I'm trying to send a push notification though Pushover API with attached image using C# .NET. The following code returns a json formatted error "message cannot be blank". But the message variable is not empty. Since SSL is outdated I tried using TLS 1.2 explicitly. The same error appears without the image parameter.
public async Task PushImage(string title, string message, Stream image, string userKey, string appKey)
{
// This does not work - error "message cannot be blank"
using (HttpClient httpClient = new HttpClient())
{
//specify to use TLS 1.2 as default connection
ServicePointManager.SecurityProtocol = SecurityProtocolType.Tls12;
MultipartFormDataContent form = new MultipartFormDataContent();
form.Add(new StringContent(appKey), "token");
form.Add(new StringContent(userKey), "user");
form.Add(new StringContent(message), "message");
var imageParameter = new StreamContent(image);
imageParameter.Headers.ContentType = MediaTypeHeaderValue.Parse("image/png");
form.Add(imageParameter, "attachment", "image.png");
// Remove content type that is not in the docs
foreach (var param in form)
param.Headers.ContentType = null;
HttpResponseMessage responseMessage = await httpClient.PostAsync(BaseApiUrl, form);
if (responseMessage.IsSuccessStatusCode)
return;
string contentText = responseMessage.Content.ReadAsStringAsync().Result;
var response = JsonConvert.DeserializeObject<PushResponse>(contentText);
throw new ApplicationException(
$"Push image request failed with status {(int)responseMessage.StatusCode} {responseMessage.StatusCode}: {response.Errors.JoinStrings(". ") ?? ""}");
}
}
Result:
{"message":"cannot be blank","errors":["message cannot be blank"],"status":0,"request":"94152901-3b8f-45d6-ae6b-f7fc10b3439c"}
I've looked at the raw request through Charles and it appears more or less as the docs suggest. However there is a small difference.
Curl - which works - produces parameters that look like this:
--------------------------30e0433d33c92cae
Content-Disposition: form-data; name="message"
my message
--------------------------30e0433d33c92cae--
HttpClient - which does not yet work - produces this for each parameter:
--70ae375f-ef30-4885-8a8a-d38363080024
Content-Disposition: form-data; name=message
my message
--70ae375f-ef30-4885-8a8a-d38363080024--
Note the difference in quotes. If I intercept the message in Charles and enclose the parameter names in double quotes as well as increase Content-Length by the same amount, it works!
