Awesome

Data server for https://humdrum.nifc.pl

This repository contains the files for the https://humdrum.nifc.pl website that serves score data files for POPC-1 and POPC-2 projects at NIFC. A mirror of the data server is also running from the URL https://data.nifc.humdrum.org in case the main server is down.

Primary files

The primary data is stored in Humdrum files. These are initially linked (or less preferably copied) to the ./kern directory). The ./Makefile contains a list of the source location for all Humdrum files to be added to the ./kern directory. Adjust the KERNREPOS variable in the Makefile to point to directories in POPC-1 and POPC-2 that contain source Humdrum files that will be managed by the server.

Then the command:

make kern

Creates symbolic links from the source locations into the ./kern directory. Once links to Humdrum files are in the ./kern directory, the caching process can begin.

This data server is designed to manage digital scores from the POPC1 and POPC2 projects of the Fryderyk Chopin Institute:

Cache preparation

The ./cache directory stores a copy of the Humdrum data as well as derivative formats and analyses created from each file. An MD5 checksum is calculated for each Humdrum file to create an 8-digit ID for that file to uniquely identify the contents. The Humdrum file is then copied to a subdirectory named with that ID. All translations and analysis files related to the Humdrum file are also placed in the same subdirectory.

Cache maintenance commands

First, create an index that maps file IDs, century enumerations and SQL enumerations that link to the MD5-derived cache ID:

cd cache
make index

This will read all of the files in ./kern to create the index file ./cache/index-new.hmd.

Next, copy the Humdrum files into the cache with this command:

make copy-kern

This will insert any new Humdrum files into the cache that are not already in the cache.

Next, create derivative files (data translations and analyses) with the following command:

make derivatives

This will create data conversion and pre-compiled analyses for each new Humdrum file.

After derivatives have been created, the new version of the database can be activated by typing the command:

make publish

This will move ./cache/index.hmd to ./cache/index-old.hmd and then move ./cache/index-new.hmd to ./cache/index.hmd. The file ./cache/index.hmd is used to map various file identifier systems to the cached version of the Humdrum file.

Optionally, run the command:

make purge

to remove older and deleted versions of the Humdrum files from the cache system. These files will be placed in the ./cache/purge folder for review.

There is also a command to do all of the above steps at one time (except purging) in the base directory:

make update

Or to run the update process in the backgroud using nohup:

make un

URL data access

Data and analysis files stored in the cache directory can be accessed on the web via the following example URLs. The primary data server is at https://humdrum.nifc.pl, with a mirror server at https://data.nifc.humdrum.org (useful if the main server is down). The files in this repository can also be downloaded to use as additional mirrors of the data server.

Setup

See also https://bit.ly/polishscores-maintenance

Apache web server

An example Apache web server configuration is given in cgi-bin/apache.config. The important part of the configuration is:

RewriteEngine On
RewriteRule ^/([^?]*\?(.*))$ /cgi-bin/data-nifc?id=$1&$2 [NC,PT,QSA]
RewriteRule ^/([^?]*)$ /cgi-bin/data-nifc?id=$1 [NC,PT,QSA]
Header add Access-Control-Allow-Origin "*"

The Header line is important in order to allow cross-origin access to the data files.

The rewrite rules are used to simplify the URLs for data access. Access to the data appears as if it were a static file, but the server converts this filename into an id parameter that is passed on to the data-nifc CGI script.

CGI script

The interface between the URL and internal access to data is done with the CGI script cgi-bin/data-nifc.pl. Copy this file (via cgi-bin/Makefile) to the location for CGI scripts for the server.

Support software

Here is a description of support software needed to create derivatives files for the cache.

verovio

Install verovio on the server with these commands:

git clone https://github.com/rism-digital/verovio
cd verovio/tools
./.configure
make
make install

Note that cmake is required (and must first be installed if not available).

Verify that verovio was installed by running the command:

which verovio

which should reply /usr/local/bin/verovio.

aton2json

The aton2json program can be installed with these commands:

npm install -g posix-argv-parser
npm install -g aton2json
wget https://raw.githubusercontent.com/craigsapp/ATON/master/example/cli/aton2json -O /usr/local/bin/aton2json

Verify that aton2json was installed by running the command:

which aton2json

which should reply /usr/local/bin/aton2json

SELinux notes

To allow CGI scripts to run programs in a shell when SELinux, turn on the general permission with the command:

setsebool -P httpd_execmem 1

Then give permissions to run a particular program:

chcon system_u:object_r:httpd_exec_t:s0 program-file

For data access logging, the log directory should be given SELinux permissions:

chcon -R -t httpd_sys_content_t logs

And the web server should be made owner of the log directory.