CGI::Uploader - Manage CGI uploads using SQL database

CGI-Uploader documentation Contained in the CGI-Uploader distribution.

Index

Code Index:

NAME

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CGI::Uploader - Manage CGI uploads using SQL database

Synopsis

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 use CGI::Uploader::Transform::ImageMagick 'gen_thumb';

 my $u = CGI::Uploader->new(
    spec       => {
        # Upload one image named from the form field 'img'
        # and create one thumbnail for it.
        img_1 => {
            gen_files => {
                'img_1_thmb_1' => gen_thumb({ w => 100, h => 100 }),
              }
        },
    },

    updir_url  => 'http://localhost/uploads',
    updir_path => '/home/user/www/uploads',
        temp_dir   => '/home/user/www/uploads',

    dbh        => $dbh,
    query      => $q, # defaults to CGI->new(),
 );

 # ... now do something with $u

Description

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This module is designed to help with the task of managing files uploaded through a CGI application. The files are stored on the file system, and the file attributes stored in a SQL database.

Introduction and Recipes

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The CGI::Uploader::Cookbook (CGI::Uploader::Cookbook) provides a slightly more in depth introduction and recipes for a basic BREAD web application. (Browse, Read, Edit, Add, Delete).

Constructor

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new()

 my $u = CGI::Uploader->new(
    spec       => {
         # The first image has 2 different sized thumbnails
           img_1 => {
             gen_files => {
                     'img_1_thmb_1' => gen_thumb({ w => 100, h => 100 }),
                     'img_1_thmb_2' => gen_thumb({ w => 50, h => 50 }),
             }
           },
       },

        # Just upload it
        img_2 => {},
        # Downsize the large image to these maximum dimensions if it's larger
        img_3 => {
            # Besides generating dependent files
            # We can also transform the file itself
            # Here, we shrink the image to be wider than 380
            transform_method => \&gen_thumb,
            # demostrating the old-style param passing
            params => [{ w => 380 }],
        }
    },

    updir_url  => 'http://localhost/uploads',
    updir_path => '/home/user/www/uploads',

    dbh        => $dbh,
    query      => $q, # defaults to CGI->new(),

    up_table   => 'uploads', # defaults to "uploads"
    up_seq     => 'upload_id_seq',  # Required for Postgres
 );
spec [required]

The specification described the examples above. The keys correspond to form field names for upload fields.

The values are hash references. The simplest case is an empty hash reference, which means to just upload the image and apply no transformations.

#####

Each key in the hash is the corresponds to a file upload field. The values are hash references used provide options for how to transform the file, and possibly generate additional files based on it.

Valid keys here are:

transform_method

This is a subroutine reference. This routine can be used to transform the upload before it is stored. The first argument given to the routine will be the CGI::Uploader object. The second will be a full path to a file name containing the upload.

Additional arguments can be passed to the subroutine using params, as in the example above. But don't do that, it's ugly. If you need a custom transform method, write a little closure for it like this:

  sub my_transformer {
      my %args = @_;
      return sub {
          my ($self, $file) = shift;
          # do something with $file and %args here...
          return $path_to_new_file_i_made;
      }

Then in the spec you can put:

 transform_method => my_tranformer(%args),

It must return a full path to a transformed file.

}

params (DEPRECATED)

NOTE: Using a closure based interface provides a cleaner alternative to using params. See CGI::Uploader::Transform::ImageMagick for an example.

Used to pass additional arguments to transform_method. See above.

Each method used may have additional documentation about parameters that can be passed to it.

gen_files

A hash reference to describe files generated from a particular upload. The keys are unique identifiers for the generated files. The values are code references (usually closures) that prove a transformation for the file. See CGI::Uploader::Transform::ImageMagick for an an example.

An older interface for gen_files is deprecated. For that, the values are hashrefs, containing keys named transform_method and params, which work as described above to generate a transformed version of the file.

updir_url [required]

URL to upload storage directory. Should not include a trailing slash.

updir_path [required]

File system path to upload storage directory. Should not include a trailing slash.

temp_dir

Optional file system path to temporary directory. Default is File::Spec->tmpdir(). This temporary directory will also be used by gen_files during image transforms.

dbh [required]

DBI database handle. Required.

query

A CGI.pm-compatible object, used for the param and upload functions. Defaults to CGI->new() if omitted.

up_table

Name of the SQL table where uploads are stored. See example syntax above or one of the creation scripts included in the distribution. Defaults to "uploads" if omitted.

up_table_map

A hash reference which defines a mapping between the column names used in your SQL table, and those that CGI::Uploader uses. The keys are the CGI::Uploader default names. Values are the names that are actually used in your table.

This is not required. It simply allows you to use custom column names.

  upload_id       => 'upload_id',
  mime_type       => 'mime_type',
  extension       => 'extension',
  width           => 'width',
  height          => 'height',
  gen_from_id     => 'gen_from_id',
  file_name       => 'file_name',

You may also define additional column names with a value of 'undef'. This feature is only useful if you override the extract_meta() method or pass in $shared_meta to store_uploads(). Values for these additional columns will then be stored by store_meta() and retrieved with fk_meta().

up_seq

For Postgres only, the name of a sequence used to generate the upload_ids. Defaults to upload_id_seq if omitted.

file_scheme
 file_scheme => 'md5',

file_scheme controls how file files are stored on the file system. The default is simple, which stores all the files in the same directory with names like 123.jpg. Depending on your environment, this may be sufficient to store 10,000 or more files.

As an alternative, you can specify md5, which will create three levels of directories based on the first three letters of the ID's md5 sum. The result may look like this:

 2/0/2/123.jpg

This should scale well to millions of files. If you want even more control, consider overriding the build_loc() method, which is used to return the stored file path.

Note that specifying the file storage scheme for the file system is not related to the file_name stored in the database, which is always the original uploaded file name.

Basic Methods

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These basic methods are all you need to know to make effective use of this module.

store_uploads()

  my $entity = $u->store_uploads($form_data);

Stores uploaded files based on the definition given in spec.

Specifically, it does the following:

o

possibily transforms the original file according to transform_method

o

possibly generates additional files based on those uploaded, according to gen_files.

o

stores all the files on the file system

o

inserts upload details into the database, including upload_id, mime_type and extension. The columns 'width' and 'height' will be populated if that meta data is available.

As input, a hash reference of form data is expected. The simplest way to get this is like this:

 use CGI;
 my $q = new CGI;
 $form_data = $q->Vars;

However, I recommend that you validate your data with a module with Data::FormValidator, and use a hash reference of validated data, instead of directly using the CGI form data.

CGI::Uploader is designed to handle uploads that are included as a part of an add/edit form for an entity stored in a database. So, $form_data is expected to contain additional fields for this entity as well as the file upload fields.

For this reason, the store_uploads method returns a hash reference of the valid data with some transformations. File upload fields will be removed from the hash, and corresponding "_id" fields will be added.

So for a file upload field named 'img_field', the 'img_field' key will be removed from the hash and 'img_field_id' will be added, with the appropriate upload ID as the value.

store_uploads takes an optional second argument as well:

  my $entity = $u->store_uploads($form_data,$shared_meta);

This is a hash refeference of additional meta data that you want to store for all of the images you storing. For example, you may wish to store an "uploaded_user_id".

The keys should be column names that exist in your uploads table. The values should be appropriate data for the column. Only the key names defined by the up_table_map in new() will be used. Other values in the hash will be ignored.

delete_checked_uploads()

 my @fk_col_names = $u->delete_checked_uploads;

This method deletes all uploads and any generated files based on form input. Both files and meta data are removed.

It looks through all the field names defined in spec. For an upload named img_1, a field named img_1_delete is checked to see if it has a true value.

A list of the field names is returned, prepended with '_id', such as:

 img_1_id

The expectation is that you have foreign keys with these names defined in another table. Having the names is format allows you to easily set these fields to NULL in a database update:

 map { $entity->{$_} = undef } @fk_names;

NOTE: This method can not currently be used to delete a generated file by itself.

fk_meta()

 my $href = $u->fk_meta(
    table    => $table,
    where    => \%where,
    prefixes => \@prefixes,

Returns a hash reference of information about the file, useful for passing to a templating system. Here's an example of what the contents of $href might look like:

 {
     file_1_id     => 523,
     file_1_url    => 'http://localhost/images/uploads/523.pdf',
 }

If the files happen to be images and have their width and height defined in the database row, template variables will be made for these as well.

This is going to fetch the file information from the upload table for using the row where news.item_id = 23 AND news.file_1_id = uploads.upload_id.

This is going to fetch the file information from the upload table for using the row where news.item_id = 23 AND news.file_1_id = uploads.upload_id.

The %where hash mentioned here is a SQL::Abstract where clause. The complete SQL that used to fetch the data will be built like this:

 SELECT upload_id as id,width,height,extension
    FROM uploads, $table
    WHERE (upload_id = ${prefix}_id AND (%where_clause_expanded here));

Class Methods

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These are some handy class methods that you can use without the need to first create an object using new().

upload()

 # As a class method
 ($tmp_filename,$uploaded_mt,$file_name) =
    CGI::Uplooader->upload('file_field',$q);

 # As an object method
 ($tmp_filename,$uploaded_mt,$file_name) =
    $u->upload('file_field');

The function is responsible for actually uploading the file.

It can be called as a class method or an object method. As a class method, it's necessary to provide a query object as the second argument. As an object method, the query object given the constructor is used.

Input: - file field name

Output: - temporary file name - Uploaded MIME Type - Name of uploaded file (The value of the file form field)

Currently CGI.pm, CGI::Simple and Apache::Request and are supported.

Upload Methods

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These methods are high level methods to manage the file and meta data parts of an upload, as well its generated files. If you are doing something more complex or customized you may want to call or overide one of the below methods.

store_upload()

 my %entity_upload_extra = $u->store_upload(
    file_field    => $file_field,
    src_file      => $tmp_filename,
    uploaded_mt   => $uploaded_mt,
    file_name     => $file_name,
    shared_meta   => $shared_meta,  # optional
    id_to_update  => $id_to_update, # optional
 );

Does all the processing for a single upload, after it has been uploaded to a temp file already.

It returns a hash of key/value pairs as described in store_uploads().

create_store_gen_files()

 my %gen_file_ids = $u->create_store_gen_files(
        file_field      => $file_field,
        meta            => $meta_href,
        src_file        => $tmp_filename,
        gen_from_id => $gen_from_id,
    );

This method is responsible for creating and storing any needed thumbnails.

Input: - file_field: file field name - meta: a hash ref of meta data, as extract_meta would produce - src_file: path to temporary file of the file upload - gen_from_id: ID of upload that generated files will be made from

delete_upload()

  $u->delete_upload($upload_id);

This method is used to delete the meta data and file associated with an upload. Usually it's more convenient to use delete_checked_uploads than to call this method directly.

This method does not delete generated files for this upload.

delete_gen_files()

 $self->delete_gen_files($id);

Delete the generated files for a given file ID, from the file system and the database

Meta-data Methods

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extract_meta()

 $meta = $self->extract_meta($tmp_filename,$file_name,$uploaded_mt);

This method extracts and returns the meta data about a file and returns it.

Input:

 - Path to file to extract meta data from
 - the name of the file (as sent through the file upload file)
 - The mime-type of the file, as supplied by the browser

Returns: a hash reference of meta data, following this example:

 {
         mime_type => 'image/gif',
         extension => '.gif',
         bytes     => 60234,
         file_name => 'happy.txt',

         # only for images
         width     => 50,
         height    => 50,
 }

store_meta()

 my $id = $self->store_meta($file_field,$meta);

This function is used to store the meta data of a file upload.

Input:

 - file field name

 - A hashref of key/value pairs to be stored. Only the key names defined by the
   C<up_table_map> in C<new()> will be used. Other values in the hash will be
   ignored.

 - Optionally, an upload ID can be passed, causing an 'Update' to happen instead of an 'Insert'

Output: - The id of the file stored. The id is generated by store_meta().

delete_meta()

 my $dbi_rv = $self->delete_meta($id);

Deletes the meta data for a file and returns the DBI return value for this operation.

transform_meta()

 my %meta_to_display = $u->transform_meta(
        meta   => $meta_from_db,
        prefix => 'my_field',
        prevent_browser_caching => 0,
        fields => [qw/id url width height/],
    );

Prepares meta data from the database for display.

Input: - meta: A hashref, as might be returned from "SELECT * FROM uploads WHERE upload_id = ?"

 - prefix: the resulting hashref keys will be prefixed with this,
   adding an underscore as well.

 - prevent_browse_caching: If set to true, a random query string
   will be added, preventing browsings from caching the image. This is very
   useful when displaying an image an 'update' page. Defaults to true.

 - fields: An arrayef of fields to format. The values here must be
   keys in the C<up_table_map>. Two field names are special. 'C<id> is
   used to denote the upload_id. C<url> combines several fields into
   a URL to link to the upload.

Output: - A formatted hash.

See fk_meta() for example output.

get_meta()

 my $meta_href = $self->get_meta($id);

Returns a hashref of data stored in the uploads database table for the requested file id.

File Methods

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store_file()

 $self->store_file($file_field,$tmp_file,$id,$ext);

Stores an upload file or dies if there is an error.

Input: - file field name - path to tmp file for uploaded image - file id, as generated by store_meta() - file extension, as discovered by extract_meta()

Output: none

delete_file()

 $self->delete_file($id);

Call from within delete_upload, this routine deletes the actual file. Dont' delete the the meta data first, you may need it build the path name of the file to delete.

Utility Methods

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build_loc()

 my $up_loc = $self->build_loc($id,$ext);

Builds a path to access a single upload, relative to updir_path. This is used to both file-system and URL access. Also see the file_scheme option to new(), which affects it's behavior.

upload_field_names()

 # As a class method
 (@file_field_names) = CGI::Uploader->upload_field_names($q);

 # As an object method
 (@file_field_names) = $u->upload_field_names();

Returns the names of all form fields which contain file uploads. Empty file upload fields may be excluded.

This can be useful for auto-generating a spec.

Input: - A query object is required as input only when called as a class method.

Output: - an array of the file upload field names.

spec_names()

 $spec_names = $u->spec_names('file_field'):

With no arguments, returns an array of all the upload names defined in the spec, including any generated file names.

With one argument, a file field from the spec, can also be provided. It then returns that name as well as the names of any related generated files.

Contributing

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Patches, questions and feedback are welcome. I maintain CGI::Uploader using git. The public repo is here: https://github.com/markstos/CGI--Uploader

Author

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Mark Stosberg <mark@summersault.com>

Thanks

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A special thanks to David Manura for his detailed and persistent feedback in the early days, when the documentation was wild and rough.

Barbie, for the first patch.

License

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This program is free software; you can redistribute it and/or modify it under the terms as Perl itself.

CGI-Uploader documentation Contained in the CGI-Uploader distribution. 
package CGI::Uploader;

use 5.008;
use strict;
use Carp;
use Params::Validate ':all';
use File::Path;
use File::Spec;
use File::Temp 'tempfile';
use Carp::Assert;
use Image::Size;
require Exporter;

our $VERSION = '2.18';


sub new {
    my $proto = shift;
    my $class = ref($proto) || $proto;
    my %in = validate( @_, {
        updir_url    => { type => SCALAR },
        updir_path   => { type => SCALAR },
        dbh          => 1,
        up_table     => {
                          type => SCALAR,
                          default=> 'uploads',
        },
        temp_dir   => {
                type    => SCALAR,
                default => File::Spec->tmpdir()
        },
        up_table_map => {
                          type    => HASHREF,
                          default => {
                              upload_id       => 'upload_id',
                              mime_type       => 'mime_type',
                              extension       => 'extension',
                              width           => 'width',
                              height          => 'height',
                              gen_from_id     => 'gen_from_id',
#                              bytes      => 'bytes',
                          }
        },
        up_seq      => { default => 'upload_id_seq'},
        spec        => { type => HASHREF },
        query       => { optional => 1  } ,
        file_scheme => {
             regex   => qr/^simple|md5$/,
             default => 'simple',
        },

    });
    $in{db_driver} = $in{dbh}->{Driver}->{Name};
    # Support PostgreSQL via ODBC
    $in{db_driver} = 'Pg' if $in{dbh}->get_info(17) eq 'PostgreSQL';
    unless (($in{db_driver} eq 'mysql') or ($in{db_driver} eq 'Pg') or ($in{db_driver} eq 'SQLite')) {
        croak "only mysql, Pg and SQLite drivers are supported at this time. You are trying to use $in{db_driver}.";
    }

    unless ($in{query}) {
        require CGI;
        $in{query} = CGI->new;
    }

    # Process the spec
    for my $k (keys %{ $in{spec} }) {
        # If the spec is an arrayref, that's a shorthand for specifying some gen_files.
        if (ref $in{spec}->{$k} eq 'ARRAY') {
            $in{spec}->{$k} = {
                gen_files => $in{spec}->{$k},
            };
        }
    }

    # Fill in missing map values
    for (keys %{ $in{up_table_map} }) {
        $in{up_table_map}{$_} = $_ unless defined $in{up_table_map}{$_};
    }

    # keep pointer to input hash for easier re-use later
    $in{input} =\%in;

    my $self  = \%in;
    bless ($self, $class);
    return $self;
}


sub store_uploads {
    validate_pos(@_,1,1,0);
    my $self        = shift;
    my $form_data   = shift;
    my $shared_meta = shift;
    assert($form_data, 'store_uploads: input hashref missing');

    my $uploads = $self->{spec};

    my %entity_all_extra;
    for my $file_field (keys %$uploads) {
        # If we have an uploaded file for this
        my ($tmp_filename,$uploaded_mt,$file_name) = $self->upload($file_field);
        if ($tmp_filename) {
            my $id_to_update = $form_data->{$file_field.'_id'};

            my %entity_upload_extra = $self->store_upload(
                file_field    => $file_field,
                src_file      => $tmp_filename,
                uploaded_mt   => $uploaded_mt,
                file_name     => $file_name,
                shared_meta   => $shared_meta,
                id_to_update  => $id_to_update,
            );

            %entity_all_extra = (%entity_all_extra, %entity_upload_extra);
        }
    }

    # Now add and delete as needed
    my $entity = { %$form_data, %entity_all_extra };
    map { delete $entity->{$_} } keys %{ $self->{spec} };
    # For good measure.
    delete $entity->{''};

    File::Temp::cleanup();

    return $entity;
}


sub delete_checked_uploads {
    my $self = shift;
    my $imgs = $self->{spec};

    my $q = $self->{query};
    my $map = $self->{up_table_map};

    croak "missing gen_from_id in up_table_map"  unless $map->{gen_from_id};


    my @to_delete;

    for my $file_field (keys %$imgs) {
        if ($q->param($file_field.'_delete') ) {
            my $upload_id = $q->param($file_field.'_id') ||
                croak "$file_field was selected to delete,
                                        but ID was missing in '${file_field}_id' field";

            $self->delete_upload($upload_id);

            # Delete generated files  as well.
            my $gen_file_ids = $self->{dbh}->selectcol_arrayref(
                "SELECT $map->{upload_id}
                                        FROM $self->{up_table}
                                        WHERE $map->{gen_from_id} = ?",{},$upload_id) || [];

            for my $gen_file_id (@$gen_file_ids) {
                $self->delete_upload($gen_file_id);
            }

            push @to_delete, map {$_.'_id'} $self->spec_names($file_field) ;
        }

    }

    return @to_delete;
}



sub fk_meta {
    my $self = shift;
    my %p = validate(@_,{
        table    => { type => SCALAR },
        where    => { type => HASHREF },
        prefixes => { type => ARRAYREF },
        prevent_browser_caching => { default => 1 }
    });


    my $table = $p{table};
    my $where = $p{where};
    my @file_fields = @{ $p{prefixes} };

    my $DBH = $self->{dbh};
    my %fields;
    require SQL::Abstract;
    my $sql = SQL::Abstract->new;
    my ($stmt,@bind) = $sql->where($where);

    # We don't want the 'WHERE' word that SQL::Abstract adds
    $stmt =~ s/^\s?WHERE//;

    # XXX There is probably a more efficient way to get this data than using N selects

    # mysql uses non-standard quoting
    my $qt = ($DBH->{Driver}->{Name} eq 'mysql') ? '`' : '"';

    my $map = $self->{up_table_map};

    for my $field (@file_fields) {
        my $upload = $DBH->selectrow_hashref(qq!
                        SELECT *
                                FROM !.$self->{up_table}.qq!, $table AS t
                                WHERE ($self->{up_table}.$map->{upload_id} = t.${qt}${field}_id${qt} and ($stmt) )!,
                {},@bind);

            my %upload_fields = $self->transform_meta(
                meta => $upload,
                prevent_browser_caching => $p{prevent_browser_caching},
                prefix => $field,
            );
           %fields = (%fields, %upload_fields);

    }

    return \%fields;
}


sub upload {
    my $self = shift;
    my $file_field = shift;
    my $q = shift || $self->{query};

    my $fh;
    my $mt = '';
    my $filename = $q->param($file_field);

    if ($q->isa('CGI::Simple') ) {
        local $CGI::Simple::DISABLE_UPLOADS = 0;  # Having uploads enabled is mandatory for this to work.
        $fh = $q->upload($filename);
        $mt = $q->upload_info($filename, 'mime' );

        if (!$fh && $q->cgi_error) {
            warn $q->cgi_error && return undef;
        }
    }
    elsif ( $q->isa('Apache::Request') ) {
        my $upload = $q->upload($file_field);
        $fh = $upload->fh;
        $mt = $upload->type;
    }
    # default to CGI.pm behavior
    else {
        local $CGI::DISABLE_UPLOADS = 0;  # Having uploads enabled is mandatory for this to work.
        $fh = $q->upload($file_field);
        $mt = $q->uploadInfo($fh)->{'Content-Type'} if $q->uploadInfo($fh);

        if (!$fh && $q->cgi_error) {
            warn $q->cgi_error && return undef;
        }
    }

    return undef unless ($fh && $filename);

    my ($tmp_fh, $tmp_filename) = tempfile('CGIuploaderXXXXX', UNLINK => 1, DIR => $self->{'temp_dir'} );

    binmode($fh);

    require File::Copy;
    import  File::Copy;
    copy($fh,$tmp_filename) || croak "upload: unable to create tmp file: $!";

    return ($tmp_filename,$mt,$filename);
}


sub store_upload {
    my $self = shift;
    my %p = validate(@_, {
            file_field    => { type => SCALAR },
            src_file      => { type => SCALAR },
            uploaded_mt   => { type => SCALAR },
            file_name     => { type => SCALAR | GLOBREF },
            shared_meta   => { type => HASHREF | UNDEF,    default => {} },
            id_to_update  => { type => SCALAR | UNDEF, optional => 1 },
        });

    my (
        $file_field,
        $tmp_filename,
        $uploaded_mt,
        $file_name,
        $shared_meta,
        $id_to_update,
    ) = ($p{file_field},$p{src_file},$p{uploaded_mt},$p{file_name},$p{shared_meta},$p{id_to_update});

    # Transform file if needed
    if (my $meth = $self->{spec}{$file_field}{transform_method}) {
        $tmp_filename = $meth->( $self,
            $tmp_filename,
            $self->{spec}{$file_field}{params},
        );
    }

    # XXX The uploaded mime type may have nothing to do with
    # the current mime-type after it's transformed
    my $meta = $self->extract_meta($tmp_filename,$file_name,$uploaded_mt);

    $shared_meta ||= {};
    my $all_meta = { %$meta, %$shared_meta };

    my $id;
    # If it's an update
    if ($id = $id_to_update) {
        # delete old generated files  before we create new ones
        $self->delete_gen_files($id);

        # It's necessary to delete the old file when updating, because
        # the new one may have a new extension.
        $self->delete_file($id);
    }

    # insert or update will be performed as appropriate.
    $id = $self->store_meta(
        $file_field,
        $all_meta,
        $id );

    $self->store_file($file_field,$id,$meta->{extension},$tmp_filename);

    my %ids = ();
       %ids = $self->create_store_gen_files(
      file_field  => $file_field,
      meta        => $all_meta,
      src_file    => $tmp_filename,
      gen_from_id => $id,
    );

    return (%ids, $file_field.'_id' => $id);

}


sub create_store_gen_files {
    my $self = shift;
    my %p = validate(@_, {
            file_field       => { type => SCALAR },
            src_file         => { type => SCALAR },
            meta             => { type => HASHREF | UNDEF,    default => {} },
            gen_from_id  => { regex => qr/^\d*$/, },
        });
    my ($file_field,
        $meta,
        $tmp_filename,
        $gen_from_id) = ($p{file_field},$p{meta},$p{src_file},$p{gen_from_id});

    my $gen_fields_key = $self->{spec}{$file_field}{gen_files} || return undef;
    my @gen_files = keys %{ $gen_fields_key };

    my $gen_files = $self->{spec}{$file_field}{gen_files};
    my $q = $self->{query};
    my %out;

    my ($w,$h) = ($meta->{width},$meta->{height});
    for my $gen_file (@gen_files) {
        my $gen_tmp_filename;

        # tranform as needed
        my $gen_file_key = $self->{spec}{$file_field}{gen_files}{$gen_file};
        # Recommended code ref API
        if (ref  $gen_file_key eq 'CODE') {
            # It needed any params, they should already have been provided via closure.
            $gen_tmp_filename = $gen_file_key->($self,$tmp_filename);
        }
        # Old, yucky hashref API
        elsif (ref $gen_file_key eq 'HASH') {
            my $meth = $gen_file_key->{transform_method};
            $gen_tmp_filename = $meth->(
                $self,
                $tmp_filename,
                $gen_file_key->{params},
            );
        }
        else {
            croak "$gen_file for $file_field was not a hashref or code ref. Check spec syntax.";
        }

        # inherit mime-type and extension from parent
        # but merge in updated details for this file
        my $meta_from_gen_file = $self->extract_meta($gen_tmp_filename,$gen_file);
           $meta_from_gen_file ||= {};
        my %t_info =  (%$meta, gen_from_id => $gen_from_id, %$meta_from_gen_file);



        # Try to get image dimensions (will fail safely for non-images)
        #($t_info{width}, $t_info{height}) = imgsize($gen_tmp_filename);

        # Insert
        my $id = $self->store_meta($gen_file, \%t_info );

        # Add to output hash
        $out{$gen_file.'_id'} = $id;

        $self->store_file($gen_file,$id,$t_info{extension},$gen_tmp_filename);
    }
    return %out;
}


sub delete_upload {
    my $self = shift;
    my ($id) = @_;

    $self->delete_file($id);
    $self->delete_meta($id);

}


sub delete_gen_files {
    validate_pos(@_,1,1);
    my ($self,$id) = @_;

    my $dbh = $self->{dbh};
    my $map = $self->{up_table_map};

    my $gen_file_ids_aref = $dbh->selectcol_arrayref(
        "SELECT   $map->{upload_id}
                        FROM  ".$self->{up_table}. "
                        WHERE $map->{gen_from_id} = ?",{},$id) || [];

    for my $gen_file_id (@$gen_file_ids_aref) {
        $self->delete_file($gen_file_id);
        $self->delete_meta($gen_file_id);
    }

}


sub extract_meta {
    validate_pos(@_,1,1,1,0);
    my $self = shift;
    my $tmp_filename = shift;
    my $file_name = shift;
    my $uploaded_mt = shift || '';

    #   Determine and set the appropriate file system parsing routines for the
    #   uploaded path name based upon the HTTP client header information.
    use HTTP::BrowserDetect;
    my $client_os = $^O;
    my $browser = HTTP::BrowserDetect->new;
    $client_os = 'MSWin32' if $browser->windows;
    $client_os = 'MacOS'   if $browser->mac;
    $client_os = 'Unix'    if $browser->macosx;
    require File::Basename;
    File::Basename::fileparse_set_fstype($client_os);
    $file_name = File::Basename::fileparse($file_name,[]);


   require File::MMagic;
   my $mm = File::MMagic->new;

   # If the uploaded  mime_type was not provided  calculate one from the file magic number
   # if that does not exist, fall back on the file name
   my $fm_mt = $mm->checktype_magic($tmp_filename);
      $fm_mt = $mm->checktype_filename($tmp_filename) if (not defined $fm_mt or not length $fm_mt) ;

   my $mt = ($uploaded_mt || $fm_mt);
   assert($mt,'found mime type');


   use MIME::Types;
   my $mimetypes = MIME::Types->new;
   my MIME::Type $t = $mimetypes->type($mt);
   my @mt_exts = $t ? $t->extensions : undef;

   my $ext;

   # figure out an extension
   my ($uploaded_ext) = ($file_name =~ m/\.([\w\d]*)?$/);

   # If there is at least one MIME-type found
   if ($mt_exts[0]) {
        # If the upload extension is one recognized by MIME::Type, use it.
        if ((defined $uploaded_ext)
            and (grep {/^$uploaded_ext$/} @mt_exts)) {
            $ext = $uploaded_ext;
        }
        # otherwise, use one from MIME::Type, just to be safe
        else {
            $ext = $mt_exts[0];
        }
   }
   else {
       # If is a provided extension but no MIME::Type extension, use that.
       # It's possible that there no extension uploaded or found)
       $ext = $uploaded_ext;
   }

   if ($ext) {
        $ext = ".$ext" if $ext;
   }
   else {
       croak "no extension found for file name: $file_name";
   }


   # Now get the image dimensions if it's an image
    my ($width,$height) = imgsize($tmp_filename);

    return {
        file_name => $file_name,
        mime_type => $mt,
        extension => $ext,
        bytes     => (stat ($tmp_filename))[7],

        # only for images
        width     => $width,
        height    => $height,
    };


}


sub store_meta {
    validate_pos(@_,1,1,1,0);
    my $self = shift;

    # Right now we don't use the the file field name
    # It seems like a good idea to have in case you want to sub-class it, though.
    my $file_field  = shift;
    my $href = shift;
    my $id = shift;

    my $DBH = $self->{dbh};

    require SQL::Abstract;
    my $sql = SQL::Abstract->new;
    my $map = $self->{up_table_map};
    my %copy = %$href;

    my $is_update = 1 if $id;

    if (!$is_update && $self->{db_driver} eq 'Pg') {
        $id = $DBH->selectrow_array("SELECT NEXTVAL('".$self->{up_seq}."')");
    $copy{$map->{upload_id} } = $id;
    }

    my @orig_keys = keys %copy;
    for (@orig_keys) {
        if (exists $map->{$_}) {
            # We're done if the names are the same
            next if ($_ eq $map->{$_});

            # Replace each key name with the mapped name
            $copy{ $map->{$_} } = $copy{$_};

        }
        # The original field is now duplicated in the hash or unknown.
        # delete in either case.
        delete $copy{$_};
    }

    my ($stmt,@bind);
    if ($is_update) {
     ($stmt,@bind)   = $sql->update($self->{up_table},\%copy, { $map->{upload_id} => $id });
    }
    else {
     ($stmt,@bind)   = $sql->insert($self->{up_table},\%copy);
    }

    $DBH->do($stmt,{},@bind);
    if (!$is_update && $self->{db_driver} eq 'mysql') {
        $id = $DBH->{'mysql_insertid'};
    }
    if (!$is_update && $self->{db_driver} eq 'SQLite') {
      $id = $DBH->func('last_insert_rowid')
    }

    return $id;
}


sub delete_meta {
    validate_pos(@_,1,1);
    my $self = shift;
    my $id = shift;

    my $DBH = $self->{dbh};
    my $map = $self->{up_table_map};

   return $DBH->do("DELETE from ".$self->{up_table}." WHERE $map->{upload_id} = $id");

}


sub transform_meta  {
    my $self = shift;
    my %p = validate(@_, {
        meta   => { type => HASHREF },
        prefix => { type => SCALAR  },
        prevent_browser_caching => { default => 1 },
        fields => { type => ARRAYREF ,
                    default => [qw/id url width height/],
                },
        });
#   return undef unless (ref $p{meta} eq 'HASH');

    my $map = $self->{up_table_map};

    my %result;

    my $qs;
    if ($p{prevent_browser_caching})  {
        # a random number to defeat image caching. We may want to change this later.
        my $rand = (int rand 100);
        $qs = "?$rand";
    }

    my %fields = map { $_ => 1 } @{ $p{fields} };

    if ($fields{url}) {
        $result{$p{prefix}.'_url'} = $self->{updir_url}.'/'.
            $self->build_loc(
                $p{meta}{ $map->{upload_id} }
               ,$p{meta}{ $map->{extension} })
               .$qs ;
        delete $fields{url};
    }

    if (exists $fields{id}) {
        $result{$p{prefix}.'_id'} = $p{meta}->{ $map->{upload_id} };
        delete $fields{id};
    }

    for my $k (keys %fields) {
        my $v = $p{meta}->{ $map->{$k} };
        $result{$p{prefix}.'_'.$k} = $v if defined $v;
    }

    return %result;


}


sub get_meta {
  validate_pos(@_,1,1);
  my ($self,$id) = @_;

  my $map = $self->{up_table_map};
  return  $self->{dbh}->selectrow_hashref("
                        SELECT * FROM $self->{up_table}
                                WHERE $map->{upload_id} = ?",{},$id);
}




sub store_file {
    validate_pos(@_,1,1,1,1,1);
    my $self = shift;
    my ($file_field,$id,$ext,$tmp_file) = @_;
    assert($ext, 'have extension');
    assert($id,'have id');
    assert(-f $tmp_file,'tmp file exists');
    assert(-d $self->{updir_path},'updir_path is a directory');
    assert(-w $self->{updir_path},'updir_path is writeable');

    require File::Copy;
    import File::Copy;
    copy($tmp_file, File::Spec->catdir($self->{updir_path},$self->build_loc($id,$ext)) )
    || croak "Unexpected error occured when uploading the image: $!";

}


sub delete_file {
    validate_pos(@_,1,1);
    my $self = shift;
    my $id   = shift;

    my $map = $self->{up_table_map};
    my $dbh = $self->{dbh};

    my $ext = $dbh->selectrow_array("
                SELECT $map->{extension}
                        FROM $self->{up_table}
                        WHERE $map->{upload_id} = ?",{},$id);
    $ext || croak "found no extension in meta data for ID $id. Deleting file failed.";


    my $file = $self->{updir_path}.'/'.$self->build_loc($id,$ext);

    if (-e $file) {
        unlink $file || croak "couldn't delete upload  file: $file:  $!";
    }
    else {
        warn "file to delete not found: $file";
    }

}


sub build_loc {
    validate_pos(@_,1,1,0);
    my ($self,$id,$ext) = @_;

    my $scheme = $self->{file_scheme};

    my $loc;
    if ($scheme eq 'simple') {
        $loc = "$id$ext";
    }
    elsif ($scheme eq 'md5') {
        require Digest::MD5;
        import Digest::MD5 qw/md5_hex/;
        my $md5_path = md5_hex($id);
        $md5_path =~ s|^(.)(.)(.).*|$1/$2/$3|;

        my $full_path = $self->{updir_path}.'/'.$md5_path;
        unless (-e $full_path) {
            mkpath($full_path);
        }


        $loc = File::Spec->catdir($md5_path,"$id$ext");
    }
}


sub upload_field_names {
    my $self = shift;
    my $q = shift || $self->{query};

    my @file_field_names;
    if ( $q->isa('CGI::Simple') ) {
        my @list_of_files   = $q->upload;
        my @all_field_names = $q->param();
        for my $field (@all_field_names) {
            my $potential_file_name = $q->param($field);
            push @file_field_names, $field , if grep {m/^$potential_file_name/} @list_of_files;
        }
    }
    elsif ($q->isa('Apache::Request') ) {
        @file_field_names = map { $_->name } @{ $q->upload() };
    }
    # default to CGI.pm behavior
    else  {
        my @all_field_names = $q->param();
        for my $field (@all_field_names) {
            push @file_field_names, $field , if $q->upload($field);
        }
    }

    return @file_field_names;

}







sub spec_names {
    my $self = shift;
    my $spec_key = shift;

    my $all_keys = $self->{spec};

    # only use $spec_key if it was passed in
    my @primary_spec_keys_to_use  =  (defined $spec_key) ? $spec_key  : keys %$all_keys;

    my @gen_files = @primary_spec_keys_to_use,
        map { keys %{ $all_keys->{$_}{gen_files} } } @primary_spec_keys_to_use;
}

1;
__END__