Network Programming - Ping_Email_Web.pptx

Ping Ping Class  Allow an application to determine whether a remote computer is accessible over the network.  Methods:  Send: you can pass the following parameters  Name or ip address  Data to be included in the ICMP packet payload  Packet options (TTL and Don’t...

Ping Ping Class  Allow an application to determine whether a remote computer is accessible over the network.  Methods:  Send: you can pass the following parameters  Name or ip address  Data to be included in the ICMP packet payload  Packet options (TTL and Don’t Fragment flags) using PingOptions class  Return PingReply object PingReply Class  Properties:  Status (of type IPStatus)  Buffer: gets the received buffer inside the ICMP echo reply message.  Options (of type PingOptions)  Address: of the sender  RoundtripTime: in milliseconds Assignment  Create a tool like tracert using Ping class to trace the connection to the destination Scan Alive PCs on Local Broadcast Domain  What will you do if firewall is configured to prevent echo reply from being sent?  Use arp –a command line with Process class Process process = new Process { StartInfo = new ProcessStartInfo { FileName = "cmd.exe", // Run cmd Arguments = "/c arp -a", // Command to execute RedirectStandardOutput = true, // Capture standard output RedirectStandardError = true, // Capture error output UseShellExecute = false, // Required for redirection CreateNoWindow = true // Do not show command window } }; process.Start(); string output = process.StandardOutput.ReadToEnd(); string error = process.StandardError.ReadToEnd(); process.WaitForExit(); Email Classes  SmtpClient  MailMessage  MailAddress  Attachment SmtpClient SmtpClient client = new SmtpClient(); client.Host = "mail.myserver.com"; client.Send("[email protected]", "[email protected]", "subject", "body"); Mail  MailMessage  MailAddress  MailAddressCollection:  Attachment  Configure Connection // SMTP server details string smtpServer = "smtp.gmail.com"; int smtpPort = 587; string smtpUsername = "[email protected]"; string smtpPassword = "your-email-password"; // Create an SMTP client SmtpClient smtpClient = new SmtpClient(smtpServer) { Port = smtpPort, Credentials = new NetworkCredential(smtpUsername, smtpPassword), EnableSsl = true, };  Create a Mail Message  Can be normal text or rich text (html) SmtpClient client = new SmtpClient(); client.Host = "mail.myisp.net"; MailMessage mm = new MailMessage(); mm.Sender = new MailAddress("[email protected]", "Kay"); mm.From = new MailAddress("[email protected]", "Kay"); mm.To.Add(new MailAddress("[email protected]", "Bob")); mm.CC.Add(new MailAddress("[email protected]", "Dan")); mm.Subject = "Hello!"; mm.Body = "Hi there. Here's the photo!"; mm.IsBodyHtml = false; mm.Priority = MailPriority.High; Attachment a = new Attachment("photo.jpg", System.Net.Mime.MediaTypeNames.Image.Jpeg); mm.Attachments.Add(a); client.Send(mm); How to Receive a Message  POP3  IMAP DHCP Server DHCP Server Protocol Assignment  Explain DHCP protocol and list all RFCs related to  Explain bootp Web Client Web Addresses  A URI is a specially formatted string that describes a resource on the internet or a LAN, such as a web page, file, or email address.  Examples: http://www.ietf.org, ftp://myisp/doc.txt, and mailto:[email protected]. URI URI | Uri Class  The Uri class is useful when you need to validate the format of a URI string or to split a URI into its component parts. Otherwise, you can treat a URI simply as a string  You can construct a Uri object by passing any of the following strings into its constructor:  A URI string, such as http://www.ebay.com or file://janespc/sharedpics/dolphin.jpg  An absolute path to a file on your hard disk, such as c:\myfiles\ data.xlsx or, on Unix, /tmp/myfiles/data.xlsx  A UNC path to a file on the LAN, such as \\janespc\sharedpics\ dolphin.jpg  Uri  Uri objects have read-only properties.  To modify an existing Uri, instantiate a UriBuilder object, which has writable properties and can be converted back via its Uri property. Uri info = new Uri("http://www.domain.com:80/info/"); Uri page = new Uri("http://www.domain.com/info/page.html"); Console.WriteLine(info.Host); // www.domain.com Console.WriteLine(info.Port); // 80 Console.WriteLine(page.Port); // 80 (Uri knows the default HTTP port) Console.WriteLine(info.IsBaseOf(page)); // True Uri relative = info.MakeRelativeUri(page); Console.WriteLine(relative.IsAbsoluteUri); // False Console.WriteLine(relative.ToString()); // page.html HttpClient  HttpClient class exposes a modern API for HTTP client operations, replacing the old WebClient and WebRequest/WebResponse types  HttpClient was written in response to the growth of HTTP-based web APIs and REST services HttpClient  HttpClient Example var client = new HttpClient(); string html = await client.GetStringAsync("http://linqpad.net");  To get the best performance with HttpClient, you must reuse the same instance (otherwise things such as DNS resolution can be unnecessarily repeated and sockets are held open longer than necessary).  HttpClient permits concurrent operations, so the following is legal and downloads two web pages at once: var client = new HttpClient(); var task1 = client.GetStringAsync("http://www.linqpad.net"); var task2 = client.GetStringAsync("http://www.albahari.com"); Console.WriteLine(await task1); Console.WriteLine(await task2); HttpClient  HttpClient properties:  Timeout: (request)  BaseAddress: which prefixes a URI to every request.  Other properties can be passed through HttpClientHandler object  HttpClientHandler contains properties to control cookies, automatic redirection, authentication, and so on var handler = new HttpClientHandler { UseProxy = false }; var client = new HttpClient(handler); GetAsync and Response Messages var client = new HttpClient(); // The GetAsync method also accepts a CancellationToken. HttpResponseMessage response = await client.GetAsync("http://..."); response.EnsureSuccessStatusCode(); // Enforce throwing Error for 404 string html = await response.Content.ReadAsStringAsync(); using (var fileStream = File.Create("linqpad.html")) await response.Content.CopyToAsync(fileStream); SendAsync and Request Messages  GetAsync, PostAsync, PutAsync, and DeleteAsync are all shortcuts for calling SendAsync  SendAsync is the single low-level method into which everything else feeds var client = new HttpClient(); var request = new HttpRequestMessage(HttpMethod.Get, "http://..."); HttpResponseMessage response = await client.SendAsync(request); response.EnsureSuccessStatusCode();...  Instantiating a HttpRequestMessage object means that you can customize properties of the request, such as the headers (see “Headers”) and the content itself, allowing you to upload data.  Cookies  By default, HttpClient ignores any cookies received from the server.  To accept cookies, create a CookieContainer object and assign it an HttpClientHandler: var cc = new CookieContainer(); var handler = new HttpClientHandler(); handler.CookieContainer = cc; var client = new HttpClient(handler);  To replay the received cookies in future requests, simply use the same CookieContainer object again.  Alternatively, you can start with a fresh CookieContainer and then add cookies manually, as follows: Cookie c = new Cookie("PREF", "ID=6b10df1da493a9c4:TM=1179...", "/", ".google.com"); HttpClient | REST API Methods  In a REST API, HTTP methods correspond to CRUD (Create, Read, Update, Delete) operations  HttpClient has the following methods to support working with REST API  GetAsync: retrieve data or resources from the server  PostAsync: create a new resource  PutAsync: update a resource or replace it entirely with a new version  PatchAsync: partially update a resource (modify only the fields provided)  DeleteAsync: delete a resource HttpContent  HttpContent is a base class that could be initialized with the following subclases that provides Http content based on a  String: StringContent  Byte array: ByteArrayContent  Stream: StreamContent  Container for name/value tuples encoded using application/x-www- form-urlencoded MIME type: FormUrlEncodedContent Uploading Form Data  To upload HTML form data, create and populate the FormUrlEncodedContent object. You can then either pass it into the PostAsync method or assign it to a request’s Content property string uri = "http://www.albahari.com/EchoPost.aspx"; var client = new HttpClient(); var dict = new Dictionary { { "Name", "Joe Albahari" }, { "Company", "O'Reilly" } }; var values = new FormUrlEncodedContent(dict); var response = await client.PostAsync(uri, values); response.EnsureSuccessStatusCode(); Console.WriteLine(await response.Content.ReadAsStringAsync()); Free Online REST APIs  Here are some free online REST APIs (limited calls) you can use for testing, learning, and experimenting:  JSONPlaceholder: Fake online REST API for testing and prototyping (https://jsonplaceholder.typicode.com/)  Example endpoints: https://jsonplaceholder.typicode.com/posts  OpenWeatherMap: Provides weather data for any location in the world.  REST Countries: Get information about countries (https://restcountries.com/)  IP Geolocation API: https://ipgeolocation.io/pricing.html , https://apiip.net/get-started  Others…..  PostAsync Example HttpClient client = new HttpClient(); var data = new { title = "foo #2", body = "what", userId = 7 }; string json = System.Text.Json.JsonSerializer.Serialize(data); StringContent content = new StringContent(json, Encoding.UTF8, "application/json"); var response = await client.PostAsync("https://jsonplaceholder.typicode.com/posts", content); string responseBody = await response.Content.ReadAsStringAsync(); txtPanel.Text = responseBody; Note that you can change the json string of a property by adding [JsonPropertyName(“Json_Name")] before it. Authenticating via Headers | Examples  Basic Authentication: HttpClient client = new HttpClient(); byte[] credsBytes = Encoding.UTF8.GetBytes("username:password"); string credentials = Convert.ToBase64String(credsBytes); client.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue("Basic",credentials);  Bearer Token Authentication: obtain the token from the authentication provider and then add it to the Authorization header as a Bearer token HttpClient client = new HttpClient(); client.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue("Bearer", bearerTokenValue); Assignment  Design/build a GUI tool to achieve similar tasks as of the following tools  PingSweep Tool  Tracert Tool  REST API  CRUD  Using (…)