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====== Customization ======
//**Part of the [[en:beginner:index|Greenstone Beginner's Guide]]**// \\
Customizing the look of your Greenstone library and collections
requires you to know how and where to make the changes that you want. This page 
provides some insight, telling you where to go if you want to make changes to the layout,
the style, the display of your documents and lists, etc. 

There are a few pages that, though not directly concerned with customization, 
can be very useful during the process:
  * The [[en:directory_structure|directory structure]] page can help you locate important files and folders in your installation.
  * Understanding how Greenstone URLs ([[en:user:gs3_urls|gs3]], [[en:user:gs2_urls|gs2]]) work, including CGI arguments, can help you create links to various pages in your collection.
  * Knowing the [[en:user:configuration_files|files that configure]] specific aspects of your installation is very important as you begin to customize.





<TABAREA tabs="Greenstone3,Greenstone2">
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===== Site, interfaces, and libraries =====
Sites and interfaces contain the content and presentation information, respectively, 
for the digital library.  

A **[[en:user:sites|site]]** is comprised of a set of collections (and possibly some
site-wide services). A site can be seen as a collection of collections. 
You can have multiple separate sites in a single Greenstone3 installation.

An **[[en:user:interfaces|interface]]** is a set of images (and, potentially, CSS and Javascript) along
with a set of XSLT files used for translating XML output from the library into an appropriate form -- 
HTML generally. XSLT (and therefore every Greenstone interface) is built around things called **templates**, which will
tell Greenstone how to display pages depending on the content for that page (e.g. a document's metadata,
the names of the collections in your site, what browsing classifier have been defined, etc.). 

//If all of that sounds really confusing, don't worry! 
Unless you want to make extreme changes to an interface (or define your own),
 you can largely avoid XSLT. //

While the interfaces (i.e. the files that dictate how each page looks) themselves are separate from the content, you can override any part of 
the interface on either the site or collection level. In fact, Greenstone3 provides some features to 
make modifying or overriding an interface easier:
  * **[[en:user:themes|Themes]]**, are the easiest way to change how your library looks. The default Greenstone3 interface is built using JQuery themes, which allow you to change the color-scheme (as well as things like roundness of corners) effortlessly. While even advanced users will find themes useful, they are especially valuable for non-technical users, because they require //absolutely no// knowledge of CSS, HTML, or XSL
  * **[[en:user:gs3_format_statements|Format statements]]**: In many cases, if you do not know XSL, you can instead use [[en:user:gs3_format_statements|Greenstone's statement format (''gsf'')]], which Greenstone will translate (behind-the-scenes) into XSL. ''gsf'' syntax is XML-based. (If you don't know XML, don't worry; it looks and acts very similarly to HTML.)
  * The GLI's **Format Features** section: The GLI provides an easy way to override parts of interface on a collection-level. Instead of having to create your own XSL files, you can type templates into the Format Features section of the Format panel. 

You can create any number of interfaces in your Greenstone3 installation, which is especially useful for when you want to 
present the same content in different ways. For example, you may want to provide two interfaces
for your sites: one interface for visitors using computers and another interface for mobile users. In addition,
multiple sites can make use of the same interface. 

Finally, every site-interface combination you create is considered a **library** 
(in technical terms, each library is actually a servlet).
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===== Collection level vs. library level =====

Customization can be done at either collection level or library level. Any changes made in the GLI
 will only effect the current collection (though, you can copy formatting into future
collections by basing them on another collection). Other methods of customization can be 
enacted on a collection or library basis. 

===== Format Statements =====
The //content// of a Greenstone collection is handled by [[en:user:gs2_format_statements|format statements]], 
which can be modified in the GLI (under ''Format -> Format Features''). So, if you want to change how documents appear
in browsing pages, search results, and on individual document pages, format statements are where
to make changes.

===== Macros =====

Greenstone2 is built on [[en:user:macros|macros]], which look like ''_this_'' and basically stand for
a block of text or code. 

===== Maintaining security when customising GS2 macros =====

A large part of Greenstone 2's security against cross-site scripting (XSS) is implemented in Greenstone 2.87+ in the macros files. This means that if you are customising it by reusing macros such as in new forms or paragraphs, you will need to be aware of how to do so in a secure way.

Every macro variable now has additional variants of itself: variants that are safe to use in an HTML context, in an HTML attribute context, CSS context, URL context, JavaScript context and SQL context. 

The additional variants of each variable are denoted by the suffixes:
<code>Htmlsafe, Attrsafe, Csssafe, Urlsafe, Jssafe, Sqlsafe</code>
The variable name suffixes of these additional variants' indicate the context in which each is to be used. 
//
For example//, the ''_cgiargq_'' variable has the following variants:
<code>_cgiargqHtmlsafe_
_cgiargqAttrsafe_
_cgiargqCsssafe_
_cgiargqUrlsafe_
_cgiargqJssafe_
_cgiargqSqlsafe_</code>

In reusing existing macros when you want to customise Greenstone 2 macro files, carefully select the appropriate variant of the variable you want depending on the context in the file where that variable needs to be used.

In some cases, this can be straightforward: if it is going into an HTML attribute, use the ''Attrsafe'' variant. If it's going to be (part of) a URL, use the Urlsafe version. If it goes into regular JavaScript code, use the Jssafe version, etc.

An example of a more complex case would be where Javascript produces HTML. If the variable is part of the HTML page produced by some JavaScript code, you need to use the ''Htmlsafe'' variant instead of the Jssafe variant.

If you make your customisations consciously and sensibly, your modified macro files will continue to keep Greenstone 2's security intact.

For more information:
  * [[https://www.owasp.org/index.php/Cross-site_Scripting_%28XSS%29|OWASP Cross Site Scripting (XSS) page]]
  * [[https://cheatsheetseries.owasp.org/cheatsheets/Cross_Site_Scripting_Prevention_Cheat_Sheet.html|OWASP XSS cheat sheet]]

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===== Useful Links for Customisation =====

  * [[en:gli:format_panel| GLI's format panel]]

**Greenstone3:**
  * [[en:user:gs3_format_statements|Format statements]]
  * [[en:user:gs3_list_of_format_options|Full list of Format options]]
  * [[en:user:gs3_sample_format_statements| Sample format statements]]
  * [[en:user:themes|Themes]]
  * [[en:user:interfaces| Customising the Greenstone 3 Interface]]
  * [[en:user:gs3_sample_interface_modifications|Sample interface modifications]]

**Greenstone2:**
  * [[en:user:gs2_format_statements|Format statements]]
  * [[en:user:gs2_sample_format_statements| Sample format statements]]
  * [[en:user:macros| Macros]]
  * [[en:user:sample_macros|Sample  macro customisations]]
  * [[en:user:collection_specific_macros|Collection specific macros]]

//**Now that you know the basics of using and customizing Greenstone, there are a few other features, functions, and resources you should be aware of. The final section of this Beginner's Guide presents [[en:beginner:additional_topics|additional Greenstone topics]].**//