create ProxyConfig helper

Sources/ContainerizationOCI/Client/ProxyConfig.swift

@@ -0,0 +1,19 @@
+import Foundation
+import AsyncHTTPClient
+
+public struct ProxyConfig {
+    public static func(for url: URL?) -> HTTPClient.Configuration.Proxy? {
+        let env = ProcessInfo.processInfo.environment
+        let proxyEnv = env["HTTPS_PROXY"] ?? env["HTTP_PROXY"]
+        guard let proxyEnv else {
+            return nil
+        }
+        guard let url.host != env["NO_PROXY"] else {
+            return nil
+        }
+        guard let proxyURL = URL(string: proxyEnv), let host = proxyURL.host(), let port = proxyURL.port else {
+            return nil
+        }
+        return HTTPClient.Configuration.Proxy.server(host: host, port: port)
+    }
+}

Sources/ContainerizationOCI/Client/RegistryClient.swift

@@ -109,16 +109,7 @@ public final class RegistryClient: ContentClient {
         self.retryOptions = retryOptions
         self.bufferSize = bufferSize
         var httpConfiguration = HTTPClient.Configuration()
-        let proxyConfig: HTTPClient.Configuration.Proxy? = {
-            let proxyEnv = ProcessInfo.processInfo.environment["HTTP_PROXY"]
-            guard let proxyEnv else {
-                return nil
-            }
-            guard let url = URL(string: proxyEnv), let host = url.host(), let port = url.port else {
-                return nil
-            }
-            return .server(host: host, port: port)
-        }()
+        let proxyConfig: ProxyConfig.proxy(for: components.url)
         httpConfiguration.proxy = proxyConfig
         if let logger {
             self.client = HTTPClient(eventLoopGroupProvider: .singleton, configuration: httpConfiguration, backgroundActivityLogger: logger)