Ubuntu Manpage: TSRemapInit - traffic Server remap plugin entry points

Provided by: trafficserver-dev_9.2.3+ds-1+deb12u1build4_amd64

NAME

       TSRemapInit - traffic Server remap plugin entry points

SYNOPSIS

          #include <ts/ts.h>
          #include <ts/remap.h>

       TSReturnCode TSRemapInit(TSRemapInterface *api_info, char *errbuff, int errbuff_size)

       void TSRemapPreConfigReload(void)

       void TSRemapPostConfigReload(TSReturnCode reloadStatus)

       void TSRemapDone(void)

       TSRemapStatus TSRemapDoRemap(void *ih, TSHttpTxn rh, TSRemapRequestInfo *rri)

       TSReturnCode TSRemapNewInstance(int argc, char *argv[], void **ih, char *errbuff, int errbuff_size)

       void TSRemapDeleteInstance(void*)

       void TSRemapOSResponse(void *ih, TSHttpTxn rh, int os_response_type)

DESCRIPTION

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 remap.config. Writing a remap plugin
consists of implementing one or more of the remap entry points and configuring remap.config to 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 TSRemapDone() 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 will call 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.

TSRemapPreConfigReload() is called before the parsing of a new remap configuration starts to notify
plugins of the coming configuration reload. It is called on all already loaded plugins, invoked by
current and all previous still used configurations. This is an optional entry point.

TSRemapPostConfigReload() is called to indicate the end of the new remap configuration load. It is called
on the newly and previously loaded plugins, invoked by the new, current and previous still used
configurations. It also indicates whether the configuration reload was successful by passing
TSREMAP_CONFIG_RELOAD_FAILURE in case of failure and to notify the plugins if they are going to be part
of the new configuration by passing TSREMAP_CONFIG_RELOAD_SUCCESS_PLUGIN_USED or
TSREMAP_CONFIG_RELOAD_SUCCESS_PLUGIN_UNUSED. This is an optional entry point.

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.

For further information, see Remap Plugins.

TYPES

       enum TSRemapStatus
              Status return value for remap callback.

              enumerator TSREMAP_DID_REMAP
                     The remap callback modified the request.

              enumerator TSREMAP_DID_REMAP_STOP
                     The remap callback modified the request and that no  more  remapping  callbacks  should  be
                     invoked.

              enumerator TSREMAP_NO_REMAP
                     The remap callback did not modify the request.

              enumerator TSREMAP_NO_REMAP_STOP
                     The  remap  callback  did  not  modify  the request and that no further remapping callbacks
                     should be invoked.

              enumerator TSREMAP_ERROR
                     The remapping attempt in general failed and the  transaction  should  fail  with  an  error
                     return to the user agent.

       enum TSRemapReloadStatus

              enumerator TSREMAP_CONFIG_RELOAD_FAILURE
                     Notify the plugin that configuration parsing failed.

              enumerator TSREMAP_CONFIG_RELOAD_SUCCESS_PLUGIN_USED
                     Configuration parsing succeeded and plugin was used by the new configuration.

              enumerator TSREMAP_CONFIG_RELOAD_SUCCESS_PLUGIN_UNUSED
                     Configuration parsing succeeded but plugin was NOT used by the new configuration.

RETURN VALUES

       TSRemapInit()  and  TSRemapNewInstance()  should  return TS_SUCCESS on success, and TS_ERROR otherwise. A
       return value of TS_ERROR is unrecoverable.

       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  or  TSREMAP_DID_REMAP_STOP;  otherwise  it  should
       return  TSREMAP_NO_REMAP  or  TSREMAP_NO_REMAP_STOP. If Traffic Server should not send the transaction to
       subsequent plugins in the remap chain, return TSREMAP_NO_REMAP_STOP or TSREMAP_DID_REMAP_STOP.  Returning
       TSREMAP_ERROR causes Traffic Server to stop evaluating the remap chain and respond with an error.

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