A Global Rule is a library defined within a configurator. Define functions, subroutines, and types here to make them available in any other rules in that configurator. You can re-use the function many times while only programming the logic once.
Types of Snap blocks which you can insert into a global rule include
Arguments
Arguments are variables passed in to the rule. You can find them by using the Get/Set variable snap blocks. In this rule type, the Get block exposes these arguments:
| Name | Type | Description |
|---|---|---|
| configurator | Configurator | the current running configurator. |
| environment | string | "dev" if you are in the development environment, "test" if you are in the test environment, and "prod" if you are in the production environment. |
| parameters | map | a map of GET or POST parameters passed into the configurator when it was launched. |
Example
Your configurator may use arrays of strings or numbers to track lists of components. You may need to know if the same component is used in two lists. More generally, is there an intersection between two arrays? Here's a function that can answer that question.
Note that the function accepts an array of "any" type, so arrays of numbers, text, or complex objects from types can all be processed by one function. Since the returned array is also of type "any", it is up to the calling code to deal with this ambiguity, such as by assuming the type matches the type passed in.
Contexts for Functions
When writing a function or subroutine in Snap, consider which location for your library would be best.
| Benefit | Safe Function |
Global Rule |
Global Event Rule |
|---|---|---|---|
| Logic available to entire environment |
|
||
| Logic available through the REST API |
|
||
| Logic hidden |
|
||
| Logic available to only this configurator/scene |
|
|
|
| Calculates faster, without network lag |
|
|
|
| Can write directly to UI elements |
|
|
|
| Can read directly from UI elements |
|
Keep your application secure
Remember the Snap rules you write for your configurator or scene are executed in one of two places: Server-side or local. Consider the best location for your code to balance needs for security and speed.
- Server-side rules
These rules are processed on the server: the Snap code is never sent to the user's workstation. For example, Safe functions are server-side, and the best place to write any proprietary calculations or patented, sensitive lookups. Your customer only sees the result of the safe function, not how it was generated.
- Local rules
These rules are processed on the user's workstation, tablet, or mobile phone. Because the are local to the user, they are very fast and responsive. However, it is possible for some users to look at the code within the rule. Local rules are the best place for code which runs often, needs to be fast, and does not contain sensitive calculations.
Snap rules run in a specific order, and in response to specific events. Learn more about rule execution order.