AEM Servlet not getting executed - servlets

I have a servlet with OSGI annotation like below
#Component( immediate = true, service = Servlet.class, property = { "sling.servlet.extensions=json",
"sling.servlet.paths=/example/search", "sling.servlet.methods=get" } )
public class SearchSevrlet
extends SlingSafeMethodsServlet {
#Override
protected void doGet( final SlingHttpServletRequest req, final SlingHttpServletResponse resp )
throws ServletException, IOException {
log.info("This is not getting called ");
}
}
But When i try to hit the servlet with JQuery
$.get( "/example/search.json", function( data ) {
$( ".result" ).html( data );
alert( "Load was performed." );
});
I am getting below information rather than servlet getting executed.
{"sling:resourceSuperType":"sling/bundle/resource","servletClass":"com.group.aem.example.servlet.SearchSevrlet","sling:resourceType":"/example/search.servlet","servletName":"com.group.aem.example.servlet.SearchSevrlet"}
Please let me know if i need to make any other configuration.

The info that you are getting is the answer of the Default JSON Servlet
Please read this: Servlets and Scripts
You are registering the "SearchServlet" with the property "sling.servlet.paths". This property is defined as:
sling.servlet.paths: A list of absolute paths under which the servlet is accessible as a Resource. The property value must either be a single String, an array of Strings...
That means that your servlet will be only triggered if you request the same exact path, in this case "/example/search", like this:
GET /example/search
I would recommend you to use the properties "resourceTypes" and "selectors" in your Servlet rather than "paths". For example, a better configuration could be:
property = {
"sling.servlet.resourceTypes=/example/search.servlet",
"sling.servlet.selectors=searchselector",
"sling.servlet.extensions=json",
"sling.servlet.methods=GET"
}
With this config, your SearchServlet should be triggered with a GET request to a resource with resourceType="/example/search.servlet", with the selector "searchselector" and the extension "json". For example:
GET /corcoran/search.searchselector.json

I had a similar problem with yours.
To find out what is wrong, I checked "Recent Requests" page.
(at http://localhost:4502/system/console/requests.)
In my case, there was a log saying, "Will not look for a servlet at (my request path) as it is not in the list of allowed paths".
So I moved to "Config Manager" page(at http://localhost:4502/system/console/configMgr), and searched for "Apache Sling Servlet/Script Resolver and Error Handler".
It has a list named "Execution Paths", and I added my request path to the list.
After adding my path to the list, the problem is solved.

Related

Spring-boot return json and xml from controllers

I have a spring-boot 1.1.7 application that uses Thymeleaf for much of the UI, so the response from my controllers hasn't really been a concern. However, now I need to provide a XML response when a user submits a request via URL.
Here is a typical Request:
http://localhost:9001/remote/search?sdnName=Victoria&address=123 Maple Ave
Here is most of my gradle configuration:
project.ext {
springBootVersion = '1.1.7.RELEASE'
}
dependencies {
compile("org.springframework.boot:spring-boot-starter-web:$springBootVersion")
compile("org.springframework.boot:spring-boot-starter-thymeleaf")
compile("org.springframework.boot:spring-boot-starter-security")
compile("org.springframework.boot:spring-boot-starter-data-jpa:$springBootVersion")
compile("org.springframework.security:spring-security-web:4.0.0.M1")
compile("org.springframework.security:spring-security-config:4.0.0.M1")
compile('org.thymeleaf.extras:thymeleaf-extras-springsecurity3:2.1.1.RELEASE')
compile("org.springframework.boot:spring-boot-starter-actuator")
compile('com.fasterxml.jackson.dataformat:jackson-dataformat-xml:2.5.0')
}
And here is my controller:
#Controller
public class RemoteSearchController {
#Autowired
private SdnSearchService sdnSearchService;
#RequestMapping(value = "/remote/search", method = RequestMethod.GET, produces = MediaType.APPLICATION_XML_VALUE)
public List<Sdn> search(#ModelAttribute SdnSearch sdnSearch) {
List<Sdn> foundSdns = sdnSearchService.find( sdnSearch );
return foundSdns;
}
Here is my Object to be returned:
#Entity
public class Sdn {
#Id
private long entNum;
private String sdnName;
...
//getters & setters here
}
I am able to receive the request via REST client (such as CocoaREST) and handle it. But When I return the list of SDN i get the following exception, even though I do have Jackson & jackson-dataformat-xml on my classpath:
org.springframework.web.HttpMediaTypeNotAcceptableException: Could not find acceptable representation
at org.springframework.web.servlet.mvc.method.RequestMappingInfoHandlerMapping.handleNoMatch(RequestMappingInfoHandlerMapping.java:229)
at org.springframework.web.servlet.handler.AbstractHandlerMethodMapping.lookupHandlerMethod(AbstractHandlerMethodMapping.java:301)
at org.springframework.web.servlet.handler.AbstractHandlerMethodMapping.getHandlerInternal(AbstractHandlerMethodMapping.java:248)
at org.springframework.web.servlet.handler.AbstractHandlerMethodMapping.getHandlerInternal(AbstractHandlerMethodMapping.java:57)
at org.springframework.web.servlet.handler.AbstractHandlerMapping.getHandler(AbstractHandlerMapping.java:299)
My REST Client is including a Accept Header of "text/xml" (but in all honesty I would rather them not have to set this. Ideally any call to this Controller would always get XML, regardless of header being present).
Is there a way to handle this? I thought the Media Converters were included and just returned whatever the controller told them to?
SOLUTION:
See below for the answer I posted.
I had the exact same problem and I found the solution on Spring documentation website : here
In synthesis, I added the following dependency to the pom.xml of my project :
<dependency>
<groupId>com.fasterxml.jackson.dataformat</groupId>
<artifactId>jackson-dataformat-xml</artifactId>
</dependency>
Then I added the following code block to the class that the service had to return :
import javax.xml.bind.annotation.XmlRootElement;
#XmlRootElement
public class Greeting {...}
And it worked.
SOLUTION: I used a combination of both answers below (thank you very much!). I am posting here in case anyone else needs help.
My modified controller:
#Controller
public class RemoteSearchController {
#Autowired
private SdnSearchService sdnSearchService;
#RequestMapping(value = "/remote/search", method = RequestMethod.GET, produces = { "application/xml", "text/xml" }, consumes = MediaType.ALL_VALUE )
#ResponseBody
public SdnSearchResults search(#ModelAttribute SdnSearch sdnSearch) {
List<Sdn> foundSdns = sdnSearchService.find( sdnSearch );
SdnSearchResults results = new SdnSearchResults();
results.setSdns( foundSdns );
return results;
}
}
And on my client, I set the request headers:
Content-type: application/text
Accept: text/xml
I think ultimately the problem was that my client headers were not being set correctly, so I may not have had to make some of these changes. But I liked the idea of a SearchResults class containing a list of results:
#XmlRootElement
public class SdnSearchResults {
private List<Sdn> sdns;
...
}
It may be better to create a new class:
public class SdnSearchResult {
private List<Sdn> sdns;
...
}
Then, a slight change will be required to the existing classes as follows:
public interface SdnSearchService {
SdnSearchResult find(SdnSearch sdnSearch);
}
#Controller
public class UISearchController {
#Autowired
private SdnSearchService sdnSearchService;
#RequestMapping("/search")
public ModelAndView search(#ModelAttribute SdnSearch sdnSearch) {
return new ModelAndView("pages/search/results", "sdns", sdnSearchService.find(sdnSearch).getSdns());
}
}
Once this is done, the other controller must be coded as:
#Controller
public class RemoteSearchController {
#Autowired
private SdnSearchService sdnSearchService;
#RequestMapping("/remote/search")
#ResponseBody
public SdnSearchResult search(#RequestBody SdnSearch sdnSearch) {
return sdnSearchService.find(sdnSearch);
}
}
A quick explanation of the changes from your code:
#RequestBody will automatically deserialize the entire HTTP request body to an SdnSearch instance. External applications will typically submit the request data as HTTP body, so #RequestBody will ensure that the deserialization to Java object happens automatically.
#ResponseBody will automatically serialize the return value according to the external client's capabilities and the libraries available on the classpath. If Jackson is available on the classpath and the client has indicated that they can accept JSON, the return value will be automatically sent as JSON. If the JRE is 1.7 or higher (which means that JAXB is included with the JRE) and the client has indicated that they can accept XML, the return value will be automatically sent as XML.
List<Sdn> needs to be changed to SdnSearchResult to ensure that the application can exchange JSON, XML, RSS and ATOM formats with a single controller method, since XML (and XML based formats) require a root-tag on the output, which a List<Sdn> cannot be translated to.
Once these changes are done, fire up a REST client such as the Postman extension for Chrome and submit a request to /remote/search with the following information:
Request header Accepts set to application/json.
Request header Content-Type set to application/json.
Request body set to the JSON string { "sdnName" : "Victoria", "address" : "123 Maple Ave" }.
This will give you a JSON response.
You've marked the controller method as producing application/xml responses (produces = MediaType.APPLICATION_XML_VALUE). The request's accept header (Accept: text/xml) doesn't match so Spring determines that your search method cannot handle the request.
There are a few different ways to fix this on the server, depending on your exact requirements:
You could remove the produces attribute entirely
You could specify multiple media types: produces = { "application/xml", "text/xml" }
I am not sure about your version of Spring Boot (1.1.7.RELEASE) but I am on version 1.5.2.RELEASE and this xml conversion / serialization happens automatically without usage of any jackson dependencies as mentioned in few of the answers.
I guess that is happening because org.springframework.http.converter.xml.Jaxb2RootElementHttpMessageConverter is automatically configured since Spring Boot version 1.5.1.RELEASE & that converter uses default JAXB implementation of JRE ( so no explicit xml conversion dependency needed ) .
Second, Accept header set by clients in request decides which format the output is expected so a request mapping like below ( i.e. a single end point ) ,
#RequestMapping(method = RequestMethod.GET, value = "/remote/search", produces = {
MediaType.APPLICATION_JSON_VALUE, MediaType.APPLICATION_XML_VALUE, MediaType.TEXT_XML_VALUE })
can be used to produce an xml as well as a JSON response ( if Accept header is set as text/xml or application/xml & application/json respectively.
Note 1 : javax.xml.bind.annotation.XmlRootElement needs to be specified on root class if xml response is expected for a Java class. This is mandatory.
Note 2 : Jackson for json is already included in Spring Boot so that is not to be explicitly included for json outputs
Note 3 : Accept header - Output match off happens automatically by framework & developer doesn't have to code anything specific for that.
So in my opinion, if you only add XmlRootElement to your base class & upgrade your Spring Boot version, your server side is all set. Responsibility to set correct Accept header lies with the clients.
In addition to what Michael told in his answer, I added the following dependencies as well to pom.xml
<dependency>
<groupId>org.codehaus.woodstox</groupId>
<artifactId>woodstox-core-asl</artifactId>
<version>4.4.1</version>
</dependency>
For some reason, the jackson-dataformat-xml alone was not helping.
I also made sure that ResponseEntity is returned in the get call and removed the produces=MediaType from the RequestMapping annotation.
With these changes, I was able to get the correct data but I had to give the extension of mime type to the REST URL during get call. ie, specify explicitly like: http://localhost:8080/hello.xml or http://localhost:8080/hello.json in browser
In my case I wanted to return a formatted XML string and it was all combined into one line.
Adding produces = { "application/xml", "text/xml" } to the request mapping was enough to return the string as formatted XML (with indentation).
example:
#RequestMapping(method= RequestMethod.GET, value="/generate/{blabla}", produces = { "application/xml", "text/xml" })
public String getBlaBla(#PathVariable("param") String param) throws IOException {
}
Goodluck.

Authentication and Custom Error pages

I have a site that is using Azure ACS for authentication, backed by ADFS. When things are going well and people do things they are supposed to its great but that doesn't happen always so we have been implementing custom error pages.
The problem is, it doesn't seem to catch authentication errors, such as
ID3206: A SignInResponse message may only redirect within the current web application
Key not valid for use in specified state.
These errors still produce the ugly yellow error screen no matter what I say in my web.config. They are clearly ASP.NET errors and not IIS errors, so my question is how and where can I put custom error pages to display such errors in a 'pretty' way, as setting a page in web.config isn't working?
EDIT: To be clear, we have ACS set up to use an error page, have customErrors on with a different error page, neither or being used.
You have to have an action on a controller in your web app that accepts a POST from ACS and takes a parameter of type string. You must also configure your relying party application in ACS to point to that action for errors. Then in the action code you can do something like this:
namespace ASPNETSimpleMVC.Controllers
{
public class ErrorController : Controller
{
// Errors can be mapped to custom strings here.
static Dictionary<string, string> ErrorCodeMapping = new Dictionary<string, string>();
static ErrorController()
{
ErrorCodeMapping["ACS50019"] = "You chose to cancel log-in to the identity provider.";
ErrorCodeMapping["ACS60001"] = "No output claims were generated. You may be unauthorized to visit this site.";
}
//
// POST: /Error/
//
// If an error occurs during sign-in, ACS will post JSON-encoded errors to this endpoint.
// This function displays the error details, mapping specific error codes to custom strings.
[AcceptVerbs( HttpVerbs.Post )]
public ActionResult Index( string ErrorDetails )
{
// The error details contain an array of errors with unique error codes to indicate what went wrong.
// Additionally, the error details contain a suggested HTTP return code, trace ID, and timestamp, which may be useful for logging purposes.
ErrorDetails parsedErrorDetails = new JavaScriptSerializer().Deserialize<ErrorDetails>( ErrorDetails );
ViewData["ErrorMessage"] = String.Format( "An error occurred during sign-in to {0}. ", parsedErrorDetails.identityProvider );
// Loop through all ACS errors, looking for ones that are mapped to custom strings.
// When a mapped error is found, stop looking and append the custom string to the error message.
foreach ( ErrorDetails.Error error in parsedErrorDetails.errors )
{
if ( ErrorCodeMapping.ContainsKey( error.errorCode ) )
{
ViewData["ErrorMessage"] += ErrorCodeMapping[error.errorCode];
break;
}
}
return View( "Error" );
}
}
}
You may also find this article helpful.

ASP.NET Web API removing HttpError from responses

I'm building RESTful service using Microsoft ASP.NET Web API.
My problem concerns HttpErrors that Web API throws back to user when something go wrong (e.g. 400 Bad Request or 404 Not Found).
The problem is, that I don't want to get serialized HttpError in response content, as it sometimes provides too much information, therefore it violates OWASP security rules, for example:
Request:
http://localhost/Service/api/something/555555555555555555555555555555555555555555555555555555555555555555555
As a response, I get 400 of course, but with following content information:
{
"$id": "1",
"Message": "The request is invalid.",
"MessageDetail": "The parameters dictionary contains a null entry for parameter 'id' of non-nullable type 'System.Int32' for method 'MyNamespaceAndMethodHere(Int32)' in 'Service.Controllers.MyController'. An optional parameter must be a reference type, a nullable type, or be declared as an optional parameter."
}
Something like this not only indicates that my WebService is based on ASP.NET WebAPI technology (which isn't that bad), but also it gives some information about my namespaces, method names, parameters, etc.
I tried to set IncludeErrorDetailPolicy in Global.asax
GlobalConfiguration.Configuration.IncludeErrorDetailPolicy = IncludeErrorDetailPolicy.Never;
Yeah, that did somehow good, now the result doesn't contain MessageDetail section, but still, I don't want to get this HttpError at all.
I also built my custom DelegatingHandler, but it also affects 400s and 404s that I myself generate in controllers, which I don't want to happen.
My question is:
Is there any convinient way to get rid of serialized HttpError from response content? All I want user to get back for his bad requests is response code.
What about using a custom IHttpActionInvoker ?
Basically, you just have to send an empty HttpResponseMessage.
Here is a very basic example :
public class MyApiControllerActionInvoker : ApiControllerActionInvoker
{
public override Task<HttpResponseMessage> InvokeActionAsync(HttpActionContext actionContext, System.Threading.CancellationToken cancellationToken)
{
var result = base.InvokeActionAsync(actionContext, cancellationToken);
if (result.Exception != null)
{
//Log critical error
Debug.WriteLine("unhandled Exception ");
return Task.Run<HttpResponseMessage>(() => new HttpResponseMessage(HttpStatusCode.InternalServerError));
}
else if (result.Result.StatusCode!= HttpStatusCode.OK)
{
//Log critical error
Debug.WriteLine("invalid response status");
return Task.Run<HttpResponseMessage>(() => new HttpResponseMessage(result.Result.StatusCode));
}
return result;
}
}
In Global.asax
GlobalConfiguration.Configuration.Services.Replace(typeof(IHttpActionInvoker), new MyApiControllerActionInvoker());
One other important thing you could do, not related to Web Api, is to remove excessive asp.net & IIS HTTP headers. Here is a good explanation.
I believe your approach of using the message handler is correct because regardless of the component in the Web API pipeline that sets the status code to 4xx, message handler can clear out response body. However, you do want to differentiate between the ones you explicitly set versus the ones set by the other components. Here is my suggestion and I admit it is a bit hacky. If you don't get any other better solution, give this a try.
In your ApiController classes, when you throw a HttpResponseException, set a flag in request properties, like so.
Request.Properties["myexception"] = true;
throw new HttpResponseException(...);
In the message handler, check for the property and do not clear the response body, if the property is set.
var response = await base.SendAsync(request, cancellationToken);
if((int)response.StatusCode > 399 && !request.Properties.Any(p => p.Key == "myException"))
response.Content = null;
return response;
You can package this a bit nicely by adding an extension method to HttpRequestMessage so that neither the ApiController nor the message handler knows anything about the hard-coded string "myException" that I use above.

How to prevent static resources from being handled by front controller servlet which is mapped on /*

I have a servlet which acts as a front controller.
#WebServlet("/*")
However, this also handles CSS and image files. How can I prevent this?
You have 2 options:
Use a more specific URL pattern such as /app/* or *.do and then let all your page requests match this URL pattern. See also Design Patterns web based applications
The same as 1, but you want to hide the servlet mapping from the request URL; you should then put all static resources in a common folder such as /static or /resources and create a filter which checks if the request URL doesn't match it and then forward to the servlet. Here's an example which assumes that your controller servlet is a #WebServlet("/app/*") and that the filter is a #WebFilter("/*") and that all your static resources are in /resources folder.
HttpServletRequest req = (HttpServletRequest) request;
String path = req.getRequestURI().substring(req.getContextPath().length());
if (path.startsWith("/resources/")) {
chain.doFilter(request, response); // Goes to default servlet.
} else {
request.getRequestDispatcher("/app" + path).forward(request, response); // Goes to your controller.
}
See also How to access static resources when mapping a global front controller servlet on /*.
I know this is an old question and I guess #BalusC 's answer probably works fine. But I couldn't modify the URL for the JSF app am working on, so I simply just check for the path and return if it is to static resources:
String path = request.getRequestURI().substring(request.getContextPath().length());
if (path.contains("/resources/")) {
return;
}
This works fine for me.

RequestDispatcher ending in infinite loop

I have two WAR applications and the mode of communication between them is via servlets.
My application (WAR A) opens a child window with the URL of a servlet in another WAR (lets say WAR B).
The servlet (in WAR B) processes the data and should send the processed data back to original application's servlet (i.e WAR A's servlet).
But this process ends in an infinite loop and also the URL parameters sent from WAR-A are null.
Here is the code snippet :
The below script opens a child window with the URL of servlet in WAR-B also passing some URL parameters.
function invokePlugin(invokeURL, custValJSON, meaCompPartJSON) {
window.open(invokeURL + '?custValJSON=' + custValJSON,'');
}
Below is servlet code in WAR-B which extracts the URL parameters and process the data and again send the request back to WAR-A's servlet...
private void processRequest(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
String custValJSON = request.getParameter("custValJSON");
System.out.println("custValJSON : " + custValJSON);
CustomValues custVal = gson.fromJson(custValJSON, CustomValues.class);
if(custVal != null) {
System.out.println("Cust val details : " + custVal.getName());
custVal.setValue("Satya");
}
String destination = "/testPlannerPluginResult";
RequestDispatcher reqDispatch = request.getRequestDispatcher(destination);
request.setAttribute("custValJSON", gson.toJson(custVal));
if(reqDispatch != null) {
reqDispatch.forward(request, response);
}
}
Does anybody have idea on this?
Regards,
Satya
That then just means that the servlet is basically calling itself everytime. I don't immediately see the cause in the information given so far, but apparently the URL which you passed into the getRequestDispatcher() matches the URL of the servlet itself.
I however see a major mistake here:
RequestDispatcher reqDispatch = request.getRequestDispatcher(destination);
request.setAttribute("custValJSON", gson.toJson(custVal));
That can impossibly invoke the servlet which runs in another servlet context (read: another WAR). You need ServletContext#getContext() first to get the other servlet context and then use ServletContext#getRequestDispatcher() to dispatch the request to there.
ServletContext otherServletContext = getServletContext().getContext("/otherContextPath");
RequestDispatcher dispatcher = otherServletContext.getRequestDispatcher(destination);
This only requires that the both WARs are configured to expose the context for sharing. On Tomcat for example, this is to be done by adding crossContext="true" to the <Context>.

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