4. Route Predicate Factories

Spring Cloud Gateway matches routes as part of the Spring WebFlux HandlerMapping infrastructure. Spring Cloud Gateway includes many built-in Route Predicate Factories. All of these predicates match on different attributes of the HTTP request. Multiple Route Predicate Factories can be combined and are combined via logical and.

4.1 After Route Predicate Factory

The After Route Predicate Factory takes one parameter, a datetime. This predicate matches requests that happen after the current datetime.

application.yml. 

spring:
  cloud:
    gateway:
      routes:
      # =====================================
      - id: after_route
        uri: https://example.org
        predicates:
        - After=2017-01-20T17:42:47.789-07:00[America/Denver]

This route matches any request after Jan 20, 2017 17:42 Mountain Time (Denver).

4.2 Before Route Predicate Factory

The Before Route Predicate Factory takes one parameter, a datetime. This predicate matches requests that happen before the current datetime.

application.yml. 

spring:
  cloud:
    gateway:
      routes:
      # =====================================
      - id: before_route
        uri: https://example.org
        predicates:
        - Before=2017-01-20T17:42:47.789-07:00[America/Denver]

This route matches any request before Jan 20, 2017 17:42 Mountain Time (Denver).

4.3 Between Route Predicate Factory

The Between Route Predicate Factory takes two parameters, datetime1 and datetime2. This predicate matches requests that happen after datetime1 and before datetime2. The datetime2 parameter must be after datetime1.

application.yml. 

spring:
  cloud:
    gateway:
      routes:
      # =====================================
      - id: between_route
        uri: https://example.org
        predicates:
        - Betweeen=2017-01-20T17:42:47.789-07:00[America/Denver], 2017-01-21T17:42:47.789-07:00[America/Denver]

This route matches any request after Jan 20, 2017 17:42 Mountain Time (Denver) and before Jan 21, 2017 17:42 Mountain Time (Denver). This could be useful for maintenance windows.

4.4 Cookie Route Predicate Factory

The Cookie Route Predicate Factory takes two parameters, the cookie name and a regular expression. This predicate matches cookies that have the given name and the value matches the regular expression.

application.yml. 

spring:
  cloud:
    gateway:
      routes:
      # =====================================
      - id: cookie_route
        uri: https://example.org
        predicates:
        - Cookie=chocolate, ch.p

This route matches the request has a cookie named chocolate who’s value matches the ch.p regular expression.

4.5 Header Route Predicate Factory

The Header Route Predicate Factory takes two parameters, the header name and a regular expression. This predicate matches with a header that has the given name and the value matches the regular expression.

application.yml. 

spring:
  cloud:
    gateway:
      routes:
      # =====================================
      - id: header_route
        uri: https://example.org
        predicates:
        - Header=X-Request-Id, \d+

This route matches if the request has a header named X-Request-Id whos value matches the \d+ regular expression (has a value of one or more digits).

4.6 Host Route Predicate Factory

The Host Route Predicate Factory takes one parameter: the host name pattern. The pattern is an Ant style pattern with . as the separator. This predicates matches the Host header that matches the pattern.

application.yml. 

spring:
  cloud:
    gateway:
      routes:
      # =====================================
      - id: host_route
        uri: https://example.org
        predicates:
        - Host=**.somehost.org

This route would match if the request has a Host header has the value www.somehost.org or beta.somehost.org.

4.7 Method Route Predicate Factory

The Method Route Predicate Factory takes one parameter: the HTTP method to match.

application.yml. 

spring:
  cloud:
    gateway:
      routes:
      # =====================================
      - id: method_route
        uri: https://example.org
        predicates:
        - Method=GET

This route would match if the request method was a GET.

4.8 Path Route Predicate Factory

The Path Route Predicate Factory takes one parameter: a Spring PathMatcher pattern.

application.yml. 

spring:
  cloud:
    gateway:
      routes:
      # =====================================
      - id: host_route
        uri: https://example.org
        predicates:
        - Path=/foo/{segment}

This route would match if the request path was, for example: /foo/1 or /foo/bar.

This predicate extracts the URI template variables (like segment defined in the example above) as a map of names and values and places it in the ServerWebExchange.getAttributes() with a key defined in PathRoutePredicate.URL_PREDICATE_VARS_ATTR. Those values are then available for use by GatewayFilter Factories

4.9 Query Route Predicate Factory

The Query Route Predicate Factory takes two parameters: a required param and an optional regexp.

application.yml. 

spring:
  cloud:
    gateway:
      routes:
      # =====================================
      - id: query_route
        uri: https://example.org
        predicates:
        - Query=baz

This route would match if the request contained a baz query parameter.

application.yml. 

spring:
  cloud:
    gateway:
      routes:
      # =====================================
      - id: query_route
        uri: https://example.org
        predicates:
        - Query=foo, ba.

This route would match if the request contained a foo query parameter whose value matched the ba. regexp, so bar and baz would match.

4.10 RemoteAddr Route Predicate Factory

The RemoteAddr Route Predicate Factory takes a list (min size 1) of CIDR-notation strings, e.g. 192.168.0.1/16 (where 192.168.0.1 is an IP address and 16 is a subnet mask.

application.yml. 

spring:
  cloud:
    gateway:
      routes:
      # =====================================
      - id: remoteaddr_route
        uri: https://example.org
        predicates:
        - RemoteAddr=192.168.1.1/24

This route would match if the remote address of the request was, for example, 192.168.1.10.