External Data extension

        Version 3.4-alpha
        Yaron Koren, Alexander Mashin and (many) others

This is free software licensed under the GNU General Public License. Please
see http://www.gnu.org/copyleft/gpl.html for further details, including the
full text and terms of the license.

== Overview ==

External Data is an extension to MediaWiki that allows for retrieving data
from various sources: external URLs, local wiki pages and files on the
server (all in CSV, GFF, JSON, XML, HTML or INI formats), plus database tables,
LDAP servers and program output.

The extension defines the following parser functions:
* `#get_web_data` - retrieves the data from a URL that holds CSV, GFF, JSON, XML,
   INI or YAML and assigns it to local variables or arrays
* `#get_soap_data` - retrieves data from a URL via SOAP
* `#get_file_data:` - retrieves data from local file(s), which can be in any of
  the same formats that `#get_web_data` handles
* `#get_db_data` - retrieves data from a database, using (in most cases)
  SQL-like syntax, and assigns it to local variables or arrays
* `#get_ldap_data` - retrieves data from an LDAP server and assigns it to local
  variables
* `#get_program_data` - retrieves data returned by a program called server-side,
  parses it and assigns it to local variables
* `#get_inline_data` - parses the passed text without connecting to any external
  services
* `#get_external_data` - can do all of the above
* `#external_value` - displays the value of any retrieved variable, or the first
  value if it's an array
* `#for_external_table` - applies processing onto multiple rows retrieved by any
  of the `#get_*_data` functions
* `#display_external_table` - like `#for_external_table`, but passes the values
  of each row to a template, which handles the formatting
* `#clear_external_data` - erases some or all of the current set of retrieved data

External Data also defines the following Lua functions, each of which act
similarly to the corresponding parser functions, and return 2D (or deeper, if the
external variables `__json` or `__xml` are used) row-based tables of values:
* `mw.ext.externalData.getWebData`
* `mw.ext.externalData.getFileData`
* `mw.ext.externalData.getDbData`
* `mw.ext.externalData.getSoapData`
* `mw.ext.externalData.getLdapData`
* `mw.ext.externalData.getProgramData`
* `mw.ext.externalData.getInlineData`
* `mw.ext.externalData.getExternalData`

Additionally, the extension allows wiki admins to define their own tags for
programs set up to run in tag  emulation mode, which handle both the
retrieval and display of data.

The extension defines a new special page, 'GetData', which exports selected
rows from a wiki page that holds CSV data, in a format that is readable by
#get_web_data.

For more information, see the extension homepage at:
https://www.mediawiki.org/wiki/Extension:External_Data

== Requirements ==

This version of the External Data extension requires MediaWiki 1.35 or
higher.

== Installation ==

To install the extension, place the entire 'ExternalData' directory
within your MediaWiki 'extensions' directory, run `composer install` there
then add the following line to your 'LocalSettings.php' file:
```
wfLoadExtension( 'ExternalData' );
```

To cache the data from the URLs being accessed, run `maintenance/update.php`
script.

You should also add a line like the following, to set the expiration time
of the cache, in seconds; this line will cache data for a week:
```
$wgExternalDataSources['*']['min cache seconds'] = 7 * 24 * 60 * 60;
```

This setting can be overridden for specific URLs, hosts, second level domains or programs.

You can also set for string replacements to be done on the URLs you call,
for instance to hide API keys. This should be set up per URL, host or second level domain
but not universally (`'*`). Either of the following would work:
```
$wgExternalDataSources['https://example.com/restricted_api.php?key=MY_API_KEY']['replacements']['MY_API_KEY'] = 'abcd1324';
$wgExternalDataSources['example.com']['replacements']['MY_API_KEY'] = 'abcd1324';
```

This setting can be overridden for specific URLs, hosts, second level domains or programs.

You can create a "whitelist" to allow retrieval of data only from trusted
sites, in the manner of MediaWiki's `$wgAllowExternalImagesFrom`:
```
$wgExternalDataSources['*']['allowed urls'] = [ 'http://example.com/api' ];
```

These settings can be overridden for specific URLs, hosts, second level domains or programs.

Finally, to use the database or LDAP retrieval capabilities or run server-side programs,
you need to set connection settings as well in `$wgExternalDataSources` --
see the online documentation for more information.

== Contact ==

Most comments, questions, suggestions and bug reports should be sent to
the main MediaWiki mailing list:

     https://lists.wikimedia.org/mailman/listinfo/mediawiki-l

If possible, please add "[ED]" at the beginning of the subject line, to
clarify the subject matter.