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Enforcing security by implementing security checks in your application c= ode is labor-intensive and a potentially dangerous practice as you can very= easily miss a check and leave a big security hole open. Standard container= -managed authentication and authorization was created to address this issue= , but it's based purely on roles and URLs, and as such, is typically too co= nstricting for modern web applications. With Tapestry 5, it's relatively ea= sy to get started with securing your application by creating custom filters= and dispatchers, but really, every user of Tapestry shouldn't need to crea= te their own security framework. Developing comprehensive, proven bullet-pr= oof security framework is difficult and time consuming. Tynamo's tapestry-security is a comprehensive security module that pro= vides tight integration with Apache Shiro, an established, high-performing = and easy-to-use security framework for Tapestry applications.
There are several aspects to providing security. Technically you can eit= her hide functionality from user's view, visibly disable or lock certain fu= nctionality or display errors when user tries accessing forbidden resources= or operations. Security can be enforced at different integration points: f= or example, you may restrict users' access to certain URLs, secure access t= o the data itself or make specific checks in an operation of the controllin= g page class or service before executing certain functionality. Tapestry-se= curity module supports all these different types of authorization mechanism= s.
To use the feature, you need to add the following dependency to your pom= .xml:
Apache Shiro, the security framework that tapestry-security is based on,= is modular and extensible, but to get started, you need to understand just= three key Shiro concepts: realms, filters and security configuration. A realm is responsible for a= uthenticating and authorizing users, so you at least need to configure a re= ady-made realm, or, if you are authenticating users against your own custom= database, likely need to implement your own custom realm. Typically, in yo= ur AppModule you provide a realm configuration such as:
Obviously, if your Realm needs to use other Tapestry services, you could= let Tapestry build your Realm implementation with @Autobuild and in= ject it as an argument to your WebSecurityManager contribution method. If y= ou create a first-class Tapestry IoC service out of your realm (you can but= there should be very little need), make sure you identify your rea= lm to the Tapestry with the right super interface= . For example, if your realm is authorizing users, the interface to use is = Autho= rizingRealm - if you claimed that the service implements Realm interface= only, your realm wouldn't be allowed to participate in authorization, but = only in authentication process. See an example of a simple, custom Hib= ernate-based entity realm (service). Shiro provides an extensive set of= interfaces, often providing different functionalities depending on which f= eatures are available.=20 =20
Shiro is based on multiple filter chains which is a natural fit with tap= estry's (filter) pipeline pattern. In the typical case, you don't have to i= mplement new filters but merely configure them to process desired urls of y= our application. Refer to the Shiro configuration for more information, but= tapestry-security makes the default Shiro filters available so you can ref= er to them by name.
Shiro supports url-based permission checking out of the box. Tapestry-se= curity also comes with several security annotations and some security compo= nents that you can use in your page classes and templates to secure specifi= c operations or access to the page.
Shiro's default configuration model uses an INI file (a property file wi= th sections). However, Tapestry-security 0.4.0 introduced a Tapestry-style = configuration through contributions and completely removed support for ini-= style configuration. Tapestry-style all-in-Java configuration has many bene= fits, including type checking, run-time filter re-configuration (should you= ever need it...) and better performance (indirectly - 0.4.0 supplies its o= wn "Shiro" filters - this feature enhancement may be pushed upstr= eam in Shiro 2.0 - see = configuration per filter instance in Version+2+Brainstorming if interes= ted).
For 0.3.x and earlier versions, you can use a standard Shiro INI configu= ration file (see Shiro's documentation for more in= fo) with tapestry-security. All versions support annotation-based security.= The simplest and most typical security models are based on url and role pe= rmissions, see the following version-specific sections for examples on them= .
0.4.1 also introduced a dependency to tapestry-exceptionpage. The security exceptions = thrown from the filters annotation handlers are all handled by the same exc= eption handler assistant. You can also handle other generic exceptions in y= our application the same way, read more about it at tapestry-exceptionpage guide. Configu= ration via shiro.ini is possible for version before 0.4.0 but the support f= or it was removed an unanimous community vote. anon() and = authc() etc. above refer to the Shiro filter names. See all Shiro filters available by default.= p>
To declaratively secure your pages, you can use the following annotation= s:
For example, to restrict access to users with roles "admin" on= ly, you would add a following annotation to a page class:
You can also secure access to services and service operations, for examp= le:
Permissions are another interesting aspect of Shiro. Shiro's default Wil= dCardPermission supports a syntax that allows representing different parts = and subparts in a permission string. For example:
In your realm, you allocate individual permission strings to each user t= hat are then matched against the permission strings from the annotations. F= or more information, read Shiro's documentation on permi= ssions. While the permission concept is flexible, it still doesn't allo= w you to declaratively secure instances of data. You can programmatically c= heck for instance level permissions but it's cumbersome to allocate the cor= rect permissions and equally cumbersome to later verify them. Entity-Relati= onship Based Access Control (ERBAC) system allows declaring subject-ins= tance security rules. For example, all users can read each other's pro= file data, but only modify their own. If you are using JPA, you are in luck= since our implementation of ERBAC security concept, tapestry-security-jpa = module allows securing your entities with simple annotations @RequiresAssoc= iation and @RequiresRole, check out tapestry-securi= ty-jpa!
There are often cases where it's not enough to simply secure the urls or= the pages. If a user doesn't have a permission to invoke a particular acti= on, it's a good practice to also hide it from his view. Tapestry-security m= odule contains several built-in conditional components to make conditional = rendering of your page templates and more fine-grained permission control e= asier.
The names of following components should give you a pretty good hint of = their purpose, can you guess what all of them do? 0.5.1 also added support = for an p:else block for all the built-in security components.
Some simple examples below:
tapestry-security comes with two very simple login and =
unauthorized pages, and also by default the success url will be /index<=
Most likely, you will want to change these URLs to point to your= own customized pages. To do that use SecuritySymbols
For more extensive examples, take a look at our full-featured integrati= on test web app. See for example the Index page te= mplate and class and the AlphaService. Also, check out tynamo-federatedaccounts, an add-on module to tapes= try-security for remote & merged authentication use cases, such as Oaut= h. We have a live example available for federatedacc= ounts but the example application also demonstrates other useful capabi= lities of tapestry-security, such as realm as a service, contributing multi= ple realms, interoperability between them, creating and using a CurrentUser= application state object and using permissions. In the example, one realm = is responsible for only authenticating users while another one is responsib= le for authorizing them. Check out the source from http://svn.codehaus.org/tynamo/trunk/tynamo-example= -federatedaccounts or browse the sources, starting from AppModule
Javamelody is one of the best open-source server hea= lth monitoring packages available for Java webapps at the moment. Javamelod= y is implemented as a ServletFilter. Each request needs to pass through the= filter to be accounted for. The same filter is also responsible for produc= ing the reports by handling requests to "/monitoring" url directl= y. This imposes a problem with securing the "/monitoring" url. If= you declare the Javamelody filter before Tapestry filter you couldn't secu= re the monitoring page (with a Tapestry-based security solution), and if yo= u declared it after the Tapestry filter, the monitoring filter would never = be invoked for requests handled by Tapestry. The solution is to inject the = Monitoring filter into your security filter chain configuration, like so:= p>
Notice that above, we are using the same instance of the monitoring filt= er in both chains, which is perfectly fine since standard servlet filters d= o not carry any chain specific configuration (unlike typical Shiro filters)= . With this configuration, we can now both analyze every request and secure= the monitoring reporting page. Any other standard ServletFilters can also = easily be configured as part of the security configuration, completely avoi= ding web.xml configuration. Also, unrelated to security, but Javamelody com= es with its own gzipping, so remember to use 1.39.0 version or better and t= urn off its gzipping (using context parameter gzip-compression-disable= d), otherwise it'll conflict with Tapestry's gzipping facilities.