I have a resource that looks something like this:
/users/{id}/summary?format={format}
When format is "xml" or "json" I respond with a user summary object that gets automagically encoded by WCF - fine so far. But when format equals "pdf", I want my response to consist of a trivial HTTP response body and a PDF file attachment.
How is this done? Hacking on WebOperationContext.Current.OutgoingResponse doesn't seem to work, and wouldn't be the right thing even if it did. Including the bits of the file in a CDATA section or something in the response isn't safe. Should I create a subclass of Message, then provide a custom IDispatchMessageFormatter that responds with it? I went a short distance down that path but ultimately found the documentation opaque.
What's the right thing?
It turns out that what I need is WCF "raw" mode, as described here. Broadly speaking, I want to do this:
[OperationContract, WebGet(UriTemplate = "/users/{id}/summary?format={format}"]
public Stream GetUserSummary(string id, string format)
{
if(format == "pdf")
{
WebOperationContext.Current.OutgoingResponse.ContentType = "application/pdf";
return new MemoryStream(CreatePdfSummaryFileForUser(id));
}
else
{
// XML or JSON serialization. I can't figure out a way to not do this explicitly, but my use case involved custom formatters anyway so I don't care.
}
}
In theory you could do it with a multi-part content MIME type (see http://www.faqs.org/rfcs/rfc2387.html). However, it would be much easier to return a URL in the XML/JSON response and the client can do a GET on that link to return the file.
Related
I’ve been working on a simple function with the serverless framework that gets some data in a http POST, does some analysis and sends the results back. I got it working locally on my machine using serverless-offline but when it comes to deploying it I’m getting an error parsing the event.body.
Logging out the event.body it’s a string that looks like this:
----------------------------267253304929569989286258
Content-Disposition: form-data; name="text"
TEST
----------------------------267253304929569989286258--
so it makes sense that the parse is failing but I have no idea why this error it happening.
Any suggestions? I’ve tried a bunch of different things but am completely stumped.
Thanks in advance!
You can't JSON.parse that event.body cause it isn't JSON. It looks like whatever POSTed that data is using a multipart form POST style request rather than sending JSON. How are you invoking the HTTP POST?
I had the same issue and after a lot of debugging noticed 2 important things:
1.When the content type is application/x-www-form-urlencoded you might need to parse the data in a different way:
const qs = require('querystring');
module.exports.run = async event => {
try {
const data = qs.parse(event.body);
console.info('DATA:', data);
} catch(e) {
console.error(e.message);
}
}
2.When the Content-Type of the request is multipart/form-data the parsing will be even more complicated. I will suggest extra dependency to parse it like multiparty or any other of your choice
Thank you #Brian Winant! I am putting the answer here as a screenshot so it's clearer. In Postman, do the following:
AWS Lambda would return event.body as encoded query strings if the content-type is x-www-urlencoded. To have it return a JSON string you can then parse, send JSON data and set content-type as application/json.
I have created a jax-rs rest api and tested it with rest-assured. All tests are green. Now I am trying to create an html/js front end for it.
My problem is I do not know how my json objects should look like to be accepted by my rest api. Thanks to restassured/jax-rs I never handled request strings. I fill in objects and I get objects, (un)marshaling (json) is invisible.
Is there any way I can see (debug) what strings are created by rest-assured/java and sent over the "wire"?
If you want to log the request body you can do:
given().log().body(). ..
Or if you want to log the response body you can do:
.. .then().log().body(). ..
See documentation on logging for more details.
I'm not a RestAssured used, so I can't answer your question directly, but here are some ideas that may help you out.
I don't know what serializer RestAssured uses under the hood, but Resteasy on Wildfly uses Jackson by default. I would get familiar with this library. For less trivial application, you may need to dig into its APIs directly to get your desired results. Here is it's documentation. For your particular case you can do something as simple as
ObjectMapper mapper = new ObjectMapper();
String jsonString = mapper.writeValueAsString(yourObject);
System.out.println(jsonString);
This will print out the POJO in JSON format, based on your getters in the class. This is at the most basic level. If you don't already have Jackson as a dependency, you can add
<dependency>
<groupId>com.fasterxml.jackson.core</groupId>
<artifactId>jackson-databind</artifactId>
<version>2.4.0</version>
</dependency>
A really good friend (tool) to have is cURL. It's a command line tool that allows you to make REST/HTTP (other protocols also) requests. Though for this particular case it wouldn't help, you could send a GET request to one your resources that serves up the same type that you accepted in your POST. That way, you can see the resulting JSON. This may be a little much at this point, but I would definitely look into this tool if you're going to be doing a lot of REST development.
You might also want to check out a Browser tool like [Postman for Chrome]
You should really get familiar with JSON format. Once you get familiar with it, and you start working with JSON framework, you'll notice that at a basic level, they all work similarly.
Java Object == JSON Object ( {} )
Java Collection/Array == JSON Array ( [] )
Java fields/properties == JSON keys
Getters are used for they keys and their values (for serialization)
Setters are used for deserialization
So for example you have this class
public class Person {
String name;
List<Person> friends;
public String getName() { return name; }
public void setName(String name) { return name; }
// Getter and Setter for friends
}
An instance of Person would produce the following JSON
{
"name" : "Peeskillet",
"friends": [
{
"name": "Lebron James"
},
{
"name": "Steph Curry"
}
]
}
It's actually pretty simple once you get the hang of it.
Oh and another thing you can do is add a logging filter on the server side as mentioned here.
As far as working with Javascript, there is a JSON.stringify(javascriptObject) that will serialize your Javacript objects to JSON strings. So generally, you can model your Javascript object like your Java objects.
Hope this helped.
In RestAssured just use this:
String body = resp.asString();
System.out.println(body);
Try this for Request Body
RequestSpecification httpRequest = RestAssured.given().urlEncodingEnabled(true);
..
..
..
System.out.println(" Body ==> "+ httpRequest.log().body());
And for response body:
System.out.println("Res Body ===>"+ response.getBody().prettyPrint());
I am writing a WCF client to a SOAP service that returns a mime multi-part result with binary data (actually, a PDF file). It uses a custom message encoder.
The service doesn't seem to mind if I make the request a single-part format, so I am able to get a result back. There are two problems with the result from what I can see:
It only seems to return the first part of the multi-part message.
The data I get back cannot be decoded by my custom encoder.
I have tried utilizing MTOM binding, but that messes up the request. It fails to add the "boundary" parameter in the content-type, so the server cannot understand the request.
I think what I want is a basic text SOAP request, but a response decoded MTOM-style. I have no idea how to set that up, however.
The closest solution I have found is this: http://blogs.msdn.com/b/carlosfigueira/archive/2011/02/16/using-mtom-in-a-wcf-custom-encoder.aspx
But it seems like a very invasive change to my project.
I figured this out. First of all, I was incorrect when I said that I was only getting the first part of the multi-part message using the MTOM encoder; I was getting the whole thing. I was looking at it in the debugger and the bottom must have gotten clipped in the debug viewer. Chalk it up to my inexperience manually looking at and deciphering multi-part messages.
To the second point, all I had to do was use the MTOM encoder when the Content-Type was multipart/related and everything worked just fine. If you read the referenced article above, it's all about dynamically detecting whether the message is multipart or regular text, and choosing the proper encoder based on that. Essentially, it's a custom encoder that has both a text encoder and MTOM encoder built into it, and switches back and forth based on the content-type of the incoming message.
Our project requires some post processing of the response message before it's handed off to the main program logic. So, we get the incoming SOAP content as an XML string, and do some XML manipulation on it.
This is a slight departure from the solution recommended in the article. All that's required in the article's solution is reading the message using the right encoder into a System.ServiceModel.Channels.Message, and returning that. In our solution, we need to interrupt this process and do the post-processing.
To do that, implement the following in your custom encoder:
public override Message ReadMessage(ArraySegment<byte> buffer, BufferManager bufferManager, string contentType)
{
//First, get the incoming message as a byte array
var messageData = new byte[buffer.Count];
Array.Copy(buffer.Array, buffer.Offset, messageData, 0, messageData.Length);
bufferManager.ReturnBuffer(buffer.Array);
//Now convert it into a string for post-processing. Look at the content-type to determine which encoder to use.
string stringResult;
if (contentType != null && contentType.Contains("multipart/related"))
{
Message unprocessedMessageResult = this.mtomEncoder.ReadMessage(buffer, bufferManager, contentType);
stringResult = unprocessedMessageResult.ToString();
}
else {
//If it's not a multi-part message, the byte array already has the complete content, and it simply needs to be converted to a string
stringResult = Encoding.UTF8.GetString(messageData);
}
Message processedMessageResult = functionToDoPostProccessing(stringResult);
return processedMessageResult;
}
I've read this example http://msdn.microsoft.com/en-us/library/ee476510.aspx about dynamic responses in wcf.
The sample on the bottom fit my goal pretty well. This is what i did:
[OperationContract]
[WebGet(UriTemplate = "/salaries({queryString})")]
Message GetSalaryByQuery(string queryString);
and my GetSalaryByQuery-Method:
public Message GetSalaryByQuery(string querystring)
{
if (WebOperationContext.Current.IncomingRequest.Accept == "application/json")
return WebOperationContext.Current.CreateJsonResponse<Result>(Salary.GetSalaryByQueryJson(querystring));
else
return WebOperationContext.Current.CreateAtom10Response(Salary.GetSalaryByQuery(querystring));
}
It is pretty similiar to the example i found.
But its not working however. It says that there is another parameter besides the message. I googled the message-class and it seems to me that its not possible to add an parameter to a message-response.
Is there a way to pass a parameter with the request and get a response with a message object?
Is there another way to get the dynamic response?
Thanks in advance.
I got it to work. I just deleted the Metadata-Enpoint and the behavior. My Webservice provides metadata on its own and therefore doesnt need to have the mex-Metadata defined.
In the latest ASP.NET MVC4 beta, how would you support conditional GET support via ETags? The ActionFilter would need to be able to complete the request to generate the ETag for the returned resource in order to compare to the If-None-Match header in the request. And then, regardless of whether the incoming ETag in the If-None-Match header was the same as the generated ETag, add the generated ETag to the ETag response header. But with ASP.NET MVC4, I have no idea where to begin. Any suggestions?
Personally, I'm not a fan of "framework magic" and prefer plain old code in the web methods, else we end up with something more akin to WCF, yuk.
So, within your Get web method, manually create the response like so:
var response = this.Request.CreateResponse(HttpStatusCode.OK, obj);
string hash = obj.ModifiedDate.GetHashCode().ToString();
response.Headers.ETag =
new EntityTagHeaderValue(String.Concat("\"", hash, "\""), true);
return response;
Please note that the ETag produced from the hash code of the timestamp is purely illustrative of a weak entity tagging system. It also shows the additional quotes required.
There is a ETagMessageHandler in the WebApiContrib which does what you need.
UPDATE
I have implemented RFC 2616's server side caching in WebApiContrib. Look for CachingHandler.
More info here.
More Update
This will be actively developed and expanded upon under CacheCow. This will include both client and server components. NuGet packages to be published soon are published now.
WebApiContrib's CachingHandler will still be maintained so any bugs or problems please let me know.
Luke Puplett's answer got me on the right track (+1), but note that you also have to read the ETag on the server side to avoid sending all the data with each request:
string hash = obj.ModifiedDate.GetHashCode().ToString();
var etag = new EntityTagHeaderValue(String.Concat("\"", hash, "\""), true);
if (Request.Headers.IfNoneMatch.Any(h => h.Equals(etag)))
{
return new HttpResponseMessage(HttpStatusCode.NotModified);
}
var response = this.Request.CreateResponse(HttpStatusCode.OK, obj);
response.Headers.ETag = etag;
return response;
It would also be a good idea to respect the If-Modified-Since header. See RFC 2616.
It seems this is what you are looking for (see section "Support for ETags"):
http://blogs.msdn.com/b/webdev/archive/2014/03/13/getting-started-with-asp-net-web-api-2-2-for-odata-v4-0.aspx
In case your model is stored deeper in domain and you are not able to apply the [ConcurrencyCheck] attribute, you can do that using the ODataModelBuilder:
ODataModelBuilder builder = new ODataConventionModelBuilder();
var myEntity = builder.EntitySet<MyEntity>("MyEntities");
myEntity.EntityType.Property(l => l.Version).ConcurrencyToken = true;
this will make it to add the "#odata.etag" property to a response body.