BaseX-Talk September 2014

basex-talk@mailman.uni-konstanz.de

35 participants
47 discussions

Transaction (rollback)
by Julien Charon 18 Sep '14

18 Sep '14

Hi everybody, I have questions regarding transactions in basex. To provide a context, we have following requirements in our application that uses basex: when executing any update or replace operations, we need to validate the modified XML structures against the corresponding schemas. We only want the result of the update / replace operations to be saved in basex, if the resulting XML structures are valid. So, what we first thought of was creating a transaction, executing the update/replace operations, perform the validation, and if the result of the operations result in invalid XML, perform a rollback. Now we weren't able to find documentation concerning rollback, the only documentation we found is http://docs.basex.org/wiki/Transaction_Management, which does not mention rollback. So my questions are: 1. Is there a rollback functionality and where can I find documentation? 2. If there is no rollback functionality, is it planned for upcoming releases? 3. Are there best practices for the requirements described above? Note: using the validation module is not an option, as apparently only single schemas / schema files are supported and our application schemas are quite complex and located in several schemas, so validation has to be performed in our application. Best regards, Julien Charon Avitech GmbH Engineering AxL Tel.: +49 (0)7541/282-177 Fax: +49 (0)7541/282-199 e-mail: julien.charon(a)avitech.aero<mailto:julien.charon@avitech.aero> ________________________________________________ Avitech GmbH Principal Office: Bahnhofplatz 1 | 88045 Friedrichshafen | Germany Court Registration: Amtsgericht Ulm | HRB 728293 Geschäftsführer/Managing Director: Antonio Maria Gonzalez Gorostiza http://avitech.aero<http://avitech.aero/> This message may contain confidential information and is intended only for the individual named. If you are not the named addressee you should not disseminate, distribute or copy this e-mail. Please notify the sender immediately by e-mail if you have received this e-mail by mistake and delete this e-mail from your system. ________________________________ Avitech GmbH Principal Office: Bahnhofplatz 1 | 88045 Friedrichshafen | Germany Court Registration: Amtsgericht Ulm | HRB 728293 Geschäftsführer/Managing Director: Antonio Maria Gonzalez Gorostiza VAT No.: DE223719716 http://avitech.aero

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Re: [basex-talk] Proxy port with basex
by Christian Grün 18 Sep '14

18 Sep '14

Hi Furqan (cc to the list), sorry for letting you wait. > how ever what i intend to do is that,after the query is issued from the web > application for the basex -db running on port 8984,i want to capture it > before it hits the database,in order to evaluate malacious queries..... What should happen in your opinion if a query is malicious? Would you like to prevent its execution, or would you rather want to be able to track that a malicious query has been evaluated at some stage? In the latter case, you could check out the log files [1], in which all commands and server requests will be listed. > So i was wondering if this would be possible using a reverse-proxy in front > of basex-db,such that all the traffic intended for the database would be > passed thrugh my proxy......say on port 80 > Or if there is any other way i could do it. > Basex comes with an option of proxy port and proxy host...will they work for > the scenerio that i described. > i mean if i set the proxy port of basex to be port 80 :where my appache or > nginx server would be running > ,will the queries from web application (xpath n xquery),pass through that > server running on port 80...... I guess that the BaseX proxy options won't help you there, because these mainly exist to handle firewall restrictions. Hope this helps, Christian [1] http://docs.basex.org/wiki/Logging > i tried out nginx without setting proxy port of basex ,but it gives n error > as nginx runs on port 80 and i want it to monitor traffic of port > 8994(basix),and at this port already basex server is running cuz of which my > nginx server cant listen to traffic (the error i got was a access > /permission error)n i guess it was cuz basex had permission rights over the > port.... > > i would greatly n highly appritiate any help and suggestions. > regards > > On Fri, Sep 12, 2014 at 8:50 AM, Christian Grün <christian.gruen(a)gmail.com> > wrote: >> >> Hi Furquan, >> >> do you use the classical REST interface to send your XQuery >> expressions to the server? In that case, you could either check out >> the logging facilities by the applied web server (possibly Jetty) or >> play around with another proxy like nginx [1]. >> >> You will be more flexible by using RESTXQ [2] and writing server-side >> XQuery code. The XQuery Module [3] or the Client Module [4] can be >> used to evaluate the received query. >> >> Hope this helps (and thanks for writing to the mailing list), >> Christian >> >> [1] http://nginx.org/ >> [2] http://docs.basex.org/wiki/RESTXQ >> [3] http://docs.basex.org/wiki/XQuery_Module >> [4] http://docs.basex.org/wiki/Client_Module > >

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validate:xsd-info & xs:import
by Hans-Juergen Rennau 16 Sep '14

16 Sep '14

Dear BaseX team, I face a problem with the "validate" module. My impression when using "validate:xsd-info" is the following: (a) if the XSD is supplied as argument - xs:import is NOT resolved (b) if the XSD is inferred from xsi:schemaLocation - xs:import IS resolved It would be wonderful if imports/includes could be automatically resolved - the "validate" module could then be extremely useful! Best regards, Hans-Juegen PS: My experiment: ====================================================== let $docURI := '... a document URI ...' let $xsdURI := '... the corresponding schema URI ...' let $xsd := doc($xsdURI) let $tns := $xsd/xs:schema/@targetNamespace let $doc1 := doc($docURI) let $doc2 := document { element {node-name($doc1/*)} { attribute xsi:schemaLocation {concat($tns, ' ', $xsdURI)}, $doc1/*/(@*, node()) } } return <results>{ <result1>{validate:xsd-info($doc1, $xsd)}</result1>, <result2>{validate:xsd-info($doc2)}</result2> }</results> ====================================================== => <results> <result1>Fatal:src-resolve: Name "communication:ShoppingCartFetchRS" kann nicht als "type definition"-Komponente aufgelöst werden.</result1> <result2/> </results>

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Multiple war instances
by Jérôme Chauveau 15 Sep '14

15 Sep '14

Hi, i would like to run 2 separate war instances in the same Tomcat server. Each instance must embbed its own data repository. I tried to use the HTTPLOCAL flag but i am not able to manage separatly the 2 instances with a basexclient command line tool. How can I manage an HTTPLOCAL instance from a basexclient? Another solution might be that each webapp instance runs its own basexserver on 2 differents port. How can I set the 1984 default port used by a basex webapp? Regards, Jérôme C. -- Jérôme Chauveau - SAIC-CERTIC - Campus 4 Université de Caen Basse-Normandie

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declare copy-namepaces - "inherit" ignored!
by Hans-Juergen Rennau 13 Sep '14

13 Sep '14

Dear BaseX team, I have a problem with a subtle bug which has been introduced with version 7.8, it seems. In 7.7, the declare copy-namespaces ..., inherit; was implemented correctly - see below for example code and result. But from 7.8 on, copy namespaces mode "inherit" is ignored. I would greatly appreciate if you could restore the correct behaviour, as I have code running which must be compatible with XQuery 1.0 and which needs to "add" in-scope namespaces dynamically. (And in XQuery 1.0 I see no alternative to the pattern shown below.) Kind regards - Hans-Juergen Example code: ================================ declare copy-namespaces preserve, inherit; declare function local:addNamespace($elem, $prefix, $uri) { let $qname := QName($uri, concat($prefix, ':dummy')) return <A>{ attribute {$qname} {""}, $elem }</A>/* }; let $elem := <foo/> return local:addNamespace($elem, 'z', 'http:example.com') ================================ => BaseX 7.7: <foo xmlns:z="http:example.com"/> BaseX >= 7.8: <foo/>

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db documents metadata
by Marc van Grootel 12 Sep '14

12 Sep '14

Hi, I was looking through the feature list in the issue tracker to see what's in the pipeline. I suddenly remembered a feature from an xml database I used a couple of years ago called Qizx. This had a very neat feature where every database document and collection could have a special map with metadata properties. These do not affect the XML content in any way but they can be accessed via special API calls or Qizx specific extension module. A better explanation of this feature can be read in the Qizx manual (for example here http://kiwi.emse.fr/DN/qizx-manual.pdf on page 18 and 57). I have used such metadata properties on nodes to implement syncing XML documents in a SCM (Subversion). I stored revision id's and other SCM control data in those properties. Authors would work in Subversion and certain directories where kept synced to a Qizx database so we could easily create PDF publications of the latest XML with zero impact on the XML itself. Maybe BaseX already uses something like that under the hood, I don't know. If so extending it or opening it for use would be useful I think, and generally cool :-) -- --Marc

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Proxy port with basex
by Furqan Khan 12 Sep '14

12 Sep '14

i was wondering if u could suggest how to use the proxy port option that comes wit basiX. Or is there any way by which i can capture the xpath queries issued from a web application ,before the actually hit the BasiX database at back end (Sort of proxy between a web app and database server 'basix in this case'.). Any suggestions would be highly appreciated.....

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Best way to understand Query result type
by Marco Lettere 12 Sep '14

12 Sep '14

Hello all, I'm in the situation where I'd have to execute an XQuery on a different Server from an external Java code (check the small example provided). What is the best way of transforming the resulting bytestream into BaseX' Value model (item()*, node()*, xs:string* whatever is returned by the query) in order to be able to treat the result as if it was generated inside the calling XQuery itself? Would the HTTPClient that ships with Basex be of any help? Or do I have to do everything manually? I hope the question is stated clearly enough anyway here is a short example (probably not working directly ;-)) that demonstrates the concept. declare namesapce ext = "my.externalClass.EC"; let $out := ext:eval("http://otherhost:8984/rest" "{1 to 10 ! <a/>}") return <total count={count($out)}> {$out} </total> EC has few methods most importantly: private String queryToXML(String query){ return "<query xmlns=\"http://basex.org/rest\">" + "<text><![CDATA[" + query + "]]></text>" + "</query>"; } public static void eval(String address, String query) { try { URL url = new URL(address); HttpURLConnection conn = (HttpURLConnection)url.openConnection(); conn.setRequestMethod("POST"); conn.setDoOutput(true); conn.getOutputStream().write(this.query.getBytes()); ByteArrayOutputStream baos = new ByteArrayOutputStream(); InputStream is = conn.getInputStream(); byte[] buf = new byte[1024]; int len = is.read(buf,0,buf.length); while(len != -1){ baos.write(buf, 0, len); len = is.read(buf,0,buf.length); } is.close(); byte[] = baos.toByteArray(); baos.close(); } catch (Exception e) { result = e; } } The Question translates to what should eval's return type be and how to generate it from ByteArrayOutputStream. Thank you. M.

2 1

BaseX CMS functionality
by Philipp Burger 11 Sep '14

11 Sep '14

Hello, I study print and media technology in the 6th semester with focus on digital publishing at the Stuttgart Media University. As a part of my Bachelor thesis following question popped up: Are there existing BaseX functions or third-party solutions for typical CMS functionalities like rights and role management, versioning, document check in and check out,… for XML files? Thanks for your help With best regards Philipp Burger Hallo, ich studiere Druck- und Medientechnologie im 6. Semester mit dem Schwerpunkt Digital Publishing an der Hochschule der Medien in Stuttgart. Im Rahmen meiner Bachelor-Arbeit ist folgende Frage aufgetaucht: Gibt es für BaseX bestehende Funktionen oder Lösungen von Drittanbietern um typische CMS Funktionalitäten wie Rechte-Rollenverwaltung/Versionierung/Dokument einchecken/auschecken im Mehrbenutzerbetrieb, Locking usw. für XML-Dateien zu realisieren? vielen Dank schon mal im Voraus gruß Philipp Burger

1 0

arrow operator, no big deal!
by Rob Stapper 11 Sep '14

11 Sep '14

Hi, I was playing with the arrow-operator and found that it doesn't work on anonymous functions, see example. ('A', 'B', 'C') => function( $sequence) { count( $sequence)} No idea why you should use a construction like this but I, kind of, expected it to work. Maybe something for a next release( together with the "apply-function";-). Regards, Rob Stapper --- Dit e-mailbericht bevat geen virussen en malware omdat avast! Antivirus-bescherming actief is. http://www.avast.com

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BaseX-Talk September 2014