I'm trying to write a simple, pass-through proxy in .NET.
I have a REST api hosted at some external domain (http://exampleapi.com),
And I want to pass through all requests sent to my application (get, post, etc). JSONP isn't an option.
So if I ask for GET localhost:1234/api/pages => GET http://exampleapi.com/pages
Likewise if I POST localhost:1234/api/pages => POST http://exampleapi.com/pages
The big problem I have, and what I can't seem to find elsewhere - is that I don't want to parse this JSON. Everything I've searched through seems to center around HttpClient, but I can't seem to figure out how to use it correctly.
Here's what I have so far:
public ContentResult Proxy()
{
// Grab the path from /api/*
var path = Request.RawUrl.ToString().Substring(4);
var target = new UriBuilder("http", "exampleapi.com", 25001);
var method = Request.HttpMethod;
var client = new HttpClient();
client.BaseAddress = target.Uri;
// Needs to get filled with response.
string content;
HttpResponseMessage response;
switch (method)
{
case "POST":
case "PUT":
StreamReader reader = new StreamReader(Request.InputStream);
var jsonInput = reader.ReadToEnd();
// Totally lost here.
client.PostAsync(path, jsonInput);
break;
case "DELETE":
client.DeleteAsync(path);
break;
case "GET":
default:
// need to capture client data
client.GetAsync(path);
break;
}
return Content(content, "application/json");
}
You'll need to create a HTTP Server, receive the request, then your code will pull the information out of that request, and generate a new request to the new server, receive the response, and then send the response back to the original client.
Client -> C# Server -> Rest API server
Here's a sample HTTP Server that is open source. https://github.com/kayakhttp/kayak
Related
I need guidance on how I can create a POST request to a web API exposed #http://server:8100/api/SoftwareProductBuild' this API takes an XML as input, let's assume the XML is in variable XMLcontent
I have done this python as follows, how to convert to C#?
import requests
with open("PRE_COMMIT_LA.UM.5.8_524f7fef-5b37-11e7-b4ee-f0921c133f10.xml") as f:
body = f.read()
headers = {'Content-Type': 'application/xml'}
response = requests.post(
'http://ctdsapi1:8100/api/SoftwareProductBuild', data=body, headers=headers)
print "Printing DEV Pool Response\n"
print response
print "Done...Printing Dev Pool Response\n"
print response.ok
print response.content
Something like the following should get you most of the way there. Most applicable is the PostAsXmlAsync method.
// In whatever async method
// Assuming actual file? Add applicable checks as well.
var xml = File.ReadAllText(fullPath + "PRE_COMMIT_LA.UM.5.8_524f7fef-5b37-11e7-b4ee-f0921c133f10.xml");
using (var client = new System.Net.Http.HttpClient())
{
var response = await client.PostAsXmlAsync("http://ctdsapi1:8100/api/SoftwareProductBuild", xml);
if (!response.IsSuccessStatusCode)
{
throw new InvalidUriException("Some error with details."));
}
Console.WriteLine("Printing DEV Pool Response\n");
...etc.
}
I have tried to create a simple console application.
We have a call system from 8x8 that provide a web streaming API but their documentation is very limited and nothing in C#.
The api service streams call statuses in near real time and I would like to get that 'stream' and be able to read and process it in realtime if possible. The response or Content Type is 'text/html'. But the actual body of the response can be declared as json - sample below:
{"Interaction":{"attachedData":{"attachedDatum":[{"attachedDataKey":"#pri","attachedDataValue":100},{"attachedDataKey":"callingName","attachedDataValue":999999999999},{"attachedDataKey":"cha","attachedDataValue":99999999999},{"attachedDataKey":"cnt","attachedDataValue":0},{"attachedDataKey":"con","attachedDataValue":0},{"attachedDataKey":"med","attachedDataValue":"T"},{"attachedDataKey":"pho","attachedDataValue":9999999999},{"attachedDataKey":"phoneNum","attachedDataValue":9999999999},{"attachedDataKey":"tok","attachedDataValue":999999999}]},"event":"InteractionCreated","inboundChannelid":9999999999,"interactionEventTS":9999999,"interactionGUID":"int-15b875d0da2-DJOJkDhDsrh3AIaFP8VkICv9t-phone-01-testist","resourceType":0}}
I have seen several posts concerning httpClient and the GetAsync methods but none of these appear to work as they appear to be for calls when a response is made, not something that constantly has a response.
Using fiddler for the call it does not appear to close so the stream is constantly running, so fiddler does not display any data until a separate user or instance connects.
When I use a browser the content is 'streamed' to the page and updates automatically and shows all the content (as above).
The api contains authentication so when another client connects and retrieves data the connected client closes and finally I am able to see the data that was gathering.
This is the code so and does return the big stream when another client connects but ideally I want a real time response and appears to just get stuck in the GETASYNC method:
var response = await client.GetAsync(address, HttpCompletionOption.ResponseHeadersRead);
if (response.IsSuccessStatusCode)
{
var responseContent = response.Content;
string responseString = await responseContent.ReadAsStringAsync();
Console.WriteLine(responseString);
}
Hopefully that's enough information for one of you clever people to help me in my predicament.
I was also having an issue consuming their streaming API and the examples I found that worked with the Twitter and CouchBase streaming API's did not work with 8x8. Both Twitter and CouchBase send line terminators in their pushes so the solution relied on ReadLine to pull in the feed. Since 8x8 does not send terminators you'll need to use ReadBlock or better ReadBlockAsync.
The following code shows how to connect using credentials and consume their feed:
private static async Task StreamAsync(string url, string username, string password)
{
var handler = new HttpClientHandler()
{
Credentials = new NetworkCredential {UserName = username, Password = password},
PreAuthenticate = true
};
// Client can also be singleton
using (var client = new HttpClient(handler))
{
client.Timeout = TimeSpan.FromMilliseconds(Timeout.Infinite);
var request = new HttpRequestMessage(HttpMethod.Get, url);
request.Headers.Connection.Add("keep-alive");
using (var response = await client.SendAsync(
request,
HttpCompletionOption.ResponseHeadersRead))
{
using (var body = await response.Content.ReadAsStreamAsync())
{
using (var reader = new StreamReader(body))
{
while (!reader.EndOfStream)
{
var buffer = new char[1024];
await reader.ReadBlockAsync(buffer, 0, buffer.Length);
Console.WriteLine(new string(buffer));
}
}
}
}
}
}
I am testing a REST API post, and it works well when I try it on Postman. However, in some scenario (related to the posting XML data) if I post with HttpClient API, I would receive the following error:
Unable to read data from the transport connection: An existing connection was forcibly closed by the remote host.
But the same XML content works fine on Postman with status OK and proper response.
What is the differences between using the C# HttpClient API and the postman testing? How can I configure my API call to match with the behavior on postman?
Here I attached the source code, and the Postman screenshot
public void createLoan()
{
string baseCreateLoanUrl = #"https://serverhost/create?key=";
var strUCDExport = XDocument.Load(#"C:\CreateLoan_testcase.xml");
using (var client = new HttpClient())
{
var content = new StringContent(strUCDExport.ToString(), Encoding.UTF8, Mediatype);
string createLoanApi = string.Concat(baseCreateLoanUrl, APIKey);
try
{
var response = client.PostAsync(createLoanApi, content).Result;
}
catch (Exception ex)
{
MessageBox.Show("Error Happened here...");
throw;
}
if (response.IsSuccessStatusCode)
{
// Access variables from the returned JSON object
string responseString = response.Content.ReadAsStringAsync().Result;
JObject jObj = JObject.Parse(responseString);
if (jObj.SelectToken("failure") == null)
{
// First get the authToken
string LoanID = jObj["loanStatus"]["id"].ToString();
MessageBox.Show("Loan ID: " + LoanID);
}
else
{
string getTokenErrorMsg = string.Empty;
JArray errorOjbs = (JArray) jObj["failure"]["errors"];
foreach (var errorObj in errorOjbs)
{
getTokenErrorMsg += errorObj["message"].ToString() + Environment.NewLine;
}
getTokenErrorMsg.Dump();
}
}
}
Thanks for Nard's comment, after comparing the header, I found the issue my client header has this:
Expect: 100-continue
While postman doesn't has.
Once I removed this by using the ServicePointManager:
ServicePointManager.Expect100Continue = false;
Everything seems fine now. Thanks all the input!
My gut tells me it's something simple. First, we know the API works, so I'm thinking it's down to how you are using the HttpClient.
First things first, try as suggested by this SO answer, creating it as a singleton and drop the using statement altogether since the consensus is that HttpClient doesn't need to be disposed:
private static readonly HttpClient HttpClient = new HttpClient();
I would think it would be either there or an issue with your content encoding line that is causing issues with the API. Is there something you are missing that it doesn't like, I bet there is a difference in the requests in Postman vs here. Maybe try sending it as JSON ala:
var json = JsonConvert.SerializeObject(strUCDExport.ToString());
var content = new StringContent(json, Encoding.UTF8, Mediatype);
Maybe the header from Postman vs yours will show something missing, I think the real answer will be there. Have fiddler running in the background, send it via Postman, check it, then run your code and recheck. Pay close attention to all the attribute tags on the header from Postman, the API works so something is missing. Fiddler will tell you.
I was struggling with this for 2 days when I stumbled over Fiddler which lets you record the traffic to the service. After comparing the calls I saw that I had missed a header in my code.
I'am trying to pass values from a controller to another controller in another domain. I'am adding data to a NameValueCollection and pass it to another controller [httppost] method and receiving data there mapped to a Model same as i passed from.
Currently i'am running it locally by opening two instance of VS simultaneously. When the both VS is opened the values are passed correctly and the information is written to db correctly and i receive a response like "{byte[0]}". Now when i try stopping the destination controller Project and try to submit data then it wont work but still i get the same response as "{byte[0]}". Can somebody please help me how to return the response command in this scenario. Is there a way a understand the UploadValues are completed or not completed.
.........
.........
NameValueCollection resumeDetails = new NameValueCollection();
resumeDetails.Add("FirstName", "KRIZTE");
byte[] res = this.Post(ConfigurationManager.AppSettings["RedirectionUrl"].ToString(), resumeDetails);
return View("Index");
}
public byte[] Post(string uri, NameValueCollection resumeDetails)
{
byte[] response = null;
WebClient client = new WebClient();
response = client.UploadValues(uri, resumeDetails);
return response;
}
You should not use the WebClient because of problems like this.
Microsoft implemented HttpClient class as a newer API and it has these benefits:
HttpClient is the newer of the APIs and it has the benefits of
has a good async programming model
1- being worked on by Henrik F Nielson who is basically one of the inventors of HTTP, and he designed the API so it is easy for you to follow the HTTP standard, e.g. generating standards-compliant headers
2- is in the .Net framework 4.5, so it has some guaranteed level of support for the forseeable future
3- also has the xcopyable/portable-framework version of the library if you want to use it on other platforms - .Net 4.0, Windows Phone etc.
so I'm gonna show you an example of using HttpClient:
var uri = "http://google.com";
var client = new HttpClient();
try
{
var values = new List<KeyValuePair<string, string>>();
// add values to data for post
values.Add(new KeyValuePair<string, string>("FirstName", "KRITZTE"));
FormUrlEncodedContent content = new FormUrlEncodedContent(values);
// Post data
var result = await client.PostAsync(uri, content);
// Access content as stream which you can read into some string
Console.WriteLine(result.Content);
// Access the result status code
Console.WriteLine(result.StatusCode);
}
catch(AggregateException ex)
{
// get all possible exceptions which are thrown
foreach (var item in ex.Flatten().InnerExceptions)
{
Console.WriteLine(item.Message);
}
}
I'm trying to make an application for Windows which acts like a server for a mobile application (PhoneGap). This application is like a remote for the server application, it invokes methods in which their turn do things.
After long searching and trying to see which components can work together I found OWIN and Web API. So I'm trying to implement this into my application, but I cannot seem to grasp how I can POST a string to invoke methods.
My thought of process is that I POST a string to the server, which it reads and with a switch statement to check the value of the string I know which method to invoke. Very simple, straightforward (not faulty proof probably), but it's a start.
But I cannot seem to get it to work. Here is my controller:
public void Post([FromBody]string value)
{
switch(value)
{
case("buttonOne"):
{
mainClass.pressButtonOne();
break;
}
}
}
I'm using HttpClient to emulate the client on the host pc:
HttpClient client = new HttpClient();
client.BaseAddress = new Uri("http://localhost:6740");
var content = "buttonOne";
var result = client.PostAsync("api/values", content).Result;
string resultContent = result.Content.ReadAsStringAsync().Result;
Console.WriteLine(resultContent);
But this is getting errors, the string isn't a valid HttpContent. But it's always asking for a pair instead of single.
When making POST requests the post content should be of type HttpContent or one of its derived types.
var content = new FormUrlEncodedContent(new Dictionary<string, string> {
{"value" , "buttonOne"} })