server.go

Documentation: github.com/go-kit/kit/transport/httprp

     1  package httprp
     2  
     3  import (
     4  	"context"
     5  	"net/http"
     6  	"net/http/httputil"
     7  	"net/url"
     8  )
     9  
    10  // RequestFunc may take information from an HTTP request and put it into a
    11  // request context. BeforeFuncs are executed prior to invoking the
    12  // endpoint.
    13  type RequestFunc func(context.Context, *http.Request) context.Context
    14  
    15  // Server is a proxying request handler.
    16  type Server struct {
    17  	proxy        http.Handler
    18  	before       []RequestFunc
    19  	errorEncoder func(w http.ResponseWriter, err error)
    20  }
    21  
    22  // NewServer constructs a new server that implements http.Server and will proxy
    23  // requests to the given base URL using its scheme, host, and base path.
    24  // If the target's path is "/base" and the incoming request was for "/dir",
    25  // the target request will be for /base/dir.
    26  func NewServer(
    27  	baseURL *url.URL,
    28  	options ...ServerOption,
    29  ) *Server {
    30  	s := &Server{
    31  		proxy: httputil.NewSingleHostReverseProxy(baseURL),
    32  	}
    33  	for _, option := range options {
    34  		option(s)
    35  	}
    36  	return s
    37  }
    38  
    39  // ServerOption sets an optional parameter for servers.
    40  type ServerOption func(*Server)
    41  
    42  // ServerBefore functions are executed on the HTTP request object before the
    43  // request is decoded.
    44  func ServerBefore(before ...RequestFunc) ServerOption {
    45  	return func(s *Server) { s.before = append(s.before, before...) }
    46  }
    47  
    48  // ServeHTTP implements http.Handler.
    49  func (s Server) ServeHTTP(w http.ResponseWriter, r *http.Request) {
    50  	ctx := r.Context()
    51  
    52  	for _, f := range s.before {
    53  		ctx = f(ctx, r)
    54  	}
    55  
    56  	s.proxy.ServeHTTP(w, r)
    57  }
    58
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