BaseX-Talk January 2013

basex-talk@mailman.uni-konstanz.de

47 participants
59 discussions

JSON or JSONML output formatting
by Zachary Pride 16 Jul '14

16 Jul '14

Hello, I've been playing with BaseX lately and all-in-all am very impressed. Something I'm wrestling with however is the JSON output options. I've got various web applications that would really be simplified by receiving JSON straight away for the obvious scripting benefits. The JSON method has been giving me a lot of grief, stipulating rules I'm not sure how to follow. right now I have an element that "is typed as string and cannot be nested." I've been able to get JSONML to output but the JSON is this morass of nested Arrays... Attributes seem to get transformed into Objects but elements/tags and their values are pushed into Arrays for some rationale - which I suppose is on purpose. My question is how can I get Objects for simple key:value properties from <tag>value</tag> 's. Are there options I'm not utilizing? Would it be feasible to transform the XML output to some middle form first - setting it up to become Objects, before serializing it to JSON? Thanks! Zach Pride Associate Software Engineer Ultra Electronics, ProLogic 1000 Green River Drive, Ste. 201 Fairmont, WV 26554 zachary.pride(a)ultra-prologic.com Tel: +1 304 333 2680 ext.308 www.ultra-prologic.com This e-mail from Ultra Electronics, ProLogic and any attachments to it are confidential to the intended recipient and may also be privileged or controlled by U.S. export control laws and regulations. No technical data, information or other items provided by Ultra Electronics, ProLogic in connection with this email shall be shared or provided to any foreign persons, entities, or subsidiaries without the expressed written authorization of Ultra Electronic, ProLogic. If you have received it in error please notify the sender and delete it from your system. If you are not the intended recipient you must not copy it or use it for any purpose nor disclose or distribute its contents to any other person. All communications may be subject to interception or monitoring for operational and/or security purposes. Please rely on your own virus checking as the sender cannot accept any liability for any damage arising from any bug or virus infection. This e-mail from Ultra Electronics, ProLogic and any attachments to it are confidential to the intended recipient and may also be privileged or controlled by U.S. export control laws and regulations. No technical data, information or other items provided by Ultra Electronics, ProLogic in connection with this email shall be shared or provided to any foreign persons, entities, or subsidiaries without the expressed written authorization of Ultra Electronic, ProLogic. If you have received it in error please notify the sender and delete it from your system. If you are not the intended recipient you must not copy it or use it for any purpose nor disclose or distribute its contents to any other person. All communications may be subject to interception or monitoring for operational and/or security purposes. Please rely on your own virus checking as the sender cannot accept any liability for any damage arising from any bug or virus infection. Please consider the environment before printing this email.

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Out of memory bug
by Ivan Lagunov 31 Jul '13

31 Jul '13

Hello, I've got 'Out of memory' error and corrupted database again, this time it's for 6.3 version. Steps: 1. Started server, started terminal client, checked there are no text and attribute indexes. 2. Started my Java application that runs several tests on database: querying, adding, removing. 3. Then I forgot to reopen terminal client and used the one that I opened in Step 1. 4. Run optimize command for the collection and got error. 5. Cannot open the collection any more as I'm getting 'Out of memory'. It's clear that I shouldn't have used the terminal client that I opened before execution of my Java application. But sometimes it's hard to remember. And it's completely unacceptable that these actions result in the corrupted database. You really should catch ArrayIndexOutOfBoundsException everywhere in order to save database from being corrupted. Terminal client stacktrace: > optimize Possible bug? Feedback is welcome: basex-talk(a)mailman.uni-konstanz.de BaseX 6.3: java.lang.ArrayIndexOutOfBoundsException: -1 org.basex.data.PathSummary.add(PathSummary.java:68) org.basex.core.cmd.Optimize.stats(Optimize.java:68) org.basex.core.cmd.Optimize.run(Optimize.java:34) org.basex.core.Command.run(Command.java:236) org.basex.core.Command.exec(Command.java:218) org.basex.core.Command.execute(Command.java:66) org.basex.server.ServerProcess.run(ServerProcess.java:161) > open products Out of Main Memory. Best regards, Ivan

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indent parameter
by Hans-Juergen Rennau 28 Jun '13

28 Jun '13

Hello, it seems to me there is a couple of issues concerning the handling of indentation (serialization parameter "indent"). a) Using "indent=no" whitespace-only text nodes between element nodes are removed b) Using "indent=yes" the content of elements with xml:space="preserve" is indented, too I suppose both behaviors are in contraction to the spec ( http://www.w3.org/TR/xslt-xquery-serialization/#xml-indent ). As a particular consequence, (a) seems to preclude making an exact copy of a document (fragment) - all whitespace-only text nodes vanish. And as a consequence of (b) one has no possibility to locally protect the whitespace used in the source document, as required for example when reusing "programlisting" elements of docbook. Or did I overlook something? Kind regards, Hans-Juergen

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Best practices for concurrency
by The Trainspotter 19 Jun '13

19 Jun '13

Hi, I've read through the online example on server concurrency, however, currently I'm not running a BaseXServer instance I'm just running things locally. I want multiple threads in my application to be able to query the database at once without treading on each others toes. What's the best approach for doing this? I have tried querying the database using different threads but I keep getting internal BaseX errors which leads me to think I'm going about this the wrong way. Cheers Gary

5 15

invalid collection name?
by C. M. Sperberg-McQueen 27 May '13

27 May '13

Using the GUI interface to BaseX 7.2, when I select Database / Open and Manage ..., I get a list of the databases I have built over the time I've been using BaseX. When I try to open the collection named MEP.bigbooks, though, I get an error box saying "Name 'MEP.bigbooks' is invalid." In the "Manage Databases" dialog box, the information about the collection appears normal and plausible (at least, the size is about what I expect, and so on). It's only when I try to open the collection that I run into the error. I get similar errors on other collections which have . in their name; I do not get errors when opening other collections built (as far as I can remember) at the same time from the same data, if their name does not include a full stop. When I try renaming the collection without the full stop, I get the same error message. When I try to issue the command ALTER DATABASE MEP.bigbooks MEPbigbooks from the server command area of the GUI, I get a short syntax summary in the Query Info area complaining about the syntax of the command. When I replace MEP.bigbooks with MEP\.bigbooks and "MEP.bigbooks", I also get syntax errors. If I close the GUI and just rename the directory within my BaseXData directory, the database appears to open normally. I think I have two questions: Q1 is just renaming the directory a safe way (assuming no server is currently working with the data) to rename a collection? Should I do the same for all the other collections I have that don't currently open? I assume that if the 7.2 GUI won't let me rename them, it also will have trouble deleting them, so a related question is: is just deleting a sub-directory of BaseXData a safe way to delete a collection? Q2 Did the rules for names of collections change? Or is there some other cause? Speaking for myself, I guess that as a user I haven't thought much about what characters should be allowed in collection names, but I may have assumed that if they are not unrestricted, they would be restricted to being legal NCNames. I do kind of like using dots in names, so you can count this as one vote for relaxing the naming rules at some convenient moment. It's not a really important point, of course. best, Michael -- **************************************************************** * C. M. Sperberg-McQueen, Black Mesa Technologies LLC * http://www.blackmesatech.com * http://cmsmcq.com/mib * http://balisage.net ****************************************************************

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XqueryDebugger
by Rob Stapper 16 May '13

16 May '13

Hi, Making intensive use of mappings {} and high-order recursive functions, I really could do with a nice debugger for the Xquery in BaseX. Is a debugger in the planning? Thnx. Regards, Rob Stapper

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Namespaces on element construction
by Arto Viitanen 14 May '13

14 May '13

Why does this query (on BaseX 7.5, basexgui) let $ns := namespace {''} {'the-namespace'} let $c1 := <c xmlns="the-namespace">text</c> let $c2 := <c>{ $ns,'text'}</c> let $c3 := element {'c'} {$ns,'text'} let $qn := QName($ns, 'c') let $c4 := element {$qn} {'text'} let $nl := "
" return ($c1,$nl, $c2,$nl, $c3,$nl, $c4,$nl, '|' || namespace-uri-from-QName(node-name($c1)) || '|',$nl, '|' || namespace-uri-from-QName(node-name($c2)) || '|',$nl, '|' || namespace-uri-from-QName(node-name($c3)) || '|',$nl, '|' || namespace-uri-from-QName(node-name($c4)) || '|',$nl) outputs <c xmlns="the-namespace">text</c> <c xmlns="the-namespace">text</c> <c xmlns="the-namespace">text</c> <c xmlns="the-namespace">text</c> |the-namespace| || || |the-namespace| I.e, the namespace seems to exist on all four cases when outputted, by node-name finds it only if the namespace is given in element as text, or as QName value in computed element. -- Arto Viitanen Microteam Oy Finland

2 2

Java User Function and Context Awareness
by Lansing, Jeff J CIV SPAWARSYSCEN-PACIFIC, 56250 01 Feb '13

01 Feb '13

It seems that there is no way for a Java user function installed in the Repository to get access to the current context node. Yes the context is available because of extending abstract QueryModule, but it seems the value of the current context node has been wiped out by the call from UserFunc.value() [at UserFunc:line 170] before it gets to the actual user function [during line 175]. Is there some way for a user function to recover that value, or is this just a limitation of the user function mechanism? Thanks.

2 10

URI resolver when calling XSLT
by Wendell Piez 01 Feb '13

01 Feb '13

Hi, I've run into a similar problem to the one described (I think) below: I can invoke XSLT in BaseX (fantastic) but I get compiler errors if the stylesheet relies on xsl:import or xsl:include (not so good). As I understand it, the JAXP interface (supported by Saxon and Xalan) allows you to provide your own URIResolver class, which is (I imagine) the way to fix this. But I'm no Java programmer. It would be very (very) nice to be able to do this right. My apologies if this post is no help but only a "me too". :-) Cheers, Wendell On Fri, Jan 25, 2013 at 4:41 PM, Christian Grün <christian.gruen(a)gmail.com> wrote: > Hi Seenivasan, > > finally some feedback.. > >> let $doc := <a /> >> let $schema := doc("../xsd/XDW.xsd") >> return validate:xsd($doc,$schema) > > Yes, I see this is a problem, and I’ve encountered similar use cases, > but I'm currently not sure how to fix this properly. The issue is that > BaseX relies on external schema validation, so we don’t have direct > access to the code executing the validation. > > It could well be that Java’s validator interface provides some methods > to set/modify the path to the current base uri. If you – or someone > else – has time, ideas and/or experience how to fix this, suggestions > and patches are welcome (see [1] for the source code). > >> Basex reports the first error while validating with xsd schema, while java >> uses to report the collection of errors that do not depend on each other. > > A similar observation applies here: the error handling in the > mentioned class could be revised in order to catch more than just the > first error [2]. > > Feel free to ask if you have more questions, > Christian > > [1] https://github.com/BaseXdb/basex/blob/master/src/main/java/org/basex/query/… > [2] https://github.com/BaseXdb/basex/blob/master/src/main/java/org/basex/query/… > _______________________________________________ > BaseX-Talk mailing list > BaseX-Talk(a)mailman.uni-konstanz.de > https://mailman.uni-konstanz.de/mailman/listinfo/basex-talk -- Wendell Piez | http://www.wendellpiez.com XML | XSLT | electronic publishing Eat Your Vegetables _____oo_________o_o___ooooo____ooooooo_^

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Compiling w/ HTTP
by Jay Straw 30 Jan '13

30 Jan '13

Hi all, I've just compiled from git the basex, basex-api, and basex-example repos, using maven. When I try to start, in basex-api, etc/basexhttp, I get: Exception in thread "main" java.lang.NoClassDefFoundError: org/eclipse/jetty/server/Handler Caused by: java.lang.ClassNotFoundException: org.eclipse.jetty.server.Handler at java.net.URLClassLoader$1.run(URLClassLoader.java:202) at java.security.AccessController.doPrivileged(Native Method) at java.net.URLClassLoader.findClass(URLClassLoader.java:190) at java.lang.ClassLoader.loadClass(ClassLoader.java:306) at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:301) at java.lang.ClassLoader.loadClass(ClassLoader.java:247) Could not find the main class: org.basex.BaseXHTTP. Program will exit. Which to me suggests I'm missing Jetty stuff, however I'm unsure why that wasn't brought to my attention during the compile? I'm all kinds of confused. Thanks for any help, Jay

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BaseX-Talk January 2013