#RequestParam How to handle incorrectly framed URLs - spring-mvc

I am having a method test like below and making a RESTful webservice call to fetch the data,
#RequestMapping(value ="/select", method = RequestMethod.GET)
#ResponseBody
public String test(
#RequestParam(value="begin", defaultValue="0",required=false) final String begin
)
{
//Some java code
}
**RESTful Webservice Call:**
http://localhost:8081/a/b/c/select?begin=1
Returning the data properly
http://localhost:8081/a/b/c/select?begin:1
Here in the url = has been replaced with : for negative testing.
Here Spring ignores the given value 1 and picks the default value 0 and returns the data accordingly without errors
Question:
But I want to capture the actual URL field with value which is begin:1, do some validation and display error message that the url is incorrect.
I understood that begin:1 is not considered as part of url by spring and hence picks the default value. Wondering is there a way in Spring to capture the wrongly framed url's.
Any pointers would be helpful. Many Thanks!

Related

Web API Complex Data in Get

I am using Web APi, as I am new to this, I dont know much about it.
I am trying to implement search, as of now I am starting with only text search, but later there may be huge search criteria. for one text that is easy, as web api works good with
primitive data types. Now I want to create a class of filter, say the pagenumber , the pagesize also all the search criteria, so I created a class. I have created a MVC application which is communicating with the web api, the web api returns Json data, then I de-serialize it to model. I am stuck with the complex object part, also as of now I am using a list to get the data, later that will be replaced by data base. Following is the code.
public IEnumerable<Document> Get(PaggingDetails request) //public async Task<IEnumerable<Note>> GetNotes() for Async (DB)
{
return _repository.GetAll(pagedetails.PageNumber, pagedetails.PageSize, pagedetails.PageFilter);
//return await db.Notes.ToListAsync<Note>(); for async
}
public string GetPage(int pagenumber,int pagesize,string pagefilter)
{
try
{
PaggingDetails PageDetails = new PaggingDetails();
PageDetails.PageFilter = pagefilter;
PageDetails.PageSize = pagesize;
PageDetails.PageNumber = pagenumber;
return new System.Net.WebClient().DownloadString
("http://.../api/Document/?pagedetails=" +
PageDetails);
//new HttpClient().GetStringAsync("http://localhost:18545/api/Emails"); for async
//also pass parameters
}
catch (Exception ex)
{
}
return "";
}
By deafult, you cannot use a class as the type of parameter of a GET Web API action. You need to use individual parameters of single types.
If you want to use a class as parameter nothing stops you to use a POST action, in which you can include the data without any problem.
However you can force a complex parameter of a GET action to be read from the URI by decorating the comples attribute with [FromUri].
You can read this document to better understand Web API parameter binding:
Parameter Binding in ASP.NET Web API
By default, Web API uses the following rules to bind parameters:
If the parameter is a “simple” type, Web API tries to get the value from the URI. Simple types include the .NET primitive types (int, bool, double, and so forth), plus TimeSpan, DateTime, Guid, decimal, and string, plus any type with a type converter that can convert from a string. (More about type converters later.)
For complex types, Web API tries to read the value from the message body, using a media-type formatter.
This is the standard way of working. If you use the [FromUri] attribute, the action selector won't be able to choose between different Get methods that receive different complex types. If you use a route with controller and action segments, you won't have that problem, becaus ethe actions selector will choose by action name, no matter what the aprameters are.
I don't like using the [FromUri] for this reason, and beacuse it's not the natural way to work with the GET action. But you can use it with the necessary precautions.

Returning null from a spring mvc controller method

I have read the Spring documentation and I was not able to find relevant information regarding the expected behavior of a Spring MVC controller method returning null (with a return type of String).
Can someone please provide a reply or direct me to relevant documentation? Or to put it another way, what would be the benefit of returning null from a Spring MVC controller method?
In Spring 2, when you returned null from a controller you were saying to the Spring dispatcher that you don't want it to search for a view.
You did this if you were handling the response yourself by writing the response content directly and then flushing the output stream (you were managing a file download for example).
If you didn't return null, Spring would have forwarded to a view who would try to write to the response also, messing up your already written data or resulting in an exception if the response was already commited.
Returning null was a way of saying back off to Spring's view resolver.
A lot of things changed in Spring 3 and now the same can be obtained by having an #RequestMapping annotated method that returns void.
If you have a return type of String but you return null I think that it uses the default RequestToViewNameTranslator for translating an incoming HttpServletRequest into a logical view name when the view name wasn't explicitly supplied.
Return type String in spring mvc generally returns your view resolver, it can be your JSP, html or any other view page.
http://www.mkyong.com/spring3/spring-3-mvc-hello-world-example/
Suppose you want to return a normal String like "hi", you can use #ResponseBody annotation to do this.

Values in braces in Spring Annotations

This might be a simple question for those who know Spring, but since I am a newbie, I will ask it anyway.
I am going through some Spring code and I am not able to understand the following-
#RequestMapping(value="/{id}")
public void show(#PathVariable("id") long id, Model model) {...}
The comment for this section of the code is - "When using URI Templates, access parameters using the #PathVariable annotation.
Now earlier, I came across code like
#RequestMapping(value="/url/path")
public String list(Model model) {...}
By this, I understand that whenever the url "/url/path" is encountered, the list() method will be called, but I am not able to make sense of the former annotation. What does it mean?
Also, the next line says #PathVariable annotations can be limited via regular expressions
#RequestMapping(value="/{id}")
public void show(#PathVariable("id:[\\d]*") String idl) {...} // will match only numberic IDs
What does it mean?
16.3.2.2 URI Template Patterns
URI templates can be used for convenient access to selected parts of a URL in a #RequestMapping method.
For example, the URI Template http://www.example.com/users/{userId} contains the variable userId. Assigning the value fred to the variable yields http://www.example.com/users/fred.
In Spring MVC you can use the #PathVariable annotation on a method argument to bind it to the value of a URI template variable:
So, in your example:
#RequestMapping(value="/{id}")
public void show(#PathVariable("id") long id, Model model) {...}
This will extract the part of the URL represented by {id}, and bind it to the id method parameter, e.g. the path /42 will bind 42 to id.

How do I get the parameter values from in a web service

I have a web service (an ASP.NET .asmx page), and for debugging purposes I need to log all calls to the webservice, including values of all parameters passed into each call. So basically the first thing each WebMethod should do is log it's state with details of all the parameter values passed in to it.
So far so good. The complication is that I also want an automated way of getting the parameter values - there's quite a few webmethods with different signatures, and some of them have up to ~30 parameters, so manually coding against each specific parameter would likely be massively error-prone. I'd rather be able to call a method that looks at the current Http context and automatically uses that to grab and parse whatever has been passed in by the client.
But I hit a snag. When I look at HttpContext.Current.Request, it turns out that both the Form and QueryString collections are empty. So if the arguments passed to the webmethod aren't in either of those collections, where would they be? Anyone know how I can retrieve them?
You can use AOP techniques for this task. Considering PostSharp, you can create custom aspect like this:
[Serializable]
public class TraceAttribute : OnMethodBoundaryAspect
{
public override void OnEntry(MethodExecutionArgs args)
{
Trace.WriteLine(string.Format("Entering {0}", args.Method.Name));
for (int i = 0; i < args.Arguments.Count; i++)
{
Trace.WriteLine(string.Format(" {0}", args.Arguments.GetArgument(i)));
}
}
}
and then apply it to your web-service methods:
[WebMethod, Trace]
public string HelloWorld()
{
return "Hello World";
}
You could use SOAP extensions and follow the example in this post to log the request which would have the method name and parameters.
SOAP Extentions is a better choice. Here is another example to retreive SOAP request and SOAP response as XML. All you do is parse the XML to retreive parameter name value pairs.

How to create a simple ASP.NET MVC action method that accepts HTTP-POST data?

i wish to have a simple Action in my controller that accepts a few optional values and some integer values.
this is my route i wish to have:
HTTP.POST
/review/create
and this is the Action method i would like...
[AcceptVerbs(HttpVerbs.Post)]
public JsonResult Create(int userId,
int addressId,
byte baseScore,
byte reviewType,
string subject,
string description)
{ ... }
I'm under the uneducated impression that all of those arguments above will be populated by the forms collection values ... but it's not happening. Also, I have no idea how I would write a route, to handle those ... because those values are form post data....
here's my global.asax....
routes.IgnoreRoute("{resource}.axd/{*pathInfo}");
// Api - Search methods.
routes.MapRoute(
"Search Methods",
"{controller}/{action}"
);
In fact, the action method is never called because it doesn't seem to find it :(
But, if create and action without any of those arguments, then it finds it ?????????
How would you write a route and action method to accept some require and some optional arguments, for the route /review/create ?
As far as i can see you may rewrite your controller action like this:
public ActionResult Create(int foo, int bar, byte blah, string name, int? xxx) {
// code here
}
The ModelBinder will then ensure that foo,bar and blah are set. Name and xxx may be null. I can't test it a the moment, but i think return type of the action should be ActionResult.
If you are POST'ing a form, just make sure that the elements in your form (textboxes, checkboxes, textarea, etc) have id's that match the parameters in your method. As an alternative you can pass a FormCollection to the method, and do myFormCollection["foo"] to get a string representation of the value (which can then be parsed to an int).
From my experience, you are missing a number of key elements and concepts with this question.
First and foremost, I don't believe you can execute a POST without a form. The form has to contain the controls from which you pull the values that get passed to the controller method. If the goal is to simply unit test your POST controller method, then just call the method directly in your test, which it appears that you're doing, based on one of your comments. If you involve the view, then you're doing integration testing, not unit testing. Regardless of the test type, the test will always fail because you are choosing not to build the form. Even if you manage to force the POST using Fiddler, Firebug or any other mechanism, you're still not testing the view, you're testing the HTTP protocol.
I highly recommend that you employ a web application testing tool, such as WatiN or Selenium, to test your web pages, rather than throw together a quick-and-dirty test that really doesn't test anything useful.
In your post request set content-type="application/json; charset=UTF-8" and pass the values for the method parameter in JSON format. This should make Asp.MVC not to look in FormCollection for those values.

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