# Package =TWiki::UI
Service functions used by the UI packages
- Package TWiki::UI
- StaticMethod run (\&method,...)
- StaticMethod checkWebExists ($session,$web,$topic,$op)
- StaticMethod topicExists ($session,$web,$topic,$op)=>boolean
- StaticMethod checkMirror ($session,$web,$topic)
- StaticMethod checkAccess ($web,$topic,$mode,$user)
- StaticMethod readTemplateTopic ($session,$theTopicName) -> ($meta,$text)
## [[StaticMethod]] **run** `(\&method,...)`
Entry point for execution of a UI function. The parameter is a reference to the method.
... is a list of name-value pairs that define initial context identifiers that must be set during initPlugin. This set will be extended to include command\_line if the script is detected as being run outside the browser.
## [[StaticMethod]] **checkWebExists** `($session,$web,$topic,$op)`
Check if the web exists. If it doesn't, will throw an oops exception. $op is the user operation being performed.
## [[StaticMethod]] **topicExists** `($session,$web,$topic,$op)=>boolean`
Check if the given topic exists, throwing an [[OopsException]] if it doesn't. $op is the user operation being performed.
## [[StaticMethod]] **checkMirror** `($session,$web,$topic)`
Checks if this web is a mirror web, throwing an [[OopsException]] if it is.
## [[StaticMethod]] **checkAccess** `($web,$topic,$mode,$user)`
Check if the given mode of access by the given user to the given web.topic is permissible, throwing a TWiki::OopsException if not.
## [[StaticMethod]] \*readTemplateTopic `($session,$theTopicName) -> ($meta,$text)`
Read a topic from the TWiki web, or if that fails from the current web.