I have a task to make a call to REST API which gives an XML output. The xml output should be deserialized into a .NET class which can be queried later. I am not sure where I am doing wrong, but the code gives an error. On debugging the code, I figured out the issue is when trying to deserialize the response stream it gives an error saying 'responsestream.Length threw an exception of type System.NotSupportedException'. Please help me to figure out this issue.
Below is my sample code.
WebRequest request = (WebRequest)WebRequest.CreateHttp(apiurl);
request.Method = "GET";
using (WebResponse response = request.GetResponse())
{
Stream responsestream = response.GetResponseStream();
XmlSerializer serializer = new XmlSerializer(typeof(List<ResponseClass>));
var apiresponse = (List<ResponseClass>)serializer.Deserialize(responsestream);
}
Related
This question already has answers here:
Deserialize JSON data with C#
(4 answers)
Closed 1 year ago.
I am a student working on a project. I am trying to use the Yahoo! Finance API as a source for my data https://www.yahoofinanceapi.com . I can use HttpWebRequests to call the API and get the "OK" code, see the code below on how I did it:
string BaseURL = "https://yfapi.net/v6/finance/quote?symbols=AAPL";
string addSymbol = "%2C";
string URL = BaseURL;
foreach (string stock in stocks)
{
URL += addSymbol + stock;
}
HttpWebRequest request = (HttpWebRequest)WebRequest.Create(URL);
request.Headers.Add("X-API-KEY", "[My API key]");
HttpWebResponse response = (HttpWebResponse)request.GetResponse();
Console.WriteLine(response.ContentType);
Console.WriteLine(response.StatusCode);
response.ContentType gives back "application/json".
response.StatusCode gives back "OK".
Since the response is a JSON I tried to parse it into a string using .ToString() but this obviously doesn't work. When I print it, it just says "System.Net.HttpWebResponse" instead of the showing the actual data in the JSON.
After that I tried to deserialize it using newtonsoft
Results result = JsonConvert.DeserializeObject<Results>(request.GetResponse().ToString());
where Results is a class I made where there is a list of stocks, Stock is also a class I made with some variables in it with the same names of variables in the JSON response.
I got a JSON response from PostMan when I tested the API, opened the response to see what kind of data it contained.
When I ran my code I got the following error message:
Newtonsoft.Json.JsonReaderException: 'Unexpected character encountered while parsing value: S. Path '', line 0, position 0.'
This was as far as I got, I tested a few other methods trying to get this working but this one worked the "best".
My biggest issue at the moment is mapping the response into a c# object.
Anything that can help me understand is appreciated :D
You're trying to serialise the HttpWebResponse object into Results, which means deserialisation won't work.
The data is still wrapped & won't be in the format of the Results object.
The GetResponseStream() method can be used to get the contents of the HTTP response as a stream, which can then be deserialised directly, in this case, using Json.NET.
Replace this section:
HttpWebResponse response = (HttpWebResponse)request.GetResponse();
Console.WriteLine(response.ContentType);
Console.WriteLine(response.StatusCode);
With this:
var serializer = new JsonSerializer();
using (var response = (HttpWebResponse)request.GetResponse())
{
var encoding = Encoding.GetEncoding(response.CharacterSet);
using var responseStream = response.GetResponseStream();
using var reader = new StreamReader(responseStream, encoding);
using (var jsonTextReader = new JsonTextReader(reader))
{
Console.WriteLine(response.ContentType);
Console.WriteLine(response.StatusCode);
Results result = serializer.Deserialize<Results>(jsonTextReader);
}
}
Alternatively, a much better solution if you're using .NET 4.5 <= would be to use HttpClient like below:
private static readonly HttpClient httpClient = new HttpClient();
...
string BaseURL = "https://yfapi.net/v6/finance/quote?symbols=AAPL";
string addSymbol = "%2C";
string URL = BaseURL;
foreach(string stock in stocks) {
URL += addSymbol + stock;
}
client.DefaultRequestHeaders.Add("X-API-KEY", "[My API key]");
var data = await httpClient.GetStringAsync(address);
Results result = JsonConvert.DeserializeObject<Results>(data);
Trying to call WebServices from C# and getting below error:
System.Net.WebException: 'The remote server returned an error: (502) Bad Gateway
Code:
WebRequest request = WebRequest.Create("https://xxxxx/cgi/webservice.pl?function=get_latest_ts_values&site_list=130105B&datasource=AT&varfrom=10.00&varto=10.00&lookback=60&format=csv");
request.Method = "GET";
WebResponse response = request.GetResponse();
using (Stream dataStream = response.GetResponseStream() )
{
StreamReader reader = new StreamReader(dataStream);
string responseFromServer = reader.ReadToEnd();
Console.WriteLine(responseFromServer);
Console.ReadLine();
}
But works fine when i use Postman or just copy url in browser and also works fine with below python code:
import requests
dataload = {}
dataurl = "https://xxxxx/cgi/webservice.pl?function=get_latest_ts_values&site_list=130105B&datasource=AT&varfrom=10.00&varto=10.00&lookback=60"
headers = {}
response = requests.request("GET", dataurl, headers=headers, data=dataload)
for dataresp in response:
print(dataresp)
What am I doing wrong with C# code?
The uri for the WebRequest has the query parameter &format=csv. Maybe this is why you are getting a 502. The Python request is missing that query parameter. Did you try the WebRequest by removing that part?
Could be incorrect content type or user agent having the wrong information. Postman could be setting these values without your knowledge. Might try in the exception seeing if there is a a response stream and read it through a streamreader to see if there is any more information you're not seeing to point you in the correct direction.
Ended up using RestSharp and it works fine. (https://www.nuget.org/packages/RestSharp)
string Uri = "https://xxxx/cgi/webservice.pl?xxxx";
var client = new RestSharp.RestClient(Uri);
client.Timeout = -1;
var request = new RestRequest(Method.GET);
IRestResponse response = client.Execute(request);
Console.WriteLine(response.Content);
I'm trying to get the order book from GDAX (link to documentation of the call) but when doing it from the c# executable I always get Error 400 - Bad request.
When taking the actual URL and pasting it into my browser, it works fine.
String URL = "https://api.gdax.com/products/BTC-USD/book?level=2";
WebRequest request = WebRequest.Create(URL);
WebResponse response = request.GetResponse();
The actual issue with your API call is , the API is expecting a user-agent string while making the request: Below is the code in working condition:
try
{
String URL = "http://api.gdax.com/products/BTC-USD/book?level=2";
HttpWebRequest request = (HttpWebRequest)WebRequest.Create(URL);
request.UserAgent = ".NET Framework Test Client";
HttpWebResponse response = (HttpWebResponse)request.GetResponse();
var encoding = ASCIIEncoding.ASCII;
using (var reader = new System.IO.StreamReader(response.GetResponseStream(), encoding))
{
string responseText = reader.ReadToEnd();
}
}
catch(WebException ex)
{
HttpWebResponse xyz = ex.Response as HttpWebResponse;
var encoding = ASCIIEncoding.ASCII;
using (var reader = new System.IO.StreamReader(xyz.GetResponseStream(), encoding))
{
string responseText = reader.ReadToEnd();
}
}
Basically ProtocolError indicates that you have received the response but there is an error related to protocol, which you can observe, when you read the response content from exception. I have added catch to handle the exception and read ex.Response (which is HttpWebResponse) and could see that the API is asking for user-agent to be suppllied while making the call. I got to see the error as "{"message":"User-Agent header is required."}"
You can ignore the code inside the exception block, I used it only to see what is the actual response message, which contains actual error details
Note: I have boxed WebRequest to HttpWebRequest to have additional http protocol related properties and most importantly "UserAgent" property which is not available with the WebRequest class.
You need to Accept the certificarte, Google for access to a https webrequest.
Like this
I'm calling an XML webservice URL from C# using standard WebRequest code:
WebRequest request = WebRequest.Create(MethodCall);
WebResponse response = request.GetResponse();
Stream stream = response.GetResponseStream();
StreamReader streamReader = new StreamReader(stream);
string xml = streamReader.ReadToEnd();
The service in question returns XML; in case of errors you often still get XML returned with detailed error information, however it also returns an HTTP error code 400.
Running the query through Chrome I can see the XML and the error code in the dev-tools but my C# code throws a .Net WebException in the GetResponse() call so I never see the detailed error information.
Is there a way I can tell .Net not to throw exception but still to report the error code, so I can inspect the returned XML?
Change WebResponse response = request.GetResponse(); to
WebResponse response;
try
{
response = request.GetResponse();
}
catch (WebException ex)
{
response = (ex.Response as WebResponse);
if (response == null)
throw;
}
This should work.
I'm new to JSON & am using VS 2013/C#. Here's the code for the request & response. Pretty straightforward, no?
Request request = new Request();
//request.hosts = ListOfURLs();
request.hosts = "www.cnn.com/www.cisco.com/www.microsoft.com/";
request.callback = "process";
request.key = "xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx";
string output = JsonConvert.SerializeObject(request);
//string test = "hosts=www.cnn.com/www.cisco.com/www.microsoft.com/&callback=process&key=xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx";
try
{
var httpWebRequest = (HttpWebRequest) WebRequest.Create("http://api.mywot.com/0.4/public_link_json2?);
httpWebRequest.ContentType = "application/json";
httpWebRequest.Method = "POST";
using (var streamWriter = new StreamWriter(httpWebRequest.GetRequestStream()))
{
string json = output;
streamWriter.Write(json);
}
var httpResponse = (HttpWebResponse) httpWebRequest.GetResponse();
using (var streamReader = new StreamReader(httpResponse.GetResponseStream()))
{
var responseText = streamReader.ReadToEnd();
}
}
catch (WebException e)
{
MessageBox.Show(e.ToString());
}
//response = true.
//no response = false
return true;
}
When I run this, I get a 405 error indicating method not allowed.
It seems to me that there are at least two possible problems here: (1) The WoT API (www.mywot.com/wiki/API) requires a GET request w/ a body, & httpWebRequest doesn't allow a GET in the httpWebRequest.Method; or (2) the serialized string isn't serialized properly.
NOTE: In the following I've had to remove the leading "http://" since I don't have enough rep to post more than 2 links.
It should look like:
api.mywot.com/0.4/public_link_json2?hosts=www.cnn.com/www.cisco.com/www.microsoft.com/&callback=process&key=xxxxxxxxxxxxxx
but instead looks like:
api.mywot.com/0.4/public_link_json2?{"hosts":"www.cnn.com/www.cisco.com/www.microsoft.com/","callback":"process","key":"xxxxxxxxxxxxxxxxxxx"}.
If I browse to:api.mywot.com/0.4/public_link_json2?hosts=www.cnn.com/www.cisco.com/www.microsoft.com/&callback=process&key=xxxxxxxxxxxxxx; I get the expected response.
If I browse to: api.mywot.com/0.4/public_link_json2?{"hosts":"www.cnn.com/www.cisco.com/www.microsoft.com/","callback":"process","key":"xxxxxxxxxxxxxxxxxxx"}; I get a 403 denied error.
If I hardcode the request & send as a GET like below:
var httpWebRequest = (HttpWebRequest) WebRequest.Create("api.mywot.com/0.4/public_link_json2? + "test"); it also works as expected.
I'd appreciate any help w/ this & hope I've made the problem clear. Thx.
Looks to me like the problem is that you are sending JSON in the URL. According to the API doc that you referenced, the API is expecting regular URL encoded parameters (not JSON), and it will return JSON to you in the body of the response:
Requests
The API consists of a number of interfaces, all of which are called using normal HTTP GET requests to api.mywot.com and return a response in XML or JSON format if successful. HTTP status codes are used for returning error information and parameters are passed using standard URL conventions. The request format is as follows:
http://api.mywot.com/version/interface?param1=value1¶m2=value2
You should not be serializing your request; you should be deserializing the response. All of your tests above bear this out.