300 lines
11 KiB
Go
300 lines
11 KiB
Go
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package runtime
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import (
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"context"
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"fmt"
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"net/http"
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"net/textproto"
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"strings"
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"github.com/grpc-ecosystem/grpc-gateway/v2/internal/httprule"
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"google.golang.org/grpc/codes"
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"google.golang.org/grpc/metadata"
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"google.golang.org/grpc/status"
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"google.golang.org/protobuf/proto"
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)
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// A HandlerFunc handles a specific pair of path pattern and HTTP method.
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type HandlerFunc func(w http.ResponseWriter, r *http.Request, pathParams map[string]string)
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// ServeMux is a request multiplexer for grpc-gateway.
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// It matches http requests to patterns and invokes the corresponding handler.
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type ServeMux struct {
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// handlers maps HTTP method to a list of handlers.
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handlers map[string][]handler
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forwardResponseOptions []func(context.Context, http.ResponseWriter, proto.Message) error
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marshalers marshalerRegistry
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incomingHeaderMatcher HeaderMatcherFunc
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outgoingHeaderMatcher HeaderMatcherFunc
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metadataAnnotators []func(context.Context, *http.Request) metadata.MD
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errorHandler ErrorHandlerFunc
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streamErrorHandler StreamErrorHandlerFunc
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routingErrorHandler RoutingErrorHandlerFunc
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disablePathLengthFallback bool
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}
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// ServeMuxOption is an option that can be given to a ServeMux on construction.
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type ServeMuxOption func(*ServeMux)
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// WithForwardResponseOption returns a ServeMuxOption representing the forwardResponseOption.
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//
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// forwardResponseOption is an option that will be called on the relevant context.Context,
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// http.ResponseWriter, and proto.Message before every forwarded response.
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//
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// The message may be nil in the case where just a header is being sent.
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func WithForwardResponseOption(forwardResponseOption func(context.Context, http.ResponseWriter, proto.Message) error) ServeMuxOption {
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return func(serveMux *ServeMux) {
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serveMux.forwardResponseOptions = append(serveMux.forwardResponseOptions, forwardResponseOption)
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}
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}
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// SetQueryParameterParser sets the query parameter parser, used to populate message from query parameters.
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// Configuring this will mean the generated OpenAPI output is no longer correct, and it should be
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// done with careful consideration.
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func SetQueryParameterParser(queryParameterParser QueryParameterParser) ServeMuxOption {
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return func(serveMux *ServeMux) {
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currentQueryParser = queryParameterParser
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}
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}
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// HeaderMatcherFunc checks whether a header key should be forwarded to/from gRPC context.
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type HeaderMatcherFunc func(string) (string, bool)
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// DefaultHeaderMatcher is used to pass http request headers to/from gRPC context. This adds permanent HTTP header
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// keys (as specified by the IANA) to gRPC context with grpcgateway- prefix. HTTP headers that start with
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// 'Grpc-Metadata-' are mapped to gRPC metadata after removing prefix 'Grpc-Metadata-'.
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func DefaultHeaderMatcher(key string) (string, bool) {
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key = textproto.CanonicalMIMEHeaderKey(key)
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if isPermanentHTTPHeader(key) {
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return MetadataPrefix + key, true
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} else if strings.HasPrefix(key, MetadataHeaderPrefix) {
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return key[len(MetadataHeaderPrefix):], true
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}
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return "", false
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}
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// WithIncomingHeaderMatcher returns a ServeMuxOption representing a headerMatcher for incoming request to gateway.
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//
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// This matcher will be called with each header in http.Request. If matcher returns true, that header will be
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// passed to gRPC context. To transform the header before passing to gRPC context, matcher should return modified header.
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func WithIncomingHeaderMatcher(fn HeaderMatcherFunc) ServeMuxOption {
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return func(mux *ServeMux) {
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mux.incomingHeaderMatcher = fn
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}
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}
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// WithOutgoingHeaderMatcher returns a ServeMuxOption representing a headerMatcher for outgoing response from gateway.
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//
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// This matcher will be called with each header in response header metadata. If matcher returns true, that header will be
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// passed to http response returned from gateway. To transform the header before passing to response,
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// matcher should return modified header.
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func WithOutgoingHeaderMatcher(fn HeaderMatcherFunc) ServeMuxOption {
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return func(mux *ServeMux) {
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mux.outgoingHeaderMatcher = fn
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}
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}
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// WithMetadata returns a ServeMuxOption for passing metadata to a gRPC context.
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//
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// This can be used by services that need to read from http.Request and modify gRPC context. A common use case
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// is reading token from cookie and adding it in gRPC context.
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func WithMetadata(annotator func(context.Context, *http.Request) metadata.MD) ServeMuxOption {
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return func(serveMux *ServeMux) {
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serveMux.metadataAnnotators = append(serveMux.metadataAnnotators, annotator)
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}
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}
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// WithErrorHandler returns a ServeMuxOption for configuring a custom error handler.
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//
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// This can be used to configure a custom error response.
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func WithErrorHandler(fn ErrorHandlerFunc) ServeMuxOption {
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return func(serveMux *ServeMux) {
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serveMux.errorHandler = fn
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}
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}
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// WithStreamErrorHandler returns a ServeMuxOption that will use the given custom stream
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// error handler, which allows for customizing the error trailer for server-streaming
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// calls.
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//
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// For stream errors that occur before any response has been written, the mux's
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// ErrorHandler will be invoked. However, once data has been written, the errors must
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// be handled differently: they must be included in the response body. The response body's
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// final message will include the error details returned by the stream error handler.
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func WithStreamErrorHandler(fn StreamErrorHandlerFunc) ServeMuxOption {
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return func(serveMux *ServeMux) {
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serveMux.streamErrorHandler = fn
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}
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}
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// WithRoutingErrorHandler returns a ServeMuxOption for configuring a custom error handler to handle http routing errors.
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//
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// Method called for errors which can happen before gRPC route selected or executed.
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// The following error codes: StatusMethodNotAllowed StatusNotFound StatusBadRequest
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func WithRoutingErrorHandler(fn RoutingErrorHandlerFunc) ServeMuxOption {
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return func(serveMux *ServeMux) {
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serveMux.routingErrorHandler = fn
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}
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}
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// WithDisablePathLengthFallback returns a ServeMuxOption for disable path length fallback.
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func WithDisablePathLengthFallback() ServeMuxOption {
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return func(serveMux *ServeMux) {
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serveMux.disablePathLengthFallback = true
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}
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}
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// NewServeMux returns a new ServeMux whose internal mapping is empty.
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func NewServeMux(opts ...ServeMuxOption) *ServeMux {
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serveMux := &ServeMux{
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handlers: make(map[string][]handler),
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forwardResponseOptions: make([]func(context.Context, http.ResponseWriter, proto.Message) error, 0),
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marshalers: makeMarshalerMIMERegistry(),
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errorHandler: DefaultHTTPErrorHandler,
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streamErrorHandler: DefaultStreamErrorHandler,
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routingErrorHandler: DefaultRoutingErrorHandler,
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}
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for _, opt := range opts {
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opt(serveMux)
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}
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if serveMux.incomingHeaderMatcher == nil {
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serveMux.incomingHeaderMatcher = DefaultHeaderMatcher
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}
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if serveMux.outgoingHeaderMatcher == nil {
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serveMux.outgoingHeaderMatcher = func(key string) (string, bool) {
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return fmt.Sprintf("%s%s", MetadataHeaderPrefix, key), true
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}
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}
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return serveMux
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}
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// Handle associates "h" to the pair of HTTP method and path pattern.
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func (s *ServeMux) Handle(meth string, pat Pattern, h HandlerFunc) {
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s.handlers[meth] = append([]handler{{pat: pat, h: h}}, s.handlers[meth]...)
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}
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// HandlePath allows users to configure custom path handlers.
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// refer: https://grpc-ecosystem.github.io/grpc-gateway/docs/inject_router.html
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func (s *ServeMux) HandlePath(meth string, pathPattern string, h HandlerFunc) error {
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compiler, err := httprule.Parse(pathPattern)
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if err != nil {
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return fmt.Errorf("parsing path pattern: %w", err)
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}
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tp := compiler.Compile()
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pattern, err := NewPattern(tp.Version, tp.OpCodes, tp.Pool, tp.Verb)
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if err != nil {
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return fmt.Errorf("creating new pattern: %w", err)
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}
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s.Handle(meth, pattern, h)
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return nil
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}
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// ServeHTTP dispatches the request to the first handler whose pattern matches to r.Method and r.Path.
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func (s *ServeMux) ServeHTTP(w http.ResponseWriter, r *http.Request) {
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ctx := r.Context()
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path := r.URL.Path
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if !strings.HasPrefix(path, "/") {
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_, outboundMarshaler := MarshalerForRequest(s, r)
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s.routingErrorHandler(ctx, s, outboundMarshaler, w, r, http.StatusBadRequest)
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return
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}
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components := strings.Split(path[1:], "/")
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if override := r.Header.Get("X-HTTP-Method-Override"); override != "" && s.isPathLengthFallback(r) {
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r.Method = strings.ToUpper(override)
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if err := r.ParseForm(); err != nil {
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_, outboundMarshaler := MarshalerForRequest(s, r)
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sterr := status.Error(codes.InvalidArgument, err.Error())
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s.errorHandler(ctx, s, outboundMarshaler, w, r, sterr)
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return
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}
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}
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// Verb out here is to memoize for the fallback case below
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var verb string
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for _, h := range s.handlers[r.Method] {
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// If the pattern has a verb, explicitly look for a suffix in the last
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// component that matches a colon plus the verb. This allows us to
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// handle some cases that otherwise can't be correctly handled by the
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// former LastIndex case, such as when the verb literal itself contains
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// a colon. This should work for all cases that have run through the
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// parser because we know what verb we're looking for, however, there
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// are still some cases that the parser itself cannot disambiguate. See
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// the comment there if interested.
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patVerb := h.pat.Verb()
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l := len(components)
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lastComponent := components[l-1]
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var idx int = -1
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if patVerb != "" && strings.HasSuffix(lastComponent, ":"+patVerb) {
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idx = len(lastComponent) - len(patVerb) - 1
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}
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if idx == 0 {
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_, outboundMarshaler := MarshalerForRequest(s, r)
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s.routingErrorHandler(ctx, s, outboundMarshaler, w, r, http.StatusNotFound)
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return
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}
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if idx > 0 {
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components[l-1], verb = lastComponent[:idx], lastComponent[idx+1:]
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}
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pathParams, err := h.pat.Match(components, verb)
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if err != nil {
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continue
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}
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h.h(w, r, pathParams)
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return
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}
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// lookup other methods to handle fallback from GET to POST and
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// to determine if it is NotImplemented or NotFound.
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for m, handlers := range s.handlers {
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if m == r.Method {
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continue
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}
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for _, h := range handlers {
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pathParams, err := h.pat.Match(components, verb)
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if err != nil {
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continue
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}
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// X-HTTP-Method-Override is optional. Always allow fallback to POST.
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if s.isPathLengthFallback(r) {
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if err := r.ParseForm(); err != nil {
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_, outboundMarshaler := MarshalerForRequest(s, r)
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sterr := status.Error(codes.InvalidArgument, err.Error())
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s.errorHandler(ctx, s, outboundMarshaler, w, r, sterr)
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return
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}
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h.h(w, r, pathParams)
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return
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}
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_, outboundMarshaler := MarshalerForRequest(s, r)
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s.routingErrorHandler(ctx, s, outboundMarshaler, w, r, http.StatusMethodNotAllowed)
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return
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}
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}
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_, outboundMarshaler := MarshalerForRequest(s, r)
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s.routingErrorHandler(ctx, s, outboundMarshaler, w, r, http.StatusNotFound)
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}
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// GetForwardResponseOptions returns the ForwardResponseOptions associated with this ServeMux.
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func (s *ServeMux) GetForwardResponseOptions() []func(context.Context, http.ResponseWriter, proto.Message) error {
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return s.forwardResponseOptions
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}
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func (s *ServeMux) isPathLengthFallback(r *http.Request) bool {
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return !s.disablePathLengthFallback && r.Method == "POST" && r.Header.Get("Content-Type") == "application/x-www-form-urlencoded"
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}
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type handler struct {
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pat Pattern
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h HandlerFunc
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}
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