HTTP Utils

The recommended way to call ServiceStack services is to use any of the C# Service Clients which have a nice DRY and typed API optimized for this use. However when doing server programming you will often need to consume 3rd Party HTTP APIs, unfortunately the built-in way to do this in .NET doesn't make for a good development experience since it makes use of WebRequest - one of the legacy classes inherited from the early .NET days. WebRequest is an example of a class that's both versatile but also suffers from exposing an out-dated and unpleasant API for your application code to bind to.

HTTP Utils - a pleasant DRY API using extension methods​

Rather than taking the normal .NET approach of wrapping WebRequest inside a suite of proxy and abstraction classes, we prefer to instead encapsulate any unnecessary boilerplate behind extension methods DRYing common access patterns behind terse, readable and chained APIs without any loss of flexibility since the underlying WebRequest remains accessible whenever it's needed.

The PocoPower project shows some good examples of what this looks like in Practice. Here's how you can retrieve a typed list of GitHub User Repos from GitHub's JSON REST API:

List<GithubRepo> repos = $"https://api.github.com/users/{user}/repos"
    .GetJsonFromUrl()
    .FromJson<List<GithubRepo>>();

Uses HttpClient in .NET 6​

As .NET's existing HttpWebRequest has been officially deprecated, the UX-friendly HTTP Utils extension methods utilize the recommended HttpClient implementation from .NET 6+ builds.

Source Compatible API​

Given .NET 6 HttpClient uses a different implementation to .NET's HttpWebRequest in previous .NET Versions it wasn't possible to enable 100% compatibility with existing code that utilize custom Request & Response filters however you can use the source compatible .With() APIs to customize a HTTP Request to support using the same source code in multi-targeted code-bases, e.g:

var response = url.GetJsonFromUrl(requestFilter:req => req.With(c => c.UserAgent = UserAgent));
var response = await url.GetJsonFromUrlAsync(requestFilter:req => req.With(c => c.UserAgent = UserAgent));

Which lets you configure a HttpRequestConfig that is equally applied to their HttpClient and HttpWebRequest implementations.

It also includes Set* methods to simplify common tasks like creating Authenticated Requests, e.g:

var json = await url.GetJsonFromUrlAsync(requestFilter: req => 
    req.With(c => {
        c.UserAgent = UserAgent;
        c.SetAuthBasic(ClientId, ClientSecret);
    }), token: token).ConfigAwait();

The full HttpRequestConfig API available in this release include:

public class HttpRequestConfig 
{
    public string? Accept { get; set; } 
    public string? UserAgent { get; set; } 
    public string? ContentType { get; set; }
    public string? Referer { get; set; }
    public string? Expect { get; set; }
    public string[]? TransferEncoding { get; set; }
    public bool? TransferEncodingChunked { get; set; }
    public NameValue? Authorization { get; set; }
    public LongRange? Range { get; set; }
    public List<NameValue> Headers { get; set; } = new();

    public void SetAuthBearer(string value) => Authorization = new("Bearer", value);
    public void SetAuthBasic(string name, string value) => 
        Authorization = new("Basic", Convert.ToBase64String(Encoding.UTF8.GetBytes(name + ":" + value)));
    public void SetRange(long from, long? to = null) => Range = new(from, to);

    public void AddHeader(string name, string value) => Headers.Add(new(name, value));
}

Inspecting Responses​

For source compatible APIs to inspect HTTP Responses you can use GetHeader() to retrieve HTTP Response Headers, GetContentLength() to retrieve the Content-Length if exists and MatchesContentType() to compare against existing MimeTypes which ignores whitespace, casing and charset suffixes, e.g:

var response = baseUrl.AppendPath("dir","sub").AddQueryParam("id", 1)
    .SendStringToUrl(method: "HEAD",
        responseFilter: res => {
            Assert.That(res.GetHeader("X-Method"), Is.EqualTo("HEAD"));
            Assert.That(res.GetHeader("X-Id"), Is.EqualTo("1"));
            Assert.That(res.MatchesContentType("video/mp4"));
            Assert.That(res.GetContentLength(), Is.EqualTo(100));
        });

Connect to HttpFactory​

The HttpClient HttpUtils use a lazy singleton for efficiency however if you're using it in a host that has an ASP.NET IOC you can configure it to make use of a HttpClient factory by using the IServiceCollection.AddHttpUtilsClient() extension method, e.g:

public class AppHost : AppHostBase, IHostingStartup
{
    public void Configure(IWebHostBuilder builder) => builder
        .ConfigureServices(services => services.AddHttpUtilsClient())
        .Configure(app => {
            if (!HasInit) 
                app.UseServiceStack(new AppHost());
        });
}

Custom HttpClient​

Alternatively you can configure it to use your own client factory with:

HttpUtils.CreateClient = () => UseMyHttpClient()

Or to utilize a custom Proxy with:

HttpUtils.HttpClientHandlerFactory = () => new() {
    UseDefaultCredentials = true,
    AutomaticDecompression = DecompressionMethods.Brotli | DecompressionMethods.Deflate | DecompressionMethods.GZip,
    Proxy = new WebProxy(proxyUrl)
};

The following Core APIs also have extension methods on HttpClient which existing HttpClient instances can make use of:

• SendStringToUrl()
• SendStringToUrlAsync()
• SendBytesToUrl()
• SendBytesToUrlAsync()
• SendStreamToUrl()
• SendStreamToUrlAsync()

HTTP Client Factory HTTP Utils​

ServiceStack registers a named IHttpClientFactory that's configured with the same defaults as the built-in HttpUtils including using Default Credentials and support for Brotli, Deflate and GZip compression.

You can access this via IHttpClientFactory.HttpUtilsClient() extension method, e.g:

public class MyServices(IHttpClientFactory clientFactory) : Service
{
    public async Task<object> Any(MyRequest request)
    {
        using HttpClient client = clientFactory.HttpUtilsClient();
        //...
    }
}

Url Extensions​

You can make use of the accompanying String Extensions to programmatically construct a url as seen in this Twitter API example:

var url = $"http://api.twitter.com/statuses/user_timeline.json?screen_name={name}";
if (sinceId != null)
    url = url.AddQueryParam("since_id", sinceId);
if (maxId != null)
    url = url.AddQueryParam("max_id", maxId);

var tweets = url.GetJsonFromUrl()
    .FromJson<List<Tweet>>();

In both these cases it uses WebRequest to make a HTTP GET request asking for the "application/json" Content-Type, that's preferably compressed with gzip or deflate encoding (if the remote web server supports it).

Alternative Content-Type​

In addition to GetJsonFromUrl there's also GetXmlFromUrl covering the 2 widely used content-types used for data containers:

List<User> users = "http://example.org/xml-rpc/users"
    .GetXmlFromUrl()
    .FromXml<List<User>>();

For any other Content-Type you can specify it with the optional accept param:

var csv = "http://example.org/users.csv"
    .GetStringFromUrl(accept:"text/csv");

Customizing the WebRequest​

Although most extension methods start on string urls, you can customize the HttpWebRequest used to make the request by specifying a requestFilter. e.g:

var json = "http://example.org/users".GetJsonFromUrl(requestFilter:webReq =>{
    webReq.Headers["X-Api-Key"] = apiKey;
});

Parsing Custom Responses​

This also works for Response Filters as well where if you need access to the Response HTTP Headers as well as the body you can add a callback for the response filter:

List<GithubRepo> repos = $"https://api.github.com/users/{user}/repos"
    .GetJsonFromUrl(responseFilter: httpRes => {
        var remaining = httpRes.Headers["X-Api-Remaining"];
    })
    .FromJson<List<GithubRepo>>();

Downloading Raw Content​

Use the GetStringFromUrl extension to download raw text:

string csv = "http://example.org/sales.csv".GetStringFromUrl();

and the GetBytesFromUrl extension to download raw bytes:

byte[] imgBytes = "http://example.org/photo.jpg".GetBytesFromUrl();

POSTing data​

Another common HTTP Request is to POST data to REST APIs. The most common way to post data to HTTP APIs is to post x-www-form-urlencoded key value pairs which you can do with:

var response = "http://example.org/login"
    .PostToUrl("Username=mythz&Password=password");

Or using a POCO Type:

var response = "http://example.org/login"
    .PostToUrl(new Login { Username="mythz", Password="password" });

An Anonymous Type:

var response = "http://example.org/login"
    .PostToUrl(new { Username="mythz", Password="password" });

Or a string Dictionary:

var login = new Dictionary<string,string> { 
    {"Username","mythz"}, {"Password","password"} };
var response = "http://example.org/login".PostToUrl(login);

Or a NameValueCollection:

var login = new NameValueCollection { 
    {"Username","mythz"}, {"Password","password"} };
var response = "http://example.org/login".PostToUrl(login.ToFormUrlEncoded());

POSTing JSON data​

Although POST'ing other Content-Types are also easily supported. An example using JSON:

Either as any serializable JSON object:

var response = "http://example.org/login"
    .PostJsonToUrl(new Login { Username="mythz", Password="password" });

Or as a raw JSON string:

var response = "http://example.org/login"
    .PostJsonToUrl(@"{""Username"":""mythz"",""Password"":""p@ssword""}");

And an example of sending any other arbitrary content types:

var response = "http://example.org/login"
  .PostStringToUrl("<User>mythz</User><Pass>p@ss</Pass>", contentType:"application/xml");

The above API's also apply to PUT or PATCH data as well by using the PutToUrl and PatchToUrl extension methods.

The same HTTP Utils extension methods for Post and Put also have Patch() equivalents.

PATCH Example​

We use the new Patch() support in Gistlyn's GitHubServices.cs to update contents of existing Gists:

var GithubApiBaseUrl = "https://api.github.com/";
var updateResponse = GithubApiBaseUrl.CombineWith("gists", gist)
    .PatchJsonToUrl(new UpdateGithubGist {
        description = request.Description,
        files = request.Files,
    }, 
    requestFilter: req => {
        req.UserAgent = "Gistlyn";
        req.Headers["Authorization"] = "token " + github.AccessTokenSecret;
    });

Creating a Proxy using HTTP Utils​

As the HTTP Utils offers a flexible API it becomes trivial to create a generic HTTP Proxy which you can implement with the ServiceStack Service below:

[Route("/proxy")]
public class Proxy : IRequiresRequestStream, IReturn<string>
{
    public string Url { get; set; }
    public Stream RequestStream { get; set; }
}

public object Any(Proxy request)
{
    if (string.IsNullOrEmpty(request.Url))
        throw new ArgumentNullException("Url");

    var hasRequestBody = base.Request.Verb.HasRequestBody();
    try
    {
        var bytes = request.Url.SendBytesToUrl(
          method: base.Request.Verb,
          requestBody: hasRequestBody ? request.RequestStream.ReadFully() : null,
          contentType: hasRequestBody ? base.Request.ContentType : null,
          accept: ((IHttpRequest)base.Request).Accept,
          requestFilter: req => req.UserAgent = "Gistlyn",
          responseFilter: res => base.Request.ResponseContentType = res.ContentType);

        return bytes;
    }
    catch (WebException webEx)
    {
        var errorResponse = (HttpWebResponse)webEx.Response;
        base.Response.StatusCode = (int)errorResponse.StatusCode;
        base.Response.StatusDescription = errorResponse.StatusDescription;
        var bytes = errorResponse.GetResponseStream().ReadFully();
        return bytes;
    }
}

Async HTTP Utils​

Many of HTTP Utils also have async versions allowing them to participate in C#'s async/await workflows. The available async APIs include:

Task<string> GetStringFromUrlAsync(...)
Task<string> PostStringToUrlAsync(...)
Task<string> PostToUrlAsync(...)
Task<string> PostJsonToUrlAsync(...)
Task<string> PostXmlToUrlAsync(...)
Task<string> PutStringToUrlAsync(...)
Task<string> PutToUrlAsync(...)
Task<string> PutJsonToUrlAsync(...)
Task<string> PutXmlToUrlAsync(...)
Task<string> DeleteFromUrlAsync(...)
Task<string> OptionsFromUrlAsync(...)
Task<string> HeadFromUrlAsync(...)
Task<string> SendStringToUrlAsync(...)

Uploading Files​

In the ServiceStack.ServiceClient.Web namespace there are more HTTP extensions available including the UploadFile extension methods to upload files using multi-part/formdata:

var httpRes = "http://example.org/upload"
    .PostFileToUrl(new FileInfo("/path/to/file.xml"), "application/xml");

Upload File from Stream​

For finer-grain control you can use the UploadFile extension method which allows you to customize the WebRequest that's used to send the File Upload HTTP Request, e.g:

var uploadFile = new FileInfo("path/to/file.csv");

var webReq = (HttpWebRequest)WebRequest.Create("http://example.org/upload");
webReq.Accept = MimeTypes.Json;
using (var stream = uploadFile.OpenRead())
{
    webReq.UploadFile(stream, uploadFile.Name, MimeTypes.GetMimeType(uploadFile.Name));
}

Exception handling​

Exception handling is another area we can DRY up using extension methods. Rather than wrapping them in our own Custom exception classes or repeating the boilerplate required to find the underlying issue on every request, we provide typed APIs over the native WebRequest Exceptions, providing typed DRY APIs to handle common HTTP Faults:

try 
{
    var response = "http://example.org/fault".GetStringFromUrl();
} 
catch (Exception ex) 
{
    var knownError = ex.IsBadRequest() 
        || ex.IsNotFound() 
        || ex.IsUnauthorized() 
        || ex.IsForbidden() 
        || ex.IsInternalServerError();

    var isAnyClientError = ex.IsAny400();
    var isAnyServerError = ex.IsAny500();

    HttpStatusCode? errorStatus = ex.GetStatus();
    string errorBody = ex.GetResponseBody(); // only available when using .NET HttpWebRequest
}

HTTP Utils are mockable​

The one disadvantage of using Extension methods is that by default they can be hard or impossible to mock which is why we've added explicit support for support for Mocking in OrmLite and now the above HTTP Util extension methods, e.g:

using (new HttpResultsFilter {
    StringResult = "mocked"
})
{
    //All return "mocked"
    "http://google.com".GetJsonFromUrl();
    "http://google.com".GetXmlFromUrl();
    "http://google.com".GetStringFromUrl(accept: "text/csv");
    "http://google.com".PostJsonToUrl(json: "{\"postdata\":1}");
}

See the HttpUtilsMockTests.cs for more examples showing how the HTTP Apis can be mocked.

HTTP API Reference​

The above description should give you a good idea of how to make use of the APIs, although for a more complete reference we'll post the full signatures here.

Most of the APIs are located in the ServiceStack.Text namespace:

string GetJsonFromUrl(this string url, Action<HttpWebRequest> requestFilter=null,
  Action<HttpWebResponse> responseFilter=null)

string GetXmlFromUrl(this string url, Action<HttpWebRequest> requestFilter=null, 
  Action<HttpWebResponse> responseFilter=null)

string GetStringFromUrl(this string url, string accept = "*/*", 
  Action<HttpWebRequest> requestFilter=null, Action<HttpWebResponse> responseFilter=null)

string PostStringToUrl(this string url, string requestBody = null,
    string contentType = null, string accept = "*/*",
    Action<HttpWebRequest> requestFilter = null, Action<HttpWebResponse> responseFilter = null)

string PostToUrl(this string url, string formData=null, string accept="*/*",
  Action<HttpWebRequest> requestFilter=null, Action<HttpWebResponse> responseFilter=null)

string PostToUrl(this string url, object formData = null, string accept="*/*",
  Action<HttpWebRequest> requestFilter=null, Action<HttpWebResponse> responseFilter=null)

string PostJsonToUrl(this string url, string json,
    Action<HttpWebRequest> requestFilter = null, Action<HttpWebResponse> responseFilter = null)

string PostJsonToUrl(this string url, object data,
    Action<HttpWebRequest> requestFilter = null, Action<HttpWebResponse> responseFilter = null)

string PostXmlToUrl(this string url, string xml,
    Action<HttpWebRequest> requestFilter = null, Action<HttpWebResponse> responseFilter = null)

string PostXmlToUrl(this string url, object data,
    Action<HttpWebRequest> requestFilter = null, Action<HttpWebResponse> responseFilter = null)

string PutStringToUrl(this string url, string requestBody = null,
    string contentType = null, string accept = "*/*",
    Action<HttpWebRequest> requestFilter = null, Action<HttpWebResponse> responseFilter = null)

string PutToUrl(this string url, string formData=null, string accept="*/*",
  Action<HttpWebRequest> requestFilter=null, Action<HttpWebResponse> responseFilter=null)

string PutToUrl(this string url, object formData = null, string accept = "*/*",
  Action<HttpWebRequest> requestFilter=null, Action<HttpWebResponse> responseFilter=null)

string PutJsonToUrl(this string url, string json,
    Action<HttpWebRequest> requestFilter = null, Action<HttpWebResponse> responseFilter = null)

string PutJsonToUrl(this string url, object data,
    Action<HttpWebRequest> requestFilter = null, Action<HttpWebResponse> responseFilter = null)

string PutXmlToUrl(this string url, string xml,
    Action<HttpWebRequest> requestFilter = null, Action<HttpWebResponse> responseFilter = null)

string PutXmlToUrl(this string url, object data,
    Action<HttpWebRequest> requestFilter = null, Action<HttpWebResponse> responseFilter = null)

string DeleteFromUrl(this string url, string accept = "*/*",
    Action<HttpWebRequest> requestFilter=null, Action<HttpWebResponse> responseFilter=null)

string OptionsFromUrl(this string url, string accept = "*/*",
    Action<HttpWebRequest> requestFilter=null, Action<HttpWebResponse> responseFilter=null)

string HeadFromUrl(this string url, string accept = "*/*",
    Action<HttpWebRequest> requestFilter=null, Action<HttpWebResponse> responseFilter=null)

string SendStringToUrl(this string url, string method = null,
    string requestBody = null, string contentType = null, string accept = "*/*",
    Action<HttpWebRequest> requestFilter=null, Action<HttpWebResponse> responseFilter=null)

byte[] GetBytesFromUrl(this string url, string accept = "*/*", 
    Action<HttpWebRequest> requestFilter=null, Action<HttpWebResponse> responseFilter=null)

byte[] PostBytesToUrl(this string url, byte[] requestBody = null, string contentType = null, 
    string accept = "*/*",
    Action<HttpWebRequest> requestFilter=null, Action<HttpWebResponse> responseFilter=null)

byte[] PutBytesToUrl(this string url, byte[] requestBody = null, string contentType = null, 
    string accept = "*/*",
    Action<HttpWebRequest> requestFilter=null, Action<HttpWebResponse> responseFilter=null)

byte[] SendBytesToUrl(this string url, string method = null,
    byte[] requestBody = null, string contentType = null, string accept = "*/*",
    Action<HttpWebRequest> requestFilter=null, Action<HttpWebResponse> responseFilter=null)

bool IsAny300(this Exception ex)
bool IsAny400(this Exception ex)
bool IsAny500(this Exception ex)
bool IsBadRequest(this Exception ex)
bool IsNotFound(this Exception ex)
bool IsUnauthorized(this Exception ex)
bool IsForbidden(this Exception ex)
bool IsInternalServerError(this Exception ex)

HttpStatusCode? GetResponseStatus(this string url)
HttpStatusCode? GetStatus(this Exception ex)
HttpStatusCode? GetStatus(this WebException webEx)
string GetResponseBody(this Exception ex)

bool HasStatus(this WebException webEx, HttpStatusCode statusCode)

Whilst some additional HTTP APIs can be found in the ServiceStack.ServiceClient.Web namespace:

HttpWebResponse GetErrorResponse(this string url)

WebResponse PostFileToUrl(this string url, FileInfo uploadFileInfo, string uploadFileMimeType,
    string accept = null, Action<HttpWebRequest> requestFilter = null)

WebResponse UploadFile(this WebRequest webRequest, FileInfo uploadFileInfo, string uploadFileMimeType)

UploadFile(this WebRequest webRequest, Stream fileStream, string fileName, string mimeType,
    string accept = null, Action<HttpWebRequest> requestFilter = null)

void UploadFile(this WebRequest webRequest, Stream fileStream, string fileName)

Which is located in the ServiceStack.Text NuGet package