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| 1 | +// Copyright (c) 2021 PassiveLogic, Inc. |
| 2 | + |
| 3 | +import Foundation |
| 4 | + |
| 5 | +/// Adds client-side [graphql-ws protocol](https://github.com/apollographql/subscriptions-transport-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 onConnectionError: (ConnectionErrorResponse) -> Void |
| 10 | + let onConnectionAck: (ConnectionAckResponse) -> Void |
| 11 | + let onConnectionKeepAlive: (ConnectionKeepAliveResponse) -> Void |
| 12 | + let onData: (DataResponse) -> Void |
| 13 | + let onError: (ErrorResponse) -> Void |
| 14 | + let onComplete: (CompleteResponse) -> Void |
| 15 | + |
| 16 | + let decoder = JSONDecoder() |
| 17 | + |
| 18 | + /// Create a new client. |
| 19 | + /// |
| 20 | + /// - Parameters: |
| 21 | + /// - onMessage: callback run on receipt of any message |
| 22 | + /// - onConnectionError: callback run on receipt of a `connection_error` message |
| 23 | + /// - onConnectionAck: callback run on receipt of a `connection_ack` message |
| 24 | + /// - onData: callback run on receipt of a `data` message |
| 25 | + /// - onError: callback run on receipt of an `error` message |
| 26 | + /// - onComplete: callback run on receipt of a `complete` message |
| 27 | + init( |
| 28 | + onMessage: @escaping (String) -> Void = { _ in () }, |
| 29 | + onConnectionError: @escaping (ConnectionErrorResponse) -> Void = { _ in () }, |
| 30 | + onConnectionAck: @escaping (ConnectionAckResponse) -> Void = { _ in () }, |
| 31 | + onConnectionKeepAlive: @escaping (ConnectionKeepAliveResponse) -> Void = { _ in () }, |
| 32 | + onData: @escaping (DataResponse) -> Void = { _ in () }, |
| 33 | + onError: @escaping (ErrorResponse) -> Void = { _ in () }, |
| 34 | + onComplete: @escaping (CompleteResponse) -> Void = { _ in () } |
| 35 | + ) { |
| 36 | + self.onMessage = onMessage |
| 37 | + self.onConnectionError = onConnectionError |
| 38 | + self.onConnectionAck = onConnectionAck |
| 39 | + self.onConnectionKeepAlive = onConnectionKeepAlive |
| 40 | + self.onData = onData |
| 41 | + self.onError = onError |
| 42 | + self.onComplete = onComplete |
| 43 | + } |
| 44 | + |
| 45 | + func attach(to messenger: Messenger) { |
| 46 | + messenger.onRecieve { message in |
| 47 | + self.onMessage(message) |
| 48 | + |
| 49 | + // Detect and ignore error responses. |
| 50 | + if message.starts(with: "44") { |
| 51 | + // TODO: Determine what to do with returned error messages |
| 52 | + return |
| 53 | + } |
| 54 | + |
| 55 | + guard let json = message.data(using: .utf8) else { |
| 56 | + let error = GraphQLWSError.invalidEncoding() |
| 57 | + messenger.error(error.message, code: error.code) |
| 58 | + return |
| 59 | + } |
| 60 | + |
| 61 | + let response: Response |
| 62 | + do { |
| 63 | + response = try self.decoder.decode(Response.self, from: json) |
| 64 | + } |
| 65 | + catch { |
| 66 | + let error = GraphQLWSError.noType() |
| 67 | + messenger.error(error.message, code: error.code) |
| 68 | + return |
| 69 | + } |
| 70 | + |
| 71 | + switch response.type { |
| 72 | + case .GQL_CONNECTION_ERROR: |
| 73 | + guard let connectionErrorResponse = try? self.decoder.decode(ConnectionErrorResponse.self, from: json) else { |
| 74 | + let error = GraphQLWSError.invalidResponseFormat(messageType: .GQL_CONNECTION_ERROR) |
| 75 | + messenger.error(error.message, code: error.code) |
| 76 | + return |
| 77 | + } |
| 78 | + self.onConnectionError(connectionErrorResponse) |
| 79 | + case .GQL_CONNECTION_ACK: |
| 80 | + guard let connectionAckResponse = try? self.decoder.decode(ConnectionAckResponse.self, from: json) else { |
| 81 | + let error = GraphQLWSError.invalidResponseFormat(messageType: .GQL_CONNECTION_ACK) |
| 82 | + messenger.error(error.message, code: error.code) |
| 83 | + return |
| 84 | + } |
| 85 | + self.onConnectionAck(connectionAckResponse) |
| 86 | + case .GQL_CONNECTION_KEEP_ALIVE: |
| 87 | + guard let connectionKeepAliveResponse = try? self.decoder.decode(ConnectionKeepAliveResponse.self, from: json) else { |
| 88 | + let error = GraphQLWSError.invalidResponseFormat(messageType: .GQL_CONNECTION_KEEP_ALIVE) |
| 89 | + messenger.error(error.message, code: error.code) |
| 90 | + return |
| 91 | + } |
| 92 | + self.onConnectionKeepAlive(connectionKeepAliveResponse) |
| 93 | + case .GQL_DATA: |
| 94 | + guard let nextResponse = try? self.decoder.decode(DataResponse.self, from: json) else { |
| 95 | + let error = GraphQLWSError.invalidResponseFormat(messageType: .GQL_DATA) |
| 96 | + messenger.error(error.message, code: error.code) |
| 97 | + return |
| 98 | + } |
| 99 | + self.onData(nextResponse) |
| 100 | + case .GQL_ERROR: |
| 101 | + guard let errorResponse = try? self.decoder.decode(ErrorResponse.self, from: json) else { |
| 102 | + let error = GraphQLWSError.invalidResponseFormat(messageType: .GQL_ERROR) |
| 103 | + messenger.error(error.message, code: error.code) |
| 104 | + return |
| 105 | + } |
| 106 | + self.onError(errorResponse) |
| 107 | + case .GQL_COMPLETE: |
| 108 | + guard let completeResponse = try? self.decoder.decode(CompleteResponse.self, from: json) else { |
| 109 | + let error = GraphQLWSError.invalidResponseFormat(messageType: .GQL_COMPLETE) |
| 110 | + messenger.error(error.message, code: error.code) |
| 111 | + return |
| 112 | + } |
| 113 | + self.onComplete(completeResponse) |
| 114 | + case .unknown: |
| 115 | + let error = GraphQLWSError.invalidType() |
| 116 | + messenger.error(error.message, code: error.code) |
| 117 | + } |
| 118 | + } |
| 119 | + } |
| 120 | +} |
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