IF statements
The
%IF% macro gives you the ability to test for macro values, URL parameters, access permissions, topic existence and more.
Syntax
%IF{"CONDITION" then="THEN" else="ELSE"}%
In the example above, if
CONDITION evaluates to TRUE, then
THEN will be included in the topic; otherwise
ELSE will be included.
Note that because of the way Foswiki evaluates, whatever is in the THEN and ELSE parameters will already have been expanded by the time the condition is actually evaluated. The standard
FormatTokens can be used in the THEN and ELSE parameters when you need to delay evaluation of (for example) a macro.
The basic syntax of a condition is the same as
the syntax used for queries, with the addition of the following special operators:
context |
True if the current context is set (see below) |
allows |
'X' allows 'Y' is true if web/topic 'X' exists and allows access mode 'Y' for the current user. Web access rights are only checked if there is no topic called 'X'. |
istopic |
istopic 'X' is true if topic 'X' exists |
isweb |
isweb 'X' is true if web 'X' exists |
ingroup |
'X' ingroup 'Y' is true if user 'X' is in group 'Y'. 'X' can be a login username or a WikiName. |
defined |
True if a preference setting or URL parameter of this name is defined. |
isempty |
True if a preference setting, URL parameter or session variable of this name has an empty value. It is equivalent to the expression (defined(x) || $x='') |
$ |
expands a URL parameter or macro name. Plugin handlers are not called. You can pass a limited subset of parameters to macros by enclosing the parameter string in single quotes; for example, $'MACRO{value}'. The 'MACRO{value}' string may not contain quotes: ' or ". |
The
%IF% statement is deliberately kept simple. In particular, note that there is no way to conditionally execute a Set statement. If you need more sophisticated control over formatting, then consider using the
SpreadSheetPlugin.
Macros
Test if macro is defined
%IF{"defined MACRO" then="THEN" else="ELSE"}%
Example:
%IF{
"defined WIKINAME"
then="WIKINAME is defined"
else="WIKINAME is not defined"
}%
Compare macro definition
%IF{"$MACRO='VALUE'" then="THEN" else="ELSE"}%
Example:
You are %IF{
"$WIKINAME='WikiGuest' and not defined 'OPEN_DAY'"
then="not"
}% allowed to
%IF{
"context view"
then="view"
else="edit"
}% this Foswiki today.
URL parameters
Test if URL param is passed
%IF{"defined PARAM" then="THEN" else="ELSE"}%
Example:
%IF{
"defined search"
then="Search:%URLPARAM{"search"}%"
else="No search passed in"
}%
Note that macro
URLPARAM is evaluated before the
IF macro, therefore the expression does not need to be escaped.
Range test on URL parameter
%IF{"$PARAM < NUMBER" then="THEN" else="ELSE"}%
Example:
URL param t is %IF{
"0 < $t and $t < 1000"
then="in"
else="out of"
}% range.
Text comparison of URL parameter
%IF{"$PARAM='VALUE'" then="THEN" else="ELSE"}%
or
%IF{"$'URLPARAM{PARAM}'='VALUE'" then="THEN" else="ELSE"}%
Example:
%IF{
"$scope='text'"
then="Plain text search"
}%
or
%IF{
"$'URLPARAM{scope}'='text'"
then="Plain text search"
}%
URL parameter test
Be careful when you test for an empty value: if the URL parameter is not defined (not passed in the URL), the outcome might not be what you expected. Use the parameter test to check your assumptions.
| Test |
IF query |
no param |
empty param |
param=text |
| |
|
test: no param URLPARAM value=. |
test: empty param |
test: param=text |
| is defined |
defined scope |
false |
|
|
| is empty |
$scope='' |
false NOTE: value is undefined, so not empty |
|
|
| is not empty |
$scope!='' |
true NOTE: value is undefined, so also 'not empty' |
|
|
has value text |
$scope='text'" |
false |
|
|
Reset test
INCLUDE parameters
%IF{"$PARAM" then="THEN" else="ELSE"}%
Parameters that are passed to the
INCLUDE macro are evaluated the same as URL parameters. Combining those may lead to unexpected results!
Example:
%INCLUDE{"%TOPIC%" section="people" name="Barry"}%
%STARTSECTION{"people"}%
%IF{"$name" then="%name%"}%
%ENDSECTION{"people"}%
INCLUDE parameter test
%INCLUDE{"%TOPIC%" section="includetest" name="Barry"}%
%STARTSECTION{"includetest"}%
%TABLE{databg="#ffffff" headeralign="left"}%
| *Test* \
| *IF query param 'name'* \
| *Result param 'name'* \
| *IF query param 'yo'* \
| *Result param 'yo'* |
| is defined \
| =defined name= \
| %IF{"defined name" then='true'}% \
| =defined yo= \
| %IF{"defined yo" else='false'}% |
| is empty \
| =$name=''= \
| %IF{"$name=''" else='false'}% \
| =$yo=''= \
| %IF{"$yo=''" else="false %RED%NOTE: value is undefined, so not empty%ENDCOLOR%"}% |
| is not empty \
| =$name!=''= \
| %IF{"$name!=''" then='true'}% \
| =$yo!=''= \
| %IF{"$yo=''" else="false %RED%NOTE: value is undefined, so not \'not empty\'%ENDCOLOR%"}% |
| has value =Barry= \
| =$name='Barry'= \
| %IF{"$name='Barry'" then='true'}% \
| =$yo='Barry'= \
| %IF{"$yo='Barry'" else='false'}% |
%ENDSECTION{"includetest"}%
Configuration values
Configuration items are defined in
configure. You cannot see the value of a configuration item, you can only test if the item is set, or test the value against a string.
Items must be one of
{AccessControlACL}{EnableDeprecatedEmptyDeny},
{AccessibleCFG},
{AdminUserLogin},
{AdminUserWikiName},
{AntiSpam}{EmailPadding},
{AntiSpam}{EntityEncode},
{AntiSpam}{HideUserDetails},
{AntiSpam}{RobotsAreWelcome},
{AttachmentNameFilter},
{AuthRealm},
{AuthScripts},
{Cache}{Enabled},
{DefaultDateFormat},
{DefaultUrlHost},
{DenyDotDotInclude},
{DisplayTimeValues},
{EnableEmail},
{EnableHierarchicalWebs},
{FormTypes},
{HomeTopicName},
{LeaseLength},
{LeaseLengthLessForceful},
{LinkProtocolPattern},
{LocalSitePreferences},
{LoginNameFilterIn},
{LowerNational},
{MaxRevisionsInADiff},
{MinPasswordLength},
{NameFilter},
{NotifyTopicName},
{NumberOfRevisions},
{PluginsOrder},
{Plugins}{WebSearchPath},
{PluralToSingular},
{Register}{AllowLoginName},
{Register}{Approvers},
{Register}{DisablePasswordConfirmation},
{Register}{EnableNewUserRegistration},
{Register}{NeedApproval},
{Register}{NeedVerification},
{Register}{RegistrationAgentWikiName},
{ReplaceIfEditedAgainWithin},
{ScriptSuffix},
{ScriptUrlPath},
{Site}{Locale},
{Site}{LocaleRegexes},
{SitePrefsTopicName},
{Stats}{TopContrib},
{Stats}{TopicName},
{Stats}{TopViews},
{SuperAdminGroup},
{SystemWebName},
{TemplateLogin}{AllowLoginUsingEmailAddress},
{TemplatePath},
{TrashWebName},
{UploadFilter},
{UpperNational},
{UseLocale},
{UserInterfaceInternationalisation},
{UsersTopicName},
{UsersWebName},
{Validation}{Method},
{WebMasterEmail},
{WebMasterName},
{WebPrefsTopicName}.
Testing if item is set
%IF{"{CONFIGURATION}" then="THEN" else="ELSE"}%
Example:
User details are %IF{
"{AntiSpam}{HideUserDetails}"
then="hidden"
else="shown"
}%
Testing the value of an item
%IF{"{CONFIGURATION}='VALUE'" then="THEN" else="ELSE"}%
Example:
Validation method is %IF{
"{Validation}{Method}='strikeone'"
then="'strikeone'"
else="no 'strikeone'"
}%
Plugin states
%IF{"context PLUGINEnabled" then="THEN" else="ELSE"}%
Example:
TablePlugin is %IF{
"context TablePluginEnabled"
then="enabled"
else="disabled"
}%.
Access permissions
%IF{"'SOME TOPIC' allows 'ACCESS'" then="THEN" else="ELSE"}%
Example:
You %IF{"'%TOPIC%' allows 'change'" then="can" else="cannot"}% change this topic.
You %IF{"'%SANDBOXWEB%.TestTopic' allows 'change'" then="can" else="cannot"}% change %SANDBOXWEB%.TestTopic.
You %IF{"'Sandbox' allows 'change'" then="can" else="cannot"}% change Sandbox web
Topic existence
%IF{"istopic 'SOME TOPIC'" then="THEN" else="ELSE"}%
Example:
Topic %SANDBOXWEB%.TestTopic %IF{"istopic '%SANDBOXWEB%.TestTopic'" then="exists" else="does not exist"}%.
Web %SANDBOXWEB% %IF{"isweb '%SANDBOXWEB%'" then="exists" else="does not exist"}%.
Group membership
To test if SOMEONE is in the GROUP:
%IF{"'SOMEONE' ingroup 'GROUP'" then="THEN" else="ELSE"}%
Or to test the currently logged in user for AdminGroup membership:
You are %IF{
"$USERNAME ingroup 'AdminGroup'"
then="an admin"
else="a normal user"
}%
Context identifiers
%IF{"context CONTEXT" then="THEN" else="ELSE"}%
Context identifiers are used in Foswiki to label various stages of the rendering process. They are especially useful for
skin authors to find out where they are in the rendering process. The following context identifiers are available:
| id |
context |
absolute_urls |
Set if absolute URLs are required |
attach |
in attach script (see CommandAndCGIScripts) |
authenticated |
a user is authenticated |
body_text |
when the body text is being processed in a view (useful in plugin handlers) |
can_login |
current environment supports login |
can_render_meta |
set by CompareRevisionsAddOn Compare.pm |
can_remember_login |
Template Login: Controls rendering of "remember login" checkbox. |
no_auto_complete_login |
Template Login: Prevents browser from remembering password |
changes |
in changes script (see CommandAndCGIScripts) |
command_line |
the running script was run from the command line, and not from CGI |
diff |
in rdiff script (see CommandAndCGIScripts) |
edit |
in edit script (see CommandAndCGIScripts) |
footer_text |
when the footer text is being processed in a view (useful in plugin handlers) |
header_text |
when the header text is being processed in a view (useful in plugin handlers) |
i18n_enabled |
when user interface I18N support is enabled (i.e., user can choose the language for UI) |
inactive |
if active links such as 'edit' and 'attach' should be disabled |
isadmin |
current user has admin rights |
login and logon |
in login / logon script (see CommandAndCGIScripts) |
manage |
in manage script (see CommandAndCGIScripts) |
mandatoryfields |
if any fields in form have mandatory attribute. |
mirror |
if this is a mirror |
new_topic |
if the topic doesn't already exist |
oops |
in oops script (see CommandAndCGIScripts) |
passwords_modifyable |
when the PasswordManager is able to modify passwords (correct as spelled) |
preview |
in preview script (see CommandAndCGIScripts) |
register |
in register script (see CommandAndCGIScripts) |
registration_supported |
registration is supported by the current user mapper |
registration_enabled |
set if {Register}{EnableNewUserRegistration} is on, and registration is supported |
rename |
in rename script (see CommandAndCGIScripts) |
resetpasswd |
in resetpasswd script (see CommandAndCGIScripts) |
rest |
in rest script (see CommandAndCGIScripts) |
rss |
if this is an RSS skin rendering |
save |
in save script (see CommandAndCGIScripts) |
search |
in search script (see CommandAndCGIScripts) |
static |
in a script that generates static content, such as PDF generation. Extensions should avoid rendering edit markup in this context. |
statistics |
in statistics script (see CommandAndCGIScripts) |
sudo_login |
if user is currently running with internal admin authority |
SUPPORTS_PARA_INDENT |
render supports the paragraph indent syntax |
SUPPORTS_PREF_SET_URLS |
Preferences can be set in the URL |
textareas_hijacked |
provided for use by editors that highjack textareas, and want to signal this fact. This is used by skins, for example, so they can suppress extra controls when textareas have been hijacked. |
upload |
in upload script (see CommandAndCGIScripts) |
view |
in view script (see CommandAndCGIScripts) |
viewfile |
in viewfile script (see CommandAndCGIScripts) |
In addition there is a context identifier for each enabled plugin; for example, if
GallousBreeksPlugin is installed
and enabled, then the context ID
GallousBreeksPluginEnabled will be set.
JQueryPlugin sets a context for each enabled JQuery plugin, for example:
LiveQueryEnabled,
UI::DialogEnabled. Other extensions may set additional context identifiers.
Query syntax
%IF{"QUERY" then="THEN" else="ELSE"}%
Examples
Display the value of a form field if the topic has form field "Summary":
%FORMFIELD{
"%IF{
"'%TOPIC%'/Summary"
then="Summary"
}%"
}%
Note that while a
query search can be used to access form fields, there are some contexts in which an IF statement may be used where there is no topic context, or the topic context is not what you want. In these cases you can use the
/ operator to indicate the name of the topic:
Test if the topic has attachments:
%IF{
"'%TOPIC%'/attachments"
then="has attachments"
}%
Test if the topic has an attachment with 'receipt' or 'Receipt' in the name:
%IF{
"'%TOPIC%'/attachments[lc(name)~'*receipt*']"
then="has 'receipt' attachment"
}%
Test if a topic text contains a certain word:
%IF{
"'%SYSTEMWEB%.%HOMETOPIC%'/lc(text)~'*welcome*'"
then="contains 'welcome'"
}%
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