HotCRP Conference Review Software

HotCRP is awesome software for managing review processes, especially for academic conferences. It supports paper submission, review and comment management, rebuttals, and PC meetings. Its main strengths are flexibility and ease of use for reviewers, especially through smart paper search and tagging. It has been widely used in computer science conferences and for internal review processes at several large companies.

HotCRP is the open-source version of the software running on hotcrp.com. If you want to run HotCRP without setting up your own server, use hotcrp.com.

Getting help

Extensive online help has more on configuring and using HotCRP. See also:

• HotCRP development manual: Learn about advanced configuration, software internals, and developing extensions.
• HotCRP OpenAPI specification: Defines the HotCRP API (local specification in devel/openapi.json).
• Hotcrapi: Command-line interface for HotCRP API access.

Prerequisites

HotCRP runs on Unix, including Mac OS X. It requires the following software:

• Nginx, https://nginx.org/
  (Or Apache, or another web server that works with PHP)
• PHP version 8.1 or higher, http://php.net/
  • Including MySQL support, php-fpm, and php-intl
  • Some features may require later versions of PHP.
• MariaDB, https://mariadb.org/
• Poppler’s version of pdftohtml, https://poppler.freedesktop.org/ (only required for format checking)

You may need to install additional packages, such as php85, php85-fpm, php85-intl, php85-mysqlnd, zip, poppler-utils, and sendmail or postfix.

Installation

1. Run lib/createdb.sh to create the database. Use lib/createdb.sh OPTIONS to pass options to MariaDB, such as --user and --password. Many MariaDB installations require privilege to create tables, so you may need sudo lib/createdb.sh OPTIONS. Run lib/createdb.sh --help for more information. You will need to decide on a name for your database (no spaces allowed).

   The username and password information for the conference database is stored in conf/options.php. You must ensure that your PHP can read this file; it is marked as world-unreadable by default.

   If you don’t want to run lib/createdb.sh, you will have to create your own database and user, initialize the database with the contents of src/schema.sql, and create conf/options.php (using etc/distoptions.php as a guide).

2. Edit conf/options.php, which is annotated to guide you.

3. Configure your web server so that all accesses to the HotCRP site are handled by HotCRP’s index.php script. The right way to do this depends on your choice of server. We recommend using php-fpm with Nginx, but Apache also works. In the following examples, SITE/testconf is configured for a HotCRP installation in /home/kohler/hotcrp.

   Nginx: Configure Nginx to redirect accesses to php-fpm and the HotCRP index.php script. This example code would go in a server block, and assumes that php-fpm is listening on port 9000:

   location /testconf/ {
       fastcgi_pass 127.0.0.1:9000;
       fastcgi_split_path_info ^(/testconf)(/[\s\S]*)$;
       fastcgi_param SCRIPT_FILENAME /home/kohler/hotcrp/index.php;
       include fastcgi_params;
   }
   

   Apache with mod_proxy and php-fpm: Add a ProxyPass.

   ProxyPass "/testconf" "fcgi://localhost:9000/home/kohler/hotcrp/index.php"
   

   (If your site path is "/", you will need something like ProxyPass "/" "fcgi://localhost:9000/home/kohler/hotcrp/index.php/"—note the trailing slash.)

   Apache with mod_php (not recommended): Add a ScriptAlias for the HotCRP index.php script and a <Directory> for the installation.

   ScriptAlias "/testconf" "/home/kohler/hotcrp/index.php"
   <Directory "/home/kohler/hotcrp">
     Options None
     AllowOverride none
     Require all denied
     <Files "index.php">
       Require all granted
     </Files>
   </Directory>
   

   General notes: Everything under the site path (here, /testconf) should be served by HotCRP. This normally happens automatically, but if the site path is /, you may need to turn off your server’s default handlers for subdirectories such as /doc.

   The images, scripts, and stylesheets subdirectories contain static files that any user may access. It is safe to configure your server to serve those directories directly, without involving PHP.

4. Update PHP settings.

   The first three settings, upload_max_filesize, post_max_size, and max_input_vars, may be changed system-wide or in HotCRP’s .htaccess and .user.ini files.

   • upload_max_filesize: Set to the largest file upload HotCRP should accept. 15M is a good default.

   • post_max_size: Set to the largest total upload HotCRP should accept. Must be at least as big as upload_max_filesize. 20M is a good default.

   • max_input_vars: Set to the largest number of distinct input variables HotCRP should accept. 4096 is a good default.

   The last setting, session.gc_maxlifetime, must be changed globally. This provides an upper bound on HotCRP session lifetimes (the amount of idle time before a user is logged out automatically). On Unix machines, systemwide PHP settings are often stored in /etc/php.ini. The suggested value for this setting is 86400, e.g., 24 hours:

   session.gc_maxlifetime = 86400
   

   If you want sessions to expire sooner, we recommend you set session.gc_maxlifetime to 86400 anyway, then edit conf/options.php to set $Opt["sessionLifetime"] to the correct session timeout.

5. Edit MariaDB’s my.cnf (typical locations: /etc/mariadb/my.cnf or /etc/mariadb/mysql.conf.d/mysqld.cnf) to ensure that MySQL can handle paper-sized objects. It should contain something like this:

    [mysqld]
    max_allowed_packet=32M
   

   max_allowed_packet must be at least as large as the largest paper you are willing to accept. It defaults to 1M on some systems, which is not nearly large enough. HotCRP will warn you if it is too small. Some MariaDB or MySQL setups, such as on Mac OS X, may not have a my.cnf by default; just create one. If you edit my.cnf, also restart the database server.

6. Enable a mail transport agent, such as Postfix or Sendmail. You may need help from an administrator to ensure HotCRP can send mail.

7. Sign in to the site to create an account. The first account created automatically receives system administrator privilege.

You can set up everything else through the web site itself.

Configuration notes:

• HotCRP PHP scripts can take a lot of memory. By default HotCRP sets the PHP memory limit to 128MB.

• Most HotCRP settings are assigned in the conference database’s Settings table. The Settings table can also override values in conf/options.php: a Settings record with name opt.XXX takes precedence over option $Opt["XXX"].

Database access

Run php batch/backupdb.php at the shell prompt to back up the database. This will write the database’s current structure and comments to the standard output. As typically configured, HotCRP stores all paper submissions in the database, so the backup file may be quite large.

Run php batch/backupdb.php -r BACKUPFILE at the shell prompt to restore the database from a backup stored in BACKUPFILE.

Run lib/runsql.sh at the shell prompt to get a SQL command prompt for the conference database.

Updates

HotCRP code can be updated at any time without bringing down the site. If you obtained the code from git, use git pull. if you obtained the code from a tarball, copy the new version over your old code, preserving conf/options.php. For instance, using GNU tar:

% cd HOTCRPINSTALLATION
% tar --strip=1 -xf ~/hotcrp-NEWVERSION.tar.gz

License

HotCRP is available under the Click license, a BSD-like license. See the LICENSE file for full license terms.

Authors

Eddie Kohler, Harvard

• HotCRP is based on CRP, which was written by Dirk Grunwald, University of Colorado
• HotCRP’s banal is substantially modified from the original banal by Geoff Voelker, UCSD