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|
package runtime
import (
"fmt"
"net"
"net/http"
"strconv"
"strings"
"time"
"golang.org/x/net/context"
"google.golang.org/grpc/codes"
"google.golang.org/grpc/grpclog"
"google.golang.org/grpc/metadata"
"google.golang.org/grpc/status"
)
// MetadataHeaderPrefix is the http prefix that represents custom metadata
// parameters to or from a gRPC call.
const MetadataHeaderPrefix = "Grpc-Metadata-"
// MetadataPrefix is the prefix for grpc-gateway supplied custom metadata fields.
const MetadataPrefix = "grpcgateway-"
// MetadataTrailerPrefix is prepended to gRPC metadata as it is converted to
// HTTP headers in a response handled by grpc-gateway
const MetadataTrailerPrefix = "Grpc-Trailer-"
const metadataGrpcTimeout = "Grpc-Timeout"
const xForwardedFor = "X-Forwarded-For"
const xForwardedHost = "X-Forwarded-Host"
var (
// DefaultContextTimeout is used for gRPC call context.WithTimeout whenever a Grpc-Timeout inbound
// header isn't present. If the value is 0 the sent `context` will not have a timeout.
DefaultContextTimeout = 0 * time.Second
)
/*
AnnotateContext adds context information such as metadata from the request.
At a minimum, the RemoteAddr is included in the fashion of "X-Forwarded-For",
except that the forwarded destination is not another HTTP service but rather
a gRPC service.
*/
func AnnotateContext(ctx context.Context, mux *ServeMux, req *http.Request) (context.Context, error) {
var pairs []string
timeout := DefaultContextTimeout
if tm := req.Header.Get(metadataGrpcTimeout); tm != "" {
var err error
timeout, err = timeoutDecode(tm)
if err != nil {
return nil, status.Errorf(codes.InvalidArgument, "invalid grpc-timeout: %s", tm)
}
}
for key, vals := range req.Header {
for _, val := range vals {
// For backwards-compatibility, pass through 'authorization' header with no prefix.
if strings.ToLower(key) == "authorization" {
pairs = append(pairs, "authorization", val)
}
if h, ok := mux.incomingHeaderMatcher(key); ok {
pairs = append(pairs, h, val)
}
}
}
if host := req.Header.Get(xForwardedHost); host != "" {
pairs = append(pairs, strings.ToLower(xForwardedHost), host)
} else if req.Host != "" {
pairs = append(pairs, strings.ToLower(xForwardedHost), req.Host)
}
if addr := req.RemoteAddr; addr != "" {
if remoteIP, _, err := net.SplitHostPort(addr); err == nil {
if fwd := req.Header.Get(xForwardedFor); fwd == "" {
pairs = append(pairs, strings.ToLower(xForwardedFor), remoteIP)
} else {
pairs = append(pairs, strings.ToLower(xForwardedFor), fmt.Sprintf("%s, %s", fwd, remoteIP))
}
} else {
grpclog.Printf("invalid remote addr: %s", addr)
}
}
if timeout != 0 {
ctx, _ = context.WithTimeout(ctx, timeout)
}
if len(pairs) == 0 {
return ctx, nil
}
md := metadata.Pairs(pairs...)
if mux.metadataAnnotator != nil {
md = metadata.Join(md, mux.metadataAnnotator(ctx, req))
}
return metadata.NewOutgoingContext(ctx, md), nil
}
// ServerMetadata consists of metadata sent from gRPC server.
type ServerMetadata struct {
HeaderMD metadata.MD
TrailerMD metadata.MD
}
type serverMetadataKey struct{}
// NewServerMetadataContext creates a new context with ServerMetadata
func NewServerMetadataContext(ctx context.Context, md ServerMetadata) context.Context {
return context.WithValue(ctx, serverMetadataKey{}, md)
}
// ServerMetadataFromContext returns the ServerMetadata in ctx
func ServerMetadataFromContext(ctx context.Context) (md ServerMetadata, ok bool) {
md, ok = ctx.Value(serverMetadataKey{}).(ServerMetadata)
return
}
func timeoutDecode(s string) (time.Duration, error) {
size := len(s)
if size < 2 {
return 0, fmt.Errorf("timeout string is too short: %q", s)
}
d, ok := timeoutUnitToDuration(s[size-1])
if !ok {
return 0, fmt.Errorf("timeout unit is not recognized: %q", s)
}
t, err := strconv.ParseInt(s[:size-1], 10, 64)
if err != nil {
return 0, err
}
return d * time.Duration(t), nil
}
func timeoutUnitToDuration(u uint8) (d time.Duration, ok bool) {
switch u {
case 'H':
return time.Hour, true
case 'M':
return time.Minute, true
case 'S':
return time.Second, true
case 'm':
return time.Millisecond, true
case 'u':
return time.Microsecond, true
case 'n':
return time.Nanosecond, true
default:
}
return
}
// isPermanentHTTPHeader checks whether hdr belongs to the list of
// permenant request headers maintained by IANA.
// http://www.iana.org/assignments/message-headers/message-headers.xml
func isPermanentHTTPHeader(hdr string) bool {
switch hdr {
case
"Accept",
"Accept-Charset",
"Accept-Language",
"Accept-Ranges",
"Authorization",
"Cache-Control",
"Content-Type",
"Cookie",
"Date",
"Expect",
"From",
"Host",
"If-Match",
"If-Modified-Since",
"If-None-Match",
"If-Schedule-Tag-Match",
"If-Unmodified-Since",
"Max-Forwards",
"Origin",
"Pragma",
"Referer",
"User-Agent",
"Via",
"Warning":
return true
}
return false
}
|
