I am having trouble trying to retrieve large datasets from Azure TableStorage. After several attempts at trying to get it in one go I have given up and am now using the TableContinuation Token, which is now not getting Deserialized correctly.The object is getting created but all the Next... values (i.e. NextRowKey, NextPartitionKey, etc are NULL, when the in stringresponse that gets created you can see the values it should be populating with...
The class I am passing contains a list of objects and the token
public class FlorDataset
{
public List<FlorData> Flors { get; set; }
public TableContinuationToken Token { get; set; }
}
The controller code is not exactly rocket science either....
[HttpGet, Route("api/list/{token}")]
public IHttpActionResult FindAll(string token)
{
try
{
TableContinuationToken actualToken = token == "None"
? null
: new TableContinuationToken()
{
NextPartitionKey = NextPartition,
NextRowKey = token,
NextTableName = NextTableName
};
var x = Run(actualToken);
Flors = x.Flors;
actualToken = x.Token;
NextTableName = actualToken.NextTableName;
NextPartition = actualToken.NextPartitionKey;
return Flors != null
? (IHttpActionResult)new IsoncOkResult<FlorDataset>(x, this)
: NotFound();
}
catch (Exception ex)
{
Trace.TraceError(ex.ToString());
return NotFound();
}
}
private FlorDataset Run(TableContinuationToken token)
{
return _repo.GetAllByYear("2016", token) as FlorDataset;
}
The calling code, which calls my fairly standard Web API 2 Controller is:
do
{
try
{
HttpResponseMessage response = null;
if (string.IsNullOrEmpty(token.NextRowKey))
{
response = await client.GetAsync("api/list/None");
}
else
{
response = await client.GetAsync($"api/list/{token.NextRowKey}");
}
if (response.IsSuccessStatusCode)
{
var stringresponse = await response.Content.ReadAsStringAsync();
var ds = JsonConvert.DeserializeObject<FlorDataset>(stringresponse);
token = ds.Token;
Flors.AddRange(ds.Flors);
}
else
{
token = null;
}
}
catch (Exception ex)
{
MessageBox.Show(ex.ToString());
token = null;
}
} while (token != null);
Okay, this is not the greatest solution, but it's the only thing that works so far in case anyone else is trying the same and stumbling across my question....
In the calling code bit you do a horrible bit of string replacement before you do the deserialisation.... I actually feel dirty just posting this, so if anyone comes up with a better answer, please feel free to share.....
if (response.IsSuccessStatusCode)
{
var stringresponse = await response.Content.ReadAsStringAsync();
stringresponse = stringresponse.Replace(">k__BackingField", "");
stringresponse = stringresponse.Replace("<", "");
var ds = JsonConvert.DeserializeObject<FlorDataset>(stringresponse);
token = ds.Token;
Flors.AddRange(ds.Flors);
}
Not nice, not pretty, but does work!!!! :-D Going to wash my fingers with bleach now!!!
Related
I am using aws_ai plugin and the response is in the form of
instance of Future<String>
I read the response as given below. I need to access specific value from json with key "confidence", how do I access it?
Future main1() async {
File sourceImagefile; //load source image in this File object
String accessKey = "",
secretKey = "",
region = "" ;
RekognitionHandler rekognition = new RekognitionHandler(accessKey, secretKey, region);
if(sourceImagefile !=null && targetImagefile !=null) {
Future<String> labelsArray = rekognition.compareFaces(
sourceImagefile, targetImagefile);
print(labelsArray);
return labelsArray.toString();
}else{
return "Enter Image";}
}
___________________________________
(later in widget build:)
___________________________________
onpressed(){
main1().then((labelsArray){
print("json value is: "+labelsArray);
});
}
the current result is :
json value is: Instance of 'Future<String>'
thanks for the help!
The reason you are getting the Instance of 'Future<String>' as a result is you are not waiting for the future to return and just getting the Future<String> object back refer this for more details:
The below code should solve your problem:
Future<String> futureFunction() async {
RekognitionHandler rekognition = new RekognitionHandler(accessKey, secretKey, region);
if(sourceImagefile !=null && targetImagefile !=null) {
var labelsArray = await rekognition.compareFaces(
sourceImagefile, targetImagefile);
print(labelsArray);
return labelsArray.toString();
} else {
return "enter image";
}
}
The title doesn't describe the issue very well so let me explain my problem.
I have a generic function to consume API's via HTTP GET calls. Which looks like this:
public async static Task<T> GetAsync<T>(string Base_Url,string relative_URL, Utility.UriExtensions.NameValueCollection Params, Utility.UriExtensions.NameValueCollection headers = null)
{
Uri CompleteURL = new Uri(Base_Url + relative_URL, UriKind.Absolute);
if (Params != null)
CompleteURL = Utility.UriExtensions.CreateUriWithQuery(CompleteURL, Params);
if(headers!=null)
{
foreach(KeyValuePair<string,string> k in headers)
{
if (ApiHttpClient.DefaultRequestHeaders.ContainsKey(k.Key))
ApiHttpClient.DefaultRequestHeaders[k.Key] = k.Value;
else
ApiHttpClient.DefaultRequestHeaders.Add(k.Key, k.Value);
}
}
Debug.WriteLine("GET : " + CompleteURL);
using (var response = await ApiHttpClient.GetAsync(CompleteURL).AsTask(cancellationToken.Token).ConfigureAwait(false))
{
string responseData="";
if (response.IsSuccessStatusCode)
{
responseData = await response.Content.ReadAsStringAsync();
Debug.WriteLine(responseData);
JsonSerializerSettings settings = new JsonSerializerSettings();
settings.DateParseHandling = DateParseHandling.DateTime;
settings.DefaultValueHandling = DefaultValueHandling.Populate;
settings.NullValueHandling = NullValueHandling.Include;
settings.TypeNameHandling = TypeNameHandling.None;
}
try
{
response.EnsureSuccessStatusCode();
return JsonConvert.DeserializeObject<T>(responseData);
}
catch
{
// Error
Debug.WriteLine(
"Error occurred, the status code is: {0} and Content : {1}",
response.StatusCode, response.Content);
}
return default(T);
}
}
In case of error, the error is handled inside catch body. I want to return these Error informations like StatusCode and Content of response when this happens. But I am unable to make any changes to this generic function. How should handle this.
For this purpose you can use out parameter, which you will pass in your method:
public async static Task<T> GetAsync<T>(string Base_Url,string relative_URL, Utility.UriExtensions.NameValueCollection Params, Utility.UriExtensions.NameValueCollection headers = null, out StatusCode code)
StatusCode statusCode;
GetAsync<Foo>(..., out statusCode);
So i am working this project on Xamarin forms, and get the error as in title on
var rootObject = deserial.Deserialize<RootObject>(gameJson);
I am supposed to return the list of games to my app.How can i remove the error?
public async Task<Game[]> GetGamesAsync(){
var client = new RestClient("http://mystore/");
var request = new RestRequest ("api/Games", Method.GET);
request.OnBeforeDeserialization = resp => { resp.ContentType = "application/json"; };
var apiKey = session ["ApiKey"];
var userId = session ["UserId"];
try
{
request.AddHeader ("authenticationkey",apiKey.ToString ());
request.AddHeader ("authenticationid",userId.ToString ());
}
catch{}
IRestResponse response = client.Execute (request);
statusCodeCheck (response);
var gameJson = response.Content;
if (response.StatusCode == HttpStatusCode.OK) {
RestSharp.Deserializers.JsonDeserializer deserial = new RestSharp.Deserializers.JsonDeserializer ();
var rootObject = deserial.Deserialize<RootObject>(gameJson);
return rootObject.games;
}
else if(response.StatusCode == HttpStatusCode.Forbidden){
return null;
}
}
Not sure you are looking for this but I also using Restsharp in portable library and I'm deserializing datacontracts with Json.NET's JsonConvert.DeserializeObject<T>
method. I have not encountered any problem with it yet.
Also another possible solution is that the returned data is wrapped and the main object is not the RootObject.
The Nancy documentation seems to say that Pipelines.OnError should return null - as opposed to BeforeResponse which allows both null and a Response object.
All the examples like this one and many code samples here on StackOverflow show a Response being returned in the OnError, just like in the BeforeRequest.
When I attempt to return an HTTPStatus string for the Pipelines.OnError, everything works OK!
But when I attempt to return a Response, I get a compiler error:
Operator '+=' cannot be applied to operands of type 'Nancy.ErrorPipeline' and 'lambda expression'
I'm emulating almost exactly the code in the Nancy example, except for the fact that mine is a TinyIocContainer while the example's is using a StructureMap container and a StructureMap derived bootstrapper
Here's my code:
const string errKey = "My proj error";
const string creationProblem = "Message creation (HTTP-POST)";
const string retrievalProblem = "Message retrieval (HTTP-GET)";
public void Initialize(IPipelines pipelines)
{
string jsonContentType = "application/json";
byte[] jsonFailedCreate = toJsonByteArray(creationProblem);
byte[] jsonFailedRetrieve = toJsonByteArray(retrievalProblem);
Response responseFailedCreate = new Response
{
StatusCode = HttpStatusCode.NotModified,
ContentType = jsonContentType,
Contents = (stream) =>
stream.Write(jsonFailedCreate, 0, jsonFailedCreate.Length)
};
Response responseFailedRetrieve = new Response
{
StatusCode = HttpStatusCode.NotFound,
ContentType = jsonContentType,
Contents = (stream) =>
stream.Write(jsonFailedRetrieve, 0, jsonFailedRetrieve.Length)
};
// POST - error in Create call
pipelines.OnError += (context, exception) =>
{
// POST - error during Create call
if (context.Request.Method == "POST")
return responsefailedCreate;
// GET - error during Retrieve call
else if (context.Request.Method == "GET")
return responseFailedRetrieve;
// All other cases - not supported
else
return HttpStatusCode.InternalServerError;
};
}
private byte[] toJsonByteArray(string plainString)
{
string jsonString = new JObject { { errKey, plainString } }.ToString();
byte[] result = Encoding.UTF8.GetBytes(jsonString);
return result;
}
I had the same problem and I found a nice approach to the problem: http://paulstovell.com/blog/consistent-error-handling-with-nancy.
you should override RequestStartup on the Bootstrapper, here my test code:
protected override void RequestStartup(TinyIoCContainer container, IPipelines pipelines, NancyContext context)
{
pipelines.OnError.AddItemToEndOfPipeline((ctx, ex) =>
{
DefaultJsonSerializer serializer = new DefaultJsonSerializer();
Response error = new JsonResponse(ex.Message,serializer);
error.StatusCode = HttpStatusCode.InternalServerError;
return error;
});
base.RequestStartup(container, pipelines, context);
}
I have the following, and it uploads without errors, but the image is always 0 bytes.
Windows Phone App (this is called after selecting or taking a photo):
private void AddImage(PhotoResult e)
{
if (e.TaskResult == TaskResult.OK)
{
string serviceUri = Globals.GreedURL + #"API/UploadPhoto/test5.jpg";
HttpWebRequest request = (HttpWebRequest)HttpWebRequest.Create(serviceUri);
request.Method = "POST";
request.BeginGetRequestStream(result =>
{
Stream requestStream = request.EndGetRequestStream(result);
e.ChosenPhoto.CopyTo(requestStream);
requestStream.Close();
request.BeginGetResponse(result2 =>
{
try
{
HttpWebResponse response = (HttpWebResponse)request.EndGetResponse(result2);
if (response.StatusCode == HttpStatusCode.Created)
{
this.Dispatcher.BeginInvoke(() =>
{
MessageBox.Show("Upload completed.");
});
}
else
{
this.Dispatcher.BeginInvoke(() =>
{
MessageBox.Show("An error occured during uploading. Please try again later.");
});
}
}
catch
{
this.Dispatcher.BeginInvoke(() =>
{
MessageBox.Show("An error occured during uploading. Please try again later.");
});
}
e.ChosenPhoto.Close();
}, null);
}, null);
}
And here is the Web API:
public class UploadPhotoController : ApiController
{
public HttpResponseMessage Post([FromUri]string filename)
{
var task = this.Request.Content.ReadAsStreamAsync();
task.Wait();
Stream requestStream = task.Result;
// Retrieve storage account from connection string.
CloudStorageAccount storageAccount = CloudStorageAccount.Parse(ConfigurationManager.ConnectionStrings["StorageConnectionString"].ConnectionString);
// Create the blob client.
CloudBlobClient blobClient = storageAccount.CreateCloudBlobClient();
// Retrieve reference to a previously created container.
CloudBlobContainer container = blobClient.GetContainerReference("profilepics");
container.CreateIfNotExists();
var permissions = container.GetPermissions();
permissions.PublicAccess = BlobContainerPublicAccessType.Blob;
container.SetPermissions(permissions);
string uniqueBlobName = string.Format("test.jpg");
CloudBlockBlob blob = container.GetBlockBlobReference(uniqueBlobName);
blob.Properties.ContentType = "image\\jpeg";
blob.UploadFromStream(task.Result);
HttpResponseMessage response = new HttpResponseMessage();
response.StatusCode = HttpStatusCode.Created;
return response;
}
}
Any ideas?
Any help would be appreciated.