dubbo.apache.org/dubbo-go/v3@v3.1.1/filter/generic/service_filter.go (about)

     1  /*
     2   * Licensed to the Apache Software Foundation (ASF) under one or more
     3   * contributor license agreements.  See the NOTICE file distributed with
     4   * this work for additional information regarding copyright ownership.
     5   * The ASF licenses this file to You under the Apache License, Version 2.0
     6   * (the "License"); you may not use this file except in compliance with
     7   * the License.  You may obtain a copy of the License at
     8   *
     9   *     http://www.apache.org/licenses/LICENSE-2.0
    10   *
    11   * Unless required by applicable law or agreed to in writing, software
    12   * distributed under the License is distributed on an "AS IS" BASIS,
    13   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    14   * See the License for the specific language governing permissions and
    15   * limitations under the License.
    16   */
    17  
    18  package generic
    19  
    20  import (
    21  	"context"
    22  	"sync"
    23  )
    24  
    25  import (
    26  	hessian "github.com/apache/dubbo-go-hessian2"
    27  
    28  	"github.com/dubbogo/gost/log/logger"
    29  
    30  	perrors "github.com/pkg/errors"
    31  )
    32  
    33  import (
    34  	"dubbo.apache.org/dubbo-go/v3/common"
    35  	"dubbo.apache.org/dubbo-go/v3/common/constant"
    36  	"dubbo.apache.org/dubbo-go/v3/common/extension"
    37  	"dubbo.apache.org/dubbo-go/v3/filter"
    38  	"dubbo.apache.org/dubbo-go/v3/protocol"
    39  	invocation2 "dubbo.apache.org/dubbo-go/v3/protocol/invocation"
    40  )
    41  
    42  var (
    43  	serviceGenericOnce sync.Once
    44  	serviceGeneric     *genericServiceFilter
    45  )
    46  
    47  func init() {
    48  	extension.SetFilter(constant.GenericServiceFilterKey, newGenericServiceFilter)
    49  }
    50  
    51  // genericServiceFilter is for Server
    52  type genericServiceFilter struct{}
    53  
    54  func newGenericServiceFilter() filter.Filter {
    55  	if serviceGeneric == nil {
    56  		serviceGenericOnce.Do(func() {
    57  			serviceGeneric = &genericServiceFilter{}
    58  		})
    59  	}
    60  	return serviceGeneric
    61  }
    62  func (f *genericServiceFilter) Invoke(ctx context.Context, invoker protocol.Invoker, invocation protocol.Invocation) protocol.Result {
    63  	if !invocation.IsGenericInvocation() {
    64  		return invoker.Invoke(ctx, invocation)
    65  	}
    66  
    67  	// get real invocation info from the generic invocation
    68  	mtdname := invocation.Arguments()[0].(string)
    69  	// types are not required in dubbo-go, for dubbo-go client to dubbo-go server, types could be nil
    70  	types := invocation.Arguments()[1]
    71  	args := invocation.Arguments()[2].([]hessian.Object)
    72  
    73  	logger.Debugf(`received a generic invocation: 
    74  		MethodName: %s,
    75  		Types: %s,
    76  		Args: %s
    77  	`, mtdname, types, args)
    78  
    79  	// get the type of the argument
    80  	ivkUrl := invoker.GetURL()
    81  	svc := common.ServiceMap.GetServiceByServiceKey(ivkUrl.Protocol, ivkUrl.ServiceKey())
    82  	method := svc.Method()[mtdname]
    83  	if method == nil {
    84  		return &protocol.RPCResult{
    85  			Err: perrors.Errorf("\"%s\" method is not found, service key: %s", mtdname, ivkUrl.ServiceKey()),
    86  		}
    87  	}
    88  	argsType := method.ArgsType()
    89  
    90  	// get generic info from attachments of invocation, the default value is "true"
    91  	generic := invocation.GetAttachmentWithDefaultValue(constant.GenericKey, constant.GenericSerializationDefault)
    92  	// get generalizer according to value in the `generic`
    93  	g := getGeneralizer(generic)
    94  
    95  	if len(args) != len(argsType) {
    96  		return &protocol.RPCResult{
    97  			Err: perrors.Errorf("the number of args(=%d) is not matched with \"%s\" method", len(args), mtdname),
    98  		}
    99  	}
   100  
   101  	// realize
   102  	newargs := make([]interface{}, len(argsType))
   103  	for i := 0; i < len(argsType); i++ {
   104  		newarg, err := g.Realize(args[i], argsType[i])
   105  		if err != nil {
   106  			return &protocol.RPCResult{
   107  				Err: perrors.Errorf("realization failed, %v", err),
   108  			}
   109  		}
   110  		newargs[i] = newarg
   111  	}
   112  
   113  	// build a normal invocation
   114  	newivc := invocation2.NewRPCInvocation(mtdname, newargs, invocation.Attachments())
   115  	newivc.SetReply(invocation.Reply())
   116  
   117  	return invoker.Invoke(ctx, newivc)
   118  }
   119  
   120  func (f *genericServiceFilter) OnResponse(_ context.Context, result protocol.Result, _ protocol.Invoker, invocation protocol.Invocation) protocol.Result {
   121  	if invocation.IsGenericInvocation() && result.Result() != nil {
   122  		// get generic info from attachments of invocation, the default value is "true"
   123  		generic := invocation.GetAttachmentWithDefaultValue(constant.GenericKey, constant.GenericSerializationDefault)
   124  		// get generalizer according to value in the `generic`
   125  		g := getGeneralizer(generic)
   126  
   127  		obj, err := g.Generalize(result.Result())
   128  		if err != nil {
   129  			err = perrors.Errorf("generalizaion failed, %v", err)
   130  			result.SetError(err)
   131  			result.SetResult(nil)
   132  			return result
   133  		}
   134  		result.SetResult(obj)
   135  	}
   136  	return result
   137  }