399 lines
12 KiB
Go
399 lines
12 KiB
Go
package gengateway
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import (
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"bytes"
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"fmt"
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"strings"
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"text/template"
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"github.com/golang/glog"
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"github.com/grpc-ecosystem/grpc-gateway/protoc-gen-grpc-gateway/descriptor"
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"github.com/grpc-ecosystem/grpc-gateway/utilities"
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)
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type param struct {
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*descriptor.File
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Imports []descriptor.GoPackage
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UseRequestContext bool
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}
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type binding struct {
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*descriptor.Binding
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}
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// HasQueryParam determines if the binding needs parameters in query string.
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//
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// It sometimes returns true even though actually the binding does not need.
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// But it is not serious because it just results in a small amount of extra codes generated.
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func (b binding) HasQueryParam() bool {
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if b.Body != nil && len(b.Body.FieldPath) == 0 {
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return false
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}
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fields := make(map[string]bool)
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for _, f := range b.Method.RequestType.Fields {
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fields[f.GetName()] = true
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}
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if b.Body != nil {
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delete(fields, b.Body.FieldPath.String())
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}
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for _, p := range b.PathParams {
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delete(fields, p.FieldPath.String())
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}
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return len(fields) > 0
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}
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func (b binding) QueryParamFilter() queryParamFilter {
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var seqs [][]string
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if b.Body != nil {
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seqs = append(seqs, strings.Split(b.Body.FieldPath.String(), "."))
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}
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for _, p := range b.PathParams {
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seqs = append(seqs, strings.Split(p.FieldPath.String(), "."))
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}
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return queryParamFilter{utilities.NewDoubleArray(seqs)}
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}
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// queryParamFilter is a wrapper of utilities.DoubleArray which provides String() to output DoubleArray.Encoding in a stable and predictable format.
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type queryParamFilter struct {
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*utilities.DoubleArray
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}
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func (f queryParamFilter) String() string {
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encodings := make([]string, len(f.Encoding))
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for str, enc := range f.Encoding {
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encodings[enc] = fmt.Sprintf("%q: %d", str, enc)
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}
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e := strings.Join(encodings, ", ")
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return fmt.Sprintf("&utilities.DoubleArray{Encoding: map[string]int{%s}, Base: %#v, Check: %#v}", e, f.Base, f.Check)
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}
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type trailerParams struct {
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Services []*descriptor.Service
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UseRequestContext bool
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}
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func applyTemplate(p param) (string, error) {
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w := bytes.NewBuffer(nil)
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if err := headerTemplate.Execute(w, p); err != nil {
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return "", err
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}
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var targetServices []*descriptor.Service
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for _, svc := range p.Services {
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var methodWithBindingsSeen bool
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for _, meth := range svc.Methods {
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glog.V(2).Infof("Processing %s.%s", svc.GetName(), meth.GetName())
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methName := strings.Title(*meth.Name)
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meth.Name = &methName
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for _, b := range meth.Bindings {
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methodWithBindingsSeen = true
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if err := handlerTemplate.Execute(w, binding{Binding: b}); err != nil {
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return "", err
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}
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}
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}
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if methodWithBindingsSeen {
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targetServices = append(targetServices, svc)
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}
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}
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if len(targetServices) == 0 {
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return "", errNoTargetService
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}
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tp := trailerParams{
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Services: targetServices,
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UseRequestContext: p.UseRequestContext,
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}
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if err := trailerTemplate.Execute(w, tp); err != nil {
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return "", err
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}
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return w.String(), nil
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}
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var (
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headerTemplate = template.Must(template.New("header").Parse(`
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// Code generated by protoc-gen-grpc-gateway
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// source: {{.GetName}}
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// DO NOT EDIT!
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/*
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Package {{.GoPkg.Name}} is a reverse proxy.
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It translates gRPC into RESTful JSON APIs.
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*/
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package {{.GoPkg.Name}}
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import (
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{{range $i := .Imports}}{{if $i.Standard}}{{$i | printf "%s\n"}}{{end}}{{end}}
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{{range $i := .Imports}}{{if not $i.Standard}}{{$i | printf "%s\n"}}{{end}}{{end}}
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)
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var _ codes.Code
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var _ io.Reader
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var _ = runtime.String
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var _ = utilities.NewDoubleArray
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`))
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handlerTemplate = template.Must(template.New("handler").Parse(`
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{{if and .Method.GetClientStreaming .Method.GetServerStreaming}}
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{{template "bidi-streaming-request-func" .}}
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{{else if .Method.GetClientStreaming}}
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{{template "client-streaming-request-func" .}}
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{{else}}
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{{template "client-rpc-request-func" .}}
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{{end}}
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`))
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_ = template.Must(handlerTemplate.New("request-func-signature").Parse(strings.Replace(`
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{{if .Method.GetServerStreaming}}
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func request_{{.Method.Service.GetName}}_{{.Method.GetName}}_{{.Index}}(ctx context.Context, marshaler runtime.Marshaler, client {{.Method.Service.GetName}}Client, req *http.Request, pathParams map[string]string) ({{.Method.Service.GetName}}_{{.Method.GetName}}Client, runtime.ServerMetadata, error)
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{{else}}
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func request_{{.Method.Service.GetName}}_{{.Method.GetName}}_{{.Index}}(ctx context.Context, marshaler runtime.Marshaler, client {{.Method.Service.GetName}}Client, req *http.Request, pathParams map[string]string) (proto.Message, runtime.ServerMetadata, error)
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{{end}}`, "\n", "", -1)))
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_ = template.Must(handlerTemplate.New("client-streaming-request-func").Parse(`
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{{template "request-func-signature" .}} {
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var metadata runtime.ServerMetadata
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stream, err := client.{{.Method.GetName}}(ctx)
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if err != nil {
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grpclog.Printf("Failed to start streaming: %v", err)
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return nil, metadata, err
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}
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dec := marshaler.NewDecoder(req.Body)
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for {
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var protoReq {{.Method.RequestType.GoType .Method.Service.File.GoPkg.Path}}
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err = dec.Decode(&protoReq)
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if err == io.EOF {
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break
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}
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if err != nil {
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grpclog.Printf("Failed to decode request: %v", err)
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return nil, metadata, grpc.Errorf(codes.InvalidArgument, "%v", err)
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}
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if err = stream.Send(&protoReq); err != nil {
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grpclog.Printf("Failed to send request: %v", err)
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return nil, metadata, err
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}
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}
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if err := stream.CloseSend(); err != nil {
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grpclog.Printf("Failed to terminate client stream: %v", err)
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return nil, metadata, err
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}
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header, err := stream.Header()
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if err != nil {
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grpclog.Printf("Failed to get header from client: %v", err)
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return nil, metadata, err
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}
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metadata.HeaderMD = header
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{{if .Method.GetServerStreaming}}
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return stream, metadata, nil
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{{else}}
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msg, err := stream.CloseAndRecv()
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metadata.TrailerMD = stream.Trailer()
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return msg, metadata, err
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{{end}}
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}
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`))
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_ = template.Must(handlerTemplate.New("client-rpc-request-func").Parse(`
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{{if .HasQueryParam}}
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var (
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filter_{{.Method.Service.GetName}}_{{.Method.GetName}}_{{.Index}} = {{.QueryParamFilter}}
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)
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{{end}}
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{{template "request-func-signature" .}} {
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var protoReq {{.Method.RequestType.GoType .Method.Service.File.GoPkg.Path}}
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var metadata runtime.ServerMetadata
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{{if .Body}}
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if err := marshaler.NewDecoder(req.Body).Decode(&{{.Body.RHS "protoReq"}}); err != nil {
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return nil, metadata, grpc.Errorf(codes.InvalidArgument, "%v", err)
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}
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{{end}}
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{{if .PathParams}}
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var (
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val string
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ok bool
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err error
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_ = err
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)
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{{range $param := .PathParams}}
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val, ok = pathParams[{{$param | printf "%q"}}]
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if !ok {
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return nil, metadata, grpc.Errorf(codes.InvalidArgument, "missing parameter %s", {{$param | printf "%q"}})
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}
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{{if $param.IsNestedProto3 }}
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err = runtime.PopulateFieldFromPath(&protoReq, {{$param | printf "%q"}}, val)
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{{else}}
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{{$param.RHS "protoReq"}}, err = {{$param.ConvertFuncExpr}}(val)
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{{end}}
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if err != nil {
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return nil, metadata, err
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}
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{{end}}
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{{end}}
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{{if .HasQueryParam}}
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if err := runtime.PopulateQueryParameters(&protoReq, req.URL.Query(), filter_{{.Method.Service.GetName}}_{{.Method.GetName}}_{{.Index}}); err != nil {
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return nil, metadata, grpc.Errorf(codes.InvalidArgument, "%v", err)
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}
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{{end}}
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{{if .Method.GetServerStreaming}}
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stream, err := client.{{.Method.GetName}}(ctx, &protoReq)
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if err != nil {
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return nil, metadata, err
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}
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header, err := stream.Header()
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if err != nil {
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return nil, metadata, err
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}
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metadata.HeaderMD = header
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return stream, metadata, nil
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{{else}}
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msg, err := client.{{.Method.GetName}}(ctx, &protoReq, grpc.Header(&metadata.HeaderMD), grpc.Trailer(&metadata.TrailerMD))
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return msg, metadata, err
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{{end}}
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}`))
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_ = template.Must(handlerTemplate.New("bidi-streaming-request-func").Parse(`
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{{template "request-func-signature" .}} {
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var metadata runtime.ServerMetadata
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stream, err := client.{{.Method.GetName}}(ctx)
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if err != nil {
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grpclog.Printf("Failed to start streaming: %v", err)
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return nil, metadata, err
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}
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dec := marshaler.NewDecoder(req.Body)
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handleSend := func() error {
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var protoReq {{.Method.RequestType.GoType .Method.Service.File.GoPkg.Path}}
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err = dec.Decode(&protoReq)
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if err == io.EOF {
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return err
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}
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if err != nil {
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grpclog.Printf("Failed to decode request: %v", err)
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return err
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}
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if err = stream.Send(&protoReq); err != nil {
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grpclog.Printf("Failed to send request: %v", err)
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return err
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}
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return nil
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}
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if err := handleSend(); err != nil {
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if cerr := stream.CloseSend(); cerr != nil {
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grpclog.Printf("Failed to terminate client stream: %v", cerr)
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}
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if err == io.EOF {
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return stream, metadata, nil
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}
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return nil, metadata, err
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}
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go func() {
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for {
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if err := handleSend(); err != nil {
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break
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}
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}
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if err := stream.CloseSend(); err != nil {
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grpclog.Printf("Failed to terminate client stream: %v", err)
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}
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}()
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header, err := stream.Header()
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if err != nil {
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grpclog.Printf("Failed to get header from client: %v", err)
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return nil, metadata, err
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}
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metadata.HeaderMD = header
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return stream, metadata, nil
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}
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`))
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trailerTemplate = template.Must(template.New("trailer").Parse(`
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{{$UseRequestContext := .UseRequestContext}}
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{{range $svc := .Services}}
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// Register{{$svc.GetName}}HandlerFromEndpoint is same as Register{{$svc.GetName}}Handler but
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// automatically dials to "endpoint" and closes the connection when "ctx" gets done.
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func Register{{$svc.GetName}}HandlerFromEndpoint(ctx context.Context, mux *runtime.ServeMux, endpoint string, opts []grpc.DialOption) (err error) {
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conn, err := grpc.Dial(endpoint, opts...)
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if err != nil {
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return err
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}
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defer func() {
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if err != nil {
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if cerr := conn.Close(); cerr != nil {
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grpclog.Printf("Failed to close conn to %s: %v", endpoint, cerr)
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}
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return
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}
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go func() {
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<-ctx.Done()
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if cerr := conn.Close(); cerr != nil {
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grpclog.Printf("Failed to close conn to %s: %v", endpoint, cerr)
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}
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}()
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}()
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return Register{{$svc.GetName}}Handler(ctx, mux, conn)
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}
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// Register{{$svc.GetName}}Handler registers the http handlers for service {{$svc.GetName}} to "mux".
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// The handlers forward requests to the grpc endpoint over "conn".
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func Register{{$svc.GetName}}Handler(ctx context.Context, mux *runtime.ServeMux, conn *grpc.ClientConn) error {
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client := New{{$svc.GetName}}Client(conn)
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{{range $m := $svc.Methods}}
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{{range $b := $m.Bindings}}
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mux.Handle({{$b.HTTPMethod | printf "%q"}}, pattern_{{$svc.GetName}}_{{$m.GetName}}_{{$b.Index}}, func(w http.ResponseWriter, req *http.Request, pathParams map[string]string) {
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{{- if $UseRequestContext }}
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ctx, cancel := context.WithCancel(req.Context())
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{{- else -}}
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ctx, cancel := context.WithCancel(ctx)
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{{- end }}
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defer cancel()
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if cn, ok := w.(http.CloseNotifier); ok {
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go func(done <-chan struct{}, closed <-chan bool) {
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select {
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case <-done:
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case <-closed:
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cancel()
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}
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}(ctx.Done(), cn.CloseNotify())
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}
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inboundMarshaler, outboundMarshaler := runtime.MarshalerForRequest(mux, req)
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rctx, err := runtime.AnnotateContext(ctx, req)
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if err != nil {
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runtime.HTTPError(ctx, outboundMarshaler, w, req, err)
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}
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resp, md, err := request_{{$svc.GetName}}_{{$m.GetName}}_{{$b.Index}}(rctx, inboundMarshaler, client, req, pathParams)
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ctx = runtime.NewServerMetadataContext(ctx, md)
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if err != nil {
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runtime.HTTPError(ctx, outboundMarshaler, w, req, err)
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return
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}
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{{if $m.GetServerStreaming}}
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forward_{{$svc.GetName}}_{{$m.GetName}}_{{$b.Index}}(ctx, outboundMarshaler, w, req, func() (proto.Message, error) { return resp.Recv() }, mux.GetForwardResponseOptions()...)
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{{else}}
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forward_{{$svc.GetName}}_{{$m.GetName}}_{{$b.Index}}(ctx, outboundMarshaler, w, req, resp, mux.GetForwardResponseOptions()...)
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{{end}}
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})
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{{end}}
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{{end}}
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return nil
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}
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var (
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{{range $m := $svc.Methods}}
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{{range $b := $m.Bindings}}
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pattern_{{$svc.GetName}}_{{$m.GetName}}_{{$b.Index}} = runtime.MustPattern(runtime.NewPattern({{$b.PathTmpl.Version}}, {{$b.PathTmpl.OpCodes | printf "%#v"}}, {{$b.PathTmpl.Pool | printf "%#v"}}, {{$b.PathTmpl.Verb | printf "%q"}}))
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{{end}}
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{{end}}
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)
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var (
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{{range $m := $svc.Methods}}
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{{range $b := $m.Bindings}}
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forward_{{$svc.GetName}}_{{$m.GetName}}_{{$b.Index}} = {{if $m.GetServerStreaming}}runtime.ForwardResponseStream{{else}}runtime.ForwardResponseMessage{{end}}
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{{end}}
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{{end}}
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)
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{{end}}`))
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)
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