I have the following web server method, that returns data to our front-end applicaiton.
[FunctionName("SearchCustomerBySearchTerm")]
public static async Task<HttpResponseMessage> SearchCustomerBySearchTerm([HttpTrigger(AuthorizationLevel.Function, WebRequestMethods.Http.Get, Route = "Customer/SearchCustomerBySearchTerm/{searchTerm}/pageSize/{pageSize}")]HttpRequestMessage req, TraceWriter log, string searchTerm, int pageSize)
{
try
{
var continuationToken = req.Headers.TryGetValues("continuationToken", out IEnumerable<string> values) ? values.FirstOrDefault() : null;
PagedResponse<CustomerSearchResult> pagedResponse = await _customerComponent.FindCustomerBy(searchTerm, continuationToken, pageSize);
if (pagedResponse == null) return req.CreateResponse(HttpStatusCode.NoContent, $"Could not find any data related to {searchTerm}");
HttpResponseMessage responseMessage = req.CreateResponse(HttpStatusCode.OK, pagedResponse.Results);
responseMessage.Content.Headers.Add("continuationToken", pagedResponse.Continuation);
responseMessage.Content.Headers.Add("Access-Control-Expose-Headers", "*");
return responseMessage;
}
catch (Exception ex)
{
log.Error(ex.Message);
return req.CreateResponse(HttpStatusCode.InternalServerError, "Something went wrong. Could not search for customers");
}
}
I am allowing all headers to be exposed, by adding the Access-Control-Expose-Headers.
From my Angular application, I am doing the request as follow:
searchCustomersPaged(searchTerm: string, continuationToken: string): Observable<HttpResponse<CustomerSearchResult>> {
let customHeaders = new HttpHeaders().set("continuationToken", this.currentContinuationToken);
const url = "http://localhost:7071/api/Customer/SearchCustomerBySearchTerm/andrew/pageSize/10";
const parsedUrl = encodeURI(url);
return this.http.get<HttpResponse<CustomerSearchResult>>(parsedUrl, { headers: customHeaders });
}
As you can see above, I am expecting an HttpResponse<CustomerSearch> back.
Here is how I try and read my headers:
nextClikcedHandle(continuationToken: string): void {
this.customerService.searchCustomersPaged(this.customerService.searchTerm, this.currentContinuationToken)
.subscribe(resp => {
//add current continuation token, to previous now, as this will be used for 'previous' searching
this.previousContinuationTokens.push(this.currentContinuationToken);
//set next continuation token received by server
this.currentContinuationToken = resp.headers.get('continuationToken');
//return search results
this.customerService.searchResults.next(resp.body);
});
}
With the above code, the resp.headers and the resp.body is always undefined. Why is this happening?
If I look at the Network tab within Chrome, I can see my data is returned, as well as my header.
What am I doing wrong?
I found a useful article here:
By default the HttpClient returns the body of the response. You can
pass-in an object with an observe key set to a value of ‘response’ to
get the full response. This can be useful to inspect for certain
headers:
So I changed my code as follow, with the added observe key.
searchCustomersPaged(searchTerm: string, continuationToken: string): Observable<HttpResponse<CustomerSearchResult>> {
let customHeaders = new HttpHeaders().set("continuationToken", this.currentContinuationToken);
const url = "http://localhost:7071/api/Customer/SearchCustomerBySearchTerm/andrew/pageSize/10";
const parsedUrl = encodeURI(url);
return this.http.get<CustomerSearchResult>(parsedUrl, { headers: customHeaders, observe: 'response' });
}
After changing above method, I could query body and headers as per normal:
nextClikcedHandle(continuationToken: string): void {
this.customerService.searchCustomersPaged(this.customerService.searchTerm, this.currentContinuationToken)
.subscribe(resp => {
//add current continuation token, to previous now, as this will be used for 'previous' searching
this.previousContinuationTokens.push(this.currentContinuationToken);
//set next continuation token received by server
this.currentContinuationToken = resp.headers.get('continuationToken');
//return search results
this.customerService.searchResults.next(resp.body);
});
Related
I am working on a WebApp (Razor Pages) that work also as API Gateway. The WebApp get some data from another project (part of the same solution) that is a WebAPI.
The problem is that when I do an HTTPRequest to the WebAPI, if the request is not too long, the WebAPI will process it, but when I try to send a longer request (long in characters) it will reject it and send back a 404.
The WebApp is a basic CMS. So the app will provide to the user, the creation of Web pages. I am using a restful request model so a request will look like this:
string baseURL = #"https://localhost:5001";
public async Task<string> CreatePageAsync(string pageTitle, string pageBody, int? pageOrder, string userID)
{
if (pageTitle != null && pageBody != null && pageOrder != null && userID != null)
{
string fullURL = baseURL + $"/api/pages/create/page/title/{pageTitle}/body/{pageBody}/order/{pageOrder}/user/{userID}";
var request = new HttpRequestMessage(HttpMethod.Post, fullURL);
HttpResponseMessage response = await _httpClient.SendAsync(request);
if (!response.IsSuccessStatusCode)
{
return "error";
}
}
return "ok";
}
As you can imagine, the "pageBody" property is the one responsible for the length of the request. So, when I test the WebAPI with short words, it works just fine, but if I copy an article from the internet (Just text) and use it as the body (simulating the user's content), if it is a long one, it will return a 404.
On the other end, the WebAPI looks like this:
[HttpPost("Create/page/title/{pageTitle}/body/{pageBody}/order/{pageOrder}/user/{userID}")]
//[ValidateAntiForgeryToken]
public async Task<string> CreatePage(string pageTitle, string pageBody, int pageOrder, string userID) //[Bind("pageName,pageHead,pageBody,userID")]
{
if (ModelState.IsValid)
{
DateTime now = DateTime.Now;
WebPage newPage = new WebPage()
{
PageID = _globalServices.GuidFromString(_globalServices.GetSeed()),
PageDateCreated = now,
PageDateUpdated = now,
PageOrder = pageOrder,
PageTitle = pageTitle,
PageBody = pageBody,
UserID = userID
};
try
{
await _pagesDBContext.Pages.AddAsync(newPage);
await _pagesDBContext.SaveChangesAsync();
}
catch (Exception e)
{
string message = "ERROR: Could not save to the database.\n";
return message + e.Message;
}
return "Page saved";
}
return "ERROR: Model invalid";
}
I am sending the request as simple text. I don't know if there is a better way.
Any ideas?
I don't have enough rep to comment but it looks like the maximum characters you can send in a GET request is 2,048.
I am trying to set up a small ASP.NET Web API projects so I can post data to the database from a small React.JS project. I tried alot of sollutions but the results made no sense and I have no idea how to fix it anymore.
I have this very simple model:
public class Hour
{
public int WeekID { get; set; }
}
And this is my controller
[HttpPost]
public IHttpActionResult AddHour(Hour hour)
{
return Ok();
}
This is the method that I use to POST my data
export const SaveWeek = weekData=> {
const headers = new Headers();
headers.append("Content-Type", "application/json");
const Week= {
method: "POST",
headers,
mode: "cors",
body: weekData
};
console.log("Hours:");
// Returns {"WeekID": 1}
console.log(Hours.body);
return axios.post("http://localhost:52350/api/REST/AddHour", {
Week
});
};
The way I call this SaveWeek method in React is:
// The JSON parameter is for testing hard coded to: {"WeekID": 1}
handleSave = async json => {
const data = await SaveWeek(json);
console.log(data);
this.closeModal();
};
I know that the axios POST request works, the way I tested that is by changing the method to not use any parameters and looking at the result that where received:
[HttpPost]
public IHttpActionResult AddHour(Hour hour)
{
// This returns a string in which the data that I sent
// can be found.
string body = Request.Content.ReadAsStringAsync().Result;
return Ok();
}
The weird thing is that the body will be filled with data when the method does not contain any parameters, but when I provide the method with the Hour object parameter the body will be an empty string (""). And also the Hour object parameter wont be filled with the values that I provide it.
What am I doing wrong here?
According to https://github.com/axios/axios#axiosposturl-data-config axios.post has following signature
axios.post(url[, data[, config]])
So you just need to change your request to
export const SaveWeek = weekData => {
//headers should be simple object, not Headers
const headers = {
"Content-Type": "application/json"
};
//removed body, because we pass data as second parameter
//removed method, because 'axios.post' implies using "post" method
const Config = {
headers,
mode: "cors"
};
const url = "http://localhost:52350/api/REST/AddHour";
return axios.post(url, weekData, Config);
}
An incoming request to the ASP.Net Web API pipeline is read as a forward-only stream for super speed. Once it has been read it cannot be read again.
[HttpPost]
public IHttpActionResult AddHour(Hour hour)
{
// With model binding
// use hour.WeekID
}
In this first example model binding is already done and once it has been read it cannot be read again. Hence, Request.Content will be empty after that.
[HttpPost]
public IHttpActionResult AddHour()
{
// Without model binding
// use Request.Content
}
In second example it does not use model binding therefore still has the Request.Content property populated.
Use one or the other, not both, do not mix with MVC model binding which works differently.
A better explanation is available in this blog post
http://www.hackered.co.uk/articles/asp-net-web-api-why-is-the-request-Content-empty-when-the-model-is-populated
So I'm prototyping some Azure Durable Functions, to try and understand to see if they will fit within a proposed solution for our internal API system.
Based on examples, I've created a Orchestrator Client (HelloOrchestratorClient.cs), that responds to a HttpTrigger. This client extracts some information from the original request, then proceeds to fire off a Orchestrator Function (HelloOrchestrator.cs) passing in some of the information extracted:
Complex HelloOrchestratorClient.cs:
[FunctionName("HttpSyncStart")]
public static async Task<HttpResponseMessage> Run(
[HttpTrigger(AuthorizationLevel.Anonymous, methods: "get", Route = "orchestrators/{functionName}/wait")]
HttpRequestMessage req,
[OrchestrationClient] DurableOrchestrationClient starter,
string functionName,
ILogger log)
{
HttpReq originalRequest = new HttpReq() {
DeveloperId = GetDevKey(req,apiHeaderKey),
QueryString = req.RequestUri.Query,
APIName = GetQueryStringValue(req,APIName),
APIVersion = GetQueryStringValue(req,APIVersion)
};
string instanceId = await starter.StartNewAsync(functionName, originalRequest);
TimeSpan timeout = GetTimeSpan(req, Timeout) ?? TimeSpan.FromSeconds(30);
TimeSpan retryInterval = GetTimeSpan(req, RetryInterval) ?? TimeSpan.FromSeconds(1);
return await starter.WaitForCompletionOrCreateCheckStatusResponseAsync(
req,
instanceId,
timeout,
retryInterval);
}
The HelloOrchestrator.cs simply for now is just calling off to one of our internal API's and returning a JsonProduct payload (Simple POCO describing, you guessed it, a title), using a ActivityTigger named HelloOrchestrator.APICall to make the API call itself.
Complex HelloOrchestrator.cs:
[FunctionName("E1_JsonProduct")]
public static async Task<List<JsonProduct>> Run(
[OrchestrationTrigger] DurableOrchestrationContextBase context,
ILogger log)
{
List<JsonProduct> output = new List<JsonProduct>();
HttpReq r = context.GetInput<HttpReq>();
if(r != null)
{
if(r.DeveloperId == null)
{
return output;
}
output.Add(await context.CallActivityAsync<JsonProduct>("E1_CallAPI",r));
return output;
}
return output;
}
[FunctionName("E1_CallAPI")]
public async static Task<JsonProduct> APICall([ActivityTrigger] HttpReq req,
ILogger log)
{
JsonProduct products = null;
string u = $"{baseAddress}{req.APIVersion}/{req.APIName}{req.QueryString}";
var request = new HttpRequestMessage(HttpMethod.Get, u);
request.Headers.Accept.Add(
new MediaTypeWithQualityHeaderValue("application/json")
);
request.Headers.Add("x-apikey",req.DeveloperId);
log.LogInformation($"URL calling = '{request.RequestUri.AbsoluteUri}'.");
HttpResponseMessage response = await client.SendAsync(request);
// return await response.Content.ReadAsStringAsync();
if(response.IsSuccessStatusCode)
{
var formatter = new JsonMediaTypeFormatter
{
SerializerSettings = HelloProj.CosmosDB.Models.Products.Converter.Settings
};
products = await response.Content.ReadAsAsync<JsonProduct>(new [] {formatter});
}
return products;
}
Side Note: The plan is if I can get this to work, is to fan out a bunch of processes to different API's and fan back in again and merge the JSON payload and return it back to the originator.
Issue I'm experiencing
So, when my List<JsonProduct> is returned back from HelloOrchestrator.Run, I receive the following NullReferenceException found on this Gist (Big stack trace) and I receive a 500 response from the Orchestrator Client.
The following proves the output returned does actually have an object at runtime:
Could it be due to the complexity of JsonProduct (Again find the model classes here)? I ask, because when I swap out my Orchestrator Function for a simpler model structure, I don't receive a 500, I receive my JSON Payload.
This example shows the Simple Orchestrator Function HelloOrchestrator.cs, returning a simple TestToDo.cs (Gist for model) flat object that doesn't error:
Simple HelloOrchestrator.cs:
[FunctionName("E1_Todo")]
public static async Task<TestToDo> RunToDo(
[OrchestrationTrigger] DurableOrchestrationContextBase context,
ILogger log)
{
HttpReq r = context.GetInput<HttpReq>();
TestToDo todo = new TestToDo();
if(r != null)
{
todo = await context.CallActivityAsync<TestToDo>("E1_CallAPITodo",r);
}
return todo;
}
[FunctionName("E1_CallAPITodo")]
public async static Task<TestToDo> APITodoCall([ActivityTrigger] HttpReq req,
ILogger log)
{
var request = new HttpRequestMessage(HttpMethod.Get, "https://jsonplaceholder.typicode.com/todos/1");
request.Headers.Accept.Add(
new MediaTypeWithQualityHeaderValue("application/json")
);
log.LogInformation($"URL calling = '{request.RequestUri.AbsoluteUri}'. for {req.QueryString}");
HttpResponseMessage response = await client.SendAsync(request);
return await response.Content.ReadAsAsync<TestToDo>();
}
More Information
If you require my full prototype projects, you can find them here:
Complex Project (Throws 500 and exception)
When you run it, use the following in something like Postman (After F5ing it):
http://localhost:7071/api/orchestrators/E1_JsonProduct/wait?timeout=20&retryInterval=0.25&api=products&apiVersion=v1&filterByImprints=W%26N&N
Simple Project (No 500 or Exception thrown)
When you run it, use the following in something like Postman (after F5ing it):
http://localhost:7071/api/orchestrators/E1_Todo/wait?timeout=20&retryInterval=0.25
Looking at the callstack you posted, the NullReferenceException appears to be a bug in the DurableOrchestrationClient class. Looking at the code (which you can find here) is seems possible that if the query string you're using cannot be parsed correctly, a null-ref is possible.
You mentioned you're using the following URL for testing:
http://localhost:7071/api/orchestrators/E1_JsonProduct/wait?timeout=20&retryInterval=0.25&api=products&apiVersion=v1&filterByImprints=W%26N&N
I wonder if the last two characters (&N) are the source of the problem. Is is possible to encode the & or remove it entirely to isolate the problem?
Either way, it would be great if you could log an issue here: https://github.com/Azure/azure-functions-durable-extension/issues
I develop au Universal App using MVVM-Light.
On a page, there is a list of comments coming from a WebService. If the current user is the author of a comment, I show a FlyoutMenu allowing him to "Edit" or "Delete" its comment. There is also a AppBarButton for adding a new comment:
My problem is that the comments are never refreshed after the first load of this page...
I use a "LoadComments()" method in the ViewModel that allows me to get the comments when I arrive on the page, but also after editing, deleted or added an item:
private async void LoadComments()
{
List<Comment> commentsWS = await WebServiceGetCommentList();
if (commentsWS != null)
Comments = new ObservableCollection<Commentaire>(commentsWS);
}
This method so calls another method "WebServiceGetCommentList()" that prepares the call to the WebService, in the same ViewModel:
private async Task<List<Comment>> WebServiceGetCommentList()
{
// Parameters
List<KeyValuePair<string, string>> parametres = new List<KeyValuePair<string, string>>();
parametres.Add(new KeyValuePair<string, string>("option", _currentUserAccount.option));
parametres.Add(new KeyValuePair<string, string>("id_article", Article.id_article.ToString()));
// Call WebService and deserialize
Exception custEx = null;
try
{
List<Comment> comments = await WebServices.GetCommentList(_currentUserAccount.url, parametres, "");
return comments;
}
// Exceptions
catch (Exception e)
{
...
}
return null;
}
I then go in the "GetComments()" method on the "WebServices" class:
public static async Task<List<Comment>> GetCommentList(String url, List<KeyValuePair<String, String>> parametres, String protocol)
{
// Call WebService and deserialize
var response = await JSONParser.getJSONFromUrl(url, parametres, "");
List<Comment> comments = new List<Comment>();
WsResponse wsResponse = ManageWsReponse(response, Constants.WebServiceTask.GetCommentList.Value);
try
{
WsResponseResult wsResponseResult = JsonConvert.DeserializeObject<WsResponseResult>(wsResponse.data.ToString());
comments = JsonConvert.DeserializeObject<List<Comment>>(wsResponseResult.result.ToString());
return comments;
}
catch (Exception e)
{
throw new DeserializeException("Deserialize exception", e, DateTime.Now, "Comment");
}
}
This method calls the "getJSONFromUrl()" method in the "JSONParser" class that launches the "client.GetAsync()":
public static async Task<string> getJSONFromUrl(String url, List<KeyValuePair<String, String>> parameters, String protocol)
{
var client = new HttpClient();
// Preparing URI
string sParameters = null;
int i = 1;
foreach (var param in parameters)
{
sParameters += param.Key + "=" + param.Value;
sParameters += i != parameters.Count ? "&" : string.Empty;
i++;
}
var uri = new Uri(url + "?" + sParameters);
// Calls the WebService
var response = await client.GetAsync(uri, HttpCompletionOption.ResponseHeadersRead);
// Code and results
var statusCode = response.StatusCode;
// EnsureSuccessStatusCode throws exception if not HTTP 200
response.EnsureSuccessStatusCode();
// responseText
var responseText = await response.Content.ReadAsStringAsync();
return responseText;
}
I can add, delete or edit a comment with success, but when I'm back to this method "LoadComments()", the changes are not taken into account, and I get the same list than at the first call...
I also placed breakpoints in the "GetJSONFromURL()" method and I don't see the added, deleted or edited comments in the response var.
In the same time, if I copy the URI in a brower, for calling the same WebService with the same parameters, the changes are taken into account.
=> I think so there is a caching on client.GetAsync(), but I don't see how to desactive it, or force it to refresh datas...
I tried this solution httpclient-caching that doesn't work for me.
I think so that there is cache managing cause when I
That's the platform caching. I haven't had any success with the Cache-Control headers, the most reliable way to address the issue is to make sure the request is different.
Add an additional parameter - a timestamp. As the request is different, the platform cannot used the cached response.
parametres.Add(new KeyValuePair<string, string>("mytmstmp", DateTime.Now.Ticks);
Or: Use an additional header that allows for a date. I've used:
"If-Modified-Since", DateTime.UtcNow.ToString(CultureInfo.InvariantCulture)
I'm writing a RESTful API in Web API and I'm not sure how to handle errors effectively. I want the API to return JSON, and it needs to consist of the exact same format every single time - even on errors. Here are a couple of examples of what a successful and a failed response might look like.
Success:
{
Status: 0,
Message: "Success",
Data: {...}
}
Error:
{
Status: 1,
Message: "An error occurred!",
Data: null
}
If there is an exception - any exception at all, I want to return a response that is formed like the second one. What is the foolproof way to do this, so that no exceptions are left unhandled?
Implement IExceptionHandler.
Something like:
public class APIErrorHandler : IExceptionHandler
{
public Task HandleAsync(ExceptionHandlerContext context, CancellationToken cancellationToken)
{
var customObject = new CustomObject
{
Message = new { Message = context.Exception.Message },
Status = ... // whatever,
Data = ... // whatever
};
//Necessary to return Json
var jsonType = GlobalConfiguration.Configuration.Formatters.JsonFormatter;
json.SerializerSettings.Formatting = Newtonsoft.Json.Formatting.Indented;
var response = context.Request.CreateResponse(HttpStatusCode.InternalServerError, customObject, jsonType);
context.Result = new ResponseMessageResult(response);
return Task.FromResult(0);
}
}
and in the configuration section of WebAPI (public static void Register(HttpConfiguration config)) write:
config.Services.Replace(typeof(IExceptionHandler), new APIErrorHandler());