106 lines
2.8 KiB
Go
106 lines
2.8 KiB
Go
package http
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import (
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"context"
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"fmt"
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"reflect"
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"unicode"
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"unicode/utf8"
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"github.com/unistack-org/micro/v3/server"
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)
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type methodType struct {
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ArgType reflect.Type
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ReplyType reflect.Type
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ContextType reflect.Type
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method reflect.Method
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stream bool
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}
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// Is this an exported - upper case - name?
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func isExported(name string) bool {
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r, _ := utf8.DecodeRuneInString(name)
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return unicode.IsUpper(r)
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}
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// Is this type exported or a builtin?
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func isExportedOrBuiltinType(t reflect.Type) bool {
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for t.Kind() == reflect.Ptr {
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t = t.Elem()
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}
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// PkgPath will be non-empty even for an exported type,
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// so we need to check the type name as well.
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return isExported(t.Name()) || t.PkgPath() == ""
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}
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// prepareEndpoint() returns a methodType for the provided method or nil
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// in case if the method was unsuitable.
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func prepareEndpoint(method reflect.Method) (*methodType, error) {
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mtype := method.Type
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mname := method.Name
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var replyType, argType, contextType reflect.Type
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var stream bool
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// Endpoint() must be exported.
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if method.PkgPath != "" {
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return nil, fmt.Errorf("Endpoint must be exported")
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}
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switch mtype.NumIn() {
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case 3:
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// assuming streaming
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argType = mtype.In(2)
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contextType = mtype.In(1)
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stream = true
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case 4:
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// method that takes a context
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argType = mtype.In(2)
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replyType = mtype.In(3)
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contextType = mtype.In(1)
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default:
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return nil, fmt.Errorf("method %v of %v has wrong number of ins: %v", mname, mtype, mtype.NumIn())
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}
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switch stream {
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case true:
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// check stream type
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streamType := reflect.TypeOf((*server.Stream)(nil)).Elem()
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if !argType.Implements(streamType) {
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return nil, fmt.Errorf("%v argument does not implement Streamer interface: %v", mname, argType)
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}
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default:
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// First arg need not be a pointer.
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if !isExportedOrBuiltinType(argType) {
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return nil, fmt.Errorf("%v argument type not exported: %v", mname, argType)
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}
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if replyType.Kind() != reflect.Ptr {
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return nil, fmt.Errorf("method %v reply type not a pointer: %v", mname, replyType)
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}
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// Reply type must be exported.
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if !isExportedOrBuiltinType(replyType) {
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return nil, fmt.Errorf("method %v reply type not exported: %v", mname, replyType)
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}
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}
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// Endpoint() needs one out.
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if mtype.NumOut() != 1 {
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return nil, fmt.Errorf("method %v has wrong number of outs: %v", mname, mtype.NumOut())
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}
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// The return type of the method must be error.
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if returnType := mtype.Out(0); returnType != typeOfError {
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return nil, fmt.Errorf("method %v returns %v not error", mname, returnType.String())
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}
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return &methodType{method: method, ArgType: argType, ReplyType: replyType, ContextType: contextType, stream: stream}, nil
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}
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func (m *methodType) prepareContext(ctx context.Context) reflect.Value {
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if contextv := reflect.ValueOf(ctx); contextv.IsValid() {
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return contextv
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}
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return reflect.Zero(m.ContextType)
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}
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