Filter (Querier)¶
Filterable layers (public)¶
Per default, layers are not filterable. If you wish to provide filter functionality, proceed as follows:
- Verify your project vars file to make sure that the functionality
filterable_layers
is made available in your project template files:- If you have a custom definition for
functionalities.available_in_templates
oradmin_interface.available_functionalities
, then ensure that the valuefilterable_layers
is contained in both of these. - Alternatively, you can add these two paths in the
update_paths
variable to use the definition provided byCONST_vars.yaml
(and keep the inheritance) instead of replacing it.
- If you have a custom definition for
- If you wish to provide layers for filtering independently of user authorization (in particular, for not-logged-in users), add the layer names as follows to your project vars file:
functionalities:
anonymous:
filterable_layers:
- my_layer_name_1
- my_layer_name_2
Note
Ngeo offers the filter functionality only for single layers, not for grouped layers.
Filterable layers (private)¶
- If you wish to provide layers for filtering only for specific user roles, define this in the
admin interface as follows:
- Add a functionality
filterable_layers
; as value provide the GeoMapFish layer name (not the WMS layer name). - Edit the role that shall be able to use this filter, and activate the corresponding functionality checkbox.
- Add a functionality
- Note that if there are functionalities associated to a role, then users with this role will
not have access to any of the “anonymous” functionalities. Instead, you will need to activate
all functionalities that this role shall be able to use in the admin interface or, for
functionalities that all registered users shall have access to, via the
functionalities.registered
variable of your vars file.
Available attributes and operators in filters¶
All attributes defined as “exported” in the layer of your map server will be automatically available as filterable attribute. If the type, and so the operator on the attribute, is not adequate for filtering, you should adapt the type in your layer definition. See WFS GetFeature for more information (MapServer only).
Enumerate available attributes for a layer¶
Project Configuration file¶
In the filter panel, instead of the standard text field, it is possible to display combos providing the
available values of the attributes. The values are automatically retrieved using a web service that does a
SELECT distinct(<column>) FROM <table>
.
The web service configuration is done in the vars.yaml
file:
layers:
enum:
<layer_name>:
dbsession: <session name>
attributes:
<attribute name>:
table: <[schema.]table name>
column_name: <column name>
separator: ","
dbsession: "<session name>"
at the enum.defaults
level can be used
to specify another DB session than the main DB session.
See Using multiple databases regarding the setup of multiple databases.
If omitted, the main DB session is used.
table: "<[schema.]table name>"
may be used at the layer defaults
level as a the default
table where following attributes may be found. It can be overridden at the
attribute level. table
is a mandatory parameter.
If column_name
is not defined, the attribute name is used.
If separator
is defined, the column is treated as a list of values.
Example:
layers
enum:
mapserver_layer:
attributes:
type: &layers-enum-mapserver-layer-defaults
table: geodata.table
country: *layers-enum-mapserver-layer-defaults
Administration interface¶
You can add some additional configuration in the administration interface as follows.
It is possible to define enumerated or directed attributes, to WMS layers only, via metadata.
The metadata to define is enumeratedAttributes
or directedFilterAttributes
.
For enumerated attributes, the value is a single string or a list of attributes (that we defined earlier
in the vars.yaml
file) separated with a comma.
For directed attributes, it is a single string or a list of attributes defined in the mapfile (columns and aliases from the selected table).
The difference is that enumerated attributes are configurable (like pointing to a specific database table), while directed attributes are ready-to-use values that come directly from the mapfile configuration.
Client-side documentation related to the enumeratedAttributes
and directedFilterAttributes
metadata
is available here:
gmfThemes.GmfMetaData.
Using DB sessions¶
It is possible to get attribute lists also
for a layer whose data is hosted in an external database, using the
dbsession: "<session name>"
parameter.
See Using multiple databases for more information.