package http
import (
"context"
"net/http"
)
// RequestFunc may take information from an HTTP request and put it into a
// request context. In Servers, RequestFuncs are executed prior to invoking the
// endpoint. In Clients, RequestFuncs are executed after creating the request
// but prior to invoking the HTTP client.
type RequestFunc func(context.Context, *http.Request) context.Context
// ServerResponseFunc may take information from a request context and use it to
// manipulate a ResponseWriter. ServerResponseFuncs are only executed in
// servers, after invoking the endpoint but prior to writing a response.
type ServerResponseFunc func(context.Context, http.ResponseWriter) context.Context
// ClientResponseFunc may take information from an HTTP request and make the
// response available for consumption. ClientResponseFuncs are only executed in
// clients, after a request has been made, but prior to it being decoded.
type ClientResponseFunc func(context.Context, *http.Response) context.Context
// SetContentType returns a ServerResponseFunc that sets the Content-Type header
// to the provided value.
func SetContentType(contentType string) ServerResponseFunc {
return SetResponseHeader("Content-Type", contentType)
}
// SetResponseHeader returns a ServerResponseFunc that sets the given header.
func SetResponseHeader(key, val string) ServerResponseFunc {
return func(ctx context.Context, w http.ResponseWriter) context.Context {
w.Header().Set(key, val)
return ctx
}
}
// SetRequestHeader returns a RequestFunc that sets the given header.
func SetRequestHeader(key, val string) RequestFunc {
return func(ctx context.Context, r *http.Request) context.Context {
r.Header.Set(key, val)
return ctx
}
}
// PopulateRequestContext is a RequestFunc that populates several values into
// the context from the HTTP request. Those values may be extracted using the
// corresponding ContextKey type in this package.
func PopulateRequestContext(ctx context.Context, r *http.Request) context.Context {
for k, v := range map[contextKey]string{
ContextKeyRequestMethod: r.Method,
ContextKeyRequestURI: r.RequestURI,
ContextKeyRequestPath: r.URL.Path,
ContextKeyRequestProto: r.Proto,
ContextKeyRequestHost: r.Host,
ContextKeyRequestRemoteAddr: r.RemoteAddr,
ContextKeyRequestXForwardedFor: r.Header.Get("X-Forwarded-For"),
ContextKeyRequestXForwardedProto: r.Header.Get("X-Forwarded-Proto"),
ContextKeyRequestAuthorization: r.Header.Get("Authorization"),
ContextKeyRequestReferer: r.Header.Get("Referer"),
ContextKeyRequestUserAgent: r.Header.Get("User-Agent"),
ContextKeyRequestXRequestID: r.Header.Get("X-Request-Id"),
ContextKeyRequestAccept: r.Header.Get("Accept"),
} {
ctx = context.WithValue(ctx, k, v)
}
return ctx
}
type contextKey int
const (
// ContextKeyRequestMethod is populated in the context by
// PopulateRequestContext. Its value is r.Method.
ContextKeyRequestMethod contextKey = iota
// ContextKeyRequestURI is populated in the context by
// PopulateRequestContext. Its value is r.RequestURI.
ContextKeyRequestURI
// ContextKeyRequestPath is populated in the context by
// PopulateRequestContext. Its value is r.URL.Path.
ContextKeyRequestPath
// ContextKeyRequestProto is populated in the context by
// PopulateRequestContext. Its value is r.Proto.
ContextKeyRequestProto
// ContextKeyRequestHost is populated in the context by
// PopulateRequestContext. Its value is r.Host.
ContextKeyRequestHost
// ContextKeyRequestRemoteAddr is populated in the context by
// PopulateRequestContext. Its value is r.RemoteAddr.
ContextKeyRequestRemoteAddr
// ContextKeyRequestXForwardedFor is populated in the context by
// PopulateRequestContext. Its value is r.Header.Get("X-Forwarded-For").
ContextKeyRequestXForwardedFor
// ContextKeyRequestXForwardedProto is populated in the context by
// PopulateRequestContext. Its value is r.Header.Get("X-Forwarded-Proto").
ContextKeyRequestXForwardedProto
// ContextKeyRequestAuthorization is populated in the context by
// PopulateRequestContext. Its value is r.Header.Get("Authorization").
ContextKeyRequestAuthorization
// ContextKeyRequestReferer is populated in the context by
// PopulateRequestContext. Its value is r.Header.Get("Referer").
ContextKeyRequestReferer
// ContextKeyRequestUserAgent is populated in the context by
// PopulateRequestContext. Its value is r.Header.Get("User-Agent").
ContextKeyRequestUserAgent
// ContextKeyRequestXRequestID is populated in the context by
// PopulateRequestContext. Its value is r.Header.Get("X-Request-Id").
ContextKeyRequestXRequestID
// ContextKeyRequestAccept is populated in the context by
// PopulateRequestContext. Its value is r.Header.Get("Accept").
ContextKeyRequestAccept
// ContextKeyResponseHeaders is populated in the context whenever a
// ServerFinalizerFunc is specified. Its value is of type http.Header, and
// is captured only once the entire response has been written.
ContextKeyResponseHeaders
// ContextKeyResponseSize is populated in the context whenever a
// ServerFinalizerFunc is specified. Its value is of type int64.
ContextKeyResponseSize
)