peridot/vendor/github.com/grpc-ecosystem/grpc-gateway/v2/runtime/mux.go
2022-07-07 22:13:21 +02:00

300 lines
11 KiB
Go

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