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// file : web/apache/service.txx -*- C++ -*-
// copyright : Copyright (c) 2014-2016 Code Synthesis Ltd
// license : MIT; see accompanying LICENSE file
#include <httpd.h> // APEXIT_CHILDSICK
#include <http_log.h> // APLOG_*
#include <cstdlib> // exit()
#include <utility> // move()
#include <exception>
namespace web
{
namespace apache
{
template <typename M>
void service::
init_worker (log& l)
{
const std::string func_name (
"web::apache::service<" + name_ + ">::init_worker");
try
{
const M* exemplar (dynamic_cast<const M*> (&exemplar_));
assert (exemplar != nullptr);
// For each directory configuration context create the module exemplar
// as a deep copy of the exemplar_ member and initialize it with the
// context-specific option list. Note that there can be contexts
// having no module options specified for them and no options
// inherited from enclosing contexts. Such contexts will not appear in
// the options_ map. Meanwhile 'SetHandler <modname>' directive can be
// in effect for such contexts, and we should be ready to handle
// requests for them (by using the "root exemplar").
//
for (const auto& o: options_)
{
const context* c (o.first);
if (c->server != nullptr) // Is a directory configuration context.
{
auto r (
exemplars_.emplace (
make_context_id (c),
std::unique_ptr<module> (new M (*exemplar))));
r.first->second->init (o.second, l);
}
}
// Options are not needed anymore. Free up the space.
//
options_.clear ();
// Initialize the "root exemplar" by default (with no options). It
// will be used to handle requests for configuration contexts having
// no options specified, and no options inherited from enclosing
// contexts.
//
exemplar_.init (name_values (), l);
}
catch (const std::exception& e)
{
l.write (nullptr, 0, func_name.c_str (), APLOG_EMERG, e.what ());
// Terminate the worker apache process. APEXIT_CHILDSICK indicates to
// the root process that the worker have exited due to a resource
// shortage. In this case the root process limits the rate of forking
// until situation is resolved.
//
// If the root process fails to create any worker process on startup,
// the behaviour depends on the Multi-Processing Module enabled. For
// mpm_worker_module and mpm_event_module the root process terminates.
// For mpm_prefork_module it keeps trying to create the worker process
// at one-second intervals.
//
// If the root process loses all it's workers while running (for
// example due to the MaxRequestsPerChild directive), and fails to
// create any new ones, it keeps trying to create the worker process
// at one-second intervals.
//
std::exit (APEXIT_CHILDSICK);
}
catch (...)
{
l.write (nullptr,
0,
func_name.c_str (),
APLOG_EMERG,
"unknown error");
// Terminate the worker apache process.
//
std::exit (APEXIT_CHILDSICK);
}
}
template <typename M>
int service::
request_handler (request_rec* r) noexcept
{
auto srv (instance<M> ());
if (!r->handler || srv->name_ != r->handler) return DECLINED;
assert (r->per_dir_config != nullptr);
// Obtain the request-associated configuration context id.
//
context_id id (
make_context_id (ap_get_module_config (r->per_dir_config, srv)));
assert (!is_null (id));
request rq (r);
log lg (r->server, srv);
return srv->template handle<M> (rq, id, lg);
}
template <typename M>
int service::
handle (request& rq, context_id id, log& lg) const
{
static const std::string func_name (
"web::apache::service<" + name_ + ">::handle");
try
{
auto i (exemplars_.find (id));
// Use the context-specific exemplar if found, otherwise use the
// default one.
//
const module* exemplar (i != exemplars_.end ()
? i->second.get ()
: &exemplar_);
const M* e (dynamic_cast<const M*> (exemplar));
assert (e != nullptr);
for (M m (*e);;)
{
try
{
if (static_cast<module&> (m).handle (rq, rq, lg))
return rq.flush ();
if (rq.state () == request_state::initial)
return DECLINED;
lg.write (nullptr, 0, func_name.c_str (), APLOG_ERR,
"handling declined being partially executed");
break;
}
catch (const module::retry&)
{
// Retry to handle the request.
//
rq.rewind ();
}
}
}
catch (const invalid_request& e)
{
if (!e.content.empty () && rq.state () < request_state::writing)
{
try
{
rq.content (e.status, e.type) << e.content;
return rq.flush ();
}
catch (const std::exception& e)
{
lg.write (nullptr, 0, func_name.c_str (), APLOG_ERR, e.what ());
}
}
return e.status;
}
catch (const std::exception& e)
{
lg.write (nullptr, 0, func_name.c_str (), APLOG_ERR, e.what ());
if (*e.what () && rq.state () < request_state::writing)
{
try
{
rq.content (
HTTP_INTERNAL_SERVER_ERROR, "text/plain;charset=utf-8")
<< e.what ();
return rq.flush ();
}
catch (const std::exception& e)
{
lg.write (nullptr, 0, func_name.c_str (), APLOG_ERR, e.what ());
}
}
}
catch (...)
{
lg.write (nullptr, 0, func_name.c_str (), APLOG_ERR, "unknown error");
if (rq.state () < request_state::writing)
{
try
{
rq.content (
HTTP_INTERNAL_SERVER_ERROR, "text/plain;charset=utf-8")
<< "unknown error";
return rq.flush ();
}
catch (const std::exception& e)
{
lg.write (nullptr, 0, func_name.c_str (), APLOG_ERR, e.what ());
}
}
}
return HTTP_INTERNAL_SERVER_ERROR;
}
}
}
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