重新想象 Windows 8 Store Apps (60) - 通信: 获取网络信息, 序列化和反序列化

/*
 * 演示如何获取网络的相关信息
 */

using System;
using System.Collections.Generic;
using Windows.Networking.Connectivity;
using Windows.UI.Xaml.Controls;
using Windows.UI.Xaml.Navigation;
using System.Linq;

namespace XamlDemo.Communication
{
    public sealed partial class NetworkInfo : Page
    {
        public NetworkInfo()
        {
            this.InitializeComponent();
        }

        protected override void OnNavigatedTo(NavigationEventArgs e)
        {
            /*
             * NetworkInformation - 用于对网络信息的访问
             */

            // 获取当前用于 Internet 连接的 ConnectionProfile 对象
            ConnectionProfile connectionProfile = NetworkInformation.GetInternetConnectionProfile();

            if (connectionProfile == null)
                return;

            // 此连接配置的名称
            lblMsg.Text = "ProfileName: " + connectionProfile.ProfileName;
            lblMsg.Text += Environment.NewLine;

            // 此连接的网络连接级别（Windows.Networking.Connectivity.NetworkConnectivityLevel 枚举）
            //     None - 无连接
            //     LocalAccess - 仅允许访问本地网络
            //     ConstrainedInternetAccess - 受限的 internet 访问
            //     InternetAccess - 本地和 internet 访问
            lblMsg.Text += "NetworkConnectivityLevel: " + connectionProfile.GetNetworkConnectivityLevel();
            lblMsg.Text += Environment.NewLine;

            // 网络状态发生变化时所触发的事件
            NetworkInformation.NetworkStatusChanged += NetworkInformation_NetworkStatusChanged;

            NetworkAdapter networkAdapter = connectionProfile.NetworkAdapter;
            if (networkAdapter != null)
            {
                lblMsg.Text += "NetworkAdapterId: " + networkAdapter.NetworkAdapterId; // 网络适配器 ID
                lblMsg.Text += Environment.NewLine;
                lblMsg.Text += "InboundMaxBitsPerSecond: " + networkAdapter.InboundMaxBitsPerSecond; // 最大入站数据传输速率（单位：bit/s）
                lblMsg.Text += Environment.NewLine;
                lblMsg.Text += "OutboundMaxBitsPerSecond: " + networkAdapter.OutboundMaxBitsPerSecond; // 最大出站数据传输速率（单位：bit/s）
                lblMsg.Text += Environment.NewLine;
                lblMsg.Text += "NetworkTypes: " + networkAdapter.NetworkItem.GetNetworkTypes(); // 网络类型
                lblMsg.Text += Environment.NewLine;
            }

            lblMsg.Text += Environment.NewLine;

            // 获取所有可用连接
            IReadOnlyList<ConnectionProfile> connectionProfiles = NetworkInformation.GetConnectionProfiles();
            foreach (ConnectionProfile cp in connectionProfiles)
            {
                lblMsg.Text += "ProfileName: " + cp.ProfileName;
                lblMsg.Text += Environment.NewLine;

                // 获取此连接的指定时间段内的本地数据的使用情况
                DataUsage dataUsage = cp.GetLocalUsage(DateTime.Now.AddHours(-1), DateTime.Now);

                lblMsg.Text += "BytesSent: " + dataUsage.BytesSent; // 已发送的字节数
                lblMsg.Text += Environment.NewLine;
                lblMsg.Text += "BytesReceived: " + dataUsage.BytesReceived; // 已收到的字节数
                lblMsg.Text += Environment.NewLine;
            }


            // 以下是一些不常用的东西
            ConnectionCost connectionCost = connectionProfile.GetConnectionCost();
            DataPlanStatus dataPlanStatus = connectionProfile.GetDataPlanStatus();
            NetworkSecuritySettings networkSecuritySettings = connectionProfile.NetworkSecuritySettings;
            IReadOnlyList<LanIdentifier> lanIdentifiers = NetworkInformation.GetLanIdentifiers();
        }

        void NetworkInformation_NetworkStatusChanged(object sender)
        {

        }
    }
}

/*
 * 用于演示序列化和反序列化的实体类
 * 
 * 通过 DataContractJsonSerializer 或 DataContractSerializer 做序列化和反序列化时，其支持 DataContract, DataMember, KnownType
 * 当然如果都不声明 DataContract, DataMember 也没问题
 */

using System;
using System.Collections.Generic;
using System.Runtime.Serialization;

namespace XamlDemo.Communication.Serializer
{
    [DataContract(Name="product")]
    public class Product
    {
        [DataMember(Name = "productId", IsRequired = true, Order = 1)]
        public int ProductId { get; set; }

        [DataMember(Name = "name", IsRequired = true, Order = 2)]
        public string Name { get; set; }

        public decimal Price { get; set; }

        [DataMember(Name = "createTime", IsRequired = true, Order = 3)]
        public DateTime CreateTime { get; set; }

        public static List<Product> GetProducts()
        {
            List<Product> products = new List<Product>();
            for (int i = 0; i < 5; i++)
            {
                products.Add(new Product
                {
                    ProductId = i,
                    Name = "name: " + i.ToString().PadLeft(4, '0'),
                    Price = i * 100,
                    CreateTime = DateTime.Now.AddDays(-i)
                });
            }

            return products;
        }
    }
}

/*
 * 演示 json 的序列化和反序列化，以及如何解析 json 字符串
 * 
 * 1、通过 DataContractJsonSerializer 做 json 的序列化和反序列化
 * 2、通过 JsonObject 和 JsonArray 解析 json 字符串
 */

using System;
using System.Collections.Generic;
using System.IO;
using System.Runtime.Serialization;
using System.Runtime.Serialization.Json;
using System.Text;
using Windows.Data.Json;
using Windows.UI.Xaml.Controls;
using Windows.UI.Xaml.Navigation;

namespace XamlDemo.Communication.Serializer
{
    public sealed partial class Json : Page
    {
        private string _jsonString = "";

        public Json()
        {
            this.InitializeComponent();
        }

        protected override void OnNavigatedTo(NavigationEventArgs e)
        {
            SerializeJson();
            DeserializeJson();
            ParseJson();
        }

        private void SerializeJson()
        {
            // 需要序列化为 json 的对象
            List<Product> products = Product.GetProducts();

            // 序列化为 json 时，定义日期类型的字符串格式
            DataContractJsonSerializerSettings settings = new DataContractJsonSerializerSettings();
            settings.DateTimeFormat = new DateTimeFormat("yyyy-MM-dd HH:mm:ss");

            // 实例化 DataContractJsonSerializer 对象，用于 json 的序列化和反序列化
            DataContractJsonSerializer serializer = new DataContractJsonSerializer(typeof(List<Product>), settings);

            using (MemoryStream ms = new MemoryStream())
            {
                // DataContractJsonSerializer.WriteObject() - 序列化
                serializer.WriteObject(ms, products);

                var bytes = ms.ToArray();
                _jsonString = Encoding.UTF8.GetString(bytes, 0, bytes.Length);

                lblMsg.Text = _jsonString;
            }
        }

        private void DeserializeJson()
        {
            // 反序列化时，定义日期类型的字符串格式
            DataContractJsonSerializerSettings settings = new DataContractJsonSerializerSettings();
            settings.DateTimeFormat = new DateTimeFormat("yyyy-MM-dd HH:mm:ss");

            // 实例化 DataContractJsonSerializer 对象，用于 json 的序列化和反序列化
            DataContractJsonSerializer serializer = new DataContractJsonSerializer(typeof(List<Product>), settings);

            using (MemoryStream ms = new MemoryStream())
            {
                var bytes = Encoding.UTF8.GetBytes(_jsonString);
                ms.Write(bytes, 0, bytes.Length);
                ms.Position = 0; // 将流的当前位置定位到起点

                // DataContractJsonSerializer.ReadObject() - 反序列化
                var result = serializer.ReadObject(ms) as List<Product>;

                lblMsg.Text += Environment.NewLine;
                lblMsg.Text += "First Product Name: " + result[0].Name;
            }
        }


        private void ParseJson()
        {
            // JsonArray - json 数组。可以通过 JsonArray.Parse() 将 json 字符串解析为 JsonArray
            // JsonObject - json 对象。可以通过 JsonObject.Parse() 将 json 字符串解析为 JsonObject

            JsonArray ja = JsonArray.Parse(_jsonString);
            JsonObject joFirst = ja[0].GetObject();
            string firstProductName = joFirst["name"].GetString();

            lblMsg.Text += Environment.NewLine;
            lblMsg.Text += "First Product Name: " + firstProductName;
        }
    }
}

/*
 * 自定义 XmlWriter，用于去掉默认生成的 xmlns
 */

using System.Xml;

namespace XamlDemo.Communication.Serializer
{
    public class MyXmlWriter : XmlWriter
    {
        private XmlWriter _writer;
        private bool _ignoreEndAttrCall = false;

        public MyXmlWriter(XmlWriter writer)
        {
            _writer = writer;
        }
        
        /*关键代码开始*/
        public override void WriteStartElement(string prefix, string localName, string ns)
        {
            if ((ns != null) && ns.StartsWith("http://schemas.datacontract.org"))
            {
                ns = null;
            }
            _writer.WriteStartElement(prefix, localName, ns);
        }

        public override void WriteStartAttribute(string prefix, string localName, string ns)
        {
            if ((ns == null) || (ns == "http://www.w3.org/2001/XMLSchema-instance"))
            {
                _ignoreEndAttrCall = true;
                return;
            }
            _writer.WriteStartAttribute(prefix, localName, ns);
        }

        public override void WriteEndAttribute()
        {
            if (_ignoreEndAttrCall)
            {
                _ignoreEndAttrCall = false;
                return;
            }
            _writer.WriteEndAttribute();
        }

        public override void WriteString(string text)
        {
            if (_ignoreEndAttrCall)
            {
                return;
            }
            _writer.WriteString(text);
        }
        /*关键代码结束*/



        #region 这部分代码保持原 XmlWriter 的逻辑不变
        public override void Flush()
        {
            _writer.Flush();
        }

        public override string LookupPrefix(string ns)
        {
            return _writer.LookupPrefix(ns);
        }

        public override void WriteBase64(byte[] buffer, int index, int count)
        {
            _writer.WriteBase64(buffer, index, count);
        }

        public override void WriteCData(string text)
        {
            _writer.WriteCData(text);
        }

        public override void WriteCharEntity(char ch)
        {
            _writer.WriteCharEntity(ch);
        }

        public override void WriteChars(char[] buffer, int index, int count)
        {
            _writer.WriteChars(buffer, index, count);
        }

        public override void WriteComment(string text)
        {
            _writer.WriteComment(text);
        }

        public override void WriteDocType(string name, string pubid, string sysid, string subset)
        {
            _writer.WriteDocType(name, pubid, sysid, subset);
        }

        public override void WriteEndDocument()
        {
            _writer.WriteEndDocument();
        }

        public override void WriteEndElement()
        {
            _writer.WriteEndElement();
        }

        public override void WriteEntityRef(string name)
        {
            _writer.WriteEntityRef(name);
        }

        public override void WriteFullEndElement()
        {
            _writer.WriteFullEndElement();
        }

        public override void WriteProcessingInstruction(string name, string text)
        {
            _writer.WriteProcessingInstruction(name, text);
        }

        public override void WriteRaw(string data)
        {
            _writer.WriteRaw(data);
        }

        public override void WriteRaw(char[] buffer, int index, int count)
        {
            _writer.WriteRaw(buffer, index, count);
        }

        public override void WriteStartDocument(bool standalone)
        {
            _writer.WriteStartDocument(standalone);
        }

        public override void WriteStartDocument()
        {
            _writer.WriteStartDocument();
        }

        public override WriteState WriteState
        {
            get { return _writer.WriteState; }
        }

        public override void WriteSurrogateCharEntity(char lowChar, char highChar)
        {
            _writer.WriteSurrogateCharEntity(lowChar, highChar);
        }

        public override void WriteWhitespace(string ws)
        {
            _writer.WriteWhitespace(ws);
        }
        #endregion
    }
}

/*
 * 演示 xml 的序列化和反序列化，以及如何解析 xml 字符串
 * 
 * 1、通过 DataContractSerializer 做 xml 的序列化和反序列化
 * 2、通过 XLinq（linq to xml）解析 xml 字符串，以及对 xml 做 crud 操作
 * 
 * 关于 xlinq 参见：http://www.cnblogs.com/webabcd/archive/2007/10/26/938122.html
 */

using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Runtime.Serialization;
using System.Text;
using System.Xml;
using System.Xml.Linq;
using Windows.UI.Xaml.Controls;
using Windows.UI.Xaml.Navigation;

namespace XamlDemo.Communication.Serializer
{
    public sealed partial class Xml : Page
    {
        private string _xmlStringWithoutXmlns = "";
        private string _xmlStringWithXmlns = "";

        public Xml()
        {
            this.InitializeComponent();
        }

        protected override void OnNavigatedTo(NavigationEventArgs e)
        {
            SerializeXml();
            DeserializeXml();
            ParseXml();
        }

        private void SerializeXml()
        {
            // 需要序列化为 xml 的对象
            List<Product> products = Product.GetProducts();

            // 实例化 DataContractSerializer 对象，用于 xml 的序列化和反序列化，可以指定根节点的名称
            DataContractSerializer serializer = new DataContractSerializer(typeof(List<Product>), "root", "");

            // 序列化，同时去掉多余的 xmlns
            using (MemoryStream ms = new MemoryStream())
            {
                // XmlWriterSettings - 用于配置 XmlWriter
                XmlWriterSettings settings = new XmlWriterSettings { Indent = true, IndentChars = "\t", NewLineChars = "\n", Encoding = Encoding.UTF8 };
                settings.OmitXmlDeclaration = true; // 是否省略掉 xml 声明

                // 通过自定义 XmlWriter（参见：MyXmlWriter.cs）的方式，来去掉全部 xml 命名空间
                XmlWriter xmlWriter = MyXmlWriter.Create(ms, settings);
                MyXmlWriter myXmlWriter = new MyXmlWriter(xmlWriter);

                // DataContractSerializer.WriteObject() - 序列化
                serializer.WriteObject(myXmlWriter, products);

                xmlWriter.Flush();
                xmlWriter.Dispose();

                var bytes = ms.ToArray();
                _xmlStringWithoutXmlns = Encoding.UTF8.GetString(bytes, 0, bytes.Length);

                /*
                 * 通过 XmlWriter 序列化的结果都具有相应编码的 preamble
                 * 比如如果序列化成 utf-8 编码的 xml 字符串，则对应的 preamble 为 3 个字节：EF(239), BB(187), BF(191)
                 * preamble 出现在字符串的头部
                 * 如果直接 WriteObject(MemoryStream, obj)，则不会出现 preamble，但是就没办法通过自定义 XmlWriter 来去掉 xmlns 了
                 */
                // 去掉 utf-8 的 preamble
                _xmlStringWithoutXmlns = TrimPreamble(_xmlStringWithoutXmlns, Encoding.UTF8);
            }

            lblMsg.Text = _xmlStringWithoutXmlns;


            // 序列化，结果不会出现 preamble，但是 xmlns 都会被保留
            using (MemoryStream ms = new MemoryStream())
            {
                serializer.WriteObject(ms, products);
                var bytes = ms.ToArray();
                _xmlStringWithXmlns = Encoding.UTF8.GetString(bytes, 0, bytes.Length);
            }
        }

        private void DeserializeXml()
        {
            // 实例化 DataContractSerializer 对象，用于 xml 的序列化和反序列化，可以指定根节点的名称
            DataContractSerializer serializer = new DataContractSerializer(typeof(List<Product>), "root", "");

            using (MemoryStream ms = new MemoryStream())
            {
                var bytes = Encoding.UTF8.GetBytes(_xmlStringWithXmlns);
                ms.Write(bytes, 0, bytes.Length);
                ms.Seek(0, SeekOrigin.Begin); // 将流的当前位置定位到起点

                // DataContractSerializer.ReadObject() - 反序列化
                var result = serializer.ReadObject(ms) as List<Product>;

                lblMsg.Text += Environment.NewLine;
                lblMsg.Text += "First Product Name: " + result[0].Name;
            }
        }

        /// <summary>
        /// 通过 xlinq 解析 xml
        /// 注意 xml 字符串不能有 preamble，否则解析失败
        /// 关于用 xlinq 对 xml 做 crud 操作，请参见：http://www.cnblogs.com/webabcd/archive/2007/10/26/938122.html
        /// </summary>
        private void ParseXml()
        {
            XDocument document = XDocument.Parse(_xmlStringWithoutXmlns);
            var products = from p in document.Root.Elements("product")
                           select new Product
                           {
                               ProductId = int.Parse(p.Element("productId").Value),
                               Name = p.Element("name").Value
                           };

            lblMsg.Text += Environment.NewLine;
            lblMsg.Text += "First Product Name: " + products.First().Name;
        }


        /// <summary>
        /// 去掉指定字符串的指定编码的 preamble
        /// </summary>
        public string TrimPreamble(string value, Encoding encoding)
        {
            if (string.IsNullOrEmpty(value))
                return value;

            var bytes = encoding.GetPreamble();
            string preamble = encoding.GetString(bytes, 0, bytes.Length);

            if (value.StartsWith(preamble))
                value = value.Remove(0, preamble.Length);

            return value;
        }
    }
}

/*
 * 演示 rss/atom 的解析
 * 
 * 注：
 * 1、AtomPub: 利用 HTTP 方法（post, get, put, delete）的用于 crud web resources 的协议，其全称为 Atom Publishing Protocol
 * 2、Windows.Web.AtomPub.AtomPubClient - 封装了对 AtomPub 协议的实现
 */

using System;
using Windows.UI.Xaml;
using Windows.UI.Xaml.Controls;
using Windows.Web.Syndication;

namespace XamlDemo.Communication.Serializer
{
    public sealed partial class RssAtom : Page
    {
        public RssAtom()
        {
            this.InitializeComponent();

            this.Loaded += Rss_Loaded;
        }

        async void Rss_Loaded(object sender, RoutedEventArgs e)
        {
            Uri rssUri = new Uri("http://feed.cnblogs.com/blog/u/18098/rss");

            // SyndicationClient - 用于解析 rss/atom 的类
            SyndicationClient client = new SyndicationClient();

            // 是否绕过缓存，即请求时是否增加头 Pragma: no-cache
            client.BypassCacheOnRetrieve = true; 
            // 设置 http 头
            client.SetRequestHeader("User-Agent", "Mozilla/5.0 (compatible; MSIE 10.0; Windows NT 6.2; WOW64; Trident/6.0)");

            lblMsg.Text = "downloading feed: " + rssUri.ToString();
            lblMsg.Text += Environment.NewLine;

            try
            {
                // 获取数据
                SyndicationFeed feed = await client.RetrieveFeedAsync(rssUri);

                ISyndicationText title = feed.Title;
                
                lblMsg.Text += "feed title: " + title.Text;
                lblMsg.Text += Environment.NewLine;

                lblMsg.Text += "items count: " + feed.Items.Count;
                lblMsg.Text += Environment.NewLine;

                foreach (SyndicationItem item in feed.Items)
                {
                    lblMsg.Text += "item title: " + item.Title.Text;
                    lblMsg.Text += Environment.NewLine;
                }
            }
            catch (Exception ex)
            {
                lblMsg.Text += Environment.NewLine;

                // 将 errCode 转换为 SyndicationErrorStatus 枚举
                SyndicationErrorStatus status = SyndicationError.GetStatus(ex.HResult);
                lblMsg.Text += status.ToString();
                lblMsg.Text += Environment.NewLine;

                lblMsg.Text += ex.ToString();
            }
        }
    }
}