NAME

    Statistics::Covid - Fetch, store in DB, retrieve and analyse Covid-19
    statistics from data providers

VERSION

    Version 0.23

DESCRIPTION

    This module fetches, stores in a database, retrieves from a database
    and analyses Covid-19 statistics from online or offline data providers,
    such as from the John Hopkins University
    <https://www.arcgis.com/apps/opsdashboard/index.html#/bda7594740fd40299423467b48e9ecf6>
    which I hope I am not obstructing (please send an email to the author
    if that is the case).

    After specifying one or more data providers (as a url and a header for
    data and optionally for metadata), this module will attempt to fetch
    the latest data and store it in a database (SQLite and MySQL, only
    SQLite was tested so far). Each batch of data should ideally contain
    information about one or more locations and at a given point in time.
    All items in this batch are extracted and stored in DB each with its
    location name and time (it was published, not fetched) as primary keys.
    Each such data item (Datum) is described in
    Statistics::Covid::Datum::Table and the relevant class is
    Statistics::Covid::Datum. It contains fields such as: population,
    confirmed, unconfirmed, terminal, recovered.

    Focus was on creating very high-level which distances as much as
    possible the user from the nitty-gritty details of fetching data using
    LWP::UserAgent and dealing with the database using DBI and DBIx::Class.

    This is an early release until the functionality and the table schemata
    solidify.

SYNOPSIS

            use Statistics::Covid;
            use Statistics::Covid::Datum;
            
            $covid = Statistics::Covid->new({   
                    'config-file' => 't/example-config.json',
                    'providers' => ['UK::BBC', 'UK::GOVUK', 'World::JHU'],
                    'save-to-file' => 1,
                    'save-to-db' => 1,
                    'debug' => 2,
            }) or die "Statistics::Covid->new() failed";
            # fetch all the data available (posibly json), process it,
            # create Datum objects, store it in DB and return an array 
            # of the Datum objects just fetched  (and not what is already in DB).
            my $newobjs = $covid->fetch_and_store();
            
            print $_->toString() for (@$newobjs);
            
            print "Confirmed cases for ".$_->name()
                    ." on ".$_->date()
                    ." are: ".$_->confirmed()
                    ."\n"
            for (@$newobjs);
            
            my $someObjs = $covid->select_datums_from_db({
                    'conditions' => {
                            belongsto=>'UK',
                            name=>'Hackney'
                    }
            });
            
            print "Confirmed cases for ".$_->name()
                    ." on ".$_->date()
                    ." are: ".$_->confirmed()
                    ."\n"
            for (@$someObjs);
            
            # or for a single place (this sub sorts results wrt publication time)
            my $timelineObjs = $covid->select_datums_from_db_for_specific_location_time_ascending('Hackney');
            # or for a wildcard match
            # $covid->select_datums_from_db_for_specific_location_time_ascending({'like'=>'Hack%'});
            # and maybe specifying max rows
            # $covid->select_datums_from_db_for_specific_location_time_ascending({'like'=>'Hack%'}, {'rows'=>10});
            for my $anobj (@$timelineObjs){
                    print $anobj->toString()."\n";
            }
    
            print "datum rows in DB: ".$covid->db_count_datums()."\n"
    
            use Statistics::Covid::Analysis::Plot;
    
            # plot something
            my $objs = $io->db_select({
                    conditions => {belongsto=>'UK', name=>{'like' => 'Ha%'}}
            });
            my $outfile = 'chartclicker.png';
            my $ret = Statistics::Covid::Analysis::Plot::plot_with_chartclicker({
                    'datum-objs' => $objs,
                    # saves to this file:
                    'outfile' => $outfile,
                    # plot this column (x-axis is time always)
                    'Y' => 'confirmed', 
                    # and make several plots, each group must have 'name' common
                    'GroupBy' => ['name']
            });
            

EXAMPLE SCRIPT

    script/statistics-covid-fetch-data-and-store.pl is a script which
    accompanies this distribution. It can be used to fetch any data from
    specified providers using a specified configuration file.

    For a quick start:

        cp t/example-config.json config.json
        # optionally modify config.json to change the destination data dirs
        # now fetch data from some default data providers:
        script/statistics-covid-fetch-data-and-store.pl --config-file config.json

    The above will fetch the latest data and insert it into an SQLite
    database in data/db/covid19.sqlite directory. When this script is
    called again, it will fetch the data again and will be saved into a
    file timestamped with publication date. So, if data was already fetched
    it will be simply overwritten by this same data.

    As far as updating the database is concerned, only newer, up-to-date
    data will be inserted. So, calling this script, say once or twice will
    make sure you have the latest data without accummulating it
    redundantly.

    But please call this script AT MAXIMUM one or two times per day so as
    not to obstruct public resources. Please, Please.

    When the database is up-to-date, analysis of data is the next step.

    In the synopis, it is shown how to select records from the database, as
    an array of Statistics::Covid::Datum objects. Feel free to share any
    modules you create on analysing this data, either under this namespace
    (for example Statistics::Covid::Analysis::XYZ) or any other you see
    appropriate.

CONFIGURATION FILE

    Below is an example configuration file which is essentially JSON with
    comments. It can be found in t/example-config.json relative to the root
    directory of this distribution.

            # comments are allowed, otherwise it is json
            # this file does not get eval'ed, it is parsed
            # only double quotes! and no excess commas
            {
                    # fileparams options
                    "fileparams" : {
                            # dir to store datafiles, each DataProvider class
                            # then has its own path to append
                            "datafiles-dir" : "datazz/files"
                    },
                    # database IO options
                    "dbparams" : {
                            # which DB to use: SQLite, MySQL (case sensitive)
                            "dbtype" : "SQLite",
                            # the name of DB
                            # in the case of SQLite, this is a filepath
                            # all non-existing dirs will be created (by module, not by DBI)
                            "dbdir" : "datazz/db",
                            "dbname" : "covid19.sqlite",
                            # how to handle duplicates in DB? (duplicate=have same PrimaryKey)
                            # only-better : replace records in DB if outdated (meaning number of markers is less, e.g. terminal or confirmed)
                            # replace     : force replace irrespective of markers
                            # ignore      : if there is a duplicate in DB DONT REPLACE/DONT INSERT
                            # (see also Statistics::Covid::Datum for up-to-date info)
                            "replace-existing-db-record" : "only-better",
                            # username and password if needed
                            # unfortunately this is in plain text
                            # BE WARNED: do not store your main DB password here!!!!
                            # perhaps create a new user or use SQLite
                            # there is no need for these when using SQLite
                            "hostname" : "", # must be a string (MySQL-related)
                            "port"     : "", # must be a string (MySQL-related)
                            "username" : "", # must be a string
                            "password" : "", # must be a string
                            # options to pass to DBI::connect
                            # see https://metacpan.org/pod/DBI for all options
                            "dbi-connect-params" : {
                                    "RaiseError" : 1, # die on error
                                    "PrintError" : 0  # do not print errors or warnings
                            }
                    }
            }

DATABASE SUPPORT

    SQLite and MySQL database types are supported through the abstraction
    offered by DBI and DBIx::Class.

    However, only the SQLite support has been tested.

    Support for MySQL is totally untested.

AUTHOR

    Andreas Hadjiprocopis, <bliako at cpan.org>, <andreashad2 at gmail.com>

BENCHMARKS

    There are some benchmark tests to time database insertion and retrieval
    performance. These are optional and will not be run unless explicitly
    stated via make bench

    These tests do not hit the online data providers at all. And they
    should not, see ADDITIONAL TESTING for more information on this. They
    only time the creation of objects and insertion to the database.

ADDITIONAL TESTING

    Testing the DataProviders is not done because it requires network
    access and hits on the providers which is not fair. However, there are
    targets in the Makefile for initiating the "network" tests by doing
    make network .

CAVEATS

    This module has been put together very quickly and under pressure.
    There are must exist quite a few bugs. In addition, the database
    schema, the class functionality and attributes are bound to change. A
    migration database script may accompany new versions in order to use
    the data previously collected and stored.

    Support for MySQL is totally untested. Please use SQLite for now or
    test the MySQL interface.

    Support for Postgres has been somehow missed but is underway!.

BUGS

    This module has been put together very quickly and under pressure.
    There are must exist quite a few bugs.

    Please report any bugs or feature requests to bug-statistics-Covid at
    rt.cpan.org, or through the web interface at
    http://rt.cpan.org/NoAuth/ReportBug.html?Queue=Statistics-Covid. I will
    be notified, and then you'll automatically be notified of progress on
    your bug as I make changes.

SUPPORT

    You can find documentation for this module with the perldoc command.

        perldoc Statistics::Covid

    You can also look for information at:

      * github repository
      <https://github.com/hadjiprocopis/statistics-covid> which will host
      data and alpha releases

      * RT: CPAN's request tracker (report bugs here)

      http://rt.cpan.org/NoAuth/Bugs.html?Dist=Statistics-Covid

      * AnnoCPAN: Annotated CPAN documentation

      http://annocpan.org/dist/Statistics-Covid

      * CPAN Ratings

      http://cpanratings.perl.org/d/Statistics-Covid

      * Search CPAN

      http://search.cpan.org/dist/Statistics-Covid/

      * Information about the basis module DBIx::Class

      http://search.cpan.org/dist/DBIx-Class/

DEDICATIONS

    Almaz

ACKNOWLEDGEMENTS

    Perlmonks <https://www.perlmonks.org> for supporting the world with
    answers and programming enlightment

    DBIx::Class

    the data providers:

      John Hopkins University
      <https://www.arcgis.com/apps/opsdashboard/index.html#/bda7594740fd40299423467b48e9ecf6>,

      UK government
      <https://www.gov.uk/government/publications/covid-19-track-coronavirus-cases>,

      https://www.bbc.co.uk (for disseminating official results)

LICENSE AND COPYRIGHT

    Copyright 2020 Andreas Hadjiprocopis.

    This program is free software; you can redistribute it and/or modify it
    under the terms of the the Artistic License (2.0). You may obtain a
    copy of the full license at:

    http://www.perlfoundation.org/artistic_license_2_0

    Any use, modification, and distribution of the Standard or Modified
    Versions is governed by this Artistic License. By using, modifying or
    distributing the Package, you accept this license. Do not use, modify,
    or distribute the Package, if you do not accept this license.

    If your Modified Version has been derived from a Modified Version made
    by someone other than you, you are nevertheless required to ensure that
    your Modified Version complies with the requirements of this license.

    This license does not grant you the right to use any trademark, service
    mark, tradename, or logo of the Copyright Holder.

    This license includes the non-exclusive, worldwide, free-of-charge
    patent license to make, have made, use, offer to sell, sell, import and
    otherwise transfer the Package with respect to any patent claims
    licensable by the Copyright Holder that are necessarily infringed by
    the Package. If you institute patent litigation (including a
    cross-claim or counterclaim) against any party alleging that the
    Package constitutes direct or contributory patent infringement, then
    this Artistic License to you shall terminate on the date that such
    litigation is filed.

    Disclaimer of Warranty: THE PACKAGE IS PROVIDED BY THE COPYRIGHT HOLDER
    AND CONTRIBUTORS "AS IS' AND WITHOUT ANY EXPRESS OR IMPLIED WARRANTIES.
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