Reviewers: shindig.remailer_gmail.com,
Description:
This patch implements a new set of URL(/I) generation interfaces
designed to replace the current UrlGenerator and LockedDomainService
interfaces.
However, it does *not* actually replace these, instead providing shim
code (GlueUrlGenerator) that binds the new interfaces together. This is
done for two reasons:
1. Use of UrlGenerator is extensive in the Shindig codebase (easy to
substitute).
2. Further, outside users are known to override
UrlGenerator/DefaultUrlGenerator for custom purposes.
As such, this should be treated as Phase I (phase II may be to provide
"reverse" shims from UrlGenerator to the new interfaces, though that may
not be possible in full).
Three new interfaces are introduced, all with roughly the same
implementation pattern:
1. IframeUriManager
- Responsible for generating IFRAME rendering URIs.
- Includes methods to create an IFRAME URI and validate a created URI
(for host, path, version, etc. matching).
- UriStatus returned from validate method includes INVALID_DOMAIN
state. Method and state intended to replace LockedDomainService.
2. JsUriManager
- Creates and validates URIs used by JsServlet and rendering code.
3. OAuthUriManager
- Generates (no validation needed) OAuth callback URIs.
In addition, the following core pieces are provided:
1. LockedDomainPrefixGenerator
- Interface used for generating a locked-domain prefix from a Gadget's
URI.
2. UriCommon
- Exports constants for Params used by Shindig, to avoid hard-coded
values.
3. UriStatus
- New, more complete enum of Uri validation statuses, including
locked-domain.
Default implementations of all interfaces are provided:
1. DefaultIframeUriManager
- Uses *new* container config values to differentiate from existing
UrlGenerator (and to cohesively bundle config in one place). This allows
config for both to coexist easily.
- Supports URI templating. This is useful for supporting metadata
services that return more highly-cacheable URIs, which are trivially
manipulated into "complete" URIs through string substitution.
- Intelligently places user prefs on the fragment or query string,
depending on whether they're needed for rendering.
- Provides hook to do the same for security token, though this is not
implemented in this CL.
2. AllJsIframeVersioner (implements IframeUriManager.Versioner)
- Implements existing algorithm for versioning IFRAME URIs (mark them
with the checksum of all JS).
- Not installed by default, since the algorithm is heuristic at best.
3. DefaultJsUriManager
- Generates extern JS URIs from host and path components.
- Pulls same apart into constituent components (collection of features
and validation status).
4. DefaultJsVersioner
- Provides version string for all features used by the given request.
This means version params of extern JS change only when their referenced
JS does.
5. DefaultOAuthUriManager
- Implements the same thing as the current oauth callback generation
algorithm: simple URI template.
The Uri class is also augmented to support fragment params in addition
to query params, to support fragment vs. query param placement.
The general design pattern for IFRAME and JS URI generation is to have
ContainerConfig supply Host (which may contain scheme) and Path info,
and to construct a Uri out of constituent components rather than
String-parsing. This tighter structure arguably leads to cleaner, more
descriptive code.
Lastly, GlueUrlGenerator is an implementation of UrlGenerator that as
aforementioned uses the three interfaces above under the hood. This
makes it possible to use the new URI generation implementation (and some
functionality) without our replacing all callers of UrlGenerator.
NOTE: Patch #1 is not yet complete, as it needs
DefaultIframeUriManagerTest filled in, as well as UriTest augmented with
fragment param tests.
Please review this at http://codereview.appspot.com/174079
Affected files:
java/common/src/main/java/org/apache/shindig/common/uri/Uri.java
java/common/src/main/java/org/apache/shindig/common/uri/UriBuilder.java
java/gadgets/src/main/java/org/apache/shindig/gadgets/UrlGenerator.java
java/gadgets/src/test/java/org/apache/shindig/gadgets/DefaultUrlGeneratorTest.java
