1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
|
#region Copyright notice and license
// Copyright 2018 gRPC authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#endregion
using System;
using System.Linq;
using Grpc.Core.Utils;
namespace Grpc.Core.Interceptors
{
/// <summary>
/// Extends the CallInvoker class to provide the interceptor facility on the client side.
/// This is an EXPERIMENTAL API.
/// </summary>
public static class CallInvokerExtensions
{
/// <summary>
/// Decorates an underlying <see cref="Grpc.Core.CallInvoker" /> to
/// intercept calls through a given interceptor.
/// </summary>
private class InterceptingCallInvoker : CallInvoker
{
readonly CallInvoker invoker;
readonly Interceptor interceptor;
/// <summary>
/// Creates a new instance of <see cref="Grpc.Core.Interceptors.CallInvokerExtensions.InterceptingCallInvoker" />
/// with the given underlying invoker and interceptor instances.
/// </summary>
public InterceptingCallInvoker(CallInvoker invoker, Interceptor interceptor)
{
this.invoker = GrpcPreconditions.CheckNotNull(invoker, "invoker");
this.interceptor = GrpcPreconditions.CheckNotNull(interceptor, "interceptor");
}
/// <summary>
/// Intercepts a simple blocking call with the registered interceptor.
/// </summary>
public override TResponse BlockingUnaryCall<TRequest, TResponse>(Method<TRequest, TResponse> method, string host, CallOptions options, TRequest request)
{
return interceptor.BlockingUnaryCall(
request,
new ClientInterceptorContext<TRequest, TResponse>(method, host, options),
(req, ctx) => invoker.BlockingUnaryCall(ctx.Method, ctx.Host, ctx.Options, req));
}
/// <summary>
/// Intercepts a simple asynchronous call with the registered interceptor.
/// </summary>
public override AsyncUnaryCall<TResponse> AsyncUnaryCall<TRequest, TResponse>(Method<TRequest, TResponse> method, string host, CallOptions options, TRequest request)
{
return interceptor.AsyncUnaryCall(
request,
new ClientInterceptorContext<TRequest, TResponse>(method, host, options),
(req, ctx) => invoker.AsyncUnaryCall(ctx.Method, ctx.Host, ctx.Options, req));
}
/// <summary>
/// Intercepts an asynchronous server streaming call with the registered interceptor.
/// </summary>
public override AsyncServerStreamingCall<TResponse> AsyncServerStreamingCall<TRequest, TResponse>(Method<TRequest, TResponse> method, string host, CallOptions options, TRequest request)
{
return interceptor.AsyncServerStreamingCall(
request,
new ClientInterceptorContext<TRequest, TResponse>(method, host, options),
(req, ctx) => invoker.AsyncServerStreamingCall(ctx.Method, ctx.Host, ctx.Options, req));
}
/// <summary>
/// Intercepts an asynchronous client streaming call with the registered interceptor.
/// </summary>
public override AsyncClientStreamingCall<TRequest, TResponse> AsyncClientStreamingCall<TRequest, TResponse>(Method<TRequest, TResponse> method, string host, CallOptions options)
{
return interceptor.AsyncClientStreamingCall(
new ClientInterceptorContext<TRequest, TResponse>(method, host, options),
ctx => invoker.AsyncClientStreamingCall(ctx.Method, ctx.Host, ctx.Options));
}
/// <summary>
/// Intercepts an asynchronous duplex streaming call with the registered interceptor.
/// </summary>
public override AsyncDuplexStreamingCall<TRequest, TResponse> AsyncDuplexStreamingCall<TRequest, TResponse>(Method<TRequest, TResponse> method, string host, CallOptions options)
{
return interceptor.AsyncDuplexStreamingCall(
new ClientInterceptorContext<TRequest, TResponse>(method, host, options),
ctx => invoker.AsyncDuplexStreamingCall(ctx.Method, ctx.Host, ctx.Options));
}
}
private class MetadataInterceptor : GenericInterceptor
{
readonly Func<Metadata, Metadata> interceptor;
/// <summary>
/// Creates a new instance of MetadataInterceptor given the specified interceptor function.
/// </summary>
public MetadataInterceptor(Func<Metadata, Metadata> interceptor)
{
this.interceptor = GrpcPreconditions.CheckNotNull(interceptor, "interceptor");
}
protected override ClientCallArbitrator<TRequest, TResponse> InterceptCall<TRequest, TResponse>(ClientInterceptorContext<TRequest, TResponse> context, bool clientStreaming, bool serverStreaming, TRequest request)
{
return new ClientCallArbitrator<TRequest, TResponse>
{
Context = new ClientInterceptorContext<TRequest, TResponse>(context.Method, context.Host, context.Options.WithHeaders(interceptor(context.Options.Headers)))
};
}
}
/// <summary>
/// Returns a <see cref="Grpc.Core.CallInvoker" /> instance that intercepts
/// the invoker with the given interceptor.
/// </summary>
/// <param name="invoker">The underlying invoker to intercept.</param>
/// <param name="interceptor">
/// An interceptor delegate that takes the request metadata to be sent with an outgoing call
/// and returns a <see cref="Grpc.Core.Metadata" /> instance that will replace the existing
/// invocation metadata.
/// </param>
/// <remarks>
/// Multiple interceptors can be added on top of each other by calling
/// "invoker.Intercept(a, b, c)". The order of invocation will be "a", "b", and then "c".
/// Interceptors can be later added to an existing intercepted CallInvoker, effectively
/// building a chain like "invoker.Intercept(c).Intercept(b).Intercept(a)". Note that
/// in this case, the last interceptor added will be the first to take control.
/// </remarks>
public static CallInvoker Intercept(this CallInvoker invoker, Func<Metadata, Metadata> interceptor)
{
return new InterceptingCallInvoker(invoker, new MetadataInterceptor(interceptor));
}
/// <summary>
/// Returns a <see cref="Grpc.Core.CallInvoker" /> instance that intercepts
/// the invoker with the given interceptor.
/// </summary>
/// <param name="invoker">The underlying invoker to intercept.</param>
/// <param name="interceptor">The interceptor to intercept calls to the invoker with.</param>
/// <remarks>
/// Multiple interceptors can be added on top of each other by calling
/// "invoker.Intercept(a, b, c)". The order of invocation will be "a", "b", and then "c".
/// Interceptors can be later added to an existing intercepted CallInvoker, effectively
/// building a chain like "invoker.Intercept(c).Intercept(b).Intercept(a)". Note that
/// in this case, the last interceptor added will be the first to take control.
/// </remarks>
public static CallInvoker Intercept(this CallInvoker invoker, Interceptor interceptor)
{
return new InterceptingCallInvoker(invoker, interceptor);
}
/// <summary>
/// Returns a <see cref="Grpc.Core.CallInvoker" /> instance that intercepts
/// the invoker with the given interceptors.
/// </summary>
/// <param name="invoker">The channel to intercept.</param>
/// <param name="interceptors">
/// An array of interceptors to intercept the calls to the invoker with.
/// Control is passed to the interceptors in the order specified.
/// </param>
/// <remarks>
/// Multiple interceptors can be added on top of each other by calling
/// "invoker.Intercept(a, b, c)". The order of invocation will be "a", "b", and then "c".
/// Interceptors can be later added to an existing intercepted CallInvoker, effectively
/// building a chain like "invoker.Intercept(c).Intercept(b).Intercept(a)". Note that
/// in this case, the last interceptor added will be the first to take control.
/// </remarks>
public static CallInvoker Intercept(this CallInvoker invoker, params Interceptor[] interceptors)
{
GrpcPreconditions.CheckNotNull(invoker, "invoker");
GrpcPreconditions.CheckNotNull(interceptors, "interceptors");
foreach (var interceptor in interceptors.Reverse())
{
invoker = Intercept(invoker, interceptor);
}
return invoker;
}
}
}
|
