I am trying to upload file using Reactive spring fremework.If I only reqeset file by postman. It works fine. When I added addtional parameter Stirng as uploadType. It is always null. I tried postman as following:-
My controller code:-
#RestController
#RequestMapping(path = "/upload")
public class ReactiveUploadResource {
Logger LOGGER = LoggerFactory.getLogger(ReactiveUploadResource.class);
#RequestMapping(method = RequestMethod.POST, consumes = MediaType.MULTIPART_FORM_DATA_VALUE, produces = MediaType.APPLICATION_JSON_VALUE)
public Flux<String> uploadHandler(#RequestBody Flux<Part> parts, String uploadType) {
return (Flux<String>) parts
.filter(part -> part instanceof FilePart)
.ofType(FilePart.class) // convert the flux to FilePart
.flatMap(item -> saveFile(item, uploadType)); // save each file and flatmap it to a flux of results
}
}
Postman:-
I always get uploadType null. What is wrong? How can pass String or Enum in this reqeust?
Related
I'm facing a strange bug, where .NET Core 2.1 API seems to ignore a JSON body on certain cases.
I advised many other questions (e.g this one, which itself references others), but couldn't resolve my problem.
I have something like the following API method:
[Route("api/v1/accounting")]
public class AccountingController
{ sometimes it's null
||
[HttpPost("invoice/{invoiceId}/send")] ||
public async Task<int?> SendInvoice( \/
[FromRoute] int invoiceId, [FromBody] JObject body
)
{
// ...
}
}
And the relevant configuration is:
public IServiceProvider ConfigureServices(IServiceCollection services)
{
services
.AddMvcCore()
.AddJsonOptions(options =>
{
options.SerializerSettings.Converters.Add(new TestJsonConverter());
})
.AddJsonFormatters()
.AddApiExplorer();
// ...
}
Where TestJsonConverter is a simple converter I created for testing why things doesn't work as they should, and it's simple as that:
public class TestJsonConverter : JsonConverter
{
public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer)
{
var token = JToken.Load(reader);
return token;
}
public override bool CanRead
{
get { return true; }
}
public override bool CanConvert(Type objectType)
{
return true;
}
public override void WriteJson(JsonWriter writer, object value, JsonSerializer serializer)
{
throw new NotImplementedException("Unnecessary (would be neccesary if used for serialization)");
}
}
Calling the api method using Postman works, meaning it goes through the JSON converter's CanConvert, CanRead, ReadJson, and then routed to SendInvoice with body containing the parsed json.
However, calling the api method using HttpWebRequest (From a .NET Framework 4, if that matters) only goes through CanConvert, then routes to SendInvoice with body being null.
The request body is just a simple json, something like:
{
"customerId": 1234,
"externalId": 5678
}
When I read the body directly, I get the expected value on both cases:
using (var reader = new StreamReader(context.Request.Body))
{
var requestBody = await reader.ReadToEndAsync(); // works
var parsed = JObject.Parse(requestBody);
}
I don't see any meaningful difference between the two kinds of requests - to the left is Postman's request, to the right is the HttpWebRequest:
To be sure, the Content-Type header is set to application/json. Also, FWIW, the HttpWebRequest body is set as follows:
using(var requestStream = httpWebRequest.GetRequestStream())
{
JsonSerializer.Serialize(payload, requestStream);
}
And called with:
var response = (HttpWebResponse)request.GetResponse();
Question
Why does body is null when used with HttpWebRequest? Why does the JSON converter read methods are skipped in such cases?
The problem was in the underlying code of the serialization. So this line:
JsonSerializer.Serialize(payload, requestStream);
Was implemented using the default UTF8 property:
public void Serialize<T>(T instance, Stream stream)
{
using(var streamWriter = new StreamWriter(stream, Encoding.UTF8) // <-- Adds a BOM
using(var jsonWriter = new JsonTextWriter(streamWriter))
{
jsonSerializer.Serialize(jsonWriter, instance); // Newtonsoft.Json's JsonSerializer
}
}
The default UTF8 property adds a BOM character, as noted in the documentation:
It returns a UTF8Encoding object that provides a Unicode byte order
mark (BOM). To instantiate a UTF8 encoding that doesn't provide a BOM,
call any overload of the UTF8Encoding constructor.
It turns out that passing the BOM in a json is not allowed per the spec:
Implementations MUST NOT add a byte order mark (U+FEFF) to the
beginning of a networked-transmitted JSON text.
Hence .NET Core [FromBody] internal deserialization failed.
Lastly, as for why the following did work (see demo here):
using (var reader = new StreamReader(context.Request.Body))
{
var requestBody = await reader.ReadToEndAsync(); // works
var parsed = JObject.Parse(requestBody);
}
I'm not very sure. Certainly, StreamReader also uses UTF8 property by default (see remarks here), so it shouldn't remove the BOM, and indeed it doesn't. Per a test I did (see it here), it seems that ReadToEnd is responsible for removing the BOM.
For elaboration:
StreamWriter and UTF-8 Byte Order Marks
The Curious Case of the JSON BOM
I am using ParallelFlux for running many task.
but when i am receiving webClient response using bodyToFlux method its merging all the output response instead of getting one by one.
i want the output should be one by one not single string, is there any other method instead of bodyToFLux need to use.
request method:
Flux<String> responsePost = webClient.build()
//removed get,url and retrieve here
.bodyToFlux(String.class);
responsePost.subscribe(s -> {
//display response
});
response method:
public ParallelFlux<String> convertListToMap() {
//created list of string str
return Flux.fromIterable(str)
.parallel(3)
.runOn(Schedulers.parallel())
.map( s -> {
//some logic here
});
}
output:
parallel fulx reponse: springwebfluxparellelExample
Here instead of returning ParallelFlux create an
ResponseBody class with variable you want to return, assign your response to
variable inside ResponseBody and return it to caller of API function.
public ParallelFlux<ResponseBody> convertListToMap() {
//created list of string str
return Flux.fromIterable(str)
.parallel(3)
.runOn(Schedulers.parallel())
.map( s -> {
//some logic here
});
}
Flux<String> responsePost = webClient.build()
//removed get,url and retrieve here
.bodyToFlux(ResponseBody.class);
I try to call my AWS Lambda function (serverless backend) with my Android mobile app client. The AWS lambda function returns an ArrayList of POJO objects (as JSON).
The problem is that the android client AWS Lambda(JSON)DataBinder does not deserialize to my ArrayList of POJOs. I get an ArrayList of LinkedTreeMap (see code at onPostExecute() below).
At the android client side I'm using Android AWS SDK: com.amazonaws:aws-android-sdk-core:2.6
Here is some code:
public void readSurveyList(String strUuid, int intLanguageID) {
// Create an instance of CognitoCachingCredentialsProvider
// You have to configure at least an AWS identity pool to get access to your lambda function
CognitoCachingCredentialsProvider credentialsProvider = new CognitoCachingCredentialsProvider(
this.getApplicationContext(),
IDENTITY_POOL_ID,
Regions.EU_CENTRAL_1);
LambdaInvokerFactory factory = LambdaInvokerFactory.builder()
.context(this.getApplicationContext())
.region(Regions.EU_CENTRAL_1)
.credentialsProvider(credentialsProvider)
.build();
// Create the Lambda proxy object with default Json data binder.
myInterface = factory.build(MyInterface.class);
//create a request object (depends on your lambda function)
SurveyListRequest surveyListRequest = new SurveyListRequest(strUuid, intLanguageID);
// Lambda function in async task with definiton of
// request object (-> SurveyListRequest)
// response object (-> ArrayList<SurveyListItem>>)
new AsyncTask<SurveyListRequest, Void, ArrayList<SurveyListItem>>() {
#Override
protected ArrayList<SurveyListItem> doInBackground(SurveyListRequest... params) {
try {
return myInterface.ReadSurveyList(params[0]);
} catch (LambdaFunctionException lfe) {
Log.e("TAG", String.format("echo method failed: error [%s], details [%s].", lfe.getMessage(), lfe.getDetails()));
return null;
}
}
#Override
protected void onPostExecute(ArrayList<SurveyListItem> surveyList) {
// PROBLEM: here i get a ArrayList of LinkedTreeMap
}
}.execute(surveyListRequest);
}
Here is the code of my lambda function Interface:
public interface MyInterface {
#LambdaFunction
ArrayList<SurveyListItem> ReadSurveyList (SurveyListRequest surveyListRequest);
}
I would expect to get a list of my POJO objects. I found a lot of discussions about Gson and ArrayList type and solutions based on TypeToken (e.g. Gson TypeToken with dynamic ArrayList item type). Maybe same problem ...
I found a solution using a custom LambdaDataBinder. I have specified the type of my POJO-class "SurveyListItem" in deserialize function. The Gson uses the TypeToken definition and converts the JSON string correct to the list of POJOs (in my case "SurveyListItem" objects).
Here is the sourcecode of MyLambdaDataBinder:
public class MyLambdaDataBinder implements LambdaDataBinder {
private final Gson gson;
Type mType;
//CUSTOMIZATION: pass typetoken via class constructor
public MyLambdaDataBinder(Type type) {
this.gson = new Gson();
mType = type;
}
#Override
public <T> T deserialize(byte[] content, Class<T> clazz) {
if (content == null) {
return null;
}
Reader reader = new BufferedReader(new InputStreamReader(new ByteArrayInputStream(content)));
//CUSTOMIZATION: Original line of code: return gson.fromJson (reader, clazz);
return gson.fromJson(reader, mType);
}
#Override
public byte[] serialize(Object object) {
return gson.toJson(object).getBytes(StringUtils.UTF8);
}
}
Here is how to use the custom MyLambdaDataBinder. Use your POJO instead of "SurveyListItem":
myInterface = factory.build(LambdaInterface.class, new MyLambdaDataBinder(new TypeToken<ArrayList<SurveyListItem>>() {}.getType()));
I am implementing Jersey based REST API and using swagger to generate HTML based documentation for the same. I am using swagger's annotations to read and scan the resources to generate documentation. I have specified response for each resource using #ApiResponse annotation as below:
#Path("/hello")
#Api(value = "Hello World" )
public class HelloRest
{
#GET
#ApiOperation(value="Hello world", httpMethod="GET")
#ApiResponses(value={ #ApiResponse(code = 200, message = "Success", response = WebservicesErrorResponse.class, reference = "C:/Desktop/hello.json")
#ApiResponse(code = 404, message = "Not found", response = WebservicesErrorResponse.class)})
#Produces({"application/json", "application/xml"})
public Response helloWorld()
{
return Response.status(WebservicesCommonTypes.SUCCESS).entity("Hello rest API").build();
}
}
It is working fine and it is generating HTML based documentation as below:
As it shows the complete structure (Model and example value) of response if response code is 404. And in example value, it is not showing the values, only showing the type for each parameter for the model.
I want to show the sample example schema for the response so that client can understand that what would be the exact response for each response. I researched on it and I found that there is one attribute:
#ApiResponse(reference = "") - Specifies a reference to the response type. The specified reference can be either local or remote and will be used as-is, and will override any specified response() class.
I tried it and I give it a path for my sample.json file as below:
#ApiResponse(code = 200, message = "Success", response = WebServicesErrorResponse, reference = "http://localhost:9001/myinstanceofapplication/html/api-doc/hello.json")
and I also tried to give another path that is local path like below:
#ApiResponse(code = 200, message = "Success", response = WebservicesErrorResponse.class, reference = "C:/Desktop/hello.json")
but when swagger generate document for it then it gives following:
It is showing C:/Desktop/hello.json is not defined!
I have researched and tried lot many solutions but couldn't able to give proper reference to it. I found that this is an issue by https://github.com/swagger-api/swagger-ui/issues/1700 and https://github.com/swagger-api/swagger-js/issues/606.
So how can I use reference attribute of #ApiResponse to that swagger could show the sample XML/JSON swagger UI. My model class is below:
#XmlRootElement(name="response")
#XmlAccessorType(XmlAccessType.FIELD)
public class WebservicesErrorResponse
{
#XmlElement
private int code;
#XmlElement
private String message;
public WebservicesErrorResponse(){ }
public WebservicesErrorResponse(int code, String message)
{
this.code = code;
this.message = message;
}
public int getCode()
{
return code;
}
public void setCode(int code)
{
this.code = code;
}
public String getMessage()
{
return message;
}
public void setMessage(String message)
{
this.message = message;
}
}
and I want to show following sample XML in the swagger UI:
<?xml version="1.0"?>
<response>
<code>200</code>
<message>success</message>
</response>
You need to annotate your model class (not the API resource/method!) with the #ApiModel and #ApiModelProperty annotations as described here.
For what you want to achieve, it would probably be enough to annotate your model members as follows:
#ApiModelProperty(example = "200")
#XmlElement
private int code;
#ApiModelProperty(example = "success")
#XmlElement
private String message;
If that doesn't work, try putting the annotation on the getters (I'm not really familiar with the XML side of this, have only done it for JSON).
...or "How to determine which WCF method will be called based on URI?"
In a WCF service, suppose a method is invoked and I have the URI that was used to invoke it. How can I get information about the WCF end point, method, parameters, etc. that the URI maps to?
[OperationContract]
[WebGet(UriTemplate = "/People/{id}")]
public Person GetPersonByID(int id)
{
//...
}
For instance, if the URI is: GET http://localhost/Contacts.svc/People/1, I want to get this information: service name (Service), Method (GetPersonByID), Parameters (PersonID=1). The point is to be able to listen for the request and then extract the details of the request in order to track the API call.
The service is hosted via http. This information is required before the .Net caching can kick in so each call (whether cached or not) can be tracked. This probably means doing this inside HttpApplication.BeginRequest.
FYI I'm hoping to not use reflection. I'd like to make use of the same methods WCF uses to determine this. E.g. MagicEndPointFinder.Resolve(uri)
Here is what I ended up doing, still interested if there is a cleaner way!
REST
private static class OperationContractResolver
{
private static readonly Dictionary<string, MethodInfo> RegularExpressionsByMethod = null;
static OperationContractResolver()
{
OperationContractResolver.RegularExpressionsByMethod = new Dictionary<string, MethodInfo>();
foreach (MethodInfo method in typeof(IREST).GetMethods())
{
WebGetAttribute attribute = (WebGetAttribute)method.GetCustomAttributes(typeof(WebGetAttribute), false).FirstOrDefault();
if (attribute != null)
{
string regex = attribute.UriTemplate;
//Escape question marks. Looks strange but replaces a literal "?" with "\?".
regex = Regex.Replace(regex, #"\?", #"\?");
//Replace all parameters.
regex = Regex.Replace(regex, #"\{[^/$\?]+?}", #"[^/$\?]+?");
//Add it to the dictionary.
OperationContractResolver.RegularExpressionsByMethod.Add(regex, method);
}
}
}
public static string ExtractApiCallInfo(string relativeUri)
{
foreach (string regex in OperationContractResolver.RegularExpressionsByMethod.Keys)
if (Regex.IsMatch(relativeUri, regex, RegexOptions.IgnoreCase))
return OperationContractResolver.RegularExpressionsByMethod[regex].Name;
return null;
}
}
SOAP
private static void TrackSoapApiCallInfo(HttpContext context)
{
string filePath = Path.GetTempFileName();
string title = null;
//Save the request content. (Unfortunately it can't be written to a stream directly.)
context.Request.SaveAs(filePath, false);
//If the title can't be extracted then it's not an API method call, ignore it.
try
{
//Read the name of the first element within the SOAP body.
using (XmlReader reader = XmlReader.Create(filePath))
{
if (!reader.EOF)
{
XmlNamespaceManager nsManager = new XmlNamespaceManager(reader.NameTable);
XDocument document = XDocument.Load(reader);
//Need to add the SOAP Envelope namespace to the name table.
nsManager.AddNamespace("s", "http://schemas.xmlsoap.org/soap/envelope/");
title = document.XPathSelectElement("s:Envelope/s:Body", nsManager).Elements().First().Name.LocalName;
}
}
//Delete the temporary file.
File.Delete(filePath);
}
catch { }
//Track the page view.
}