I would like to ask if it is possible for a created ASP.NET Web API (written in C#) to post to an external API?
If it is possible, please share sample code that can post to an url with adding headers and receive a callback from the external API.
A simple way to make HTTP-Request out of a .NET-Application is the System.Net.Http.HttpClient (MSDN). An example usage would look something like this:
// Should be a static readonly field/property, wich is only instanciated once
var client = new HttpClient();
var requestData = new Dictionary<string, string>
{
{ "field1", "Some data of the field" },
{ "field2", "Even more data" }
};
var request = new HttpRequestMessage() {
RequestUri = new Uri("https://domain.top/route"),
Method = HttpMethod.Post,
Content = new FormUrlEncodedContent(requestData)
};
request.Headers // Add or modify headers
var response = await client.SendAsync(request);
// To read the response as string
var responseString = await response.Content.ReadAsStringAsync();
// To read the response as json
var responseJson = await response.Content.ReadAsAsync<ResponseObject>();
Essentially you need use an instance of HttpClient to send an HttpRequestMessage to an endpoint.
Here is an example to post some jsonData to someEndPointUrl:
var client = new HttpClient();
var request = new HttpRequestMessage(HttpMethod.Post, someEndPointUrl);
request.Headers.Accept.Clear();
request.Headers.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));
request.Headers.Authorization = new AuthenticationHeaderValue("Bearer", token);
request.Content = new StringContent(jsonData, Encoding.UTF8, "application/json");
var response = await client.SendAsync(request, CancellationToken.None);
var str = await response.Content.ReadAsStringAsync();
if (response.StatusCode == HttpStatusCode.OK)
{
// handle your response
}
else
{
// or failed response ?
}
Related
I'm fairly new to use HTTPClient and sending REST requests to APIs, I'm currently practicing multipart upload using this Google Drive API endpoint:
POST https://www.googleapis.com/upload/drive/v3/files?uploadType=multipart
There's an instruction that states there to split the request body into two parts, I tried to recreate this but was unable to do so.
https://developers.google.com/drive/api/guides/manage-uploads#multipart
Here's my current code:
async void UploadFile(StorageFile fileName)
{
using (HttpClient client = new HttpClient())
{
// Opens files and convert it to stream
var resultStream = await fileName.OpenReadAsync();
var fileStreamContent = new StreamContent(resultStream.AsStream());
// Create file MetaData
var fileMetaData = JsonConvert.SerializeObject(
new { name = fileName.Name, mimetype = fileName.ContentType });
// Create POST request
var requestMessage = new HttpRequestMessage(HttpMethod.Post, uploadFileEndpoint);
requestMessage.Headers.Authorization = new AuthenticationHeaderValue(tokenType, accessToken);
// Add request body
requestMessage.Content = new StringContent(fileMetaData, Encoding.UTF8, "application/json");
requestMessage.Content.Headers.ContentType = new MediaTypeHeaderValue("multipart/related");
var response = await client.SendAsync(requestMessage);
string responseString = await response.Content.ReadAsStringAsync();
output(responseString);
}
}
Any help would be greatly appreciated, thank you!
According to the documentation on Perform a multipart upload (HTTP tab), you need the MultipartFormDataContent as suggested by #Jeremy.
There are a few things needed to perform/migrate:
Add AuthenticationHeaderValue into client.DefaultRequestHeaders.Authorization.
Create a StreamContent instance, fileStreamContent (which you have done) and specify its Headers.ContentType.
Create a StringContent instance, stringContent (which you have done).
Append both StreamContent and StringContent into the MultipartFormDataContent instance, formData.
Specify the formData's Headers.ContentType as requested in API docs.
Post the formData with await client.PostAsync(/* API Url */, formData);
using (HttpClient client = new HttpClient())
{
client.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue(tokenType, accessToken);
// Opens files and convert it to stream
var resultStream = await fileName.OpenReadAsync();
var fileStreamContent = new StreamContent(resultStream.AsStream());
fileStreamContent.Headers.ContentType = new MediaTypeHeaderValue(fileName.ContentType);
// Create file MetaData
var fileMetaData = JsonConvert.SerializeObject(new { name = fileName.Name, mimetype = fileName.ContentType });
var stringContent = new StringContent(fileMetaData, Encoding.UTF8, "application/json");
// Create POST request
MultipartFormDataContent formData = new MultipartFormDataContent();
formData.Add(stringContent, "metadata");
formData.Add(fileStreamContent, "media");
formData.Headers.ContentType = new MediaTypeHeaderValue("multipart/related");
var response = await client.PostAsync(uploadFileEndpoint, formData);
string responseString = await response.Content.ReadAsStringAsync();
}
I want to post my parameter with HttpClient .
what is the Content in httpclient request body? I wrote it int the body part and when I run the project I get Error.
my code is:
string baseAddress = "https://WebServiceAddress";
Client.DefaultRequestHeaders.Authorization = new System.Net.Http.Headers.AuthenticationHeaderValue("Bearer", token);
HttpRequestMessage bodyRequest = new HttpRequestMessage(HttpMethod.Post, baseAddress)
bodyRequest.Content = new StringContent(JsonConvert.SerializeObject(Prescriptionrequest), Encoding.UTF8, "application/json");
var responseApi = Client.PostAsync(baseAddress, bodyRequest.Content, new System.Threading.CancellationToken(false));
what should be the format of bodyRequest.Content?
Use this code:
HttpClient client = new HttpClient();
var dictionary = new Dictionary<string, string>
{
{ "parameter0", "value0" },
{ "parameter1", "value1" }
};
var content = new FormUrlEncodedContent(dictionary);
var response = await client.PostAsync("https://WebServiceAddress", content);
var responseString = await response.Content.ReadAsStringAsync();
How do I pass request content in the HttpClient.GetAsync method? I need to fetch data depending upon request content.
[HttpGet]
public async Task<HttpResponseMessage> QuickSearch()
{
try
{
using (HttpClient client = new HttpClient())
{
client.DefaultRequestHeaders.Accept.Clear();
HttpResponseMessage response =await client.GetAsync("http://localhost:8080/document/quicksearch");
if (response.IsSuccessStatusCode)
{
Console.Write("Success");
}
If you are using .NET Core, the standard HttpClient can do this out-of-the-box. For example, to send a GET request with a JSON body:
HttpClient client = ...
...
var request = new HttpRequestMessage
{
Method = HttpMethod.Get,
RequestUri = new Uri("some url"),
Content = new StringContent("some json", Encoding.UTF8, ContentType.Json),
};
var response = await client.SendAsync(request).ConfigureAwait(false);
response.EnsureSuccessStatusCode();
var responseBody = await response.Content.ReadAsStringAsync().ConfigureAwait(false);
If you want to send content, then you need to send it as query string (According to your API route)
HttpResponseMessage response =await client.GetAsync("http://localhost:8080/document/quicksearch/paramname=<dynamicName>¶mValue=<dynamicValue>");
And in API check for "paramName" and "paramValue"
this works for me:
using (var httpClient = new HttpClient())
{
var request = new HttpRequestMessage
{
Method = HttpMethod.Get,
RequestUri = new Uri("your url"),
Content = new StringContent("your json", Encoding.UTF8, ContentType.Json),
};
using (var response = await httpClient.SendAsync(request))
{
string apiResponse = await response.Content.ReadAsStringAsync();
}
}
EDITED:
This is minor different then #SonaliJain answer above:
MediaTypeNames.Application.Json instead of ContentType.Json
I'm assuming that your "request content" would be POST data, no?
If you're sending it using the standard form content way of doing it, you would first have to build the content:
var content = new FormUrlEncodedContent(new[]
{
new KeyValuePair<string, string>("username", "theperplexedone"),
new KeyValuePair<string, string>("password", "mypassword123"),
});
And then submit it using PostAsync instead:
var response = await client.PostAsync("http://localhost:8080/document/quicksearch", content);
Hi all thank you for your comments, i got the solution
[HttpGet]
public async Task<HttpResponseMessage> QuickSearch(HttpRequestMessage Query)
{
Debugger.Launch();
try
{
using (HttpClient client = new HttpClient())
{
client.DefaultRequestHeaders.Accept.Clear();
Console.WriteLine(Query);
HttpResponseMessage response = await client.GetAsync("http://localhost:8080/document/quicksearch/"+ Query.RequestUri.Query);
if (response.IsSuccessStatusCode)
{
Console.Write("Success");
}
else
{
Console.Write("Failure");
}
return response;
}
}
catch (Exception e)
{
throw e;
}
I am trying to call Rest API with content and headers in c#. Actually I am trying to convert to c# from Python code which is:
import requests
url = 'http://url.../token'
payload = 'grant_type=password&username=username&password=password'
headers = {
'Content-Type': 'application/x-www-form-urlencoded'
}
response = requests.request('POST', url, headers = headers, data = payload, allow_redirects=False)
print(response.text)
So far I am trying with:
HttpClient client = new HttpClient();
client.BaseAddress = new Uri(Url);
var tmp = new HttpRequestMessage
{
Method = HttpMethod.Post,
Content =
{
}
};
var result = client.PostAsync(Url, tmp.Content).Result;
}
I have no idea how to put from Python code Headers (Content-Type) and additional string (payload).
If you use RestSharp, you should be able to call your service with the following code snipped
var client = new RestClient("http://url.../token");
var request = new RestRequest(Method.POST);
request.AddHeader("content-type", "application/x-www-form-urlencoded");
request.AddParameter("application/x-www-form-urlencoded", "grant_type=password&username=username&password=password", ParameterType.RequestBody);
IRestResponse response = client.Execute(request);
var result = response.Content;
I based my answer on the anwser of this answer.
Here a sample I use in one of my apps:
_client = new HttpClient { BaseAddress = new Uri(ConfigManager.Api.BaseUrl),
Timeout = new TimeSpan(0, 0, 0, 0, -1) };
_client.DefaultRequestHeaders.Accept.Clear();
_client.DefaultRequestHeaders.Accept.Add(
new MediaTypeWithQualityHeaderValue("application/json"));
_client.DefaultRequestHeaders.Add("Bearer", "some token goes here");
using System.Net.Http;
var content = new StringContent("grant_type=password&username=username&password=password");
content.Headers.Add("Content-Type", "application/x-www-form-urlencoded");
client.PostAsync(Url, content);
Or use FormUrlEncodedContent without set header
var data = new Dictionary<string, string>
{
{"grant_type", "password"},
{"username", "username"},
{"password", "password"}
};
var content = new FormUrlEncodedContent(data);
client.PostAsync(Url, content);
If you write UWP application, use HttpStringContent or HttpFormUrlEncodedContent instead in Windows.Web.Http.dll.
using Windows.Web.Http;
var content = new HttpStringContent("grant_type=password&username=username&password=password");
content.Headers.Add("Content-Type", "application/x-www-form-urlencoded");
client.PostAsync(Url, content);
var data = new Dictionary<string, string>
{
{"grant_type", "password"},
{"username", "username"},
{"password", "password"}
};
var content = new FormUrlEncodedContent(data);
client.PostAsync(Url, content);
When I use HttpClient class to send a POST request to an API URL, it modifies the URL that I've passed to it. For example, when I use the main API URL the RequestUri is incorrect and I receive the not found response. This problem happens when I use api word in the URL !!
Concept:
The Incorrect, modified URL:
Url: https://sandbox-api.alopeyk.com/api/v2/order
Request Url: https://sandbox-api.alopeyk.com
The Correct, and expected URL (This is the one I specify)
Url: https://google.com/api/v2/order
Request Url: https://google.com/api/v2/order
Code:
public async Task<CreateOrderResponse> CreateOrderAsync(CreateOrderRequest request)
{
var endPoint = EndPointFactory<CreateOrderResponse>.Build(HttpMethod.Post);
var jsonString = JsonConvert.SerializeObject(request);
var url = new Uri("https://sandbox-api.alopeyk.com");
var encodedFrom = new StringContent(jsonString);
var httpClient = endPoint.GetHttpClient(url);
var httpResponse = await httpClient.PostAsync("api/v2/orders", encodedFrom).ConfigureAwait(false);
// when use api it's https://sandbox-api.alopeyk.com it should be https://sandbox-api.alopeyk.com/api/v2/orders
// when use other host name for example it's correct
var requesturl = httpResponse.RequestMessage.RequestUri;
return await httpResponse.Content.ReadAsAsync<CreateOrderResponse>().ConfigureAwait(false);
}
// in the EndPoint class
public HttpClient GetHttpClient(Uri url)
{
return new Http.HttpClientFactory().GetOrCreate(Url, Headers);
}
If you want to see HttpClientFactory it's here.
The HttpClient have a problem with my main hostname that it's https://sandbox-api.alopeyk.com
Your Uri must end with a slash like this:
var url = new Uri("https://sandbox-api.alopeyk.com/");
That's a rather silly restriction of HttpClient.
Try this code:
HttpClient client = new HttpClient();
client.BaseAddress = new Uri("https://sandbox-api.alopeyk.com");
HttpResponseMessage response = client.PostAsync("api/v2/orders", new StringContent(jsonString, Encoding.UTF8, "text/json")).Result;
if (response.IsSuccessStatusCode)
{
// Parse the response body. Blocking!
var responseData = response.Content.ReadAsStringAsync().Result;
}
You can try with this code
HttpResponseMessage response = null;
using (var client = new HttpClient())
{
using (var request = new HttpRequestMessage(HttpMethod.Post,"https://sandbox-api.alopeyk.com/api/v2/orders"))
{
request.Headers.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));
request.Headers.Authorization = new AuthenticationHeaderValue("Bearer", /*token herer*/);
var data = new StringContent(JsonConvert.SerializeObject(request, Encoding.UTF8, "application/json"));
request.Content = data;
response = await client.SendAsync(request);
}
}