wip add some decoding methods (where were these meant to be? earlier …

…on i suppose)
ably · Dec 16, 2024 · ec350e4 · ec350e4
1 parent 6fc93a9
commit ec350e4
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Showing 3 changed files with 152 additions and 2 deletions.
diff --git a/Sources/AblyChat/DefaultMessages.swift b/Sources/AblyChat/DefaultMessages.swift
@@ -77,12 +77,12 @@ internal final class DefaultMessages: Messages, EmitsDiscontinuities {
                     throw ARTErrorInfo.create(withCode: 50000, status: 500, message: "Received incoming message without clientId")
                 }
 
-                let metadata: Metadata? = if let metadataJSONObject = data["metadata"]?.objectValue {
+                let metadata: Metadata? = if let metadataJSONObject = try data.optionalObjectValueForKey("metadata") {
                     try metadataJSONObject.mapValues { try MetadataValue(jsonValue: $0) }
                 } else {
                     nil
                 }
-                let headers: Headers? = if let headersJSONObject = extras["headers"]?.objectValue {
+                let headers: Headers? = if let headersJSONObject = try extras.optionalObjectValueForKey("headers") {
                     try headersJSONObject.mapValues { try HeadersValue(jsonValue: $0) }
                 } else {
                     nil

diff --git a/Sources/AblyChat/JSONCodable.swift b/Sources/AblyChat/JSONCodable.swift
@@ -25,6 +25,9 @@ internal protocol JSONObjectDecodable: JSONDecodable {
 
 internal enum JSONValueDecodingError: Error {
     case valueIsNotObject
+    case noValueForKey(String)
+    // TODO: inform which
+    case wrongTypeForKey(String)
 }
 
 // Default implementation of `JSONDecodable` conformance for `JSONObjectDecodable`

diff --git a/Sources/AblyChat/JSONValue.swift b/Sources/AblyChat/JSONValue.swift
@@ -195,3 +195,150 @@ internal extension [String: JSONValue] {
         mapValues(\.toAblyCocoaData)
     }
 }
+
+// MARK: - Extracting values from a dictionary
+
+// TODO: this is really a helper for JSONDecodable, put there
+// TODO: Update comments
+
+internal extension [String: JSONValue] {
+    func nonOptionalObjectValueForKey(_ key: String) throws -> [String: JSONValue] {
+        guard let value = self[key] else {
+            throw JSONValueDecodingError.noValueForKey(key)
+        }
+
+        guard case let .object(objectValue) = value else {
+            throw JSONValueDecodingError.wrongTypeForKey(key)
+        }
+
+        return objectValue
+    }
+
+    func optionalObjectValueForKey(_ key: String) throws -> [String: JSONValue]? {
+        guard let value = self[key] else {
+            return nil
+        }
+
+        if case .null = value {
+            return nil
+        }
+
+        guard case let .object(objectValue) = value else {
+            throw JSONValueDecodingError.wrongTypeForKey(key)
+        }
+
+        return objectValue
+    }
+
+    func arrayValueForKey(_ key: String) throws -> [JSONValue] {
+        guard let value = self[key] else {
+            throw JSONValueDecodingError.noValueForKey(key)
+        }
+
+        guard case let .array(arrayValue) = value else {
+            throw JSONValueDecodingError.wrongTypeForKey(key)
+        }
+
+        return arrayValue
+    }
+
+    func optionalArrayValueForKey(_ key: String) throws -> [JSONValue]? {
+        guard let value = self[key] else {
+            return nil
+        }
+
+        if case .null = value {
+            return nil
+        }
+
+        guard case let .array(arrayValue) = value else {
+            throw JSONValueDecodingError.wrongTypeForKey(key)
+        }
+
+        return arrayValue
+    }
+
+    func stringValueForKey(_ key: String) throws -> String {
+        guard let value = self[key] else {
+            throw JSONValueDecodingError.noValueForKey(key)
+        }
+
+        guard case let .string(stringValue) = value else {
+            throw JSONValueDecodingError.wrongTypeForKey(key)
+        }
+
+        return stringValue
+    }
+
+    func optionalStringValueForKey(_ key: String) throws -> String? {
+        guard let value = self[key] else {
+            return nil
+        }
+
+        if case .null = value {
+            return nil
+        }
+
+        guard case let .string(stringValue) = value else {
+            throw JSONValueDecodingError.wrongTypeForKey(key)
+        }
+
+        return stringValue
+    }
+
+    func numberValueForKey(_ key: String) throws -> Double {
+        guard let value = self[key] else {
+            throw JSONValueDecodingError.noValueForKey(key)
+        }
+
+        guard case let .number(numberValue) = value else {
+            throw JSONValueDecodingError.wrongTypeForKey(key)
+        }
+
+        return numberValue
+    }
+
+    func optionalNumberValueForKey(_ key: String) throws -> Double? {
+        guard let value = self[key] else {
+            return nil
+        }
+
+        if case .null = value {
+            return nil
+        }
+
+        guard case let .number(numberValue) = value else {
+            throw JSONValueDecodingError.wrongTypeForKey(key)
+        }
+
+        return numberValue
+    }
+
+    func boolValueForKey(_ key: String) throws -> Bool {
+        guard let value = self[key] else {
+            throw JSONValueDecodingError.noValueForKey(key)
+        }
+
+        guard case let .bool(boolValue) = value else {
+            throw JSONValueDecodingError.wrongTypeForKey(key)
+        }
+
+        return boolValue
+    }
+
+    func optionalBoolValueForKey(_ key: String) throws -> Bool? {
+        guard let value = self[key] else {
+            return nil
+        }
+
+        if case .null = value {
+            return nil
+        }
+
+        guard case let .bool(boolValue) = value else {
+            throw JSONValueDecodingError.wrongTypeForKey(key)
+        }
+
+        return boolValue
+    }
+}