AbstractHttpCache (Apache Shindig Gadget Renderer 2.5.2 API)

java.lang.Object
- org.apache.shindig.gadgets.http.AbstractHttpCache

All Implemented Interfaces:

HttpCache

Direct Known Subclasses:

DefaultHttpCache
```
public abstract class AbstractHttpCache
extends Object
implements HttpCache
```
Base class for content caches. Defines cache expiration rules and and restrictions on allowed content. Note that in the case where refetchStrictNoCacheAfterMs is non-negative, strict no-cache resources are stored in the cache. In this case, only the Cache-Control/Pragma headers are stored and not the original content or other headers. This is used primarily for automatic fetches internal to shindig from triggering lots of back end fetches. Especially comes to play for fetch in CacheEnforcementVisitor. Now since this response is not usable for serving the content, we need to explicitly check if the content is strictNoCache. DefaultRequestPipeline does this correctly, and any implementation of RequestPipeline should do this as well. To prevent breakages for existing implementations, we are keeping the default value to -1. Example: GET /private.html \r\n Host: www.example.com \r\n Cache-Control: private, max-age=1000 \r\n \r\n My credit card number is 1234-5678-1234-5678 And with refetch-after=3000, then we store the response as: GET /private.html \r\n Host: www.example.com \r\n Cache-Control: private, max-age=1000 \r\n \r\n For non user facing requests, www.example.com/private.html is considered as private and will not be refetched before 3000ms. For user facing requests, response.isStale() is always true, and will be fetched even before 1000ms. The max-age=1000 is completely ignored by shindig, because that value is for the client browser and not for proxies. isStale() = false always, for all time >= 0 shouldRefetch() = false when time < date + 3000ms shouldRefetch() = true when time >= date + 3000ms Note that error cases are handled differently. (Even for strict no cache) Implementations that override this are discouraged from using custom cache keys unless there is actually customization in the request object itself. It is highly recommended that you still use createKey(org.apache.shindig.gadgets.http.HttpRequest) in the base class and append any custom data to the end of the key instead of building your own keys from scratch.

Field Summary

Fields
Modifier and Type Field and Description

static long REFETCH_STRICT_NO_CACHE_AFTER_MS_DEFAULT

Fields
Modifier and Type	Field and Description
`static long`	`REFETCH_STRICT_NO_CACHE_AFTER_MS_DEFAULT`

Constructor Summary

Constructors
Constructor and Description

AbstractHttpCache()

Constructors
Constructor and Description
`AbstractHttpCache()`

Method Summary

Methods
Modifier and Type	Method and Description
`HttpResponse`	`addResponse(HttpRequest request, HttpResponse response)` Add a request/response pair to the cache.
`protected abstract void`	`addResponseImpl(String key, HttpResponse response)`
`String`	`createKey(HttpRequest request)` Produce a key from the given request.
`protected static String`	`getAppUrl(HttpRequest request)`
`protected static String`	`getInstanceId(HttpRequest request)`
`protected static String`	`getOwnerId(HttpRequest request)`
`HttpResponse`	`getResponse(HttpRequest request)`
`protected abstract HttpResponse`	`getResponseImpl(String key)`
`protected static String`	`getServiceName(HttpRequest request)`
`protected static String`	`getTokenName(HttpRequest request)`
`protected static String`	`getTokenOwner(HttpRequest request)`
`protected static String`	`getViewerId(HttpRequest request)`
`protected boolean`	`isCacheable(HttpRequest request)`
`protected boolean`	`isCacheable(HttpRequest request, HttpResponse response, boolean allowStrictNoCacheResponses)`
`HttpResponse`	`removeResponse(HttpRequest request)`
`protected abstract void`	`removeResponseImpl(String key)`
`protected boolean`	`responseStillUsable(HttpResponse response)` Utility function to verify that an entry is usable The cache still serve staled data, it is the responsible of the user to decide if to use it or not (use isStale).
`void`	`setRefetchStrictNoCacheAfterMs(long refetchStrictNoCacheAfterMs)`

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Field Detail
  - REFETCH_STRICT_NO_CACHE_AFTER_MS_DEFAULT
```
@Inject(optional=true)
public static long REFETCH_STRICT_NO_CACHE_AFTER_MS_DEFAULT
```
- Constructor Detail
  - AbstractHttpCache
```
public AbstractHttpCache()
```
- Method Detail
  - getResponseImpl
```
protected abstract HttpResponse getResponseImpl(String key)
```
  - addResponseImpl
```
protected abstract void addResponseImpl(String key,
                   HttpResponse response)
```
  - removeResponseImpl
```
protected abstract void removeResponseImpl(String key)
```
  - getResponse
```
public HttpResponse getResponse(HttpRequest request)
```
    Specified by:
    
    getResponse in interface HttpCache
  - addResponse
```
public HttpResponse addResponse(HttpRequest request,
                       HttpResponse response)
```
    Description copied from interface: HttpCache
    
    Add a request/response pair to the cache.
    
    Specified by:
    
    addResponse in interface HttpCache
    
    Returns:
    The response that was cached, null otherwise.
  - setRefetchStrictNoCacheAfterMs
```
public void setRefetchStrictNoCacheAfterMs(long refetchStrictNoCacheAfterMs)
```
  - removeResponse
```
public HttpResponse removeResponse(HttpRequest request)
```
    Specified by:
    
    removeResponse in interface HttpCache
  - isCacheable
```
protected boolean isCacheable(HttpRequest request)
```
  - isCacheable
```
protected boolean isCacheable(HttpRequest request,
                  HttpResponse response,
                  boolean allowStrictNoCacheResponses)
```
  - createKey
```
public String createKey(HttpRequest request)
```
    Produce a key from the given request. Relevant pieces of the cache key: - request URI - authentication type - owner id - viewer id - owner of the token - gadget url (from security token; we don't trust what's on the URI itself) - instance id - oauth service name - oauth token name - the resize height parameter - the resize width parameter - the resize quality parameter - the no_expand parameter - the User-Agent request header Except for the first two, all of these may be unset or null, depending on authentication rules. See individual methods for details. New cache key items should always be inserted using CacheKeyBuilder#setParam(String, Object).
    
    Specified by:
    
    createKey in interface HttpCache
  - getOwnerId
```
protected static String getOwnerId(HttpRequest request)
```
  - getViewerId
```
protected static String getViewerId(HttpRequest request)
```
  - getTokenOwner
```
protected static String getTokenOwner(HttpRequest request)
```
  - getAppUrl
```
protected static String getAppUrl(HttpRequest request)
```
  - getInstanceId
```
protected static String getInstanceId(HttpRequest request)
```
  - getServiceName
```
protected static String getServiceName(HttpRequest request)
```
  - getTokenName
```
protected static String getTokenName(HttpRequest request)
```
  - responseStillUsable
```
protected boolean responseStillUsable(HttpResponse response)
```
    Utility function to verify that an entry is usable The cache still serve staled data, it is the responsible of the user to decide if to use it or not (use isStale).
    
    Returns:
    true If the response can be used.

Class AbstractHttpCache

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

REFETCH_STRICT_NO_CACHE_AFTER_MS_DEFAULT

Constructor Detail

AbstractHttpCache

Method Detail

getResponseImpl

addResponseImpl

removeResponseImpl

getResponse

addResponse

setRefetchStrictNoCacheAfterMs

removeResponse

isCacheable

isCacheable

createKey

getOwnerId

getViewerId

getTokenOwner

getAppUrl

getInstanceId

getServiceName

getTokenName

responseStillUsable