BaseX-Talk

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9 participants
5241 discussions

Decoding error
by Graydon Saunders 19 Jul '23

19 Jul '23

Hello -- I have some mainframe files which start off in no-known-encoding. Using Basex 10.6, I'm trying to use the bin module to make some character substitutions so the content of these files can be UTF-8. let $charMap as map(*) := map { 33: 93, (: exclamation point ! to close bracket ] :) 162: 91, (: cent-sign ¢ to open bracket [ :) 124: 33, (: pipe character | to exclamation point ! :) 160: 32, (: non-breaking space to plain space :) 26: 32 (: U+001A SUBSTITUTION CHARACTER at the end of the file; do not want :) } let $fromList as xs:integer+ := map:keys($charMap) let $fileList as xs:string+ := file:children($localPath) for $x in $fileList return (file:read-binary($x) ! bin:to-octets(.) ! (if (. = $fromList) then $charMap(.) else .) ! bin:from-octets(.) ! bin:decode-string(.,'UTF-8')) => string-join('') Four of the five sample files work; one of them returns "Decoding error: xff" If I restrict the process to the problematic file and use return (file:read-binary($x) ! bin:to-octets(.) ! (if (. = $fromList) then $charMap(.) else .)) => distinct-values() => sort() I don't find a 255 value. And I'm pretty sure all the codepoints I do have are simple, less than 255, single octet UTF-8 characters. Any suggestions for what I ought to be looking at? Thanks! Graydon -- Graydon Saunders | graydonish(a)fastmail.com Þæs oferéode, ðisses swá mæg. -- Deor ("That passed, so may this.")

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How to get stack trace from an Query Exception?
by Eliot Kimber 13 Jul '23

13 Jul '23

The docs for Try/Catch in in the XQuery_3.0 page say: · $err:additional: error stack trace However, in my testing, this only returns the place where the error was thrown, not the complete stack trace as is shown e.g., in a web app when an exception is thrown. Is it possible to get the stack trace in XQuery? I didn’t find anything searching on the BaseX-supplied DBA app. Thanks, E. _____________________________________________ Eliot Kimber Sr Staff Content Engineer O: 512 554 9368 M: 512 554 9368 servicenow.com<https://www.servicenow.com> LinkedIn<https://www.linkedin.com/company/servicenow> | Twitter<https://twitter.com/servicenow> | YouTube<https://www.youtube.com/user/servicenowinc> | Facebook<https://www.facebook.com/servicenow>

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PHP Client Session Object: infinite loop in read method when bpos is null
by Tamara Marnell 13 Jul '23

13 Jul '23

Hello everyone, Once in a while, my server running BaseX will suddenly experience a big spike in write operations, the hard disk space will fill up to 100%, and the whole server will lock up. I can't say what initiates this, because the logs and metrics disprove every theory I can think of. (There's nothing unusual in the access logs or BaseX data logs, memory usage stays consistently at 45% and CPU usage at 5%, no user attempted anything like a huge bulk upload, etc.) However, one thing that always happens during these incidents is that the Apache error log blows up to a crazy size like 1 GB, filled with the message: PHP Notice: Trying to access array offset on value of type null in /[path]/client/session.php on line 164 This line is in the read method of the Session class from GitHub, and it indicates that the byte position passed to the buffer property is null. My error log probably fills up because read() is called by readString() in a while loop that never terminates. There might be extraordinary circumstances in which during construction, socket_connect returns "true" but the response is not valid or expected. -Tamara -- Tamara Marnell Program Manager, Systems Orbis Cascade Alliance (orbiscascade.org <https://www.orbiscascade.org/>) Pronouns: she/her/hers

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sequences after the path operator
by Graydon Saunders 07 Jul '23

07 Jul '23

Hello -- Using BaseX 10.6, the test query let $test as xs:string := "And O Lord the pride of man, broken in the dust again" let $syntax1 as xs:string := analyze-string($test,'\p{Lu}')/(fn:match/concat('[',.,']'),fn:non-match/string()) => string-join('') let $syntax2 as xs:string := analyze-string($test,'\p{Lu}')/*/(self::fn:match/concat('[',.,']'),self::fn:non-match/string()) => string-join('') return ($syntax1,$syntax2) produces [A][O][L]nd ord the pride of man, broken in the dust again [A]nd [O] [L]ord the pride of man, broken in the dust again I'm surprised by this, because I expected document order to apply to the result of analyze-string and for syntax1 to work in the sense of having the results emerging in the same order as the input. Have I miscomprehended something? Anyone care to have a go at explaining why syntax1 doesn't maintain the order of the input? (I'm possibly mistakenly confident that I understand why syntax2 does.) Thanks! Graydon -- Graydon Saunders | graydonish(a)fastmail.com Þæs oferéode, ðisses swá mæg. -- Deor ("That passed, so may this.")

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Apparent bug when setting @xml:base on element with @base
by Eliot Kimber 07 Jul '23

07 Jul '23

This XQuery demonstrates the problem: (:--------:) let $xmlBaseAtt as attribute() := attribute {'xml:base'}{'/foo/bar.xml'} let $transformed1 as element() := try { $doc1 transform with { insert node $xmlBaseAtt into .} } catch * { <error code="{$err:code}" desc="{$err:description}" object="doc1"/> } let $transformed2 as element() := try { $doc2 transform with { insert node $xmlBaseAtt into .} } catch * { <error code="{$err:code}" desc="{$err:description}" object="doc2"/> } return ( ``[No @base attribute:]`` ,$transformed1 ,``[Has @base attribute:]`` ,$transformed2 ,() ) (:--------:) The results I get with 10.6 are: No @base attribute: <root xml:base="/foo/bar.xml"/> Has @base attribute: <error code="err:XUDY0021" desc="Duplicate attribute name: xml:base." object="doc2"/> It looks like the transform processor is matching @xml:base to @base even though they are different attributes. Is this a bug or is there a different way I should be specifying the @xml:base attribute? This is an issue because @base is a DITA-defined attribute that occurs on elements on which I need to set @xml:base (which is how I found the problem). Cheers, Eliot _____________________________________________ Eliot Kimber Sr Staff Content Engineer O: 512 554 9368 M: 512 554 9368 servicenow.com<https://www.servicenow.com> LinkedIn<https://www.linkedin.com/company/servicenow> | Twitter<https://twitter.com/servicenow> | YouTube<https://www.youtube.com/user/servicenowinc> | Facebook<https://www.facebook.com/servicenow>

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Whitespaces not preserved in TEI documents.
by Montserrat Matías 06 Jul '23

06 Jul '23

Hello. I have a bug with BaseX version 10 and higher related to handling whitespaces in documents with mixed content elements. I'm working with narrative documents (TEI). Following the instructions in the documentation about this type of documents (containing mixed elements) I have disabled the indentation and the STRIPWS option. When I execute queries with connection to the database, the result is as explained in the documentation (blanks are preserved). However, when I use the BaseX libraries to execute queries in a local context (without a connection to the database) the spaces are sometimes removed. Same error if I run the query in the Database Administration interface. Query: db:option('stripws') Result: false Query: db:option('serializer') Result: map{"omit-xml-declaration":"yes","binary":"yes","method":"basex","use-character-maps":"","tabulator":"no","allow-duplicate-names":"no","media-type":"","doctype-public":"","escape-uri-attributes":"no","standalone":"omit","csv":map{"lax":true(),"backslashes":false(),"separator":"comma","allow":"","header":false(),"quotes":true(),"format":"direct"},"indents":2,"json-node-output-method":"xml","json":map{"escape":true(),"strings":false(),"lax":false(),"indent":(),"format":"direct","merge":false()},"doctype-system":"","item-separator":(),"indent":"no","suppress-indentation":"","byte-order-mark":"no","include-content-type":"yes","encoding":"UTF-8","newline":"\n","normalization-form":"none","html-version":"","version":"","limit":-1,"undeclare-prefixes":"no","cdata-section-elements":"","parameter-document":""} Query: let $doc := <doc><entry><sense id='1'><def>Gente grosera o vulgar.</def><cit><quote><seg>La</seg> <oRef>chusma</oRef>.</quote></cit></sense></entry></doc> return $doc/entry//sense[@id = '1'] Result: <sense id="1"><def>Gente grosera o vulgar.</def><cit><quote><seg>La</seg><oRef>chusma</oRef>.</quote></cit></sense> The whitespace contained between the </seg> and <oRef> tags has been stripped. In version 9.3.5 this problem did not occur. Can you please have a look at this? In a TEI document whitespaces are important. Thanx in advance, Montse. ___________________________________________ NOTA LEGAL El contenido de este mensaje de correo electrónico, incluidos los ficheros adjuntos, es confidencial y está protegido por el artículo 18.3 de la Constitución española, que garantiza el secreto de las comunicaciones. Si usted recibe este mensaje por error, le rogamos que se ponga en contacto con el remitente para informarle de este hecho y no difunda su contenido ni haga copias. La Real Academia Española informa de que los datos que en esta comunicación figuran, así como los que mantiene de usted y/o de su empresa, son tratados con la finalidad de mantener el contacto, así como de realizar las gestiones que en esta aparecen, y son utilizados de forma autorizada por las partes y sin cederse a terceros ajenos. Puede ejercer sus derechos a través de proteccion_de_datos(a)rae.es<mailto:proteccion_de_datos@rae.es>. Puede obtener más información sobre protección de datos en nuestra página web<https://www.rae.es/aviso-legal> o contactando directamente con nosotros (Reglamento UE 2016/679).

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Determining if a node is a database node
by Eliot Kimber 06 Jul '23

06 Jul '23

I need to be able to determine if an arbitrary node is or is not a database node. I implemented this function: declare function util:isDatabaseNode($node as node()) as xs:boolean { let $isDbNode as xs:boolean := try { let $nodeId as xs:integer? := db:node-id($node) (: let $msg := prof:dump(``[[DEBUG] relpath:isDatabaseNode(): nodeId: "`{$nodeId}`"]``) :) return exists($nodeId) } catch * { (: let $msg := prof:dump(``[[DEBUG] relpath:isDatabaseNode(): Got exception `{$err:code}` - `{$err:description}`]``) :) (: return :) false() } let $msg := prof:dump(``[[DEBUG] relpath:isDatabaseNode(): Returning `{$isDbNode}``]``) return $isDbNode }; With the prof:dump() calls commented out as shown here, it always returns true, even when it returned false. If I comment in the prof:dumps then I get the expected correct false result. This must be the result some optimization at compile time but I haven’t been able to find a construction of this function that works without the debug messages. Is there a better way to determine if a node is a database node? This is with 10.6. Cheers, E. _____________________________________________ Eliot Kimber Sr Staff Content Engineer O: 512 554 9368 M: 512 554 9368 servicenow.com<https://www.servicenow.com> LinkedIn<https://www.linkedin.com/company/servicenow> | Twitter<https://twitter.com/servicenow> | YouTube<https://www.youtube.com/user/servicenowinc> | Facebook<https://www.facebook.com/servicenow>

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Possible bug in the interaction between db:attribute(), data() and Sequences.
by Andreas Hengsbach | nexoma 05 Jul '23

05 Jul '23

Hello all, we have probably found a bug, the cause of which is currently unclear to us. Fortunately, the problem is reproducible in a small test case. Steps to reproduce the problem: 1. import the following XML into a BaseX database "testcase". ### schnipp <attributes foo="bar"> <attribute name="test1" seq="foo"/> <attribute name="test2"/> <attribute name="test3" seq="bar"/> </attributes> ### schnapp 2. make sure that an attribute index has been created. 3. execute the following script. ### schnipp let $source := db:attribute('testcase', 'bar', 'foo')/.. let $value := ( $source/attribute[@name="test1"]/@seq/data(), $source/attribute[@name="test2"]/@seq/data(), $source/attribute[@name="test3"]/@seq/data() ) return ( $value[2] => inspect:type() ) ### schnapp Explanation: The example is really only meant as a test case. For our case we have already found a workaround, so we don't have a serious problem. The important thing is that the element is read from the database via db:attribute() and then the individual values are combined again into a sequence. In doing so, we get an untypedAtomic from attribute test1, an empty-sequence() for test2 and an untypedAtomic again for test3. Observation: When we read the second value of the sequence by index ($value[2]), we get back an "attribute()" instead of an untypedAtomic. Expectation: We would expect an untypedAtomic here again. Workaround: We simply used string() instead of data() to explicitly cast the value to a string. Versions: We were able to reproduce the problem with 10.4 and the current 10.6. With a very old version 7.9, however, it was not reproducible. Many thanks and best regards Andreas

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Performance of db:get-value() for large maps
by Eliot Kimber 03 Jul '23

03 Jul '23

I’m working on constructing DITA key spaces for our content. My current implementation builds an XQuery map that contains the key space data as well as the XML data from which the key space was constructed, which can be quite a bit (1-2 megabytes of XML all told—key space construction effectively requires constructing a single “resolved” DITA map from a tree of map documents, which I’m then storing in my key space map). A given key space might have 100,000 individual name-to-element mappings in addition to the raw DITA content. I tried saving these maps into a database using db:put-value(), which worked. But, when I went to fetch them back out, it took 30 seconds to fetch one of these maps. My expectation was that retrieving a map would be quite fast. I’m sure that it was silly to try to store all the raw markup in these maps, and I will change that aspect of my implementation to store the resolved maps separately and then use node IDs in the key space map. Worst case I can do what I have been doing with BaseX 9 and convert the XQuery map to an XML representation and use that for retrieval, which of course will work fine, at the cost of more code and a few more milliseconds of ingestion processing. Before I spend any more time trying to optimize the storage and retrieval of these maps, I wanted to ask a few questions: 1. Is my expectation that map retrieval should generally be very fast correct, modulo not having gobs of raw XML in them? 2. Is there a more efficient way to query over maps that are stored in a database? My initial attempt was to simply pull the entire map from the database and then operate on it as I would any other map, i.e.: $keySpace as map(*) := getKeySpace($rootMap) (: Pulls the map from the database :) $keydefs as element()* := $keySpace?keyscopes?($scopeKey)?keydefs?($keyName) 3. Is there some other maps-in-a-database optimization technique I’m overlooking? Thanks, Eliot _____________________________________________ Eliot Kimber Sr Staff Content Engineer O: 512 554 9368 M: 512 554 9368 servicenow.com<https://www.servicenow.com> LinkedIn<https://www.linkedin.com/company/servicenow> | Twitter<https://twitter.com/servicenow> | YouTube<https://www.youtube.com/user/servicenowinc> | Facebook<https://www.facebook.com/servicenow>

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Calling a Java function with varargs parameter from XQuery
by Lizzi, Vincent 03 Jul '23

03 Jul '23

Hello BaseX people, The Java language bindings in BaseX look like a very good way to use Java libraries from XQuery. I'm currently trying to use Lingua (https://github.com/pemistahl/lingua) with BaseX, and mostly have it working, but I've not been able to figure out how to call a Java function that takes a vararg (variable arguments) parameter. Here is a bit of XQuery code that shows the problem. I'm using BaseX version 10.6 and the jar for Lingua version 1.2.2 has been added to the classpath. This query should return a LanguageDetectorBuilder object. declare namespace Builder = "java:com.github.pemistahl.lingua.api.LanguageDetectorBuilder"; declare namespace Detector = "java:com.github.pemistahl.lingua.api.LanguageDetector"; declare namespace Language = "java:com.github.pemistahl.lingua.api.Language"; let $builder := Builder:fromLanguages( [ Language:ENGLISH(), Language:DUTCH(), Language:GERMAN(), Language:SPANISH(), Language:FRENCH() ] ) return $builder The above code produces this error message in the BaseX GUI: [XPTY0004] com.github.pemistahl.lingua.api.LanguageDetectorBuilder:fromLanguages(com.github.pemistahl.lingua.api.Language[]) expected, (CArray) found. If I try making the parameter a sequence instead of an array, replacing () parenthesis for the [] brackets, then this is the error message: [XPTY0004] com.github.pemistahl.lingua.api.LanguageDetectorBuilder:fromLanguages(com.github.pemistahl.lingua.api.Language[]) expected, (List) found. I've read through the Java Bindings page in the wiki and tried to rewrite the parameter in different ways, but so far have only gotten different error messages. The signature for the fromLanguages function can be seen at https://github.com/pemistahl/lingua/blob/main/src/main/kotlin/com/github/pe… Is there a way to make this work? Thanks, Vincent ______________________________________________ Vincent M. Lizzi Head of Information Standards | Taylor & Francis Group 530 Walnut St., Suite 850, Philadelphia, PA 19106 E-Mail: vincent.lizzi(a)taylorandfrancis.com<mailto:vincent.lizzi@taylorandfrancis.com> Web: www.tandfonline.com<http://www.tandfonline.com> Taylor & Francis is a trading name of Informa UK Limited, registered in England under no. 1072954 "Everything should be made as simple as possible, but not simpler." Information Classification: General

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