I have a simple C# Windows UAP project that uses a HttpClient to call a PHP script on a web server. The script returns an XML document that contains some GUIDs (*.xml files with the extension omitted, leaving a GUID). My app then uses that data. If I make a change on the server, coincidently causing the PHP script to return different data, my app still uses the old data (to be exact, it does this until the app is restarted). If a call the script using a browser, the data appears how I expect it to, but the app doesn't do what it should with the data. It almost seems like the first response is being cached.
Here's an example:
Say I start with one file in the folder where my PHP script finds all *.xml files (eef8401a-b5cd-4da7-ad36-0fb7a8fa6c62.xml in this case).
The script should and does return:
<?xml version="1.0"?>
<eventlist>
<id>eef8401a-b5cd-4da7-ad36-0fb7a8fa6c62</id>
</eventlist>
When I run the app, its response is the same.
So far, all is working as it should.
However, say I add a new XML file in the folder (now eee8401a-b5cd-4da7-ad36-0fb7a8fa6c62.xml and eef8401a-b5cd-4da7-ad36-0fb7a8fa6c62.xml). The script returns just like I expect it to:
<?xml version="1.0"?>
<eventlist>
<id>eee8401a-b5cd-4da7-ad36-0fb7a8fa6c62</id>
<id>eef8401a-b5cd-4da7-ad36-0fb7a8fa6c62</id>
</eventlist>
The app's response this time is still the previous one (with only one id element).
This persists until the app restarts. After that, it works like it should--until I make another change in the folder.
Here's my PHP script:
<?php
header('Content-type: text/xml');
$handler = opendir('C:\path\to\folder\\');
$ids = '';
while (($file = readdir($handler)) !== FALSE) {
if (strpos($file, '.xml') !== FALSE) {
$ids .= '<id>'.str_replace('.xml', '', $file).'</id>';
}
}
closedir($handler);
exit('<eventlist>'.$ids.'</eventlist>');
?>
And my app's C# code:
public static async Task<string> ContactServer(ApiMethod m, IProgress<double[]> prog, params KeyValuePair<string, string>[] args) {
using (var client = new HttpClient()) {
var path = m.ToString().ToLower() + "/"; // in this case, is 'list/'.
//...
// other stuff, omitted for simplicity
//...
var fullUrl = "http://example.com/path/to/api/" + path; // in this case, is 'http://example.com/path/to/api/list/'.
var d = await client.GetAsync(new Uri(fullUrl));
var data = await d.Content.ReadAsStringAsync();
Debug.WriteLine(data);
return data;
}
}
Again, my PHP script works fine, but my app gets a different response than I do when I run the script in my browser manually.
Why is this happening?
Windows Runtime which provides the HTTPClient has a very aggressive webcaching strategy to save user's bandwidth. Unless your server explicitly sets a cache duration header, it will return all** requests with the same Uri directly from the cache without even contacting your server.
You can turn off this behaviour by:
Setting a cache duration header (cache-control: no-cache, etc.).
var request = (HttpWebRequest)WebRequest.Create(url.ToString());
if (request.Headers == null)
request.Headers = new WebHeaderCollection();
request.Headers.Add("Cache-Control", "no-cache");
Adding a random number to your requests query string.
string uri = "http://host.com/path?cache=" + Guid.NewGuid().ToString();
Or, as CodeCaster suggested, you could also avoid the caching by using the If-Modified-Since header
HttpWebRequest request = HttpWebRequest.CreateHttp(url);
if (request.Headers == null)
request.Headers = new WebHeaderCollection();
// Make sure that you format time string according RFC.
request.Headers[HttpRequestHeader.IfModifiedSince] = DateTime.UtcNow.ToString("r");
or you can add to every request the client makes with
httpClient.DefaultRequestHeaders.IfModifiedSince = DateTime.UtcNow.ToString("r");
Using Windows.Web.Http you could also use
var httpFilter = new Windows.Web.Http.Filters.HttpBaseProtocolFilter();
httpFilter.CacheControl.ReadBehavior =
Windows.Web.Http.Filters.HttpCacheReadBehavior.MostRecent;
var httpClient = new Windows.Web.Http.HttpClient(httpFilter);
** I have said all requests, but I don't know if that is strictly correct, I will take a look and check and update here, though CodeCaster has suggested GET and HEAD only; I have certainly seen on GET, unsure about others off the top of my head
Related
I am new to Google APIs. I want to know how to call Google Dialogflow API in C# to get intent form the input text. But I can't find any example to call Dialogflow using C#.
Please provide some example to call Dialogflow from C#.
If I understand your question correctly you want to call the DialogFlow API from within a C# application (rather than writing fulfillment endpoint(s) that are called from DialogFlow. If that's the case here's a sample for making that call:
using Google.Cloud.Dialogflow.V2;
...
...
var query = new QueryInput
{
Text = new TextInput
{
Text = "Something you want to ask a DF agent",
LanguageCode = "en-us"
}
};
var sessionId = "SomeUniqueId";
var agent = "MyAgentName";
var creds = GoogleCredential.FromJson("{ json google credentials file)");
var channel = new Grpc.Core.Channel(SessionsClient.DefaultEndpoint.Host,
creds.ToChannelCredentials());
var client = SessionsClient.Create(channel);
var dialogFlow = client.DetectIntent(
new SessionName(agent, sessionId),
query
);
channel.ShutdownAsync();
In an earlier version of the DialogFlowAPI I was running into file locking issues when trying to re-deploy a web api project which the channel.ShutDownAsync() seemed to solve. I think this has been fixed in a recent release.
This is the simplest version of a DF request I've used. There is a more complicated version that passes in an input context in this post:
Making DialogFlow v2 DetectIntent Calls w/ C# (including input context)
(Nitpicking: I assume you know DialogFlow will call your code as specified/registered in the action at DialogFlow? So your code can only respond to DialogFlow, and not call it.)
Short answer/redirect:
Don't use Google.Apis.Dialogflow.v2 (with GoogleCloudDialogflowV2WebhookRequest and GoogleCloudDialogflowV2WebhookResponse) but use Google.Cloud.Dialogflow.v2 (with WebhookRequest and WebhookResponse) - see this eTag-error. I will also mention some other alternatives underneath.
Google.Cloud.Dialogflow.v2
Using Google.Cloud.Dialogflow.v2 NuGet (Edit: FWIW: this code was written for the beta-preview):
[HttpPost]
public dynamic PostWithCloudResponse([FromBody] WebhookRequest dialogflowRequest)
{
var intentName = dialogflowRequest.QueryResult.Intent.DisplayName;
var actualQuestion = dialogflowRequest.QueryResult.QueryText;
var testAnswer = $"Dialogflow Request for intent '{intentName}' and question '{actualQuestion}'";
var dialogflowResponse = new WebhookResponse
{
FulfillmentText = testAnswer,
FulfillmentMessages =
{ new Intent.Types.Message
{ SimpleResponses = new Intent.Types.Message.Types.SimpleResponses
{ SimpleResponses_ =
{ new Intent.Types.Message.Types.SimpleResponse
{
DisplayText = testAnswer,
TextToSpeech = testAnswer,
//Ssml = $"<speak>{testAnswer}</speak>"
}
}
}
}
}
};
var jsonResponse = dialogflowResponse.ToString();
return new ContentResult { Content = jsonResponse, ContentType = "application/json" }; ;
}
Edit: It turns out that the model binding may not bind all properties from the 'ProtoBuf-json' correctly (e.g. WebhookRequest.outputContexts[N].parameters),
so one should probably use the Google.Protobuf.JsonParser (e.g. see this documentation).
This parser may trip over unknown fields, so one probably also wants to ignore that. So now I use this code (I may one day make the generic method more generic and thus useful, by making HttpContext.Request.InputStream a parameter):
public ActionResult PostWithCloudResponse()
{
var dialogflowRequest = ParseProtobufRequest<WebhookRequest>();
...
var jsonResponse = dialogflowResponse.ToString();
return new ContentResult { Content = jsonResponse, ContentType = "application/json" }; ;
}
private T ParseProtobufRequest<T>() where T : Google.Protobuf.IMessage, new()
{
// parse ProtoBuf (not 'normal' json) with unknown fields, else it may not bind ProtoBuf correctly
// https://github.com/googleapis/google-cloud-dotnet/issues/2425 "ask the Protobuf code to parse the result"
string requestBody;
using (var reader = new StreamReader(HttpContext.Request.InputStream))
{
requestBody = reader.ReadToEnd();
}
var parser = new Google.Protobuf.JsonParser(JsonParser.Settings.Default.WithIgnoreUnknownFields(true));
var typedRequest = parser.Parse<T>(requestBody);
return typedRequest;
}
BTW: This 'ProtoBuf-json' is also the reason to use WebhookResponse.ToString() which in turn uses Google.Protobuf.JsonFormatter.ToDiagnosticString.
Microsoft's BotBuilder
Microsoft's BotBuilder packages and Visual Studio template.
I havent't used it yet, but expect approximately the same code?
Hand written proprietary code
A simple example of incoming request code (called an NLU-Response by Google) is provided by Madoka Chiyoda (Chomado) at Github. The incoming call is simply parsed to her DialogFlowResponseModel:
public static async Task<HttpResponseMessage> Run([...]HttpRequestMessage req, [...]CloudBlockBlob mp3Out, TraceWriter log)
...
var data = await req.Content.ReadAsAsync<Models.DialogFlowResponseModel>();
Gactions
If you plan to work without DialogFlow later on, please note that the interface for Gactions differs significantly from the interface with DialogFlow.
The json-parameters and return-values have some overlap, but nothing gaining you any programming time (probably loosing some time by starting 'over').
However, starting with DialogFlow may gain you some quick dialog-experience (e.g. question & answer design/prototyping).
And the DialogFlow-API does have a NuGet package, where the Gactions-interface does not have a NuGet-package just yet.
Im trying to move a file from one folder to another using the Google Drive API v3. I found documentation how to this here. I used the .NET sample code from the documentation page and created a method that looks like this:
public ActionResult MoveFile(string fileToMove, string destination)
{
DriveService service = new DriveService(new BaseClientService.Initializer
{
HttpClientInitializer = <USER CREDENTIAL>,
ApplicationName = "APPNAME"
});
var searchFiles = service.Files.List();
searchFiles.Corpus = FilesResource.ListRequest.CorpusEnum.User;
searchFiles.Q = "name = '" + fileToMove + "'";
searchFiles.Fields = "files(*)";
string fileToMoveId = searchFiles.Execute().Files[0].Id;
searchFiles.Q = "name = '" + destination + "'";
string destinationId = searchFiles.Execute().Files[0].Id;
//Code used from documentation
// Retrieve the existing parents to remove
var getRequest = service.Files.Get(fileToMoveId);
getRequest.Fields = "parents";
var file = getRequest.Execute();
var previousParents = String.Join(",", file.Parents);
// Move the file to the new folder
var updateRequest = service.Files.Update(file, fileToMoveId);
updateRequest.Fields = "id, parents";
updateRequest.AddParents = destinationId;
updateRequest.RemoveParents = previousParents;
file = updateRequest.Execute();
return RedirectToAction("Files", new {folderId = destinationId});
}
When I execute this code I get the following error:
The parents field is not directly writable in update requests. Use the
addParents and removeParents parameters instead.
The error doesn't really makes sense to me because this code sample came from the documentation page itself. I can't figure out what other paramters they mean. What addParents and removeParents parameters do they mean? Are updateRequest.AddParents and updateRequest.RemoveParents not the right parameters?
Ok here is the problem.
var updateRequest = service.Files.Update(file, fileToMoveId);
The method is requiring that you send a body of a file to be updated. This normally makes sense as any changes you want to make you can add to the body.
Now the problem you are having is that you got your file from a file.get. Which is totally normal. This is how you should be doing it. THe problem is there are some fields in that file that you cant update. So by sending the full file the API is rejecting your update. If you check Files: update under Request body you will see which fiends are updateable.
Issue:
Now this is either a problem with the client library or the API I am going to have to track down a few people at Google to see which is the case.
Fix:
I did some testing and sending an empty file object as the body works just fine. The file is moved.
var updateRequest = service.Files.Update(new Google.Apis.Drive.v3.Data.File(), fileToMove.Id);
updateRequest.AddParents = directoryToMove.Id;
updateRequest.RemoveParents = fileToMove.Parents[0];
var movedFile = updateRequest.Execute();
This method works well when working in your own drive, but not in a team drive where a file (folder) can only have 1 parent strictly. I do not have the solution in a team drive
Using Visual Studio, and AWS .NET V 3.0.
I'm trying to perform a real-time Predict operation, and to verify the basic setup works, I first perform a GetMLModel() which works and returns the endpoint (Somewhere in the documentation is was mentioned to use that result as the service endpoint, but it's the same that is listed in the console). Is has status "READY", so far so good.
The exception occurs below on the line below "Prediction P = RTP.Predict(Data)". Data contains a Dictionary with all the prediction values.
Error: Error making request with Error Code UnknownOperationException and Http Status Code BadRequest. No further error information was returned by the service.
public static APIResult GetRealTimePrediction(Dictionary<string, string> Data, string PayloadJSON = null) {
AmazonMachineLearningConfig MLConfig = new AmazonMachineLearningConfig();
MLConfig.RegionEndpoint = Amazon.RegionEndpoint.USEast1;
MLConfig.Validate();
AmazonMachineLearningClient MLClient = new AmazonMachineLearningClient("xxx", "xxx", MLConfig);
GetMLModelResponse MLMOdelResp = MLClient.GetMLModel("xxx"); // <-- WORKS
MLConfig.ServiceURL = MLMOdelResp.EndpointInfo.EndpointUrl;
Console.WriteLine(MLConfig.ServiceURL);
MLConfig.Validate();
Amazon.MachineLearning.Util.RealtimePredictor RTP = new Amazon.MachineLearning.Util.RealtimePredictor(MLClient, "xxx");
Prediction P = RTP.Predict(Data); // <----------------EXCEPTION HERE
}
(Obviously replace xxx with relevant values) :)
It turns out that this line:
MLConfig.ServiceURL = MLMOdelResp.EndpointInfo.EndpointUrl;
cases the MLConfig.RegionEndpoint to be reset. Even though the documentation indicates the RegionEndpoint can be determined from the ServiceURL (I'm pretty sure I read that), the RegionEndpoint needs to be set again before the RTP.Predict(Data) call.
Once I figured that out, I was able to reduce the code to just this, in case anyone else needs help. I guess adding too much information to the Configuration is NOT a good thing, as the AWS. NET library seems to figure all this out on its own.
public static APIResult GetRealTimePrediction(Dictionary<string, string> Data, string PayloadJSON = null) {
AmazonMachineLearningConfig MLConfig = new AmazonMachineLearningConfig();
MLConfig.RegionEndpoint = Amazon.RegionEndpoint.USEast1;
MLConfig.Validate(); // Just in case, not really needed
AmazonMachineLearningClient MLClient = new AmazonMachineLearningClient("xxx", "xxx", MLConfig);
Amazon.MachineLearning.Util.RealtimePredictor RTP = new Amazon.MachineLearning.Util.RealtimePredictor(MLClient, "xxx");
Prediction P = RTP.Predict(Data);
}
I am attempting to allow users to add events from an online calendar to the calendars on their device using DDay.iCal. This seems to work fine on iOS and on desktop platforms, but I am running into a snag with Android devices. I run into this message:
Is there a better way to serve this event that would keep that from happening?
public ActionResult ICS(int id)
{
// Get event from Database
var heEvent = HEEvent.GetEventDetails(id);
// Create iCal object
var iCal = new iCalendar();
iCal.Method = "PUBLISH";
// Create iCal Event
var icalEvent = iCal.Create<DDay.iCal.Event>();
icalEvent.Summary = heEvent.Name;
icalEvent.Start = new iCalDateTime(heEvent.TimeBegin.Year, heEvent.TimeBegin.Month, heEvent.TimeBegin.Day, heEvent.TimeBegin.Hour, heEvent.TimeBegin.Minute, 00);
TimeSpan calculatedEventDuration = heEvent.DateEnd.Subtract(heEvent.TimeBegin);
if (calculatedEventDuration.Hours > 1) { icalEvent.Duration = calculatedEventDuration; }
else { icalEvent.Duration = TimeSpan.FromHours(1); } // default to 1 hour if event time is less
icalEvent.Location = heEvent.Location;
// Create a serialization context and serializer factory.
// These will be used to build the serializer for our object.
ISerializationContext ctx = new SerializationContext();
ISerializerFactory factory = new DDay.iCal.Serialization.iCalendar.SerializerFactory();
// Get a serializer for our object
IStringSerializer serializer = factory.Build(iCal.GetType(), ctx) as IStringSerializer;
string output = serializer.SerializeToString(iCal);
var contentType = "text/calendar";
var bytes = Encoding.UTF8.GetBytes(output);
return File(bytes, contentType, String.Format(#"{0}.ics", heEvent.Name.Replace(" ", "_")));
}
Your error, you don't need me to tell you, has nothing to do with Ical. It's entirely between you, your phone, and your technology budget. (Buy an SD card !)
As regards serving Icalendars, you often hear them called feeds, but clients subscribed to an Icalendar poll the calendar url regularly, requesting the whole calendar each time. To avoid lots of needless processing, you will want to persist the calendar(s) somehow so that changes propagate without regenerating the same calendar thousands of times. For this, I suggest the file system and good use of HTTP caching headers. When your calendar is modified, write it as a static file in a web facing directory. Perhaps you're already doing this. Then set sensible caching headers on your webserver and away you go.
Is there a way to synchronously process an uploaded file POSTed to a controller in the ASP.Net Web API?
I've tried the process Microsoft proposed here, and it works as described, but I'd like to return something other than a Task<> from the Controller method in order to match the rest of my RESTful API.
Basically, I'm wondering if there is there any way to make this work:
public MyMugshotClass PostNewMugshot(MugshotData data){
//get the POSTed file from the mime/multipart stream <--can't figure this out
//save the file somewhere
//Update database with other data that was POSTed
//return a response
}
Again, I have made the asynchronous example work but am hoping for a way to process the uploaded file before responding to the client.
public class UploadController : ApiController
{
public async Task<HttpResponseMessage> Post()
{
if (!Request.Content.IsMimeMultipartContent())
{
throw new HttpResponseException(HttpStatusCode.UnsupportedMediaType);
}
var appData = HostingEnvironment.MapPath("~/App_Data");
var folder = Path.Combine(appData, Guid.NewGuid().ToString());
Directory.CreateDirectory(folder);
var provider = new MultipartFormDataStreamProvider(folder);
var result = await Request.Content.ReadAsMultipartAsync(provider);
if (result.FileData.Count < 1)
{
// no files were uploaded at all
// TODO: here you could return an error message to the client if you want
}
// at this stage all files that were uploaded by the user will be
// stored inside the folder we specified without us needing to do
// any additional steps
// we can now read some additional FormData
string caption = result.FormData["caption"];
// TODO: update your database with the other data that was posted
return Request.CreateResponse(HttpStatusCode.OK, "thanks for uploading");
}
}
You might notice that the uploaded files are stored inside the specified folder with names that might look like this: BodyPart_beddf4a5-04c9-4376-974e-4e32952426ab. That's a deliberate choice that the Web API team made that you could override if you want.