Change the POST method to DELETE - servlets

I built a servlet with jersay and in the Initially of the project all my fuctions was written with POST or GET only. I want to change the metoud to DELETE and PUT in respectively.
this is the old situation(that work well):
#POST
#Path("removeCompany")
#Produces(MediaType.TEXT_PLAIN)
public Response removeCompany(#QueryParam("id") long id) {
try {
getFacaed().removeCompany(id);
} catch (SystemMalfunctionException | CompanyNotExistsException e) {
return Response.status(Response.Status.INTERNAL_SERVER_ERROR).entity(e.getMessage()).build();
}
return Response.ok("Company successfully deleted").build();
}
I would like to change this situation:
#DELETE
#Path("removeCompany")
#Produces(MediaType.TEXT_PLAIN)
public Response removeCompany(#QueryParam("id") long id) {
try {
getFacaed().removeCompany(id);
} catch (SystemMalfunctionException | CompanyNotExistsException e) {
return Response.status(Response.Status.INTERNAL_SERVER_ERROR).entity(e.getMessage()).build();
}
return Response.ok("Company successfully deleted").build();
}
In the old situation everything work well but when I change the method to DELETE I get this error :
Of course I keep the changes, restarts the server and restarts the project.
editation:
if I change the method in postman from DELETE to POST its work although in the code It is noted that the method is DELETE.
Perhaps this will help to understand the problem.

Related

Checking if a Part inside of a PartStack was closed by pressing the close icon on the corresponding tab

Platform: Windows 8.1 Pro, E4 with e(fx)clipse
I'm currently working on caching opened Parts to reopen then when reloading the PartStack. This reloading method uses EPartService.hidePart() to close all Parts in the PartStack. Since I also need to remove Parts from the cache, I need to differentiate between reloading and actually closing a tab/Part.
I already tried to add the part to the cache a second time before removing it again by sending an event from the preDestroy() method of the Part. But this is less than ideal.
Is there a special event I can catch when clicking on the close icon or another way I could check for this?
Thanks for your help.
Turns out, the easiest way to do what I wanted to do was to use tags.
Since I could only access the code for when the Part was closed by the program, I needed to set a tag on the part.
if (part.isDirty()) {
if(!partService.savePart(part, true)) {
return;
}
part.getTags().add(Tag.PART_CLOSED_BY_PROGRAM);
partService.hidePart(part);
} else if (part.isCloseable()) {
part.getTags().add(Tag.PART_CLOSED_BY_PROGRAM);
partService.hidePart(part);
}
}
Now I can just check in the preDestroy() method if the Part is being closed by the program or by the user.
#PreDestroy
protected void preDestroy() {
if (part.getTags().contains(Tag.PART_CLOSED_BY_PROGRAM)) {
part.getTags().remove(Tag.PART_CLOSED_BY_PROGRAM);
} else {
try {
//remove "Part" from cache
} catch (IllegalAccessException e) {
} catch (InvocationTargetException e) {
} catch (NoSuchMethodException e) {
}
}
}

Spring MVC Validation - Avoiding POST-back

I'd like to validate a Spring 3 MVC form. When an element is invalid, I want to re-display the form with a validation message. This is pretty simple so far. The rub is, when the user hits refresh after an invalid submission, I don't want them to POST, I want them to GET. This means I need to do a redirect from the form POST (submission) to re-display the form with validation messages (the form is submitted via a POST).
I'm thinking the best way to do this is to use SessionAttributeStore.retrieveAttribute to test if the form is already in the user's session. If it is, use the store form, otherwise create a new form.
Does this sound right? Is there a better way to do this?
To solve this problem, I store the Errors object in the session after a redirect on a POST. Then, on a GET, I put it back in the model. There are some holes here, but it should work 99.999% of the time.
public class ErrorsRedirectInterceptor extends HandlerInterceptorAdapter {
private final static Logger log = Logger.getLogger(ErrorsRedirectInterceptor.class);
private final static String ERRORS_MAP_KEY = ErrorsRedirectInterceptor.class.getName()
+ "-errorsMapKey";
#Override
public void postHandle(HttpServletRequest request, HttpServletResponse response,
Object handler, ModelAndView mav)
throws Exception
{
if (mav == null) { return; }
if (request.getMethod().equalsIgnoreCase(HttpMethod.POST.toString())) {
// POST
if (log.isDebugEnabled()) { log.debug("Processing POST request"); }
if (SpringUtils.isRedirect(mav)) {
Map<String, Errors> sessionErrorsMap = new HashMap<String, Errors>();
// If there are any Errors in the model, store them in the session
for (Map.Entry<String, Object> entry : mav.getModel().entrySet()) {
Object obj = entry.getValue();
if (obj instanceof Errors) {
if (log.isDebugEnabled()) { log.debug("Adding errors to session errors map"); }
Errors errors = (Errors) obj;
sessionErrorsMap.put(entry.getKey(), errors);
}
}
if (!sessionErrorsMap.isEmpty()) {
request.getSession().setAttribute(ERRORS_MAP_KEY, sessionErrorsMap);
}
}
} else if (request.getMethod().equalsIgnoreCase(HttpMethod.GET.toString())) {
// GET
if (log.isDebugEnabled()) { log.debug("Processing GET request"); }
Map<String, Errors> sessionErrorsMap =
(Map<String, Errors>) request.getSession().getAttribute(ERRORS_MAP_KEY);
if (sessionErrorsMap != null) {
if (log.isDebugEnabled()) { log.debug("Adding all session errors to model"); }
mav.addAllObjects(sessionErrorsMap);
request.getSession().removeAttribute(ERRORS_MAP_KEY);
}
}
}
}
It's not clear from your question but it sounds like your GET and POST actions are mapped to the same handler. In that case you can do something like:
if ("POST".equalsIgnoreCase(request.getMethod())) {
// validate form
model.addAttribute(form);
return "redirect:/me.html";
}
model.addAttribute(new MyForm());
return "/me.html";
In the JSP check if there are any error on the form and display as needed.
Such approach is called PRG (POST/REdirect/GET) design pattern I explained it few days ago as one of the answers:
Spring MVC Simple Redirect Controller Example
Hope it helps :)

How do i improve the legacy code implementation, Response.Redirect?

Some scenarios to ponder. There is a legacy code which has following implementation Example1 and Example2. If we try to implement MSDN recommendation then the legacy code fails.
Here is a Legacy code example:
Example 1:
void Page_Load() {
.... some code
if(condition) {
/// some condition
} else {
RedirectPage(url);
}
// another code block
// some other conditions.
}
Example 2:
a. File1.ascx
void Page_Load() {
try {
.. some code
base.CheckPreference();
RedirectPage(defaultPage);
}
catch(Exception ex) {
ExceptionHandling.GetErrorMessage(ex);
}
}
b. BaseClass.cs // this is the base class
void CheckPreference() {
try {
if(condition) {
RedirectPage(url1);
} else if(condition2) {
RedirectPage(url2);
} else {
// update session
}
}
catch(Exception ex) {
ExceptionHandling.GetErrorMessage(ex);
throw;
}
}
void RedirectPage(string url) {
Response.Redirect(url);
}
One possible way is to add a boolean field in the class e.g endExecution, set the field to true whenever RedirectPage is called.
We have to update RedirectPage code see code snippet below:
// Updated code - MSDN recommendation.
void RedirectPage(url) {
Response.Redirect(url, false);
this.Context.ApplicationInstance.CompleteRequest();
endExecution = true;
}
Please suggest some other better ways to improve the legacy code implementation.
Probably the most unintuitive thing for folks issuing a redirect is that in our minds we've already returned from the method what we call Respond.Redirect (or whatever the equivilent is in your language/platform of the day. All we've done is call a method.
Bottom line is that you have to stop processing the request to avoid trying to commit to responses for the same request. That would throw an exception on just about any platform I've worked with.
ASP.NET MVC improved this with the ActionResponse so that you are returning from the method (and terminating the remainder of request processing) with code that looks like this:
return Redirect(url);
Bottom line is that you need to get in the habit of returning from your event right after you perform your redirect. Any deviation from that habit needs to be documented in the code why. This will help make the application perform the way you expect.
The approach that you've taken is perfectly reasonable.

SEAM: Component "disinjected" "too soon" in interceptor?

Let's say I have the following interceptor in a SEAM app:
public class MyInterceptor {
#In
private Monitor myMonitor;
#AroundInvoke
public Object aroundInvoke(InvocationContext ctx) throws Exception {
try {
myMonitor.a();
return ctx.proceed();
}
finally {
myMonitor.b();
}
}
}
myMonitor.a() works (so Monitor is correctly injected), myMonitor.b() fails because Monitor is already null. Seam Doc says: "Injected values are disinjected (i.e., set to null) immediately after method completion and outjection."
Is that what is happening? Can I do something to tell SEAM to "not yet" "disinject" the component? I can of course also do something like XContext.get(..), but I'm wondering whether this is a bug or a mistake from my side. thanks!
Try this one instead
Object response = null;
try {
myMonitor.a();
response = ctx.proceed();
} finally {
myMonitor.b();
}
return response;
regards,
Avoid using injection.
Try working around this problem. I see you have some sort of monitoring going on. Look at this interceptor that captures the amount of time a method is executed in Seam components. Try modifying your code to match that.
It works great!
Here is the link
Seam is working as advertised.
You could just ignore the disinjection:
public class MyInterceptor {
private Monitor myMonitor;
#In
private void setMonitor(Monitor aMonitor) {
if (aMonitor != null) {
myMonitor = aMonitor;
}
}
#AroundInvoke
public Object aroundInvoke(InvocationContext ctx) throws Exception {
try {
myMonitor.a();
return ctx.proceed();
}
finally {
myMonitor.b();
myMonitor = null; //perform disinjection yourself
}
}
}
The caveat here is that Seam is disinjecting the reference for a reason. Seam wants to control the lifecycle and identity of "myMonitor" and by keeping a reference to it, you are not abiding by your contract with Seam. This could lead to unexpected behavior.
For instance, if myMonitor were for some reason in the Stateless scope, Seam might destroy it before ctx.proceed() returns, leaving you with a reference to a broken proxy. Best advice is to know the scope and lifecycle of what you are retaining since you are "living on the edge."

Redirecting users from edit page back to calling page

I am working on a project management web application. The user has a variety of ways to display a list of tasks. When viewing a list page, they click on task and are redirected to the task edit page.
Since they are coming from a variety of ways, I am just curious as to the best way to redirect the user back to the calling page. I have some ideas, but would like to get other developers input.
Would you store the calling url in session? as a cookie? I like the concept of using an object handle the redirection.
I would store the referring URL using the ViewState. Storing this outside the scope of the page (i.e. in the Session state or cookie) may cause problems if more than one browser window is open.
The example below validates that the page was called internally (i.e. not requested directly) and bounces back to the referring page after the user submits their response.
public partial class _Default : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
if (Request.UrlReferrer == null)
{
//Handle the case where the page is requested directly
throw new Exception("This page has been called without a referring page");
}
if (!IsPostBack)
{
ReturnUrl = Request.UrlReferrer.PathAndQuery;
}
}
public string ReturnUrl
{
get { return ViewState["returnUrl"].ToString(); }
set { ViewState["returnUrl"] = value; }
}
protected void btn_Click(object sender, EventArgs e)
{
//Do what you need to do to save the page
//...
//Go back to calling page
Response.Redirect(ReturnUrl, true);
}
}
This message my be tagged asp.net but I think it is a platform independent issue that pains all new web developers as they seek a 'clean' way to do this.
I think the two options in achieving this are:
A param in the url
A url stored in the session
I don't like the url method, it is a bit messy, and you have to remember to include the param in every relevent URL.
I'd just use an object with static methods for this. The object would wrap around the session item you use to store redirect URLS.
The methods would probably be as follows (all public static):
setRedirectUrl(string URL)
doRedirect(string defaultURL)
setRedirectUrl would be called in any action that produces links / forms which need to redirect to a given url. So say you had a projects view action that generates a list of projects, each with tasks that can be performed on them (e.g. delete, edit) you would call RedirectClass.setRedirectUrl("/project/view-all") in the code for this action.
Then lets say the user clicks delete, they need to be redirected to the view page after a delete action, so in the delete action you would call RedirectClass.setRedirectUrl("/project/view-all"). This method would look to see if the redirect variable was set in the session. If so redirect to that URL. If not, redirect to the default url (the string passed to the setRedirectUrl method).
I agree with "rmbarnes.myopenid.com" regarding this issue as being platform independent.
I would store the calling page URL in the QueryString or in a hidden field (for example in ViewState for ASP.NET). If you will store it outside of the page scope (such as Session, global variable - Application State and so on) then it will not be just overkill as Tom said but it will bring you trouble.
What kind of trouble? Trouble if the user has more than one tab (window) of that browser open. The tabs (or windows) of the same browser will probably share the same session and the redirection will not be the one expected and all the user will feel is that it is a bug.
My 2 eurocents..
I personally would store the required redirection info in an object and handle globally. I would avoid using a QueryString param or the like since they could try bouncing themselves back to a page they are not supposed to (possible security issue?). You could then create a static method to handle the redirection object, which could read the information and act accordingly. This encapsulates your redirection process within one page.
Using an object also means you can later extend it if required (such as adding return messages and other info).
For example (this is a 2 minute rough guideline BTW!):
public partial class _Default : System.Web.UI.Page
{
void Redirect(string url, string messsage)
{
RedirectionParams paras = new RedirectionParams(url, messsage);
RedirectionHandler(paras); // pass to some global method (or this could BE the global method)
}
protected void Button1_Click(object sender, EventArgs e)
{
Redirect("mypage.aspx", "you have been redirected");
}
}
public class RedirectionParams
{
private string _url;
public string URL
{
get { return _url; }
set { _url = value; }
}
private string _message;
public string Message
{
get { return _message; }
set { _message = value; }
}
public RedirectionParams(string url, string message)
{
this.URL = url;
this.Message = message;
}
}

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