How to get content body from a httpclient call?

2019-01-16 09:15发布

问题:

I've been trying to figure out how to read the contents of a httpclient call, and I can't seem to get it. The response status I get is 200, but I can't figure out how to get to the actual Json being returned, which is all I need!

The following is my code:

        async Task<string> GetResponseString(string text)
    {
        var httpClient = new HttpClient();

        var parameters = new Dictionary<string, string>();
        parameters["text"] = text;
        Task<HttpResponseMessage> response = httpClient.PostAsync(BaseUri, new FormUrlEncodedContent(parameters));

        return await response.Result.Content.ReadAsStringAsync();
    }

And I am getting it just calling it from a method:

Task<string> result =  GetResponseString(text);

And This is what I get

response Id = 89, Status = RanToCompletion, Method = "{null}", Result = "StatusCode: 200, ReasonPhrase: 'OK', Version: 1.1, Content: System.Net.Http.StreamContent, Headers:\r\n{\r\n Connection: keep-alive\r\n Date: Mon, 27 Oct 2014 21:56:43 GMT\r\n ETag: \"5a266b16b9dccea99d3e76bf8c1253e0\"\r\n Server: nginx/0.7.65\r\n Content-Length: 125\r\n Content-Type: application/json\r\n}" System.Threading.Tasks.Task<System.Net.Http.HttpResponseMessage>

Update: This is my current code per Nathan's response below

            async Task<string> GetResponseString(string text)
    {
        var httpClient = new HttpClient();

        var parameters = new Dictionary<string, string>();
        parameters["text"] = text;

        var response = await httpClient.PostAsync(BaseUri, new FormUrlEncodedContent(parameters));
        var contents = await response.Content.ReadAsStringAsync();

        return contents;
    }

And I call it from this method....

 string AnalyzeSingle(string text)
    {
        try
        {
            Task<string> result = GetResponseString(text);
            var model = JsonConvert.DeserializeObject<SentimentJsonModel>(result.Result);

            if (Convert.ToInt16(model.pos) == 1)
            {
                _numRetries = 0;
                return "positive";
            }

            if (Convert.ToInt16(model.neg) == 1)
            {
                _numRetries = 0;
                return "negative";
            }

            if (Convert.ToInt16(model.mid) == 1)
            {
                _numRetries = 0;
                return "neutral";
            }

            return "";

        }
        catch (Exception e)
        {
            if (_numRetries > 3)
            {
                LogThis(string.Format("Exception caught [{0}] .... skipping", e.Message));
                _numRetries = 0;
                return "";
            }
            _numRetries++;
            return AnalyzeSingle(text);
        }
    }

And it keeps running forever, It hits the line var model = JsonConvert.DeserializeObject<SentimentJsonModel>(result.Result); Once, and it continues to go without stopping at another breakpoint.

When I pause execution, It say

Id = Cannot evaluate expression because the code of the current method is optimized., Status = Cannot evaluate expression because the code of the current method is optimized., Method = Cannot evaluate expression because the code of the current method is optimized., Result = Cannot evaluate expression because the code of the current method is optimized.

.. I Continue execution, but it just runs forever. Not sure what the problem is

回答1:

The way you are using await/async is poor at best, and it makes it hard to follow. You are mixing await with Task'1.Result, which is just confusing. However, it looks like you are looking at a final task result, rather than the contents.

I've rewritten your function and function call, which should fix your issue:

async Task<string> GetResponseString(string text)
{
    var httpClient = new HttpClient();

    var parameters = new Dictionary<string, string>();
    parameters["text"] = text;

    var response = await httpClient.PostAsync(BaseUri, new FormUrlEncodedContent(parameters));
    var contents = await response.Content.ReadAsStringAsync();

    return contents;
}

And your final function call:

Task<string> result = GetResponseString(text);
var finalResult = result.Result;

Or even better:

var finalResult = await GetResponseString(text);


回答2:

If you are not wanting to use async you can add .Result to force the code to execute synchronously:

    private string GetResponseString(string text)
    {
        var httpClient = new HttpClient();

        var parameters = new Dictionary<string, string>();
        parameters["text"] = text;

        var response = httpClient.PostAsync(BaseUri, new FormUrlEncodedContent(parameters)).Result;
        var contents = response.Content.ReadAsStringAsync().Result;

        return contents;
     }