Spring StandardServletMultipartResolver - spring

I was wondering where is located the code that automatically create a temporary file when you send a multipart request using StandardServletMultipartResolver?
Can i disable that behavior? I want to decide how its going to be stored and where. I don't want spring to do it for me.
I'm considering creating my own resolver but I cant find information on how to disable spring default behavior.

To quote from API docs StandardServletMultipartResolver does not support temporary file configuration on resolver level rather it is to be done on servlet registration level -
In order to use Servlet 3.0 based multipart parsing, you need to mark the affected servlet with a "multipart-config" section in web.xml, or with a MultipartConfigElement in programmatic servlet registration, or (in case of a custom servlet class) possibly with a MultipartConfig annotation on your servlet class.
Configuration settings such as maximum sizes or storage locations need to be applied at that servlet registration level; Servlet 3.0 does not allow for them to be set at the MultipartResolver level.
So either you can configure it on servlet or switch to CommonsMultipartResolver which has the support to set the temp directory out-of-the-box as it inherits it from CommonsFileUploadSupport.setUploadTempDir (see respective docs here and here)

Related

Spring MVC: log all requests, even the resource not founds

How can I log all requests in Spring MVC, even the resource not founds ones?
I guess interceptors can not log resource not found requests. What do you suggest?
Have you tried using implementation of javax.servlet.Filter?
Filter in contrary to Spring's interceptor is part of a Java's standard and is executed by the servlet container for each incoming HTTP request..
Spring MVC use exactly one servlet and that is DispatcherServlet which, as the name suggest, disptach received request to correct controller which process the request futher.
Spring even provide few concrete implementations of Filter that can log incoming request for you such as: CommonsRequestLoggingFilter or ServletContextRequestLoggingFilter.
You can choose one of the above implementations or implement Filter interface by yourself - whatever you decide, by using Filter you should be able to log every single request received by your servlet container.

Configure Spring HTTP Security at Runtime

All http security is applied at startup:
protected void configure(HttpSecurity http) throws Exception {
http
.authorizeRequests()
.antMatchers("/admin/**").hasRole("admin")
}
During runtime, I am trying to add more to it ...
applicationContext.getBean(WebSecurityConfigurerAdapter).http.authorizeRequests().antMatchers("bla").hasRole("admin")
When that line is executed, it adds it to http.authorizeRequests()'s but /bla is still accessible by "non admins"
When server is restarted, this change takes effect because it is loading bla from the database.
How do I make the security take effect instantly without restarting the server?
You are trying to dynamicaly change a spring bean at runtime which is very hard to do unless you use tools like spring-loaded or JRebel.
There is a lot of SO about it :
Update spring beans dynamically. Is it possible?
dynamically change spring beans
Can I replace a Spring bean definition at runtime?
The best approach (in my opinion) for your use case is to use spring profiles.
Define a bean with authorisations for /bla and another bean without. Then use them in different profiles.
see dynamically declare beans at runtime in Spring
My solution to these case scenarios is to make a dynamic custom spring security rule to match with all the path.
http
.authorizeRequests()
.antMatchers("/**").access("#customSecurityRule.check(authentication)");
This way new endpoint will automatically be configured with our custom security rule, and in our custom security rule we can preety much do anything we want, checking their roles, validate it againts our database and etc.

Spring security - implement oauth with existing FilterChainProxy

we have existing web application built with Spring security 3.1 ,Wink(for rest)
we now need to add oauth2 (client_credentials flow) for several resources, i looked into many examples and all of them using the Http namespace configuration along with spring dispatcher servlet (which we didn't have till now)
problem is that http namespace is creating a springSecurityFilterChain which we already had in the application , so first thing i renamed the existing filter so the default could co-exist with the old one.
but this does not work, its either the existing chain working for requests or the new one.
i have tried the following already
1. disabled dispatcher servlet context by giving empty config location (in web.xml)
2. tried to have the oauth configuration in application-context.xml (right to the existing FilterChainProxy)
3. Allow the /oauth/token in existing chain by setting its filter to none (so the new can take over)
4. tried to declare the oauth filters in the existing chain but there was a problem with its not getting the right clientAuthentication
i really don't know what else to try - so the question is : is it possible to have both declared in the same webapp ? or is it possible to declare oauth2 configuration in the old fashion.
thanks
Shlomi
I managed to do that eventually, having the API (protected with oauth) completey separated url from the rest of the application.
so the Http namespace is creating the springSecurityFilterChain bean and the others just have different bean names. everyone is delegated through the DelegatingProxy in web.xml
i needed to puth the API URL prefix in other chains and allow all requests through , leaving the oauth security chanin to deal with security.
(i.e filter-chain pattern="/api/**" filters="none)
regarding the spring oauth2 bounded to spring MVC so tight i think is not a good implementation.
the mapping of the dispatcher servlet cannot be for /* but have to be something like /auth/*
so a special filter inherit from ClientCredentialsTokenEndpointFilter with special path like super("/auth/oauth/token") was needed.
it also cannot be /api/* since this is the real API URI mapped by our rest framework (wink RestServlet)
so we have something like this
http://server:port/context/auth/oauth/token
http://server:port/context/api/someresource (protected with oauth2)
http://server:port/context/rest/someresource (old rest for application)
Shlomi

Spring environment validation

We're building a Spring-based application which will be delivered to end users as a distribution package. Users are responsible for properly configuring whatever needs to be configured (it's mostly about various filesystem locations, folder access permissions, etc). There's a good idea to make the app help users understand what is not configured or which parts of configuration are invalid.
Our current approach is a custom ApplicationContextInitializer which does all the environment validation "manually" and then registers few "low level" beans in the application context explicitly. If something is wrong, initializer throws, exception is caught somewhere in main(), interpreted (converted into plain English) and then displayed.
While this approach works fine, I'm wondering if there are any best practices to minimize hand-written code and use Spring whenever possible.
Here's an illustrative example. The application requires a folder for file uploads. This means:
There should be a configuration file
This file should be accessible by the app
This file should have no syntax errors
This file should explicitly define some specific property (let it be app.uploads.folder)
This property should describe the existing filesystem entity
This entity should be a folder
The app should have read/write access to this folder
Does Spring provide any tools to implement this sort of validation easily?
Spring Boot has a nice feature for context and external configuration validation. If you define a POJO class and declare it as #ConfigurationProperties then Spring will bind the Environment (external properties and System/OS typically) to its properties using a DataBinder. E.g.
#ConfigurationProperties(name="app.uploads")
public class FileUploadProperties {
private File folder;
// getters and setters ommitted
}
will bind to app.uploads.folder and ensure that it is a File. For extra validation you can do it manually in the setter, or you can implement Validator in your FileUploadProperties or you can use JSR-303 annotations on the fields. By default an external property in app.uploads.* that doesn't bind will throw an exception (e.g. a mis-spelled property name, or a conversion/format error).
If you use Spring Boot Autoconfigure #EnableAutoConfigure you don't have to do anything else, but if it's just vanilla Spring (Boot) you need to say #EnableConfigurationProperties in your #Configuration somewhere as well.
A bonus feature: if you also use the Spring Boot Actuator you will also get JMX and HTTP support (in a webapp) for inspecting the bindable and bound properties of #ConfigurationProperties beans. The HTTP endpoint is "/configprops".

Spring HandlerInterceptor vs Servlet Filters

HandlerInterceptors in Spring can now be configured to be invoked only on certain URLs using <mvc:interceptors>.
Servlet Filters can achieve same functionality (logging, security etc). So which one should be used?
I think with Interceptors, one can use ModelAndView object to work with Models so it has more advantages. Can anyone draw out scenarios where Filters or Interceptors have advantages over the other?
The org.springframework.web.servlet.HanderInterceptor Interface JavaDoc itself has a two paragraphs that discuss this question:
HandlerInterceptor is basically similar to a Servlet 2.3 Filter, but
in contrast to the latter it just allows custom pre-processing with
the option of prohibiting the execution of the handler itself, and
custom post-processing. Filters are more powerful, for example they
allow for exchanging the request and response objects that are handed
down the chain. Note that a filter gets configured in web.xml, a
HandlerInterceptor in the application context.
As a basic guideline, fine-grained handler-related preprocessing tasks
are candidates for HandlerInterceptor implementations, especially
factored-out common handler code and authorization checks. On the
other hand, a Filter is well-suited for request content and view
content handling, like multipart forms and GZIP compression. This
typically shows when one needs to map the filter to certain content
types (e.g. images), or to all requests.
Spring Handler interceptors allow you to hook into more parts of the request lifecycle, and get access to more information in the process. They're often more intimately coupled to the request/response cycle than filters.
Filters are more suitable when treating your request/response as a black box system. They'll work regardless of how the servlet is implemented.
If you're using Spring MVC, there's little reason to write new logic as a servlet filter. Everything filters can do, interceptors can do more easily and more elegantly.
Remember also, servlet filters have been around for much longer than interceptors.
With a Spring interceptor, you have access to the Handler which may be useful. Also, with a Spring interceptor, you have access to execute logic before the view renders and after the view is rendered.
Servlet Filter:
A filter as the name suggests is a Java class executed by the servlet container for each incoming http request and for each http response. This way, is possible to manage HTTP incoming requests before them reach the resource, such as a JSP page, a servlet or a simple static page; in the same way is possible to manage HTTP outbound response after resource execution.
This behaviour allow to implement common functionality reused in many different contexts.
As shown in the figure above, the filter runs in the web container so its definition will also be contained in the web.xml file.
The filter include three main methods:
init: Executed to initialize filter using init-param element in
filter definition.
doFilter: Executed for all HTTP incoming request that satisfy
"url-pattern".
destroy: Release resources used by the filter.
Interceptor:
Spring Interceptors are similar to Servlet Filters but they acts in Spring Context so are many powerful to manage HTTP Request and Response but they can implement more sofisticated behaviour because can access to all Spring context.
The Spring interceptor are execute in SpringMVC context so they have be defined in rest-servlet.xml file:
The interceptor include three main methods:
preHandle: Executed before the execution of the target resource.
afterCompletion: Executed after the execution of the target resource
(after rendering the view).
postHandle: Intercept the execution of a handler.

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