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| 1 | +// Copyright (c) 2021 PassiveLogic, Inc. |
| 2 | + |
| 3 | +import Foundation |
| 4 | + |
| 5 | +/// Adds client-side [graphql-transport-ws protocol](https://github.com/enisdenjo/graphql-ws/blob/master/PROTOCOL.md) |
| 6 | +/// support, namely parsing and adding callbacks for each type of server respose. |
| 7 | +class Client { |
| 8 | + let onMessage: (String) -> Void |
| 9 | + let onConnectionAck: (ConnectionAckResponse) -> Void |
| 10 | + let onNext: (NextResponse) -> Void |
| 11 | + let onError: (ErrorResponse) -> Void |
| 12 | + let onComplete: (CompleteResponse) -> Void |
| 13 | + |
| 14 | + let decoder = JSONDecoder() |
| 15 | + |
| 16 | + /// Create a new client. |
| 17 | + /// |
| 18 | + /// - Parameters: |
| 19 | + /// - onMessage: callback run on receipt of any message |
| 20 | + /// - onConnectionAck: callback run on receipt of a `connection_ack` message |
| 21 | + /// - onNext: callback run on receipt of a `next` message |
| 22 | + /// - onError: callback run on receipt of an `error` message |
| 23 | + /// - onComplete: callback run on receipt of a `complete` message |
| 24 | + init( |
| 25 | + onMessage: @escaping (String) -> Void = { _ in () }, |
| 26 | + onConnectionAck: @escaping (ConnectionAckResponse) -> Void = { _ in () }, |
| 27 | + onNext: @escaping (NextResponse) -> Void = { _ in () }, |
| 28 | + onError: @escaping (ErrorResponse) -> Void = { _ in () }, |
| 29 | + onComplete: @escaping (CompleteResponse) -> Void = { _ in () } |
| 30 | + ) { |
| 31 | + self.onMessage = onMessage |
| 32 | + self.onConnectionAck = onConnectionAck |
| 33 | + self.onNext = onNext |
| 34 | + self.onError = onError |
| 35 | + self.onComplete = onComplete |
| 36 | + } |
| 37 | + |
| 38 | + func attach(to messenger: Messenger) { |
| 39 | + messenger.onRecieve { message in |
| 40 | + self.onMessage(message) |
| 41 | + |
| 42 | + // Detect and ignore error responses. |
| 43 | + if message.starts(with: "44") { |
| 44 | + // TODO: Determine what to do with returned error messages |
| 45 | + return |
| 46 | + } |
| 47 | + |
| 48 | + guard let json = message.data(using: .utf8) else { |
| 49 | + let error = GraphqlTransportWsError.invalidEncoding() |
| 50 | + messenger.error(error.message, code: error.code) |
| 51 | + return |
| 52 | + } |
| 53 | + |
| 54 | + let response: Response |
| 55 | + do { |
| 56 | + response = try self.decoder.decode(Response.self, from: json) |
| 57 | + } |
| 58 | + catch { |
| 59 | + let error = GraphqlTransportWsError.noType() |
| 60 | + messenger.error(error.message, code: error.code) |
| 61 | + return |
| 62 | + } |
| 63 | + |
| 64 | + switch response.type { |
| 65 | + case .connectionAck: |
| 66 | + guard let connectionAckResponse = try? self.decoder.decode(ConnectionAckResponse.self, from: json) else { |
| 67 | + let error = GraphqlTransportWsError.invalidResponseFormat(messageType: .connectionAck) |
| 68 | + messenger.error(error.message, code: error.code) |
| 69 | + return |
| 70 | + } |
| 71 | + self.onConnectionAck(connectionAckResponse) |
| 72 | + case .next: |
| 73 | + guard let nextResponse = try? self.decoder.decode(NextResponse.self, from: json) else { |
| 74 | + let error = GraphqlTransportWsError.invalidResponseFormat(messageType: .next) |
| 75 | + messenger.error(error.message, code: error.code) |
| 76 | + return |
| 77 | + } |
| 78 | + self.onNext(nextResponse) |
| 79 | + case .error: |
| 80 | + guard let errorResponse = try? self.decoder.decode(ErrorResponse.self, from: json) else { |
| 81 | + let error = GraphqlTransportWsError.invalidResponseFormat(messageType: .error) |
| 82 | + messenger.error(error.message, code: error.code) |
| 83 | + return |
| 84 | + } |
| 85 | + self.onError(errorResponse) |
| 86 | + case .complete: |
| 87 | + guard let completeResponse = try? self.decoder.decode(CompleteResponse.self, from: json) else { |
| 88 | + let error = GraphqlTransportWsError.invalidResponseFormat(messageType: .complete) |
| 89 | + messenger.error(error.message, code: error.code) |
| 90 | + return |
| 91 | + } |
| 92 | + self.onComplete(completeResponse) |
| 93 | + case .unknown: |
| 94 | + let error = GraphqlTransportWsError.invalidType() |
| 95 | + messenger.error(error.message, code: error.code) |
| 96 | + } |
| 97 | + } |
| 98 | + } |
| 99 | +} |
| 100 | + |
| 101 | +extension Messenger { |
| 102 | + /// - Parameters: |
| 103 | + /// - onMessage: callback run on receipt of any message |
| 104 | + /// - onConnectionAck: callback run on receipt of a `connection_ack` message |
| 105 | + /// - onNext: callback run on receipt of a `next` message |
| 106 | + /// - onError: callback run on receipt of an `error` message |
| 107 | + /// - onComplete: callback run on receipt of a `complete` message |
| 108 | + func graphQLTransportWSClient( |
| 109 | + onMessage: @escaping (String) -> Void = { _ in () }, |
| 110 | + onConnectionAck: @escaping (ConnectionAckResponse) -> Void = { _ in () }, |
| 111 | + onNext: @escaping (NextResponse) -> Void = { _ in () }, |
| 112 | + onError: @escaping (ErrorResponse) -> Void = { _ in () }, |
| 113 | + onComplete: @escaping (CompleteResponse) -> Void = { _ in () } |
| 114 | + ) { |
| 115 | + let decoder = JSONDecoder() |
| 116 | + |
| 117 | + self.onRecieve { message in |
| 118 | + onMessage(message) |
| 119 | + |
| 120 | + // Detect and ignore error responses. |
| 121 | + if message.starts(with: "44") { |
| 122 | + // TODO: Determine what to do with returned error messages |
| 123 | + return |
| 124 | + } |
| 125 | + |
| 126 | + guard let json = message.data(using: .utf8) else { |
| 127 | + let error = GraphqlTransportWsError.invalidEncoding() |
| 128 | + self.error(error.message, code: error.code) |
| 129 | + return |
| 130 | + } |
| 131 | + |
| 132 | + let response: Response |
| 133 | + do { |
| 134 | + response = try decoder.decode(Response.self, from: json) |
| 135 | + } |
| 136 | + catch { |
| 137 | + let error = GraphqlTransportWsError.noType() |
| 138 | + self.error(error.message, code: error.code) |
| 139 | + return |
| 140 | + } |
| 141 | + |
| 142 | + switch response.type { |
| 143 | + case .connectionAck: |
| 144 | + guard let connectionAckResponse = try? decoder.decode(ConnectionAckResponse.self, from: json) else { |
| 145 | + let error = GraphqlTransportWsError.invalidResponseFormat(messageType: .connectionAck) |
| 146 | + self.error(error.message, code: error.code) |
| 147 | + return |
| 148 | + } |
| 149 | + onConnectionAck(connectionAckResponse) |
| 150 | + case .next: |
| 151 | + guard let nextResponse = try? decoder.decode(NextResponse.self, from: json) else { |
| 152 | + let error = GraphqlTransportWsError.invalidResponseFormat(messageType: .next) |
| 153 | + self.error(error.message, code: error.code) |
| 154 | + return |
| 155 | + } |
| 156 | + onNext(nextResponse) |
| 157 | + case .error: |
| 158 | + guard let errorResponse = try? decoder.decode(ErrorResponse.self, from: json) else { |
| 159 | + let error = GraphqlTransportWsError.invalidResponseFormat(messageType: .error) |
| 160 | + self.error(error.message, code: error.code) |
| 161 | + return |
| 162 | + } |
| 163 | + onError(errorResponse) |
| 164 | + case .complete: |
| 165 | + guard let completeResponse = try? decoder.decode(CompleteResponse.self, from: json) else { |
| 166 | + let error = GraphqlTransportWsError.invalidResponseFormat(messageType: .complete) |
| 167 | + self.error(error.message, code: error.code) |
| 168 | + return |
| 169 | + } |
| 170 | + onComplete(completeResponse) |
| 171 | + case .unknown: |
| 172 | + let error = GraphqlTransportWsError.invalidType() |
| 173 | + self.error(error.message, code: error.code) |
| 174 | + } |
| 175 | + } |
| 176 | + } |
| 177 | +} |
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