go.uber.org/yarpc@v1.72.1/api/middleware/router.go (about)

     1  // Copyright (c) 2022 Uber Technologies, Inc.
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    13  // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
    14  // IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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    16  // AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
    17  // LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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    19  // THE SOFTWARE.
    20  
    21  package middleware
    22  
    23  import (
    24  	"context"
    25  
    26  	"go.uber.org/yarpc/api/transport"
    27  )
    28  
    29  // Router is a middleware for defining a customized routing experience for procedures
    30  type Router interface {
    31  	// Procedures returns the list of procedures that can be called on this router.
    32  	// Procedures SHOULD call into router that is passed in.
    33  	Procedures(transport.Router) []transport.Procedure
    34  
    35  	// Choose returns a HandlerSpec for the given request and transport.
    36  	// If the Router cannot determine what to call it should call into the router that was
    37  	// passed in.
    38  	Choose(context.Context, *transport.Request, transport.Router) (transport.HandlerSpec, error)
    39  }
    40  
    41  // ApplyRouteTable applies the given Router middleware to the given Router.
    42  func ApplyRouteTable(r transport.RouteTable, m Router) transport.RouteTable {
    43  	if m == nil {
    44  		return r
    45  	}
    46  	return routeTableWithMiddleware{r: r, m: m}
    47  }
    48  
    49  type routeTableWithMiddleware struct {
    50  	r transport.RouteTable
    51  	m Router
    52  }
    53  
    54  func (r routeTableWithMiddleware) Procedures() []transport.Procedure {
    55  	return r.m.Procedures(r.r)
    56  }
    57  
    58  func (r routeTableWithMiddleware) Choose(ctx context.Context, req *transport.Request) (transport.HandlerSpec, error) {
    59  	return r.m.Choose(ctx, req, r.r)
    60  }
    61  
    62  func (r routeTableWithMiddleware) Register(procedures []transport.Procedure) {
    63  	r.r.Register(procedures)
    64  }