QGIS Web Client

Deprecation information

Please note that QGIS Web Client version 1 is not actively maintained anymore. It has been superseded by QGIS web client 2 (QWC2).

Installation and Configuration Guide

Last Updated: Monday Dec 11, 2017

• 1 For the terminally lazy
• 2 Purpose
• 3 Installation
• 4 Configuration of Client
• 4.1 Per Project Startup Options
• 4.2 Configuration of search panels
• 4.3 Configuration of the theme switcher
• 4.4 Configuring of background layers
• 4.5 Extending the interface
• 4.6 Customize languages
• 5 URL Rewriting
• 6 Configuration of the search
• 6.1 PHP Search
• 6.2 WSGI Search
• 7 License
• 8 Developers and Contributors
• 9 Acknowledgements

1. For the terminally lazy

Edit (if necessary) the needed parameters in install.sh and run:

sudo ./install.sh

This will install all needed packages and get the server up and running.

2. Purpose

This is a WMS based webgis client that makes use of QGIS specific WMS extensions (e.g. highlighting, printing, metadata, etc.). QGIS webclient reads the configuration from the WMS GetCapabilities command and builds the layer tree accordingly. Supports legend graphic, feature info requests and printing.

The client builds on existing Web-GIS libraries OpenLayers and GeoExt, as well as ExtJS 3 for the GUI widgets.

All major browsers should be supported.

3. Installation

Running the install.sh script will take care of the following requirements. Adjust to your needs.

Requirements (Server):

• Apache2 - Webserver (Ubuntu: apache2) with php enabled
• mod-fcgid (Ubuntu: libapache2-mod-fcgid)
• QGIS and QGIS Server (best installed from source)

On ubuntu you can meet these requirements by simply doing:

sudo apt-get install libapache2-mod-fcgid

The QGIS Server compilation and installation will is covered in the online QGIS manual. See http://www.qgis.org/en/docs/index.html for the current version.

For searching:

• python-wsgi for searching (Ubuntu: libapache2-mod-wsgi)
• psycopg2 PostgreSQL db driver (Ubuntu: python-psycopg2)
• webob - Python module providing WSGI request and response objects (Ubuntu: python-webob)

The client part needs to be git cloned with the following command:

git clone https://github.com/qgis/qgis-web-client.git

4. Configuration of Client

All settings are available in the following files.

Global Settings for all projects (make a copy from one of the templates provided):

site/js/GlobalOptions.js

Translations (additional languages):

site/js/Translations.js

Project settings and index:

site/index.xml, site/index.php or site/index.html

Stylesheet of project index:

site/gis-project_listing.xsl

Thumbnails for individual projects (if you take the index.xml route):

thumbnails/projectname.png

4.1. Per Project Startup Options

These options are usually defined in the file site/index.xml. The stylesheet then generates the startup URL parameter options. On the client, the file site/js/GetUrlParams.js is responsible for the proper handling of the startup options. The following options are available:

• lang

An optional language parameter. Normally, this parameter is defined in the file site/js/GlobalOptions.js. Optionally this can be overwritten on a per project base. Allowed values are two-character language codes that must be present in the file site/js/Translations.js or site/js/Translations_custom.js if a custom translations file is used.

• visibleLayers

A comma-separated list of layers that should be set visible on the project start.

• visibleBackgroundLayer

Optionally the name of the background layer that should be set visible on project start. You must have background layers enabled in GlobalOptions.js by setting enableBGMaps to true and a background layer must exist with this name. If either of these prerequisites is not met nothing happens and the parameter is simply ignored.

• format

This optional parameter allows a per project definition of the file format. Valid values are image/png, image/jpeg and image/png;mode=8bit. Defaults to image/png if no format is given per project. For correct specification of image/png;mode=8bit in a URL please encode it correctly: image%2fpng%3b%20mode%3d8bit. If you specify this in site/js/GISProjectListing.js you do not need to encode it.

• fullColorLayers

An optional comma-separated list of layers that need to be in full color (24bit). This parameter is only relevant if the project default image format is set to image/png or image/png;mode=8bit. If any of the layers in the fullColorLayers parameter list is set visible, the format changes to image/jpeg.

• maxExtent

The maximum extent of the project. This parameter is used if the 'Full View' navigation button is clicked. If the startExtent parameter is not specified, maxExtent will also be used as the startExtent. The format is: left,bottom,right,top in map units.

• startExtent

The initial extent on project load if the project should start with a given, but not the maximum extent (e.g. for zooming to a specific project area). Not to be confused with the maxExtent parameter. The format is: left,bottom,right,top in map units.

• searchtables

An optional list of additional search tables specific to the project. The format is schemaname.tablename. These additional search tables will be used for the search field at the top-right corner of the Webclient-GUI. The default search tables are hard-coded in the file wsgi/search.wsgi, in the searchtables array.

4.2. Configuration of search panels

There are two types of search panels supported, using a direct WMS GetFeatureInfo request or using URL rewriting with a much shorter search URL.

The search panels are configured in site/js/GlobalOptions.js.

The following options are available:

• mapSearchPanelOutputRegion

SearchPanel search results output configuration (string), possible values: default, right, bottom, popup By default, search results will be shown in left panel, under the search form. Sometimes this is not desired, here you can choose to show the results in one of the other panels, like BottomPanel and RightPanel. These additional panels are hidden by default because their expansion and collapse trigger a map resize->reload cycle that can slow down the application. Example:

• var mapSearchPanelOutputRegion = 'popup';

4.2.1. Using WMS GetFeatureInfo

var simpleWmsSearch = {
  title: "Search continent",
  query: 'simpleWmsSearch',
  useWmsRequest: true,
  queryLayer: "Country",
  formItems: [
    {
      xtype: 'textfield',
      name: 'name',
      fieldLabel: "Name",
      allowBlank: false,
      blankText: "Please enter a name (e.g. 'africa')"
    }
  ],
  gridColumns: [
    {header: 'Name', dataIndex: 'name', menuDisabled: 'true'}
  ],
  highlightFeature: false,
  highlightLabel: 'name',
  selectionLayer: 'Country',
  selectionZoom: 0,
  doZoomToExtent: true
};

• title: title of the search tab
• query: identifier for this search
• useWmsRequest: enabled for WMS GetFeatureInfo request
• queryLayer: name of query layer
• formItems: list of Ext.form.FormPanel item configs
• xtype: form field type
• name: name of query layer attribute
• fieldLabel: visible text for this field
• blankText: popup text for blank fields
• gridColumns: list of Ext.grid.GridPanel column configs to show search results
• highlightFeature (optional): use QGIS WMS highlight instead of QGIS WMS selection if enabled
• highlightLabel (optional): show this feature attribute as label if highlightFeature is enabled
• selectionLayer: name of layer for marking selected results (the same as queryLayer) if highlightFeature is not enabled
• selectionZoom: zoom level for jump-to when selecting results
• doZoomToExtent (optional): zoom to feature extent when selecting results, overrides selectionZoom

Request URL:

When performing a search query using the above configuration, the following get request will be made:

http://localhost/wms/helloworld?SERVICE=WMS&VERSION=1.1.1& REQUEST=GetFeatureInfo&LAYERS=Country&QUERY_LAYERS=Country& FEATURE_COUNT=10&INFO_FORMAT=text/xml&SRS=EPSG:4326& FILTER=Country:"name"+=+'africa'

4.2.2. Using URL Rewriting

For security and neatness, you may prefer to use rewritten URLs (so that your internal server file paths are not revealed. In that case your options file would contain something like this:

var urlRewriteSearch = {
  title: "Search letter",
  query: 'samplesearch',
  formItems: [
    {
      xtype: 'hidden',
      name: 'query',
      value: 'samplesearch'
    },
    {
      xtype: 'textfield',
      name: 'colour',
      fieldLabel: "Colour",
      allowBlank: false,
      blankText: "Please enter a colour (e.g. 'orange')"
    }
  ],
  gridColumns: [
    {header: 'PKUID', dataIndex: 'pkuid', menuDisabled: 'true'},
    {header: 'Colour', dataIndex: 'colour', menuDisabled: 'true'}
  ],
  highlightFeature: false,
  highlightLabel: 'colour',
  selectionLayer: 'Hello',
  selectionZoom: 1,
  doZoomToExtent: true
};

• title: title of the search tab
• query: identifier for this search
• formItems: list of Ext.form.FormPanel item configs, the query form field is required to match the rewrite rule (value is the same as query)
• xtype: form field type
• name: name of query layer attribute
• fieldLabel: visible text for this field
• blankText: popup text for blank fields
• gridColumns: list of Ext.grid.GridPanel column configs to show search results
• highlightFeature (optional): use QGIS WMS highlight instead of QGIS WMS selection if enabled
• highlightLabel (optional): show this feature attribute as label if highlightFeature is enabled
• selectionLayer: name of layer for marking selected results if highlightFeature is not enabled
• selectionZoom: zoom level for jump-to when selecting results
• doZoomToExtent (optional): zoom to feature extent when selecting results, overrides selectionZoom

For every search of this type you have to add a URL rewrite rule in the Apache config.

RewriteCond %{QUERY_STRING} ^(?:.*)query=samplesearch&*(?:.*)$
RewriteCond %{QUERY_STRING} ^(?:(?:.*)&)?colour=([^&]*)(?:.*)$
RewriteRule ^/wms/(.+)$ /cgi-bin/qgis_mapserv.fcgi?map=/
<path-to-qgis-server-projects>/$1.qgs&SERVICE=WMS&VERSION=1.1.1&
REQUEST=GetFeatureInfo&LAYERS=Hello&QUERY_LAYERS=Hello&FEATURE_COUNT=20&
INFO_FORMAT=text/xml&SRS=EPSG:4326&FILTER=Hello:"colour"\ =\ '%1' [PT]

The first RewriteCond matches the query id of the search panel config. The second RewriteCond extracts the values of the search request parameters.

The RewriteRule composes the actual WMS GetFeatureInfo request to QGIS Server.

Request URL:

http://localhost/wms/helloworld?query=samplesearch&colour=orange

4.2.3. Add search panels to projects

In order for your search panel to appear in the web UI, you must enumerate them in your GlobalOptions.js for example (with url rewriting):

var mapSearchPanelConfigs = {
  "helloworld": [simpleWmsSearch, urlRewriteSearch]
};

Example (no rewriting):

var mapSearchPanelConfigs = {
  "../projects/helloworld.qgs": [simpleWmsSearch, urlRewriteSearch]
};

Search panels are added to a project by adding a new key for the map name with a list of search panel configs to mapSearchPanelConfigs. If there is no search panel configuration for a project, the search will be hidden in the GUI.

The map name is whatever is passed in the get request for your .qgs file. For example if your url includes this:

http://localhost/cgi-bin/qgis_mapserv.fcgi?map=../projects/helloworld.qgs

then your mapSearchPanelConfigs should reflect ../projects/helloworld.qgs as the key for the search list.

4.3. Configuration of the theme switcher

The theme switcher allows to change to a diffent QGIS project (or map theme) without having to leave the application and using the map extent. To enable/disable the theme switcher you have to set the variable var mapThemeSwitcherActive = true; in the site/js/GlobalOptions.js file to true|false. In addition you should place thumbnail images of your map into the directory site/thumbnails where the file name equals the projectname. All thumbnails should be 300x200 pixels in size and in .png format. If your .qgs project is called helloworld.qgs then your thumbnail should be called helloworld.png.

In addition you need to make entries for topics and projects in the file 'site/js/GISProjectListing.js'. Please use the given file as a template. The file is in JSON format and starts with a few central parameters.

4.3.1. Central theme switcher parameters

• path

The 'path' is the URL part used at the start of the application telling the QGIS Webclient where to find the QGIS projects (see also Apache URL rewriting). This path may be overwritten in some projects if you password-protect them in a separate Apache location.

• mapserver

This is the path to the WMS server used for WMS requests (e.g. for GetCapabilities, GetFeatureInfo, etc. requests). Again, this parameter may be overwritten in some projects if you want to password-protect the WMS in a separate Apache location.

• thumbnails

The URL where QGIS web client can find the project thumbnail images.

• title

The overall title of your Web-GIS. This will be later appended with the name of your project, separated by a dash. It appears in the title bar of the browser window and in the title bar of the web application.

4.3.2. Per topic theme switcher parameters

You can group your projects into topics. A topic only has a single parameter with the name of the topic. In a topic element you can have several project entries in a JSON array called project.

• name: The name of the topic.

4.3.3. Per project theme switcher parameters

In a topic you can have several project entries. A project can overwrite the global 'path' and 'mapserver' entries.

• name

The name of the project or map. Will be displayed in the theme switcher below the thumbnail and in the title strings of the application.

• path

Optional. Overrides the central settings in case you need to password-protect certain projects. The 'path' is the URL part used at the start of the application telling the QGIS Webclient where to find the QGIS projects (see also Apache URL rewriting).

• mapserver

Optional. Overrides the central settings in case you need to password-protect certain projects. This is the path to the WMS server used for WMS requests (e.g. for GetCapabilities, GetFeatureInfo``, etc. requests).

• projectpath

The projectpath (directory) or part of the Apache rewrite expression necessary to find the project file. This parameter is mandatory.

• projectfile

The QGIS project file or part of the Apache rewrite expression necessary to find the project file. This parameter is mandatory. Depending on the Apache rewrite expression you may have to omit the .qgs extension.

• format

Optional. The image format that QGIS web client should request. Valid values are: image/jpeg, image/png or image/png;mode=8bit. If omitted, the value is taken from site/js/GlobalOptions.js. If it is not defined there either, the value defaults to image/png.

• visibleLayers

Optional. A comma separated list of layers that should be visible after loading the projects. A future QGIS Webclient version will also read the layer visibility directly from the GetProjectSettings command.

• fullColorLayers

Optional. A comma separated list of layers that would trigger a format change from image/png to image/jpeg. Per default, the project would use image/png or image/png;mode=8bit but if the user toggles the visibility of a layer with orthophoto data or satellit images, the format will change to image/jpeg.

• updateInterval

Optional. A prosa text indicating how often the project will get data update. E.g. daily, weekly, monthly, weekly or occasional.

• lastUpdate

Optional. The date of the last data update, e.g. 2012-10-23.

• responsible

Optional. The organization and/or person responsible for the project and the data involved.

• startExtent

Optional. The bounding box (left,bottom,right,top in map units) used when starting the project. If not specified, maxExtent or the extent from GetProjectSettings is used.

• maxExtent

Optional. The maximum bounding box (left,bottom,right,top in map units) of the project. If not specified the extent from the GetProjectSettings is used.

• showFeatureInfoLayerTitle

Optional. Boolean (true``|``false). Defines whether the layer title is displayed or not at the top of the popup bubble displaying the feature info results. Influences both the hover and the click popups.

• tags

Optional. Tags or keywords displayed in the tooltips in the theme switcher. The tags are also used in the search filter used in the theme switcher.

4.4. Configuring of background layers

You can use any OpenLayers.Layer (http://dev.openlayers.org/releases/OpenLayers-2.13.1/doc/apidocs/files/OpenLayers/Layer-js.html) subclass as background layer. This layer must be added to baseLayers. You should do this in customBeforeMapInit() in Customizations.js. Example:

// called before map initialization
function customBeforeMapInit() {
    // define base layer
    var myBaseLayer = new OpenLayers.Layer.WMS("myBaseLayerName",
        "myBaseLayerWmsUrl", {
            layers: "myLayer",
            format: format,
            dpi: screenDpi,
            VERSION: "1.3.0"
        },
        {
            buffer:0,
            singleTile:true,
            ratio:1,
            transitionEffect:"resize",
            isBaseLayer: true, // important!
            projection:authid // requests the base layer in the projection defined in GlobalOptions
        }
    );

    // now add to baseLayers array
    baseLayers.push(myBaseLayer);
}

4.5. Extending the interface

You can add buttons to implements additional functions (editing, advanced identify, etc.). See the example in site/js/Customizations.js.

4.6. Customize languages

In order to provide shorter loading times you can reduce the languages in Translations.js to those you really need. For this purpose the Python script site/js/build/translations.py is shipped with QGIS Web Client.

Write the languages you need into site/js/build/translations.cfg and run the script, i.e. in a shell change to site/js/build and enter python translations.py

A new file site/js/Translations_custom.js is created. Copy this file to your server and adapt qgiswebclient.html accordingly.

5. URL Rewriting

Using a standard installation of QGIS Server, GlobalOptions.js will have a WMS server configuration like var serverAndCGI = "/cgi-bin/qgis_mapserv.fcgi";

A sample URL for QGIS Web Client installed in /var/www/qgis-web-client:

http://localhost/qgis-web-client/qgiswebclient.html?map=/opt/geodata/maps/NaturalEarth.qgs&visibleLayers=HYP_50M_SR_W

With the following rules for Apache mod_rewrite you can shorten the URLs to var serverAndCGI = "/wms"; and http://localhost/maps/NaturalEarth?visibleLayers=HYP_50M_SR_W

Rules in VirtualHost configuration:

# Forbid direct access
RewriteRule ^/cgi-bin/.*$ - [F]

# Search with SearchPanel (e.g. Address)
RewriteCond %{QUERY_STRING} ^(?:.*)query=address&*(?:.*)$
RewriteCond %{QUERY_STRING} ^(?:(?:.*)&)?street=([^&]*)(?:(?:.*)&)+number=([^&]*)(?:.*)$
RewriteRule ^/wms/(.+)$ /cgi-bin/qgis_mapserv.fcgi?map=/opt/geodata/maps/$1.qgs&SERVICE=WMS&VERSION=1.1.1&REQUEST=GetFeatureInfo&LAYERS=addresses&QUERY_LAYERS=addresses&FEATURE_COUNT=10&INFO_FORMAT=text/xml&SRS=EPSG:21781&FILTER=addresses:"street"\ =\ '%1' AND "number"\ =\ %2 [PT]

# Rewrite /wms/mapname to qgis_mapserv.fcgi?map=mappath/mapname.qgs
RewriteRule ^/wms/(.+)$ /cgi-bin/qgis_mapserv.fcgi?map=/opt/geodata/maps/$1.qgs [QSA,PT]
# Rewrite /maps/mapname to qgis-web-client main page. mapname will be extracted for wms calls in Javascript code.
RewriteRule ^/maps/([^\.]+)$ /qgis-web-client/site/qgiswebclient.html [PT]
# Rewrite /maps/* to qgis-web-client/site (e.g. /maps/gis_icons/mActionZoomNext.png -> /qgis-web-client/site/gis_icons/mActionZoomNext.png)
RewriteRule ^/maps/(.*) /qgis-web-client/site/$1 [PT]

For supporting qgs files in subdirectories (e.g. /maps/subdir/mapnampe) replace last rule with RewriteRule ^/maps/[^/]+/(.*) /qgis-web-client/site/$1 [PT]

For adding zones in different subdirecories (e.g. maps and maps-protected) add the following rules:

RewriteRule ^/wms-protected/(.+)$ /cgi-bin/qgis_mapserv.fcgi?map=/opt/geodata/maps-protected/$1.qgs [QSA,PT]
RewriteRule ^/maps-protected/([^\.]+)$ /qgis-web-client/site/qgiswebclient.html [PT]
RewriteRule ^/maps-protected/(.*) /qgis-web-client/site/$1 [PT]

6. Configuration of the search

Searching is handled by two separate scripts: "search" lists back a hit list while the user is typing in the searchbox. It groups the results and returns a bounding box of the result. getSearchGeom returns the actual wkt geometry for a selected search result.

These scripts are provided in two flavors: PHP and WSGI (Python). The PHP version should run out-of-the-box with just a few lines of configuration. There is no need to alter the DB table structure in order to use PHP search scripts because all needed informations are read from the project file. Another notable difference is that layer names are used instead of table names, this is in order to not disclose internal DB details. The PHP scripts are available under the php folder.

The Python wsgi search scripts provide an advanced, more configurable and more detailed search solution. They draw their results directly from dedicated relations in a PostGIS database. The WSGI scripts are available under the wsgi folder. It is recommended to install the wsgi scripts in a separate directory, e.g. /home/www/wsgi, a place that is not reachable by regular web traffic.

There are two options to highlight a feature that is selected from the search results. If the option enableSearchBoxWmsHighlight in GlobalOptions.js is enabled, the selected feature will be highlighted using QGIS WMS highlight. Otherwise the feature will be added as a vector feature to the highlight layer.

6.1. PHP Search

6.1.1. Available PHP scripts

6.1.1.1. Search

The search.php scripts works as described above. Accepted parameters:

• map (map name or path)
• query (search text)
• searchtables (optional: layer names to search in)

The companion is search_geom.php.

• map (map name or path)
• searchtable (layer name)
• displaytext (the matched string)

6.1.1.2. Unique list

This simple script returns the unique values of a given column of a given PostgreSQL layer. Accepted parameters:

• map (map name or path)
• layer (layer name)
• field (column name)

The script returns a json array of unique values and can be useful to implement select combo boxes for the search panels.

6.1.1.3. Get legend

This script has no wsgi counterpart, it works with recent QGIS Server versions (2.0.1 and newer) and can be used to build a template-based HTML legend instead of the image provided by GetLegendGraphic calls.

To use this feature you must activate it in GlobalOptions.js, search for the commented line below:

var interactiveLegendGetLegendURL = '../php/get_legend.php?map=' + project_map + '&';

Legends generated by this script can be cached for speed, see the paragraph on configuration below.

Accepted parameters:

• map: (map name or path)
• layer: (layer name)

6.1.2. PHP configuration file

Configuration for the services is stored in config.php.

Example:

/****************************
 * Map rewrite configuration
 */
// Prefix map name with path
#define('MAP_PATH_REWRITE', '/home/xxx/public_html/QGIS-Web-Client/projects/');
// Append .qgs to the map name
#define('MAP_PATH_APPEND_QGS', true);


/**************************************
 * search configuration
 */
// Configuration for searchable layers
$searchlayers_config = array(
    // Key is layer name
    'Country' => array(
        // SQL for text search: where to search
        'search_column' => 'name'
    )
);

// Default search tables
define('DEFAULT_SEARCH_LAYERS', 'Country');
// Limit search results
define('SEARCH_LIMIT', 100);


/**************************************
 *  Get legend configuration
 */
// Cache expiry time in seconds 0=never cache
define('GET_LEGEND_CACHE_EXPIRY', 60*60);
// Cache directory, defaults to dirname(__FILE__) . '/legend_cache'
define('GET_LEGEND_CACHE_DIRECTORY', null);
// Defaults to current URL + '../cgi-bin/qgis_mapserv.fcgi?'
define('WMS_ONLINE_RESOURCE', null);

/* End configuration */

QGIS Web Client needs to know where to find the scripts, since most configuration is read from the project file, this must be passed in the query string, the file where this parameters are set is GlobalOptions.js see the example below:

// Adds project_map, read value from query string
var project_map = Ext.urlDecode(window.location.search.substring(1)).map;

var searchBoxQueryURL = '../php/search.php?map=' + project_map;
var searchBoxGetGeomURL = '../php/search_geom.php?map=' + project_map;

6.1.3. TODO

Permalinks: the permalinks script is not yet implemented in PHP.

6.2. WSGI Search

6.2.1. Configuration of mod_wsgi

You need to enable mod_wsgi as root. (Ubuntu: a2enmod mod_wsgi).

You need to configure apache with the following lines (e.g. in file /etc/apache2/sites-available/default):

#mod_wsgi
WSGIDaemonProcess gis processes=5 threads=15 display-name=%{GROUP}
WSGIScriptAlias /wsgi/ /home/www/wsgi/
WSGIScriptAliasMatch ^/wsgi/([^/]+) /home/www/wsgi/$1.wsgi

6.2.2. Adaption of the wsgi scripts to your settings and needs

6.2.2.1. DB connection

In the file qwc_connect.py please edit the first line containing the db connection string.

DB_CONN_STRING="host='myhost' dbname='mydb' port='5432' user='myuser' password='secret'"

This connection will be used in all wsgi scripts.

Adapt the parameters according to your server/db. It is highly recommended to connect with a database user having limited rights only (e.g. select rights on relevant tables only).

6.2.2.2. Search type to be used

The search can use PostgreSQL's tsvector data type. "A tsvector value is a sorted list of distinct lexemes, which are words that have been normalized to merge different variants of the same word." from the PostgreSQL doc (http://www.postgresql.org/docs/9.0/interactive/datatype-textsearch.html#DATATYPE-TSVECTOR). Thus tsvector skips all the fill words and reduces nouns to their single form, a behaviour useful for searching texts. However as we are normally dealing with place names here we want them to stay as they are. If you use a language where the single form is a lot different from the plural form but your name contains a plural you will not get a suitable result. If you want to use the tsvector search option you should activate the lines

sql += "searchstring_tsvector @@ to_tsquery(\'not_your_language\', %s)"
data += (querystrings[j]+":*",)

not_your_language is to be replaced with an entry e.g. finnish if you have German place names. Thus plural forms and fillwords are kept as they are. Be aware of side effects! Be sure to fill the field searchstring_tsvector with to_tsvector('not_your_language', 'yourstring').

The use of

sql += "searchstring::tsvector @@ lower(%s)::tsquery"
data += (querystrings[j]+":*",)

is discouraged as it does not find a place name like Stoke-sub-Hamden when you enter Stoke.

If you do not want to use tsvector at all you can enable the full string comparison on the field searchstring (activated by default).

sql += "searchstring ILIKE %s"
data += ("%" + querystrings[j] + "%",)

This method however is slower than tsvector but not relevantly at least if you only have a couple 1000 datasets.

6.2.3. PostgreSQL table setup for searching

CREATE TABLE cadastre.searchtable
(
  searchstring text, --the search string (all lower case), e.g. "zürichstrasse 46, 8610 uster"
  displaytext text NOT NULL, --the display text for the search combobox, e.g. "Zürichstrasse 46, 8610 Uster (address)"
  search_category text, --should have a leading two digit number:, e.g.
                        --"03_parcels", where 03 is the order of the search categories, the number
                        --should be unique across all search tables
  the_geom geometry,    --the actual geometry
  geometry_type text,   --the geometry type as returned by ST_GeometryType(the_geom)
  searchstring_tsvector tsvector, -- be sure to fill this with to_tsvector()
  showlayer varchar(256), -- holds the layer name to be set visible if user chooses a respective result
  CONSTRAINT searchtable_pkey PRIMARY KEY (displaytext)
)
WITH (
  OIDS=FALSE
);
GRANT SELECT ON TABLE cadastre.searchtable TO qwc_user;

-- Index: cadastre.in_cadastre_searchstring_tsvector_gin

CREATE INDEX in_cadastre_searchstring_tsvector_gin
  ON cadastre.searchtable
  USING gin
  (searchstring_tsvector);

The above search table can also be a view or materialized view. One can combine several search tables by specifying the searchtables=searchtable1,searchtable_n parameter when requesting the search.wsgi script. Any searchtable passed to search.wsgi may only contain the letters A to Z, a to z and the underscore. Double quoting the search table throws an error, thus searchtables' names must contain lower characters only.

Using views is generally slower than properly indexed tables, check for yourself what works best.

7. License

The QGIS web client is released under a BSD license.

Copyright (2010-2012), The QGIS Project All rights reserved.

Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:

• Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.
• Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

8. Developers and Contributors

Developers:

• Jürgen Fischer
• Marco Hugentobler
• Pirmin Kalberer
• Andreas Neumann
• Alessandro Pasotti
• Niccolo Rigacci
• Denis Rouzaud
• Bernhard Ströbl
• Tim Sutton
• Mathias Walker
• Marco Bernasocchi

Translators:

• Giovanni Allegri
• Germán Carrillo
• Paolo Cavallini
• Diana Galindo
• Mayeul Kauffmann
• Samuel Mesa
• Alessandro Pasotti
• Nelson Silva
• Pavlo Taranov
• Tudor Bărăscu
• Uroš Preložnik
• Klas Karlsson
• Carl Defevere

9. Acknowledgements

We'd like to thank the OpenLayers, GeoExt and ExtJS teams for providing their base libraries we build upon.