 'HASH' ) { return %{ $self->{'field_pos'} }; } else { return; } } # ---------------------------------------------------------------- sub field_separator { =pod =head2 field_separator $p->field_separator("\t"); # splits fields on tabs $p->field_separator('::'); # splits fields on double colons $p->field_separator(qr/\s+/); # splits fields on whitespace my $sep = $p->field_separator; # returns the current separator Gets and sets the token to use as the field delimiter. Regular expressions can be specified using qr//. If not specified, it will take a guess based on the filename extension ("comma" for ".txt," ".dat," or ".csv"; "tab" for ".tab"). The default is a comma. =cut my $self = shift; if ( @_ ) { $self->{'field_separator'} = shift; } if ( !$self->{'field_separator'} ) { my $guess; if ( my $filename = $self->filename ) { if ( $filename =~ /\.(csv|txt|dat)$/ ) { $guess = q{,}; } elsif ( $filename =~ /\.tab$/ ) { $guess = qq{\t}; } } if ( $guess ) { $self->{'field_separator'} = $guess; } } return $self->{'field_separator'} || $COMMA; } # ---------------------------------------------------------------- sub filename { =pod =head2 filename $p->filename('/path/to/file.dat'); Gets or sets the complete path to the file to be read. If a file is already opened, then the handle on it will be closed and a new one opened on the new file. =cut my $self = shift; if ( my $filename = shift ) { if ( -d $filename ) { croak "Cannot use directory '$filename' as input source"; } elsif ( -f _ and -r _ ) { if ( my $fh = $self->fh ) { if ( !close($fh) ) { croak "Can't close previously opened filehandle: $!\n"; } $self->{'fh'} = undef; $self->bind_fields([]); } $self->{'filename'} = $filename; } else { croak "Cannot use '$filename' as input source: ", 'file does not exist or is not readable.' ; } } return $self->{'filename'} || $EMPTY_STR; } # ---------------------------------------------------------------- sub get_field_aliases { =pod =head2 get_field_aliases my @aliases = $p->get_field_aliases('name'); Allows you to define alternate names for fields, e.g., sometimes your input file calls city "town" or "township," sometimes a file uses "Moniker" instead of "name." =cut my $self = shift; my $field_name = shift or return; if ( !$self->{'field_alias'} ) { return; } return @{ $self->{'field_alias'}{ $field_name } || [] }; } # ---------------------------------------------------------------- sub header_filter { =pod =head2 header_filter $p->header_filter( sub { $_ = shift; s/\s+/_/g; lc $_ } ); A callback applied to column header names. The callback will be passed the current value of the header. Whatever is returned will become the new value of the header. The above example collapses spaces into a single underscore and lowercases the letters. To unset a filter, pass in the empty string. =cut my ( $self, $filter ) = @_; if ( defined $filter ) { if ( $filter eq $EMPTY_STR ) { $self->{'header_filter'} = $EMPTY_STR; # allows nullification } elsif ( ref $filter eq 'CODE' ) { $self->{'header_filter'} = $filter; if ( my %field_pos = $self->field_positions ) { my @new_order; while ( my ( $field, $order ) = each %field_pos ) { my $xform = $filter->( $field ); $new_order[ $order ] = $xform; } $self->bind_fields( @new_order ); } } else{ croak q[Argument to field_filter doesn't look like code]; } } return $self->{'header_filter'} || $EMPTY_STR; } # ---------------------------------------------------------------- sub record_separator { =pod =head2 record_separator $p->record_separator("\n//\n"); $p->field_separator("\n"); Gets and sets the token to use as the record separator. The default is a newline ("\n"). The above example would read a file that looks like this: field1 field2 field3 // data1 data2 data3 // =cut my $self = shift; if ( @_ ) { $self->{'record_separator'} = shift; } return $self->{'record_separator'} || $NEW_LINE; } # ---------------------------------------------------------------- sub set_field_alias { =pod =head2 set_field_alias $p->set_field_alias({ name => 'Moniker,handle', # comma-separated string city => [ qw( town township ) ], # or anonymous arrayref }); Allows you to define alternate names for fields, e.g., sometimes your input file calls city "town" or "township," sometimes a file uses "Moniker" instead of "name." =cut my $self = shift; my %args = ref $_[0] eq 'HASH' ? %{ $_[0] } : @_; my %is_field = map { $_, 1 } $self->field_list; ARG: while ( my ( $field_name, $aliases ) = each %args ) { if ( ref $aliases ne 'ARRAY' ) { $aliases = [ split(/,/, $aliases) ]; } if ( !$is_field{ $field_name } ) { push @$aliases, $field_name; ( $field_name ) = grep { $is_field{ $_ } } @$aliases; next ARG unless $field_name; } $self->{'field_alias'}{ $field_name } = [ grep { $_ ne $field_name } uniq( @$aliases ) ]; } return 1; } # ---------------------------------------------------------------- sub trim { =pod =head2 trim my $trim_value = $p->trim(1); Provide "true" argument to remove leading and trailing whitespace from fields. Use a "false" argument to disable. =cut my ( $self, $arg ) = @_; if ( defined $arg ) { $self->{'trim'} = $arg ? 1 : 0; } return $self->{'trim'}; } 1; # ---------------------------------------------------------------- # I must Create a System, or be enslav'd by another Man's; # I will not Reason and Compare; my business is to Create. # -- William Blake, "Jerusalem" # ---------------------------------------------------------------- =pod =head1 AUTHOR Ken Youens-Clark Ekclark@cpan.orgE =head1 CREDITS Thanks to the following: =over 4 =item * Benjamin Tilly For Text::xSV, the inspirado for this module =item * Tim Bunce et al. For DBI, from which many of the methods were shamelessly stolen =item * Tom Aldcroft For contributing code to make it easy to parse whitespace-delimited data =item * Liya Ren For catching the column-ordering error when parsing with "no-headers" =item * Sharon Wei For catching bug in C that sets up infinite loops =item * Lars Thegler For bug report on missing "script_files" arg in Build.PL =back =head1 BUGS None known. Please use http://rt.cpan.org/ for reporting bugs. =head1 LICENSE AND COPYRIGHT Copyright (C) 2006-9 Ken Youens-Clark. All rights reserved. This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; version 2. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. =cut