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Wiki source code of Scripting

Version 40.1 by Sergiu Dumitriu on 2012/05/19
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1 {{box cssClass="floatinginfobox" title="**Contents**"}}
2 {{toc/}}
3 {{/box}}
4
5 Scripting allows you to create basic to complex web applications at the XWiki page (or view) layer without the need for compiling code or deploying software components. In other words, you can use scripting syntax in addition to wiki and HTML syntax as the contents of an XWiki page.
6
7 XWiki integrates [[jsr-223>>http://scripting.dev.java.net/]] scripting. You can script using several available languages by using one of the following macros:
8
9 * [[Velocity Macro>>extensions:Extension.Velocity Macro]] (installed by default in XWiki Enterprise)
10 * [[Groovy Macro>>extensions:Extension.Groovy Macro]] (installed by default in XWiki Enterprise)
11 * [[Python Macro>>extensions:Extension.Python Macro]] (installed by default in XWiki Enterprise)
12 * [[Ruby Macro>>extensions:Extension.Ruby Macro]] (not installed by default in XWiki Enterprise)
13 * [[PHP Macro>>extensions:Extension.PHP Macro]] (not installed by default in XWiki Enterprise)
14
15 = Choosing a Scripting language =
16
17 Since XWiki supports several scripting languages you might be wondering which one to use. Most of the code written by XWiki developers is in Velocity, with a few more complex extensions written in Groovy; these two are thoroughly tried and tested, so they are both a safe bet. The other languages //should// work just as well, but there are less developers that could help answering any questions.
18
19 == Velocity ==
20
21 The first thing to know is that Velocity is different from the other scripting languages on 2 aspects:
22 * It's a templating language rather than a pure scripting language, which means that its content is actually wiki markup interspersed with Velocity directives, whereas pure scripting languages are written in that language and they need to explicitly output wiki markup. For example:(((
23 Velocity:
24
25 {{code}}
26 {{velocity}}
27 Your username is $xcontext.getUser(), welcome to the site.
28 {{/velocity}}
29 {{/code}}
30
31 Groovy:
32
33 {{code}}
34 {{groovy}}
35 println("Your username is " + xcontext.getUser() + " welcome to the site.");
36 {{/groovy}}
37 {{/code}}
38 )))
39 * It doesn't require special permissions since it runs in a Sandbox, with access to only a few safe objects, and each API call will check the rights configured in the wiki, forbidding access to resources or actions that the current user shouldn't be allowed to retrieve/perform. Other scripting language require the user that wrote the script to have Programming Rights to execute them, but except this initial precondition, access is granted to all the resources on the server. Note that starting with XWiki 4.1 we've introduced a [[Sandbox for Groovy>>platform:AdminGuide.Configuration#HSecuringGroovyScripts]] too, but it's still in an early stage.
40
41 Being a templating engine, Velocity doesn't offer many means of structuring code. In fact, there's only one useful directive in this regard, ###macro##. However, because it is a templating engine, its syntax is much simpler and easier to understand by non-developers, which means that it's accessible to a wider range of users, without a serious background in programming.
42
43 Without programming rights, it's impossible to instantiate new objects, except literals and those safely offered by the XWiki APIs. Nevertheless, the XWiki API is powerful enough to allow a wide range of applications to be safely developed, if "the XWiki way" is properly followed.
44
45 Velocity is also available in some other parts of XWiki: it is the language in which all the templates that generate the HTML UI of XWiki are written, it can be optionally activated in skin extensions, and it is executed when sending CSS and JavaScript skin resources from the filesystem.
46
47 In conclusion, **Velocity is suited for projects with small to medium complexity, and which don't require access to other resources except the provided XWiki API and registered script services. It allows very quick and easy development, offers good security and decent performance, and can easily be packaged and distributed as a XAR.**
48
49 == Groovy ==
50
51 Groovy is a full-fledged scripting language, which supports almost the entire Java syntax, and provides its own syntax delicacies and custom APIs that enhance the Java language even further. While it is recommended that complex code be written in Java as components accessible via script services, Groovy has the advantage that it is written live in the wiki, without requiring compilation, deployment and server restarts, thus enabling faster development.
52
53 The XWiki API is available in the context when executing Groovy scripts, but unlike in Velocity, the code isn't limited to this API, and any other classes or objects can be accessed freely. New classes can be defined in Groovy, compatible with Java classes, and this allows more structured code to be written, unlike in Velocity. A particular case of classes is new component roles and component implementations, which allows, for example, new script services or new event listeners to be defined in the wiki. It is possible to load attached jar files into the classpath of an executing script, which means that a wiki document can contain a complex program AND its required libraries not already provided by the platform.
54
55 Other than being available as a scripting language for writing custom code, it is also the language in which scheduler tasks are written.
56
57 In conclusion, **Groovy is suited for complex projects or for custom wiki enhancement through new components, when speedy live development is required. Being written in wiki documents, it can also be easily packaged and distributed as a XAR.**
58
59 After taking into account these considerations and if requiring Programming Rights isn't an issue for you, you should pick the script language that you're most familiar with!
60
61 = XWiki Scripting API =
62
63 The API is documented in Javadoc format and can be accessed here: [[XWiki API Javadoc>>DevGuide.API]]. If you are not familiar with Java or object oriented programming, you will probably be confused by the API documentation. It is not within the scope of our documentation to teach you all the details about Java, or object oriented programming. You can find all of that information already online. You can also explore the page code found throughout the [[Extensions wiki>>extensions:Main.WebHome]] area to see how others have figured out how to achieve a variety of results.
64
65 == [[Bindings>>extensions:Extension.Script Macro#HBindings]] ==
66
67 These objects are available to you in scripting languages.
68
69 * [[The current Document>>http://maven.xwiki.org/site/xwiki-core-parent/xwiki-core/apidocs/com/xpn/xwiki/api/Document.html]]: **##doc##**
70 * [[The Context of the request>>http://maven.xwiki.org/site/xwiki-core-parent/xwiki-core/apidocs/com/xpn/xwiki/api/Context.html]]: **##xcontext##**
71 * [[The Request object>>http://maven.xwiki.org/site/xwiki-core-parent/xwiki-core/apidocs/com/xpn/xwiki/web/XWikiRequest.html]]: **##request##**
72 * [[The Response object>>http://maven.xwiki.org/site/xwiki-core-parent/xwiki-core/apidocs/com/xpn/xwiki/web/XWikiResponse.html]]: **##response##**
73 * [[The XWiki object>>http://maven.xwiki.org/site/xwiki-core-parent/xwiki-core/apidocs/com/xpn/xwiki/api/XWiki.html]]: **##xwiki##**
74 * [[The XWiki utils>>http://maven.xwiki.org/site/xwiki-core-parent/xwiki-core/apidocs/com/xpn/xwiki/api/Util.html]]: **##util##**
75
76 == [[XWiki Component>>extensions:Extension.Component Module]] Access ==
77
78 You can also gain direct access to XWiki components using the following code snippet (also see: [[Accessing components from Groovy>>DevGuide.WritingComponents#HAccessingacomponentfromgroovy]]):
79
80 {{info}}
81 This snippet is written in Groovy and will have to be converted to your scripting language.
82 {{/info}}
83
84 {{code language="java"}}
85 {{groovy}}
86 def greeter = com.xpn.xwiki.web.Utils.getComponent(org.xwiki.component.HelloWorld.class);
87 println greeter.sayHello();
88 {{/groovy}}
89 {{/code}}
90
91 == XWiki Core Access ==
92
93 Sometimes the XWiki Api doesn't provide the methods which you need for your application. You can gain raw access the core of XWiki but it presents an increased security risk and requires **Programming Rights** to be able to save the page containing the script (Programming Rights are not required for viewing a page containing a script requiring Programming Rights, rights are only needed at save time). Using the core should be avoided if at all possible.
94
95 {{code language="java"}}
96 {{groovy}}
97 def xc = xcontext.getContext();
98 def wiki = xc.getWiki();
99 def xdoc = doc.getDocument();
100 {{/groovy}}
101 {{/code}}
102
103 After using this snippet, you will have 3 new objects:
104
105 * [[The underlying XWikiContext behind the Context object>>http://maven.xwiki.org/site/xwiki-core-parent/xwiki-core/apidocs/com/xpn/xwiki/XWikiContext.html]]: **##xc##**
106 * [[The underlying XWiki object which backs the **##xwiki##** object>>http://maven.xwiki.org/site/xwiki-core-parent/xwiki-core/apidocs/com/xpn/xwiki/XWiki.html]]: **##wiki##**
107 * [[The underlying XWikiDocument behind the current Document>>http://maven.xwiki.org/site/xwiki-core-parent/xwiki-core/apidocs/com/xpn/xwiki/doc/XWikiDocument.html]]: **##xdoc##**
108
109 You will find that many of the methods in **##wiki##** and **##xdoc##** require an instance of the XWikiContext, this is the underlying xcontext **##xc##** not the Api context **##xcontext##**.
110
111 Again, these methods are only for the rare cases when functionality is not provided by the public Api. We put a lot of effort into preserving the behavior of the public Api and much less into preserving the behavior of core methods so you may find that core methods are deprecated, removed, or their behavior is changed in subsequent versions.
112
113 == Querying XWiki's Model ==
114
115 From your script you can query the full XWiki's Model. Check the [[Query Module>>extensions:Extension.Query Module]] for more information.
116
117 {{id name="velocity"/}}
118
119 = Velocity Specific Information =
120
121 Velocity is currently the only scripting language which can be used without Programming [[AdminGuide.Access Rights]]. This means you can save velocity scripts using a user with less permission and an exploit of your script is less of a security breach.
122
123 You can [[gain access to the XWiki core>>#HXWikiCoreAccess]] from Velocity but this will require Programming Rights. Strictly speaking, protected APIs are only available when the page that contains them was last saved by someone who had Programming Rights (see above).
124
125 In Velocity you can't import classes and as such you cannot gain direct access to XWiki components as shown [[above>>#HXWikiComponentAccess]]. This leaves you with the provided [[bindings>>#HBindings]] (NOTE: In Velocity, these bindings all start with **##$##** as with all other Velocity variables)
126
127 For more information about programming in the Velocity language, you can refer to the [[Velocity User Guide>>http://velocity.apache.org/engine/releases/velocity-1.6.2/user-guide.html]].
128
129 For more details on using Velocity check the [[Velocity Module Documentation>>extensions:Extension.Velocity Module]] which also contains the full list of Velocity Tools that you can use in your scripts.
130
131 {{info}}
132 If you wish to add new Velocity tools you'll need to edit your ##xwiki.properties## file and follow the instructions in there.
133 {{/info}}
134
135 To include Velocity scripts in other Velocity scripts, see [[How to include a velocity page into another page>>DevGuide.IncludeInVelocity]].
136
137 == Other Velocity Variables ==
138
139 {{warning}}
140 These variables can be used but are subject to change in the future.
141 {{/warning}}
142
143 {{id name="HControllingwhethertodisplayCommentsHistoryAttachmentInformationsectionsornot"/}}
144
145 === Controlling Which Sections to Display ===
146
147 You can control whether to display Comments/History/Attachment/Information sections or not by setting some velocity variable to "no":
148
149 {{code language="velocity"}}
150 #set ($showcomments = "no")
151 #set ($showattachments = "no")
152 #set ($showhistory = "no")
153 #set ($showinformation = "no")
154 {{/code}}
155
156 To remove them all you can set:
157
158 {{code language="velocity"}}
159 #set($docextras = [])
160 {{/code}}
161
162 === Information about the current user ===
163
164 The following variables (set in the {{scm path="xwiki-platform-core/xwiki-platform-web/src/main/webapp/templates/xwikivars.vm"}}xwikivars.vm{{/scm}} template) are shortcuts for checking various information **for the current user**:
165
166 * ##$isGuest##: checks if the current user is ##XWiki.XWikiGuest##
167 * ##$isSuperAdmin##: checks if the current user is the special user ##superadmin##
168
169 * ##$hasComment##: checks comment rights on the current document
170 * ##$hasEdit##: checks edit rights on the current document
171 * ##$hasWatch##: checks if the user is authenticated and the watch service is available
172
173 * ##$hasAdmin##: checks admin rights on the current document
174 * ##$hasSpaceAdmin##: checks admin rights on the ##XWikiPreferences## document of the current space
175 * ##$hasGlobalAdmin##: checks admin rights on ##XWiki.XWikiPreferences##
176
177 * ##$hasCreateSpace##: checks edit rights on that page that does not exist, in a space that doesn't exist
178 * ##$hasCreatePage##: checks edit rights on that page that does not exist, in the current space
179
180 * ##$hasProgramming##: checks if the current user has programming rights
181
182 * ##$isAdvancedUser##: advanced users: ##superadmin##, users with the ##usertype## property set to "Advanced", guest users with admin rights
183
184 Example:
185
186 {{code language="velocity"}}
187 {{velocity}}
188 #if ($hasAdmin)
189 ## This link will only be visible to users that have admin rights on this document
190 [[Do some admin action>>Some.Document]]
191 #end
192 {{/velocity}}
193 {{/code}}
194
195 === Information about the current wiki ===
196
197 The following variables (set in the {{scm path="xwiki-platform-core/xwiki-platform-web/src/main/webapp/templates/xwikivars.vm"}}xwikivars.vm{{/scm}} template) are shortcuts for checking various information **about the current wiki**:
198
199 * ##$isReadOnly##
200 * ##$isInServletMode##
201 * ##$isInPortletMode##
202
203 = Groovy Specific Information =
204
205 {{info}}
206 Currently all non Velocity scripting languages are only allowed users having Programming Rights.
207 {{/info}}
208
209 * See Groovy snippets in the [[Extensions wiki>>extensions:Main.WebHome]] (click on the "Groovy" tag in the Tag Cloud)
210 * [[Groovy web site>>http://groovy.codehaus.org/]]
211
212 == Groovy Example ==
213
214 The following example demonstrates how to use a groovy script to interact with velocity code in your page. This example performs a DNS lookup from the velocity variable ##$hostname## and stores the result in the variable ##$address##.
215
216 **Using XWiki Syntax 2.0:**
217
218 Objects can be passed back and forth between scripting languages by storing them in commonly available objects. One such commonly available object which only lasts the length of the request is the context object, known as xcontext.
219
220 {{code language="velocity"}}
221 {{velocity}}
222 #set($hostname = "www.xwiki.org")
223 Host Name: $hostname
224 $xcontext.put("hostname", $hostname)
225 {{/velocity}}
226 {{groovy}}
227 import java.net.InetAddress;
228 host = xcontext.get("hostname");
229 InetAddress addr = InetAddress.getByName(host);
230 String address = addr.getHostAddress();
231 xcontext.put("address", address);
232 {{/groovy}}
233 {{velocity}}
234 IP Address: $xcontext.get("address")
235 {{/velocity}}
236 {{/code}}
237
238 **Using XWiki Syntax 1.0:**
239
240 Because Groovy and Velocity code are parsed together, variables defined in Groovy can be used directly in velocity without storing in and retrieving from the context.
241
242 {{code language="velocity"}}
243 #set ($hostname = "www.xwiki.org")
244 Host Name: $hostname
245 <%
246 import java.net.InetAddress;
247 vcontext = context.get("vcontext");
248 host = vcontext.get("hostname");
249 InetAddress addr = InetAddress.getByName(host);
250 String address = addr.getHostAddress();
251 %>
252 IP Address: $address
253 {{/code}}
254
255 = Python Specific Information =
256
257 You can run Python code in XWiki just like Velocity or Groovy.
258
259 {{code language="python"}}
260 {{python}}
261 print "The full name of this document is " + doc.getFullName()
262 {{/python}}
263 {{/code}}
264
265 {{warning}}
266 Versions prior to [[XWiki Enterprise 2.4>>xwiki:ReleaseNotes.ReleaseNotesXWikiEnterprise24]] have a bug which prevents you from having access to the default objects (doc, xcontext, request, etc.) a [[workaround is available in the Extensions wiki>>extensions:Extension.Access To Bindings In Python]]
267 {{/warning}}
268
269 = Scripting In XWiki Syntax 1.0 =
270
271 XWiki Syntax 1.0 is rendered by an old rendering engine which still supported but for which no further development is planned (it will eventually be removed). Syntax 1.0 has some idiosyncrasies which were solved by syntax 2.0.
272
273 * The only scripting languages available to you are Velocity and Groovy.
274 * In Groovy, the context is known as: **##context##** not **##xcontext##**
275 * The beginning and end of Groovy scripts are denoted by <% and %> rather than through the [[extensions:Extension.Groovy Macro]] (using ~{~{groovy}} and ~{~{/groovy}})
276 * Velocity is parsed in a page no matter what (there is no need to invoke the [[extensions:Extension.Velocity Macro]] using ~{~{velocity}} and ~{~{/velocity}})
277
278 The last part is important because it means you need to be careful of using $ and # in your document. This is still true inside of <% and %> so you have to be careful writing Groovy.

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