Traffic Server remap plugin entry points.
#include <ts/ts.h> #include <ts/remap.h>
The Traffic Server remap interface provides a simplified mechanism for
plugins to manipulate HTTP transactions. A remap plugin is not global; it
is configured on a per-remap rule basis, which enables you to customize
how URLs are redirected based on individual rules in
Writing a remap plugin consists of implementing one or more of the
remap entry points and configuring
route the transaction through your plugin. Multiple remap plugins can be
specified for a single remap rule, resulting in a remap plugin chain
where each plugin is given an opportunity to examine the HTTP transaction.
TSRemapInit() is a required entry point. This function will be called
once when Traffic Server loads the plugin. If the optional
entry point is available, Traffic Server will call then when unloading
the remap plugin.
A remap plugin may be invoked for different remap rules. Traffic Server
will call the entry point each time a plugin is specified in a remap
rule. When a remap plugin instance is no longer required, Traffic Server
TSRemapDeleteInstance(). At that point, it’s safe to remove
any data or continuations associated with that instance.
TSRemapDoRemap() is called for each HTTP transaction. This is a mandatory
entry point. In this function, the remap plugin may examine and modify
the HTTP transaction.
TSRemapConfigReload() is called once for every remap plugin just before the
remap configuration file (
remap.config) is reloaded. This is an optional
entry point, which takes no arguments and has no return value.
Generally speaking, calls to these functions are mutually exclusive. The exception is for functions which take an HTTP transaction as a parameter. Calls to these transaction-specific functions for different transactions are not necessarily mutually exclusive of each other.
Status return value for remap callback.
The remap callback modified the request.
The remap callback modified the request and that no more remapping callbacks should be invoked.
The remap callback did not modify the request.
The remap callback did not modify the request and that no further remapping callbacks should be invoked.
The remapping attempt in general failed and the transaction should fail with an error return to the user agent.
TSRemapDoRemap() returns a status code that indicates whether the HTTP transaction has been
modified and whether Traffic Server should continue to evaluate the chain of remap plugins. If the
transaction was modified, the plugin should return
TSREMAP_DID_REMAP_STOP; otherwise it should return
TSREMAP_NO_REMAP_STOP. If Traffic Server should not send the transaction to subsequent
plugins in the remap chain, return
TSREMAP_ERROR causes Traffic Server to stop evaluating the remap chain and respond
with an error.