133 lines
4.3 KiB
Go
133 lines
4.3 KiB
Go
package runtime
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import (
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"net/http"
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"strings"
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"golang.org/x/net/context"
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"github.com/golang/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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}
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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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// 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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}
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for _, opt := range opts {
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opt(serveMux)
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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(s.handlers[meth], handler{pat: pat, h: h})
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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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path := r.URL.Path
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if !strings.HasPrefix(path, "/") {
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OtherErrorHandler(w, r, http.StatusText(http.StatusBadRequest), http.StatusBadRequest)
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return
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}
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components := strings.Split(path[1:], "/")
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l := len(components)
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var verb string
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if idx := strings.LastIndex(components[l-1], ":"); idx == 0 {
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OtherErrorHandler(w, r, http.StatusText(http.StatusNotFound), http.StatusNotFound)
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return
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} else if idx > 0 {
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c := components[l-1]
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components[l-1], verb = c[:idx], c[idx+1:]
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}
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if override := r.Header.Get("X-HTTP-Method-Override"); override != "" && 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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OtherErrorHandler(w, r, err.Error(), http.StatusBadRequest)
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return
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}
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}
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for _, h := range s.handlers[r.Method] {
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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 MethodNotAllowed 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 isPathLengthFallback(r) {
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if err := r.ParseForm(); err != nil {
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OtherErrorHandler(w, r, err.Error(), http.StatusBadRequest)
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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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OtherErrorHandler(w, r, http.StatusText(http.StatusMethodNotAllowed), http.StatusMethodNotAllowed)
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return
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}
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}
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OtherErrorHandler(w, r, http.StatusText(http.StatusNotFound), 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 isPathLengthFallback(r *http.Request) bool {
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return 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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