I wish to use streams as recommended by the json.net performance tips documentation, however I'm unable to find how to get a hold of the http status codes without the typical awaiting the HttpResponse.
Is there perhaps a way of getting the status code first without reading the data? So still taking advantage of streams?
I haven't tested to ensure it's performance, however this seems promising:
using(HttpClient client = new HttpClient())
{
var response = await client.GetAsync("http://httpbin.org/get", HttpCompletionOption.ResponseHeadersRead);
response.EnsureSuccessStatusCode();
using (var stream = await response.Content.ReadAsStreamAsync())
using (var streamReader = new StreamReader(stream))
using (var jsonReader = new JsonTextReader(streamReader))
{
var serializer = new JsonSerializer();
//do some deserializing http://www.newtonsoft.com/json/help/html/Performance.htm
}
}
HttpCompletionOption is definitely the intended way of achieving what you were after.I prefer to dispose of the HttpResponseMessage via using as it is disposable. I also prefer to not rely on exception handling to deal with failed requests. Instead I prefer to check against the IsSuccessStatusCode boolean value and proceed accordingly. For example:
using(HttpClient client = new HttpClient())
{
using(var response = await client.GetAsync("http://httpbin.org/get", HttpCompletionOption.ResponseHeadersRead))
{
if(response.IsSuccessStatusCode)
{
using (var stream = await response.Content.ReadAsStreamAsync())
using (var streamReader = new StreamReader(stream))
using (var jsonReader = new JsonTextReader(streamReader))
{
var serializer = new JsonSerializer();
//do some deserializing http://www.newtonsoft.com/json/help/html/Performance.htm
}
}
else {
//do your error logging and/or retry logic
}
}
}
EDIT: If you're doing work with a rate limited api sending the HEAD request just isn't sometimes feasible. As such, here's a code sample using the good ol' fashion
HttpWebRequest(note that there isn't a better way to deal with http errors thanWebExceptionin this case):
var req = WebRequest.CreateHttp("http://httpbin.org/get");
/*
* execute
*/
try
{
using (var resp = await req.GetResponseAsync())
{
using (var s = resp.GetResponseStream())
using (var sr = new StreamReader(s))
using (var j = new JsonTextReader(sr))
{
var serializer = new JsonSerializer();
//do some deserializing http://www.newtonsoft.com/json/help/html/Performance.htm
}
}
}
catch (WebException ex)
{
using (HttpWebResponse response = (HttpWebResponse)ex.Response)
{
using (StreamReader sr = new StreamReader(response.GetResponseStream()))
{
string respStr = sr.ReadToEnd();
int statusCode = (int)response.StatusCode;
//do your status code logic here
}
}
}
