Difference between revisions of "Parsers"
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To turn the internal XML parser and DTD parsing on/off,
To turn the internal XML parser and DTD parsing on/off, the <code>INTPARSE</code> and <code>DTD</code> options:
SET [[Options#INTPARSE|INTPARSE]] true
SET [[Options#INTPARSE|INTPARSE]] true
Revision as of 16:39, 8 July 2014
This article is part of the Getting Started Section. It presents the available parsers that can be used to import various data sources in BaseX databases. Please visit the Serialization article if you want to know how to export data.
- 1 XML Parsers
- 2 HTML Parser
- 3 JSON Parser
- 4 CSV Parser
- 5 Text Parser
- 6 Changelog
BaseX provides two parsers to import XML data:
- By default, the internal, built-in XML parser is used, which is more fault-tolerant than Java’s XML parser. It supports standard HTML entities out-of-the-box, and is faster in most cases. In turn, it does not support all oddities specified by DTDs, and cannot resolve catalogs.
- Java’s SAXParser can also be selected for parsing XML documents. This parser is stricter than the built-in parser, but it refuses to process some large documents.
Go to Menu Database → New, then choose the Parsing tab and (de)activate Use internal XML parser. The parsing of DTDs can be turned on/off by selecting the checkbox below.
To turn the internal XML parser and DTD parsing on/off, modify the
The db:add and db:replace functions can also be used to add new XML documents to the database. The following example query uses the internal XML parser and adds all files to the database
DB that are found in the directory
declare option db:intparse "yes"; for $file in file:list("2Bimported") return db:add('DB', $file)
With TagSoup, HTML can be imported in BaseX without any problems. TagSoup ensures that only well-formed HTML arrives at the XML parser (correct opening and closing tags, etc.). Hence, if TagSoup is not available on a system, there will be a lot of cases where importing HTML fails, no matter whether you use the GUI or the standalone mode.
TagSoup is already included in the full BaseX distributions (
BaseX.exe, etc.). It can also be manually downloaded and embedded on the appropriate platforms.
An easy way to add TagSoup to your own project is to follow this steps:
1. visit MVN TagSoup Repository
2. click on the version you want
3. you can see on the first tab called Maven a XML like this :
<dependency> <groupId>org.ccil.cowan.tagsoup</groupId> <artifactId>tagsoup</artifactId> <version>1.2.1</version> </dependency>
4. copy that in your own maven project's pom.xml under the <dependencies> tag.
5. don't forget to run
mvn jetty:run again
With Debian, TagSoup will be automatically detected and included after it has been installed via:
apt-get install libtagsoup-java
TagSoup offers a variety of options to customize the HTML conversion. For the complete list please visit the TagSoup website. BaseX supports most of these options with a few exceptions:
- encoding: BaseX tries to guess the input encoding but this can be overwritten by the user if necessary.
- files: not supported as input documents are piped directly to the XML parser.
- method: set to 'xml' as default. If this is set to 'html' ending tags may be missing for instance.
- version: dismissed, as TagSoup always falls back to 'version 1.0', no matter what the input is.
- standalone: deactivated.
- pyx, pyxin: not supported as the XML parser can't handle this kind of input.
- output-encoding: not supported, BaseX already takes care of that.
- reuse, help: not supported.
Go to Menu Database → New and select "HTML" in the input format combo box. There's an info in the "Parsing" tab about whether TagSoup is available or not. The same applies to the "Resources" tab in the "Database Properties" dialog.
These two dialogs come with an input field 'Parameters' where TagSoup options can be entered.
Turn on the HTML Parser before parsing documents, and set a file filter:
SET PARSER html SET HTMLPARSER method=xml,nons=true,ncdata=true,nodefaults=true,nobogons=true,nocolons=true,ignorable=true SET CREATEFILTER *.html
The HTML Module provides a function for converting HTML to XML documents.
Documents can also be converted by specifying the parser and additional options in the query prolog:
declare option db:parser "html"; declare option db:htmlparser "html=false,nodefaults=true"; doc("index.html")
BaseX can also import JSON documents. The resulting format is described in the documentation for the XQuery JSON Module:
Go to Menu Database → New and select "JSON" in the input format combo box. You can set the following options for parsing JSON documents in the "Parsing" tab:
- Encoding: Choose the appropriate encoding of the JSON file.
- JsonML: Activate this option if the incoming file is a JsonML file.
Turn on the JSON Parser before parsing documents, and set some optional, parser-specific options and a file filter:
SET PARSER json SET JSONPARSER encoding=utf-8, jsonml=true SET CREATEFILTER *.json
The JSON Module provides functions for converting JSON objects to XML documents.
BaseX can be used to import CSV documents. Different alternatives how to proceed are shown in the following:
Go to Menu Database → New and select "CSV" in the input format combo box. You can set the following options for parsing CSV documents in the "Parsing" tab:
- Encoding: Choose the appropriate encoding of the CSV file.
- Separator: Choose the column separator of the CSV file. Possible:
spaceor an arbitrary character.
- Header: Activate this option if the incoming CSV files have a header line.
Turn on the CSV Parser before parsing documents, and set some optional, parser-specific options and a file filter. Unicode code points can be specified as separators;
32 is the code point for spaces:
SET PARSER csv SET CSVPARSER encoding=utf-8, lines=true, header=false, separator=space SET CREATEFILTER *.csv
The CSV Module provides a function for converting CSV to XML documents.
Documents can also be converted by specifying the parser in the query prolog.
The following example query adds all CSV files that are located in the
2Bimported to the database
DB and interprets
the first lines as column headers:
declare option db:parser "csv"; declare option db:csvparser "header=yes"; for $file in file:list("2Bimported", false(), "*.csv") return db:add('DB', $file)
Plain text can be imported as well:
Go to Menu Database → New and select "TEXT" in the input format combobox. You can set the following option for parsing text documents in the "Parsing" tab:
- Encoding: Choose the appropriate encoding of the text file.
- Lines: Activate this option to create a
<line>...</line>element for each line of the input text file.
Turn on the CSV Parser before parsing documents and set some optional, parser-specific options and a file filter:
SET PARSER text SET TEXTPARSER lines=yes SET CREATEFILTER *
Similar to the other formats the text parser can be specified in the prolog of an XQuery expression:
declare option db:parser "text"; for $file in file:list("2Bimported", true(), "*.txt") return db:add('DB', $file)
- Version 7.8
- Updated: parser options
- Version 7.7.2
- Removed: CSV option "format"
- Version 7.3
- Updated: the CSV
SEPARATORoption may now be assigned arbitrary single characters
- Version 7.2
- Updated: Enhanced support for TagSoup options