#webrequest

The Http system has a quick and easy API for making http requests within Unity. The Http instance will run the WebRequest coroutines for you so you dont have to create it per request.

Singleton

Fluent API for configuration

Success, error and network error events

Super headers

TLS version handling with http web request CSharp

Since you’re reading this, probably your C# code broke the connection to the website or a third-party API you’re hitting using the HttpWebRequest. The below code shows one such scenario where my application code broke which is running in .net framework 4.0. The company running the API upgraded their security with the TLS version upgrade to 1.2.

The exception that you’re seeing as below while…

Web request is composed of just four(yeah, it is true, just 4(for Romans it is IV)) operations. These are POST, GET, UPDATE, and DELETE.

When you write a text, or take a picture from your device and submit it to your favourite app, under the hood, the app talks with a cloud server, then cloud server save the data to its database. This is the high level picture of the how client server architect works.

Most of the application we use everyday on smart phones, are just capable of the GET request. It means they asks for the server for the data, and server give them the data they requested. It is just that. For the code snippets below, I will show how this kind of web request works.

Applications

Web request can be challenging and sometimes difficult to debug, because you have to differentiate problem source is whether your code or your request. To eliminate the possibilities of having a bad request, it is nice to check to request before put it into the code. For this aim, I use postman. You can click the link at the end of the page. You can read the comments in order to have better idea about the process.

//It is better to call this function in your view controller func webRequest(){

//It is our request. I check it with the postman app before I put the code        let urlString = "http://jsonplaceholder.typicode.com/comments/5"        //I create shared session in order to start request let session = NSURLSession.sharedSession() //This is for our session need NSURL kind of url, it looks like just parsing        let url = NSURL(string: urlString)!

       session.dataTaskWithURL(url) { (let data: NSData?, let response: NSURLResponse?, let error: NSError?) -> Void in            if let responseData = data {                do {                    let json = try NSJSONSerialization.JSONObjectWithData(responseData, options: NSJSONReadingOptions.AllowFragments)                    print(json)                }                catch {                    print("There is an error")                }            }

       }.resume()        } }

The apps & technologies used for web requests

Postman JSON HTTP NSURL

C# WebRequest POST returns Html page – how to display it in browser

I’m working with the SagePay payment gateway.

On a checkout button click I’m using the method below to postData (contains the transaction data) to SagePay who then return the result in the form of a html page.

public string SendRequest(string url, string postData) { var uri = new Uri(url); var request = WebRequest.Create(uri); var encoding = new UTF8Encoding(); var requestData =…

The System.Net namespace is a helpful library containing tools to network. In this post we'll wrap HttpWebResponse and WebResponse streaming of data for HTTP requests in a utility class HttpRemoteCall.

Nuts-n-Bolts:

public enum HttpMethods { GET = 0, POST = 1, DELETE = 2, PUT = 3 } public class HttpRemoteCall { public int TimeoutMilisecs = 5000; public HttpMethods HttpMethod = HttpMethods.GET; public string NetworkUserID; public string NetworkPassword; private HttpWebRequest _request; private readonly string _url; public HttpRemoteCall(string url) { _url = url; } public HttpRemoteCall(string url, string networkUser, string networkPin) : this(url) { NetworkUserID = networkUser; NetworkPassword = networkPin; } }

The basics of the class are the default values and network credentials required to make a web request.

Some logic to construct the WebRequest instance:

public void Create(WebHeaderCollection headers, string send) { _request = (HttpWebRequest)WebRequest.Create(_url); _request.CachePolicy = new HttpRequestCachePolicy(HttpRequestCacheLevel.BypassCache); bool hasCredentials = !string.IsNullOrEmpty(NetworkUserID); if (hasCredentials) _request.Credentials = new NetworkCredential(NetworkUserID, NetworkPassword); if (!string.IsNullOrEmpty(send) && HttpMethod == HttpMethods.GET) { //default to POST HttpMethod = HttpMethods.POST; } _request.Method = HttpMethod.ToString(); _request.ReadWriteTimeout = TimeoutMilisecs; _request.Timeout = TimeoutMilisecs; _request.Headers = headers; } public void Create() { Create(new WebHeaderCollection(), null); } public void Create(string send) { Create(new WebHeaderCollection(), send); } public void Create(WebHeaderCollection headers) { Create(headers, null); }

So far, so good. This is what a trivial implementation might look like.

HttpRemoteCall remoteWS = new HttpRemoteCall("http://google.com"); remoteWS.Create();

How To Post To A Remote Server

We need to amend the Create method to handle the writing of data. To do this we will create a postToRemote method where we will assume UTF8 encoding which is a starting point for extensions into multiple encodings which I have not found a use for myself so have not implemented.

So the core functionality will look like:

private void postToRemote(string send) { byte[] b = new byte[] {}; if (!string.IsNullOrEmpty(send)) { b = Encoding.UTF8.GetBytes(send); } _request.ContentLength = b.Length; _request.GetRequestStream().Write(b, 0, b.Length); _request.GetRequestStream().Flush(); _request.GetRequestStream().Close(); } public void Create(WebHeaderCollection headers, string send) { _request = (HttpWebRequest)WebRequest.Create(_url); bool hasCredentials = !string.IsNullOrEmpty(NetworkUserID); if (hasCredentials) _request.Credentials = new NetworkCredential(NetworkUserID, NetworkPassword); if (!string.IsNullOrEmpty(send) && HttpMethod == HttpMethods.GET) { //default to POST HttpMethod = HttpMethods.POST; } _request.Method = HttpMethod.ToString(); _request.ReadWriteTimeout = TimeoutMilisecs; _request.Timeout = TimeoutMilisecs; _request.Headers = headers; if (HttpMethod != HttpMethods.GET) { postToRemote(send); } }

This is all cool but it lacks some basic stuff like cache policy as well as content type and accept headers (as well as other header options but those are the most common ones I found re-occur in patterns for web remote calls).

So we need to define:

public class HttpRemoteCall { public enum WebRemoteCallAccepts { //[Description("text/xml")] Default = 1, //[Description("text/html, application/xhtml+xml, */*")] StdHttp = 2 } public WebRemoteCallAccepts Accepts = WebRemoteCallAccepts.StdHttp; public enum WebRemoteCallContentTypes { //[Description("text/xml;charset=\"utf-8\"")] Default = 1, //[Description("text/html;charset=\"utf-8\"")] StdHttp = 2 } public WebRemoteCallContentTypes ContentType = WebRemoteCallContentTypes.StdHttp; public int TimeoutMilisecs = 5000; public HttpMethods HttpMethod = HttpMethods.GET; public string NetworkUserID; public string NetworkPassword; private HttpWebRequest _request; private readonly string _url; public HttpRemoteCall(string url) { _url = url; } public HttpRemoteCall(string url, string networkUser, string networkPin) : this(url) { NetworkUserID = networkUser; NetworkPassword = networkPin; } public void Create() { Create(new WebHeaderCollection(), null); } public void Create(string send) { Create(new WebHeaderCollection(), send); } public void Create(WebHeaderCollection headers) { Create(headers, null); } public void Create(WebHeaderCollection headers, string send) { _request = (HttpWebRequest)WebRequest.Create(_url); _request.CachePolicy = new System.Net.CacheHttpRequestCachePolicy(System.Net.Cache.HttpRequestCacheLevel.BypassCache); bool hasCredentials = !string.IsNullOrEmpty(NetworkUserID); if (hasCredentials) _request.Credentials = new NetworkCredential(NetworkUserID, NetworkPassword); if (!string.IsNullOrEmpty(send) && HttpMethod == HttpMethods.GET) { //default to POST HttpMethod = HttpMethods.POST; } _request.Method = HttpMethod.ToString(); _request.ReadWriteTimeout = TimeoutMilisecs; _request.Timeout = TimeoutMilisecs; _request.Headers = headers; _request.ContentType = ContentType.Description(); _request.Accept = Accepts.Description(); if (HttpMethod != HttpMethods.GET) { postToRemote(send); } } //etc... } //... public static class Extensions { public static string Description(this Enum value) { string name = Enum.GetName(value.GetType(), value); System.ReflectionFieldInfo field = value.GetType().GetField(name); if (field != null) { DescriptionAttribute attr = Attribute.GetCustomAttribute(field, typeof(DescriptionAttribute)) as DescriptionAttribute; return attr != null ? attr.Description : name.AddSpaces(); } return name.AddSpaces(); } }

And we'll need to do some error handling into the posting method:

//... //part of HttpRemoteCall private void postToRemote(string send) { byte[] b = new byte[] {}; if (!string.IsNullOrEmpty(send)) { b = Encoding.UTF8.GetBytes(send); } _request.ContentLength = b.Length; try { _request.GetRequestStream().Write(b, 0, b.Length); _request.GetRequestStream().Flush(); _request.GetRequestStream().Close(); } catch (Exception e) { if (Handy.TypeTester(e.GetType(), new Type[] { typeof (ArgumentException), typeof (ArgumentNullException), typeof (ArgumentOutOfRangeException), typeof (IOException) })) { throw new NetworkException(string.Format("Request stream write fail =>{0}", e.Message), e.InnerException); } if (Handy.TypeTester(e.GetType(), new Type[] { typeof (ProtocolViolationException), typeof (InvalidOperationException), typeof (WebException) })) { throw new NetworkException(string.Format("Request send fail =>{0}", e.Message), e.InnerException); } throw; } } //... public class NetworkException : ApplicationException { public NetworkException(string message) : base(message) { } public NetworkException(string message, Exception inner) : base(message, inner) { } } //... public static class Handy { public static bool TypeTester(Type isType, IEnumerable<Type> testTypes) { return testTypes.Any(testType => testType == isType); } }

Such that the implementation will be:

HttpRemoteCall remoteWS = new HttpRemoteCall("http://google.com"); try { remoteWS.Create(); } catch (NetworkException e) { Console.WriteLine(e); }

Putting It All Together

That takes care of the request construct. Now we need to retrieve and parse the response.

We'll wrap the response data in a custom class:

public class HttpRemoteResponse { public string Raw; public int StatusCode; public string ContentType; public List<KeyValuePair<string, string>> Headers; public string CharSet; }

Then add a method to HttpRemoteCall to stream the content from the remote server and output an object of this type:

public HttpRemoteResponse Response() { HttpRemoteResponse returnResponse = new HttpRemoteResponse { Raw = null }; WebResponse webResponse = null; try { webResponse = _request.GetResponse(); } catch (WebException wex) { if (webResponse != null) webResponse.Close(); HttpWebResponse httpResponse = wex.Response as HttpWebResponse; if (httpResponse != null) returnResponse.StatusCode = (int)httpResponse.StatusCode; //infer default Internal Server fault returnResponse.StatusCode = (int)HttpStatusCode.InternalServerError; return returnResponse; } //infer default bad request returnResponse.StatusCode = (int)HttpStatusCode.BadRequest; using (HttpWebResponse response = (HttpWebResponse)webResponse) { //get actual returnResponse.StatusCode = (int)response.StatusCode; using (Stream stream = response.GetResponseStream()) { try { if (stream == null) { //infer... returnResponse.StatusCode = (int)HttpStatusCode.NoContent; } //don't handle catch; auto re-throw if error returnResponse.Raw = new StreamReader(stream).ReadToEnd(); returnResponse.ContentType = response.ContentType; returnResponse.Headers = webResponseHeaders .AllKeys .Select(headerKey => new KeyValuePair<string, string>(headerKey, webResponse.Headers[(string)headerKey])) .ToList(); returnResponse.CharSet = response.CharacterSet; } finally { webResponse.Close(); } } } return returnResponse; }

Such that the implementation becomes: