doc/reference/api/TSCacheWrite.en.rst

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TSCacheWrite
============

Asks the Traffic Server cache if contp can start writing the object
(corresponding to key) to the cache.


Synopsis
--------

`#include <ts/ts.h>`

.. c:function:: TSAction TSCacheWrite(TSCont contp, TSCacheKey key)


Description
-----------

If the object can be written, the cache calls contp back with the
event :c:data:`TS_EVENT_CACHE_OPEN_WRITE`.  In this case, the cache
also passes contp a cache vconnection and contp can then initiate a
write operation on that vconnection using :c:type:`TSVConnWrite`.  The
object is not committed to the cache until the vconnection is closed.
When all data has been transferred, the user (contp) must do an
:c:type:`TSVConnClose`.  In case of any errors, the user MUST do an
``TSVConnAbort(contp, 0)``.

If the object cannot be written, the cache calls contp back with the
event :c:data:`TS_EVENT_CACHE_OPEN_WRITE_FAILED`.  This can happen,
for example, if there is another object with the same key being
written to the cache.  The user (contp) has the option to cancel the
action returned by :c:type:`TSCacheWrite`.

Note that reentrant calls are possible, i.e. the cache can call back
the user (contp) in the same call.