google.appengine.ext.ndb.Context

Inherits From: expected_type

google.appengine.ext.ndb.Context(
    conn=None,
    auto_batcher_class=google.appengine.ext.ndb.AutoBatcher,
    config=None,
    parent_context=None
)

Methods

`allocate_ids`

View source

allocate_ids(
    key, size=None, max=None, **ctx_options
)

`call_on_commit`

View source

call_on_commit(
    callback
)

Call a callback upon successful commit of a transaction.

If not in a transaction, the callback is called immediately.

In a transaction, multiple callbacks may be registered and will be called once the transaction commits, in the order in which they were registered. If the transaction fails, the callbacks will not be called.

If the callback raises an exception, it bubbles up normally. This means:

If the callback is called immediately, any exception it raises will bubble up immediately.
If the call is postponed until commit, remaining callbacks will be skipped and the exception will bubble up through the transaction() call. However, the transaction is already committed at that point.

`clear_cache`

View source

clear_cache()

Clears the in-memory cache.

NOTE: This does not affect memcache.

`default_cache_policy`

View source

@staticmethod
default_cache_policy(
    key
)

Default cache policy.

This defers to _use_cache on the Model class.

Args
`key`	Key instance.

Returns
A bool or `None`.

`default_datastore_policy`

View source

@staticmethod
default_datastore_policy(
    key
)

Default Datastore policy.

This defers to _use_datastore on the Model class.

Args
`key`	Key instance.

Returns
A bool or `None`.

`default_memcache_policy`

View source

@staticmethod
default_memcache_policy(
    key
)

Default Memcache policy.

This defers to _use_memcache on the Model class.

Args
`key`	Key instance.

Returns
A bool or `None`.

`default_memcache_timeout_policy`

View source

@staticmethod
default_memcache_timeout_policy(
    key
)

Default Memcache timeout policy.

This defers to _memcache_timeout on the Model class.

Args
`key`	Key instance.

Returns
Memcache timeout to use (integer), or `None`.

`delete`

View source

delete(
    key, **ctx_options
)

`flush`

View source

flush()

`get`

View source

get(
    key, **ctx_options
)

Returns a Model instance given the entity key.

It will use the context cache if the cache policy for the given key is enabled.

Args
`key`	Key instance.
`**ctx_options`	Context options.

Returns
A `Model` instance if the key exists in the datastore; `None` otherwise.

`get_cache_policy`

View source

get_cache_policy()

Return the current context cache policy function.

Returns
A function that accepts a `Key` instance as argument and returns a bool indicating if it should be cached. May be `None`.

`get_datastore_policy`

View source

get_datastore_policy()

Return the current context datastore policy function.

Returns
A function that accepts a `Key` instance as argument and returns a bool indicating if it should use the datastore. May be `None`.

`get_indexes`

View source

get_indexes(
    **ctx_options
)

`get_memcache_policy`

View source

get_memcache_policy()

Return the current memcache policy function.

Returns
A function that accepts a `Key` instance as argument and returns a bool indicating if it should be cached. May be `None`.

`get_memcache_timeout_policy`

View source

get_memcache_timeout_policy()

Return the current policy function for memcache timeout (expiration).

`in_transaction`

View source

in_transaction()

Return whether a transaction is currently active.

`iter_query`

View source

iter_query(
    query, callback=None, pass_batch_into_callback=None, options=None
)

`map_query`

View source

map_query(
    query,
    callback,
    pass_batch_into_callback=None,
    options=None,
    merge_future=None
)

`memcache_add`

View source

memcache_add(
    key, value, time=0, namespace=None, deadline=None
)

`memcache_cas`

View source

memcache_cas(
    key, value, time=0, namespace=None, deadline=None
)

`memcache_decr`

View source

memcache_decr(
    key, delta=1, initial_value=None, namespace=None, deadline=None
)

`memcache_delete`

View source

memcache_delete(
    key, seconds=0, namespace=None, deadline=None
)

`memcache_get`

View source

memcache_get(
    key, for_cas=False, namespace=None, use_cache=False, deadline=None
)

An auto-batching wrapper for memcache.get() or .get_multi().

Args
`key`	Key to set. This must be a string; no prefix is applied.
`for_cas`	If `True`, request and store CAS ids on the Context.
`namespace`	Optional namespace.
`deadline`	Optional deadline for the RPC.

Returns
A Future (!) whose return value is the value retrieved from memcache, or `None`.

`memcache_gets`

View source

memcache_gets(
    key, namespace=None, use_cache=False, deadline=None
)

`memcache_incr`

View source

memcache_incr(
    key, delta=1, initial_value=None, namespace=None, deadline=None
)

`memcache_replace`

View source

memcache_replace(
    key, value, time=0, namespace=None, deadline=None
)

`memcache_set`

View source

memcache_set(
    key, value, time=0, namespace=None, use_cache=False, deadline=None
)

`put`

View source

put(
    entity, **ctx_options
)

`set_cache_policy`

View source

set_cache_policy(
    func
)

Set the context cache policy function.

Args
`func`	A function that accepts a `Key` instance as argument and returns a bool indicating if it should be cached. May be `None`.

`set_datastore_policy`

View source

set_datastore_policy(
    func
)

Set the context datastore policy function.

Args
`func`	A function that accepts a `Key` instance as argument and returns a bool indicating if it should use the datastore. May be `None`.

`set_memcache_policy`

View source

set_memcache_policy(
    func
)

Set the memcache policy function.

Args
`func`	A function that accepts a Key instance as argument and returns a bool indicating if it should be cached. May be None.

`set_memcache_timeout_policy`

View source

set_memcache_timeout_policy(
    func
)

Set the policy function for memcache timeout (expiration).

If the function returns 0, it implies the default timeout.

Args
`func`	A function that accepts a key instance as argument and returns an integer indicating the desired memcache timeout. May be `None`.

`transaction`

View source

transaction(
    callback, **ctx_options
)

`urlfetch`

View source

urlfetch(
    url,
    payload=None,
    method='GET',
    headers={},
    allow_truncated=False,
    follow_redirects=True,
    validate_certificate=None,
    deadline=None,
    callback=None
)