grails xml unmarshalling - grails

Since Grails 1.1.x, they have supported XML and JSON unmarshalling for REST requests. I can't seem to get this working in version 2.1.0. Here is the relevant files from the example project I am using to test the functionality:
UrlMappings.groovy
static mappings = {
"/$action/$id?"(controller:'verification',parseRequest:true)
"/"(view:"/index")
"500"(view:'/error')
}
Tester.groovy
class Tester {
String name
String vendor
String toString() {
return "$name $vendor"
}
}
VerificationController.groovy
class VerificationController {
def save() {
Tester tester = new Tester(params.tester)
log.error "Tester = ${tester}"
log.error "Request XML = ${request.XML}"
}
}
XML send with REST call
<?xml version="1.0" encoding="utf-8"?>
<tester>
<name>Windows</name>
<vendor>Microsoft</vendor>
</tester>
When I pass the XML in, the controller log statements output this:
Tester = null null
Request XML = WindowsMicrosoft
My bewilderment would be in why it recognizes it as XML (by putting it in the XML field of the request) but won't parse it and put it in params as defined here

After trying for a few hours with the same problem I found a solution for me.
My problem was that I didn't had a content-type defined in my REST call.
So if you add content-type: application/xml to your rest call it should work.

I had the same problem, with almost exactly the same setup. I believe your problem could lie within the UrlMapping configuration. Initially I had the following.
"/rest/airport/$iata?"(controller: "airport", action: "restHandler", parseRequest: "true")
When I PUT/POST XML to that URI, it would show up correctly in request.XML, but it would never show up in the params object. I then realized I had the parseRequest boolean in quotes. Removing that fixed the issue.
"/rest/airport/$iata?"(controller: "airport", action: "restHandler", parseRequest: true)
Now, if your code is truly the same as what you have above, your problem may not be exactly the same. However, what might help is making some kind of change to your UrlMappings to see if you could get it working a different way.
At first I thought it might have been the single quotes you had, but that seemed to work fine either way I tried it. So, I would suggest just changing your URI mapping to something else and be very picky about the formatting. In the end it was just a minor formatting issue in the UrlMappings.groovy file that fixed my problem.

Related

Grails 2.5.5: Unable to access the request body of a PUT request?

I'm attempting to implement a RESTful API using Grails 2.5.5, and I'm running into a few issues.
It appears that Grails does not automatically map any methods for the corresponding HTTP methods, so I'm editing UrlMappings.groovy.
For example, take the following URLs:
GET /v1/1/persons/ <--- List of persons
POST /v1/1/persons/ <--- Create a new person
PUT /v1/1/persons/1234 <--- Edit person with ID of 1234
These are my url mappings:
"/v1/$appId/$controller/$action?/$id?(.$format)?" {
namespace = "v1"
}
"/v1/$appId/$controller"(action: "save", method: "POST") {
namespace = "v1"
}
"/v1/$appId/$controller/$id"(action: "update", method: "PUT") {
namespace = "v1"
}
So now, the first mapping will handle the GET request in my example urls as well as other generic urls.
The second mapping will handle the second url from my example urls.
And lastly, the third mapping handles the third url from my example urls.
The issue I'm facing now is that my command object isn't getting bound properly for my PUT request. The POST request works fine however.
These are my methods:
def save(MyCommand cmd) {
// works great
}
def update(MyCommand cmd) {
// cmd properties are null
// params.id is bound though. So I'm getting the path variable.
}
As you can see, the logic is very simple.
But I'm completely stumped as to why I can't get the request body in the PUT method.
Additional question: How can I get the above urls to work in addition to this url?:
/v1/1/persons/1234/status
I tried the following mapping, but it does not seem to work:
"/v1/$appId/$controller/$id/$action" {
namespace = "v1"
}
It feels like I'm stuck in this URLMappings hell!

Dynamic view id using pretty faces navigation refuses to work

I am attempting to migrate an application from JSF 1.2 to JSF 2.1. The code below worked in the 1.2.
I am using PrettyFaces 3.3.3, MyFaces 2.1.
in pretty-config.xml:
<url-mapping id="seSite">
<pattern value="/sites/#{seViewChooserBean.urlSiteType}/#{seViewChooserBean.siteId}"/>
<view-id value="#{seViewChooserBean.getSiteViewId}"/>
</url-mapping>
<url-mapping id="seSiteProps">
<pattern value="/sites/#{sePropsBean.urlSiteType}/#{sePropsBean.siteId}/properties"/>
<view-id value="/pages/se/site/props.xhtml"/>
<action>#{sePropsBean.init}</action>
</url-mapping>
I have a request with URL: http://example.com/myapp/sites/object/309847
This request successfully matches the url mapping id "seSite" and getSiteViewId is invoked on seViewChooserBean and returns the result "pretty:seSiteProps". I have debugged and confirmed this. For your reference this is the bean code for ViewChooserBean.java:
public String getSiteViewId() {
if (siteType == SiteType.TYPE) {
// redirect to tag list view
initSiteBean("seTagListBean", TagListBean.class);
return "pretty:seTagList";
}
else {
// redirect to site properties view
initSiteBean("sePropsBean", PropertiesBean.class);
return "pretty:seSiteProps";
}
}
After that prettyfaces then attempts to forward to the new view id seSiteProps but the new generated URL is not processed by pretty faces because (from the logs): "Request is not mapped using PrettyFaces. Continue."
So I get 404 response for URL http:://example.com/myapp/sites/object/309847/properties.
Note that this url match to view id seSiteProps.
I have debugged this up into the pretty faces filter and discovered the following:
After the initial request for http://example.com/myapp/sites/object/309847, the DynaviewEngine.processDynaView is invoked and generates the correct target url http:://example.com/sites/object/309847/properties and forwards via faces request.
Then, with a breakpoint in PrettyFilter.doFilter() I observed the following:
In PrettyFilter.doFilter() method: isUrlMappingForward(req) returns false, therefore request is not processed by prettyfaces. Why??
// isUrlMappingForward returns false. The request has url http:://example.com/myapp/sites/object/309847/properties on it.
if (!isUrlMappingForward(req))
{
mapping = getConfig().getMappingForUrl(url);
}
Also, note that if I put the request http:://example.com/myapp/sites/object/309847/properties directly in the browser the page IS processed by prettyfaces and isUrlMappingForward(req) returns true and it loads correctly in the browser.
I was thinking I've missed something obvious here as the problem hasn't been reported elsewhere as far as I can tell. Any help is greatly appreciated. Thanks.
Brett
Actually I'm very surprised that returning PrettyFaces navigation strings from dynaview methods ever worked. This isn't documented anywhere and I doubt that this has been tested in detail. So basically you are using the dynaview feature in an very weird way.
So I recommend to return plain JSF view IDs instead which should work fine. See the documentation for details:
http://ocpsoft.org/docs/prettyfaces/3.3.3/en-US/html/Configuration.html#config.dynaview

Using the Json.NET serializer in an MVC4 project

I'm starting to learn Json.NET, but I'm having trouble using its serializer. I have a new MVC4 project with a Web.API service:
public class PTE_TestsController : ApiController {
PTE_TestsRepository _repository = new PTE_TestsRepository();
// GET /api/PTE_Tests/5
public HttpResponseMessage<string> Get(int id) {
try {
PTE_Test test = _repository.GetTest(id);
return new HttpResponseMessage<string>(JsonConvert.SerializeObject(test));
} catch {
return new HttpResponseMessage<string>(HttpStatusCode.NotFound);
}
}
}
JsonConvert.SerializeObject() works as expected and returns a string. My Web.API controller returns that as part of an HttpResponseMessage. The end result, when viewed in Fiddler, is not JSON data, but JSON data being serialized again (I think):
"{\"ID\":1,\"Name\":\"Talar Tilt\",\"TagID\":1,\"PracticeID\":1,
\"SpecificAreaID\":1,\"TypeID\":1,\"VideoID\":1,\"PicID\":1}"
Does someone know how to turn off the default serializer so I can use Json.NET directly? By the way, I'm not using the default serializer because I can't figure out how to make it work with complex objects (PTE_Test will eventually contain members of type List).
Alternately, it will also solve my problem if someone can explain how to use the default serializer with complex objects. MSDN's explanation didn't help me.
Rick Strahl has a blog on that here with a code that works.
As others have pointed out, you need to create a formatter and replace the DataContractSerializer with the JSON.NET serializer. Although, if you're not in a rush for JSON.NET specifically, rumor has it that next beta/rc is going to have support for JSON.NET built in.
Conceptually, however, you're missing part of the magic of WebAPI. With WebAPI you return your object in it's native state (or IQueryable if you want OData support). After your function call finishes the Formatter's take over and convert it into the proper shape based on the client request.
So in your original code, you converted PTE_Test into a JSON string and returned it, at which point the JSON Formatter kicked in and serialized the string. I modified your code as follows:
public class PTE_TestsController : ApiController {
PTE_TestsRepository _repository = new PTE_TestsRepository();
public HttpResponseMessage<PTE_Test> Get(int id) {
try {
PTE_Test test = _repository.GetTest(id);
return new HttpResponseMessage(test);
} catch {
return new HttpResponseMessage<string>(HttpStatusCode.NotFound);
}
}
}
Notice how your function returns PTE_Test instead of string. Assuming the request came in with a request header of Accept = application/json then the JSON formatter will be invoked. If the request had a header of : Accept = text/xml the XML formatter is invoked.
There's a decent article on the topic here. If you're a visual learner, Scott Gu shows some examples using fiddler in this video, starting around 37 minutes. Pedro Reys digs a little deeper into content negotiation here.
The way to do this is to use formatters.
Check out: https://github.com/WebApiContrib/WebAPIContrib/tree/master/src/WebApiContrib.Formatting.JsonNet.
Json.NET support will be in the RC release of Web API.

What is the correct response to an HTTP POST request?

For a POST method, the W3 specs say:
If a resource has been created on the origin server, the response
SHOULD be 201 (Created) and contain an entity which describes the
status of the request and refers to the new resource, and a Location
header (see Section 10.4).
http://www.ietf.org/internet-drafts/draft-ietf-httpbis-p2-semantics-05.txt (section 8.5)
The standard response actually seems to be to send a Redirect to the newly created resource.
I'm building my site with ASP.NET MVC, and tried to follow the spec, so created a ResourceCreatedResult class:
public class ResourceCreatedResult : ActionResult
{
public string Location { get; set; }
public override void ExecuteResult(ControllerContext context)
{
context.HttpContext.Response.Clear();
context.HttpContext.Response.StatusCode = 201;
context.HttpContext.Response.ClearHeaders();
context.HttpContext.Response.AddHeader("Location", Location);
}
}
And my action looks something like this:
[AcceptVerbs(HttpVerbs.Post)]
public ActionResult CreateNew(string entityStuff)
{
Entity newEntity = new Entity(entityStuff);
IEntityRepository entityRepository = ObjectFactory.GetInstance<IEntityRepository>();
entityRepository.Add(newEntity);
ActionResult result = new ResourceCreatedResult()
{ Location = Url.Action("Show", new { id = newEntity.Id }) };
return result;
}
However, IE, Firefox and Chrome all fail to redirect to the new resource. Have I messed up generating the correct response, or do web browsers not expect this type of response, instead relying on servers to send a Redirect response?
To be explicit, browsers (including modern browsers like Firefox 3 and IE8) do not "take the hint" and follow up an HTTP 201: Created response with a GET request to the URI supplied in the Location header.
If you want browsers to go to the URI supplied in the Location header, you should send an HTTP 303: See Other status instead.
Redirect after post or post/redirect/get is something your application must do to be user friendly.
Edit. This is above and beyond the HTTP specifications. If we simply return a 201 after a POST, the browser back button behaves badly.
Note that Web Services requests (which do NOT respond to a browser) follow the standard completely and do NOT redirect after post.
It works like this.
The browser POSTS the data.
Your application validates the data. If it's invalid, you respond with the form so they can fix it and POST.
Your application responds with a redirect.
The browser gets the redirect and does a GET.
Your application sees the GET and responds.
Now -- hey presto! -- the back button works.
My solution is to respond with a '201 Created' containing a simple page with a link to the new resource, and a javascript redirect using location.replace().
This lets the same code work for API and browser requests, plays nicely with Back and Refresh buttons, and degrades gracefully in old browsers.
As stated in the spec the response SHOULD be a HTTP 201 with redirect. So it isn't mandatory for a browser vendor to implement the correct answer...
You should try to change to a 30x code to see if it is correctly redirected. If so, it's a browser problem, else it may come from your code (I don't know anything in ASP.NET so I can't "validate" your code)
Shouldn't that only count for when something is "Created" and therefore a simple redirect to action should be genuinely sufficient?

Is it possible to implement X-HTTP-Method-Override in ASP.NET MVC?

I'm implementing a prototype of a RESTful API using ASP.NET MVC and apart from the odd bug here and there I've achieve all the requirements I set out at the start, apart from callers being able to use the X-HTTP-Method-Override custom header to override the HTTP method.
What I'd like is that the following request...
GET /someresource/123 HTTP/1.1
X-HTTP-Method-Override: DELETE
...would be dispatched to my controller method that implements the DELETE functionality rather than the GET functionality for that action (assuming that there are multiple methods implementing the action, and that they are marked with different [AcceptVerbs] attributes). So, given the following two methods, I would like the above request to be dispatched to the second one:
[ActionName("someresource")]
[AcceptVerbs(HttpVerbs.Get)]
public ActionResult GetSomeResource(int id) { /* ... */ }
[ActionName("someresource")]
[AcceptVerbs(HttpVerbs.Delete)]
public ActionResult DeleteSomeResource(int id) { /* ... */ }
Does anybody know if this is possible? And how much work would it be to do so...?
You won't be able to use the [AcceptVerbs] attribute as-is since it's tied to the request's actual HTTP verb. Fortunately the [AcceptVerbs] attribute is very simple; you can see the source for yourself at http://www.codeplex.com/aspnet/SourceControl/changeset/view/21528#266431.
In short, subclass AcceptsVerbsAttribute and override the IsValidForRequest() method. The implementation would be something like the following:
string incomingVerb = controllerContext.HttpContext.Request.Headers["X-HTTP-Method-Override"] ?? controllerContext.HttpContext.Request.Method;
return Verbs.Contains(incomingVerb, StringComparer.OrdinalIgnoreCase);
Levi's answer is great. Additionally, I added a check in the custom AcceptsVerbsAttribute that also examines the FORM collection, so you can simply put a hidden input to trigger the DELETE (similar to MVC 2's Html.HttpMethodOverride(HttpVerbs.Delete)).
<input name="X-HTTP-Method-Override" type="hidden" value="DELETE" />
Change the incomingVerb assignment to:
string incomingVerb = controllerContext.HttpContext.Request.Headers["X-HTTP-Method-Override"] ?? controllerContext.HttpContext.Request.Form["X-HTTP-Method-Override"] ??controllerContext.HttpContext.Request.HttpMethod;
Be careful with this approach! See a related post by Stephen Walther.
Hopefully this helps someone.
Insert to Form:
<%= Html.HttpMethodOverride(HttpVerbs.Delete) %>
This conversation is a bit old, but I wanted to share what I have found using mvc 2:
Browsers support two HTTP verbs: GET and POST, but ASP.NET MVC 2 allows you to simulate Put, Get, and Delete using Html.HttpMethodOverride helper method. Internally, this works by sending the verb in an X-HTTP-Method-Override form field. The behavior of HttpMethodOverride is used by the [AcceptVerbs] attribute as well as the new shorter verb attributes:
For example, the action declaration:
[ActionName("someresource")]
[HttpDelete]
public ActionResult DeleteSomeResource()
should take responsibility for your get request that has the X-HTTP-Method-Override set to Delete.
I'm surprised that this hasn't been mentioned yet, but ASP.NET MVC natively supports X-HTTP-Method-Override and has been doing so from at least version 2. There's no need to write custom code to handle this.
It work in the following way:
Inside AcceptVerbsAttribute (also proxied by [HttpPut], [HttpPost], etc), there's an IsValidForRequest method. Inside that method, it checks with Request.GetHttpMethodOverride(), which returns the proper overriden HTTP method with the following conditions:
Overriding is only supported in POST requests. All others are ignored.
If the X-HTTP-Method-Override value is GET or POST, it's ignored. This makes sense, as you'd never need to override with these values.
It looks for X-HTTP-Method-Override in the following places in this priority:
1) HTTP Header
2) Form Body
3) Query String
If you're really curious, here's how GetHttpMethodOverride() looks (from MVC 3's source code):
public static class HttpRequestExtensions {
internal const string XHttpMethodOverrideKey = "X-HTTP-Method-Override";
public static string GetHttpMethodOverride(this HttpRequestBase request) {
if (request == null) {
throw new ArgumentNullException("request");
}
string incomingVerb = request.HttpMethod;
if (!String.Equals(incomingVerb, "POST", StringComparison.OrdinalIgnoreCase)) {
return incomingVerb;
}
string verbOverride = null;
string headerOverrideValue = request.Headers[XHttpMethodOverrideKey];
if (!String.IsNullOrEmpty(headerOverrideValue)) {
verbOverride = headerOverrideValue;
}
else {
string formOverrideValue = request.Form[XHttpMethodOverrideKey];
if (!String.IsNullOrEmpty(formOverrideValue)) {
verbOverride = formOverrideValue;
}
else {
string queryStringOverrideValue = request.QueryString[XHttpMethodOverrideKey];
if (!String.IsNullOrEmpty(queryStringOverrideValue)) {
verbOverride = queryStringOverrideValue;
}
}
}
if (verbOverride != null) {
if (!String.Equals(verbOverride, "GET", StringComparison.OrdinalIgnoreCase) &&
!String.Equals(verbOverride, "POST", StringComparison.OrdinalIgnoreCase)) {
incomingVerb = verbOverride;
}
}
return incomingVerb;
}
}
Have you looked at Simply Restful Routing? It already does this.
Edited Feb 2010 to add: Method overrides are built into MVC 2.
The X-HTTP-Method-Override is a custom header and most likely isn't supported by your web container.
Are you calling this from a web page? If so, you should probably use XmlHttpRequest with DELETE (or whatever verb you want). Better yet, use a JS framework to do the heavy lifting for you.
You could create an ActionFilter that implements OnActionExecuting, which fires before the controller action is invoked. You could then interrogate the request headers, and redirect based on the value of the X-HTTP-Method-Override header, when present.

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