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diff --git a/examples/xmlpatterns/trafficinfo/doc/src/trafficinfo.qdoc b/examples/xmlpatterns/trafficinfo/doc/src/trafficinfo.qdoc deleted file mode 100644 index 8b32563..0000000 --- a/examples/xmlpatterns/trafficinfo/doc/src/trafficinfo.qdoc +++ /dev/null @@ -1,149 +0,0 @@ -/**************************************************************************** -** -** Copyright (C) 2012 Digia Plc and/or its subsidiary(-ies). -** Contact: http://www.qt-project.org/legal -** -** This file is part of the documentation of the Qt Toolkit. -** -** $QT_BEGIN_LICENSE:FDL$ -** Commercial License Usage -** Licensees holding valid commercial Qt licenses may use this file in -** accordance with the commercial license agreement provided with the -** Software or, alternatively, in accordance with the terms contained in -** a written agreement between you and Digia. For licensing terms and -** conditions see http://qt.digia.com/licensing. For further information -** use the contact form at http://qt.digia.com/contact-us. -** -** GNU Free Documentation License Usage -** Alternatively, this file may be used under the terms of the GNU Free -** Documentation License version 1.3 as published by the Free Software -** Foundation and appearing in the file included in the packaging of -** this file. Please review the following information to ensure -** the GNU Free Documentation License version 1.3 requirements -** will be met: http://www.gnu.org/copyleft/fdl.html. -** $QT_END_LICENSE$ -** -****************************************************************************/ - -/*! - \example xmlpatterns/trafficinfo - \title TrafficInfo Example - \ingroup xmlpattern_examples - Shows how XQuery can be used extract information from WML documents provided by a WAP service. - - \section1 Overview - - The WAP service used in this example is \l{Trafikanten}{wap.trafikanten.no} - that is run by the Norwegian governmental agency for public transport in - Oslo. The service provides real time information about the departure of - busses, trams and undergrounds for every station in the city area. - - This example application displays the departure information for a specific - station and provides the feature to filter for a special bus or tram line. - - \image trafficinfo-example.png - - \section1 Retrieving the Data - - Without the knowledge of XQuery, one would use QNetworkAccessManager to - query the WML document from the WAP service and then using the QDom - classes or QXmlStreamReader classes to iterate over the document and - extract the needed information. - However this approach results in a lot of glue code and consumes valuable - developer time, so we are looking for something that can access XML - documents locally or over the network and extract data according to given - filter rules. That's the point where XQuery enters the stage! - - If we want to know when the underground number 6 in direction - \Aring\c{}sjordet is passing the underground station in Nydalen on November - 14th 2008 after 1pm, we use the following URL: - - \c{http://wap.trafikanten.no/F.asp?f=03012130&t=13&m=00&d=14.11.2008&start=1} - - The parameters have the following meanings: - \list - \li \e{f} The unique station ID of Nydalen. - \li \e{t} The hour in 0-23 format. - \li \e{m} The minute in 0-59 format. - \li \e{d} The date in dd.mm.yyyy format. - \li \e{start} Not interesting for our use but should be passed. - \endlist - - As a result we get the following document: - - \quotefile xmlpatterns/trafficinfo/time_example.wml - - So for every departure we have a \c <a> tag that contains the time as a - text element, and the following text element contains the line number - and direction. - - To encapsulate the XQuery code in the example application, we create a - custom \c TimeQuery class. This provides the \c queryInternal() function - that takes a station ID and date/time as input and returns the list of - times and directions: - - \snippet xmlpatterns/trafficinfo/timequery.cpp 1 - - The first lines of this function synthesize the XQuery strings that fetch - the document and extract the data. - For better readability, two separated queries are used here: the first one - fetches the times and the second fetches the line numbers and directions. - - The \c doc() XQuery method opens a local or remote XML document and returns - it, so the \c{/wml/card/p/small/} statement behind it selects all XML nodes - that can be reached by the path, \c wml \rarrow \c card \rarrow \c p \rarrow - \c small. - Now we are on the node that contains all the XML nodes we are interested in. - - In the first query we select all \c a nodes that have a \c href attribute - starting with the string "Rute" and return the text of these nodes. - - In the second query we select all text nodes that are children of the - \c small node which start with a number. - These two queries are passed to the QXmlQuery instance and are evaluated - to string lists. After some sanity checking, we have collected all the - information we need. - - In the section above we have seen that an unique station ID must be passed - as an argument to the URL for retrieving the time, so how to find out which - is the right station ID to use? The WAP service provides a page for that - as well, so the URL - - \c{http://wap.trafikanten.no/FromLink1.asp?fra=Nydalen} - - will return the following document: - - \snippet xmlpatterns/trafficinfo/station_example.wml 0 - - The names of the available stations are listed as separate text elements - and the station ID is part of the \c href attribute of the parent \c a - (anchor) element. In our example, the \c StationQuery class encapsulates - the action of querying the stations that match the given name pattern with - the following code: - - \snippet xmlpatterns/trafficinfo/stationquery.cpp 0 - - Just as in the \c TimeQuery implementation, the first step is to - synthesize the XQuery strings for selecting the station names and the - station IDs. As the station name that we pass in the URL will be input - from the user, we should protect the XQuery from code injection by using - the QXmlQuery::bindVariable() method to do proper quoting of the variable - content for us instead of concatenating the two strings manually. - - So, we define a XQuery \c $station variable that is bound to the user - input. This variable is concatenated inside the XQuery code with the - \c concat method. To extract the station IDs, we select all \c a elements - that have an \c title attribute with the content "Velg", and from these - elements we take the substring of the \c href attribute that starts at the - 18th character. - - The station name can be extracted a bit more easily by just taking the - text elements of the selected \a elements. - - After some sanity checks we have all the station IDs and the corresponding - names available. - - The rest of the code in this example is just for representing the time and - station information to the user, and uses techniques described in the - \l{Widget Examples}. -*/ |