Condition Grammar

Basic Concepts

• Condition Primitive

  • Basic conditional judgment unit, which defines the primitive of comparison

  • e.g.

    req_host_in(“www.bfe-networks.com|bfe-networks.com”)  # host is one of the configured domains

• Condition Expression

  • Expression using “and/or/not” to connect condition primitive

  • e.g.

    req_host_in(“bfe-networks.com”) && req_method_in(“GET”) # domain is bfe-networks.com and HTTP method is "GET"

• Condition Variable

  • Variable that is defined by Condition Expression

  • e.g.

    bfe_host = req_host_in(“bfe-networks.com”)  # variable bfe_host is defined by condition expression

• Advanced Condition Expression

  • Expression using “and/or/not” to connect condition primitive and condition variable

  • In advanced condition expression, condition variable is identified by “$” prefix

  • e.g.

    $news_host && req_method_in("GET") # match condition variable and HTTP method is "GET"

Condition Primitive Grammar

• Basic conditional judgment unit, format is shown as follows:

​ FuncName( params )

• Condition primitive like function definition: FuncName is name of condition primitive; params are input parameters
• Return value type of Condition Primitive is bool
• Note: All builtin condition primitives

Condition Expression Grammar

Condition Expression grammar is defined as follows:

• Priority and combination rule of “&&/||/!” is same as them in C language

• Expression description

  Condition Expression(CE) -> 
                     CE && CE
                   | CE || CE
                   | ( CE )
                   | ! CE
                   | Condition Primitive

Advanced Condition Expression Grammar

Advanced Condition Expression grammar is defined as follows:

• Priority and combination rule of “&&/||/!” is same as them in C language

• Expression description

  Advanced Condition Expression(ACE) -> 
                     ACE && ACE
                   | ACE || ACE
                   | ( ACE)
                   | ! ACE
                   | Condition Primitive
                   | Condition Variable