Wiki source code of Saving Data
Version 2.1 by Caleb James DeLisle on 2012/08/20
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| author | version | line-number | content |
|---|---|---|---|
| 1 | {{box cssClass="floatinginfobox" title="**Contents**"}} | ||
| 2 | {{toc/}} | ||
| 3 | {{/box}} | ||
| 4 | |||
| 5 | There are times when you wish to save data. The XWiki platform offers various places that you can use depending on your needs. Here's a rundown of all the options you have. | ||
| 6 | |||
| 7 | = Transient Saves = | ||
| 8 | |||
| 9 | == Execution Context == | ||
| 10 | |||
| 11 | If the data to be saved should only be saved for the duration of a Request (i.e. a call to a XWiki URL), then you should use the **Execution Context**. | ||
| 12 | |||
| 13 | For example, from Java in a Component: | ||
| 14 | |||
| 15 | {{code language="java"}} | ||
| 16 | import org.xwiki.execution.*; | ||
| 17 | |||
| 18 | @Inject Execution execution; | ||
| 19 | ... | ||
| 20 | // Saving | ||
| 21 | ExecutionContext ec = execution.getContext(); | ||
| 22 | ec.setProperty("mykey", myvalue); | ||
| 23 | ... | ||
| 24 | // Retrieving | ||
| 25 | Object myvalue = e.getProperty("mykey"); | ||
| 26 | {{/code}} | ||
| 27 | |||
| 28 | From a wiki page (Note that [[we currently cannot access easily the Execution Context from a wiki page but this should be improved>>http://jira.xwiki.org/browse/XCOMMONS-242]] and currently it's not available only from Velocity but it is from Groovy for example): | ||
| 29 | |||
| 30 | {{code}} | ||
| 31 | {{groovy}} | ||
| 32 | import org.xwiki.context.* | ||
| 33 | |||
| 34 | def ec = services.component.getInstance(Execution.class).getContext() | ||
| 35 | ec.setProperty("mykey", myvalue) | ||
| 36 | {{/groovy}} | ||
| 37 | {{/code}} | ||
| 38 | |||
| 39 | Note that from a wiki page it's much easier to use the older **XWiki Context** (which is supposed to be fully replaced by the Execution Context at some point in the future). For example: | ||
| 40 | |||
| 41 | {{code}} | ||
| 42 | {{velocity}} | ||
| 43 | $xcontext.put("mykey", value) | ||
| 44 | {{/velocity}} | ||
| 45 | {{/code}} | ||
| 46 | |||
| 47 | == Servlet Session == | ||
| 48 | |||
| 49 | If the data should last a little longer (i.e. for example span more than 1 request), you could save it in the Servlet Session. | ||
| 50 | |||
| 51 | For example, from Java in a Component: | ||
| 52 | |||
| 53 | {{code language="java"}} | ||
| 54 | import org.xwiki.container.*; | ||
| 55 | |||
| 56 | @Inject Container container; | ||
| 57 | ... | ||
| 58 | Request request = container.getRequest(); | ||
| 59 | // Note that this is a bit of a hack and the notion of Session exists in the Container class (getSession()) but the Session interface is empty at the moment, making it useless) | ||
| 60 | if (request instanceof ServletRequest) { | ||
| 61 | HttpServletRequest servletRequest = (ServletRequest) request; | ||
| 62 | HttpSession session = servletRequest.getSession(); | ||
| 63 | session.setAttribute("mykey", myvalue); | ||
| 64 | } | ||
| 65 | {{/code}} | ||
| 66 | |||
| 67 | == Temporary Directory == | ||
| 68 | |||
| 69 | If the data should last even a little longer than a session, you could save it in a File in the Environment's Temporary Directory. | ||
| 70 | |||
| 71 | For example, from Java in a Component: | ||
| 72 | |||
| 73 | {{code language="java"}} | ||
| 74 | import org.xwiki.environment.*; | ||
| 75 | import org.apache.commons.io.*; | ||
| 76 | |||
| 77 | @Inject Environment environment; | ||
| 78 | ... | ||
| 79 | File tmpDir = environment.getTemporaryDirectory(); | ||
| 80 | FileUtils.write(tmpDir, "something"); | ||
| 81 | {{/code}} | ||
| 82 | |||
| 83 | == Servlet Context == | ||
| 84 | |||
| 85 | If the Data should last as long as the web application is up, you could use the Servlet Context. It's not very easy to access it but it's possible. | ||
| 86 | |||
| 87 | For example, from Java in a Component: | ||
| 88 | |||
| 89 | {{code language="java"}} | ||
| 90 | import org.xwiki.container.*; | ||
| 91 | import com.xpn.xwiki.*; | ||
| 92 | import com.xpn.xwiki.web.*; | ||
| 93 | |||
| 94 | @Inject Execution execution; | ||
| 95 | ... | ||
| 96 | // Get the older XWiki Context | ||
| 97 | XWikiContext xc = (XWikiContext) execution.getContext().getProperty("xwikicontext"); | ||
| 98 | XWikiEngineContext ec = xc.getEngineContext(); | ||
| 99 | ec.setAttribute("mykey", myvalue); | ||
| 100 | {{/code}} | ||
| 101 | |||
| 102 | = Permanent Saves = | ||
| 103 | |||
| 104 | == Wiki Model == | ||
| 105 | |||
| 106 | The best place to save Data is usually in the wiki itself in an XObject attached to a wiki page (See the [[Data Model>>DevGuide.DataModel]]). | ||
| 107 | |||
| 108 | === In an attachment === | ||
| 109 | |||
| 110 | You can store data inside of attachments, this velocity script will attach a small piece of data to the current document. | ||
| 111 | |||
| 112 | {{code language="none"}} | ||
| 113 | #set($content = "This is some small arbitrary content") | ||
| 114 | #set($discard = $doc.addAttachment("myfile.txt", $content.getBytes())) | ||
| 115 | $doc.save() | ||
| 116 | {{/code}} | ||
| 117 | |||
| 118 | == Permanent Directory == | ||
| 119 | |||
| 120 | Another possibility is to use the Environment's Permanent Directory. | ||
| 121 | |||
| 122 | For example, from Java in a Component: | ||
| 123 | |||
| 124 | {{code language="java"}} | ||
| 125 | import org.xwiki.environment.*; | ||
| 126 | import org.apache.commons.io.*; | ||
| 127 | |||
| 128 | @Inject Environment environment; | ||
| 129 | ... | ||
| 130 | File permDir = environment.getPermanentDirectory(); | ||
| 131 | FileUtils.write(permDir, "something"); | ||
| 132 | {{/code}} |
