Re: [xwiki-users] Scripting - Saving calculated results for a macro

On 26 May 2012 14:02, Ludovic Dubost &lt;ludovic(a)xwiki.com&gt; wrote: Interesting, thanks. I'm not quite sure how it would work in practice, it seems that I'd end up with macros nested up to 3 times, at which point my brain explodes :-) It might help if I show the content of my current macro here: {{groovy}} import java.security.* // Calculate SHA1 of content - the idea is that we can avoid regenerating if we've calculated this output before def content = xcontext.macro.content def messageDigest = MessageDigest.getInstance("SHA1") messageDigest.update(content.getBytes()) def contentSHA1 = new BigInteger(1, messageDigest.digest()).toString(16).padLeft(40, '0') // Generate the output - ideally, only if we don't have saved output for this SHA1 def cmd = 'generate-png.exe' def proc = cmd.execute() proc << content proc.out.close() def png = proc.in.bytes def out = png.encodeBase64().toString() println "{{html}}" println "<img src=\"data:image/png;base64,$out\"/>" println "{{/html}}" {{/groovy}} It's running that executable that I want to skip - it will always give the same output for the same input. The output should be persistent (over restarts of XWiki, ideally). As a concrete example of generate-png.exe, think of the Graphviz "dot" command. For any given graph, the PNG won't change. Essentially, that's what I'm implementing here (longer term, the idea would be that the precise command to generate the image would be configurable). I've looked at the PlantUML and Graphviz extensions, but I don't really follow how they work. On the other hand, they seem pretty complex compared to the code above, so I'm not sure how much understanding them would help. Paul.