NAME

uSAC::MIME - MIME Type database with concise lookups

SYNOPSIS

    use uSAC::MIME;

    #Create a new DB using inbuild data
    my $db=uSAC::MIME->new;         

    #Database with no entries
    my $db=uSAC::MIME->new_empty;

    #Create data base from contents of file
    my $db=uSAC::MIME->new_from_file("path_to_nginx_or_apache_mime");

    #Create default from internal database and then add a custom entry
    my $db=uSAC::MIME->new("xyz"=>"special/type");


    #Add a custom entry to an existing database
    $db->add("abc"=>"another/type");

    #Remove a file extension from a mime type
    $db->rem("abc"=>"another/type");


    #Index the database. Forward only mapping in scalar context
    my $forward=$db->index;
    
    #Index the database. Forward and reverse mapping in list context
    my ($forward,$reverse)=$db->index;



    #Do Lookups 
    $forward->{txt};           #return  "text/plain"
    $backward->{"text/plain"}; #returns a array ref of extension

DESCRIPTION

Provides concise file extension to MIME type (forward) mapping and MIME type to file extension set (backwards) mapping.

Features include:

• Internal Default Database

  Internally it has its own MIME database source, however when you create a new instance you receive a copy which you can add or remove entries as you please.

• Load and Save from file

  An external MIME type database in nginx or Apache formats can be used to create an instance

• Low overhead

  The database in indexed into a anonymous hash ref for direct lookup

Motivation

Performance. The indexed database is a straight perl hash so no method or subroutine overheads. When responding to as many HTTP requests as possible, this seemed like easy pickings to improve performance.

What this module doesn't do

It is not a general purpose MIME type manipulator or generator. Module such as MIME::Type more suited for that purpose.

It also doesn't export and lookup methods/subs. All lookups are done via the hashes returned from calling the index method

File paths are not really handled. You need to split them off before hand.

API

Constructors

new(%mappings_to_add)

Creates a new mime database from the internal database. Adds the optional mappings to it The index method needs to be called on the returned object to perform lookups

new_empty(%mappings_to_add)

Creates a new empty database. Adds the optional mappings to it The index method needs to be called on the returned object to perform lookups

File IO

load_from_handle

Reads the contents of a handle and adds it to the db

save_to_handle

Writes out the DB as a text to the specified handle

Indexing

index

Generates the hash tables for forward (extension to mime) mappings, and backwards(mime to extension set) mapping.

    my ($forward,$backward)=$db->index; $forward->{"txt");

Database Manipulation

add

Adds a single mapping from file extension to mime type. The index method will need to be called after to construct a new lookup hashes

rem

Removes a single mapping from file extension to mime type. The index method will need to be called after to construct a new lookup hashes

Forward Lookups

Once indexed, lookups are simply done via hash reference:

    my $forward=$db->index; #Previously index db to $forward
    
    $forward->{ext};        #Direct hash lookup

A single MIME type will be returned in the forward lookup. If the hash doesn't contain the extension to MIME mapping, undef is returned.

Reverse Lookups

To get the reverse lookup table, list context must be used when indexing:

    my ($forward, $revsere)=$db->index; #previously index

    $reverse->{mime};       #Direct hash lookup

An anonymous array of extension types are returned with zero or more file extensions

Default/Fallback

When forward lookups fails to locate a MIME type for the extension, use the 'defined or' operator to specify a fallback.

    $forward->{unkown_extension}//"my_default/type";

For reverse lookup failure, an empty anonymous array is returned.

    my @exts=$reverse->{unkown_mime}->@*||qw<my_default>;

PERFORMANCE

A very basic benchmark of performing a forward lookup of a "txt" extension. Comparing this modules to Plack::MIME and MIME::Detect locally on my laptop give the following lookup rates:

    Module                 Lookup rate

    MIME::Detect                 167/s
    Plack::MIME              5208333/s
    uSAC::MIME              43478261/s

REPOSITORY

Checkout the repo at https://github.com/drclaw1394/perl-usac-mime

AUTHOR

Ruben Westerberg

COPYRIGHT

Copyright (C) 2022 Ruben Westerberg

LICENSE

MIT or Perl, whichever you choose.