调用web api时，C#不支持授权类型{ “ error “:“ unsupported _ grant _ type “ }

Posted 2022-12-05 花开花落的个人博客

使用postman

使用代码，代码如下

" error ":" unsupported _ grant _ type "

public static string GetToken(string url,string username ,string password)

    GetTokenDto getTokenDto = new GetTokenDto()  Username = username,Password = password, grant_type = "password" ;
    //设定小驼峰模式，属性名首字母小写
    var setting = new JsonSerializerSettings
    
        ContractResolver = new Newtonsoft.Json.Serialization.CamelCasePropertyNamesContractResolver()
    ;

    string jsonData = JsonConvert.SerializeObject(getTokenDto, setting);
            
    var logger = SingleService.Services.GetService<ILogger>();
    ServicePointManager.ServerCertificateValidationCallback = ServicePointManager.ServerCertificateValidationCallback = new RemoteCertificateValidationCallback(delegate 
        return true;
    );//https请求 忽略证书，可以直接访问
    using (HttpClient httpClient = new HttpClient())
    
        using (HttpRequestMessage request = new HttpRequestMessage())
        
            using (HttpContent content = new StringContent(jsonData, Encoding.UTF8, "application/x-www-form-urlencoded"))
            //using (HttpContent content = new StringContent(string.Format("grant_type=password&username=0&password=1",HttpUtility.UrlEncode(username),HttpUtility.UrlEncode(password)), Encoding.UTF8,"application/x-www-form-urlencoded"))
            
                string contentType = content.Headers.ContentType.ToString();
                request.RequestUri = new Uri(url);
                request.Content = content;
                request.Method = new HttpMethod("GET");
                var result = httpClient.SendAsync(request).Result;
                var str = result.Content.ReadAsStringAsync().Result;
                logger.Info(typeof(DataSubHelper), str);
                return str;
            
        
    
    return url;

原因是什么呢，原因是的默认实现OAuthAuthorizationServerHandler仅接受表单编码(即application/x-www-form-urlencoded)而不是JSON编码(application/JSON).

修改下代码关键部分

using (HttpContent content = new StringContent(string.Format("grant_type=password&username=0&password=1",HttpUtility.UrlEncode(username),HttpUtility.UrlEncode(password)), Encoding.UTF8,"application/x-www-form-urlencoded"))

这样就可以返回正确的结果了