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// file : brep/module -*- C++ -*-
// copyright : Copyright (c) 2014-2015 Code Synthesis Tools CC
// license : MIT; see accompanying LICENSE file
#ifndef BREP_MODULE
#define BREP_MODULE
#include <brep/diagnostics>
namespace brep
{
// This exception is used to signal that the request is invalid
// (4XX codes) rather than that it could not be processed (5XX).
// By default 422 is returned, which means the request was
// semantically invalid.
//
struct invalid_request
{
web::status_code status {422};
std::string description;
//@@ Maybe optional "try again" link?
//
};
// And this exception indicated a server error (5XX). In particular,
// it is thrown by the fail diagnostics stream and is caught by the
// module implementation where it is both logged as an error and
// returned to the user with the 5XX status code.
//
struct server_error
{
diag_data data;
};
// Adaptation of the web::module to our needs.
//
class module: public web::module
{
public:
virtual void
handle (request&, response&) = 0;
// Diagnostics.
//
protected:
const basic_mark error;
const basic_mark warn;
const basic_mark info;
const fail_mark<server_error> fail;
// Trace verbosity level.
//
// 0 - tracing disabled.
// 1 - @@ TODO: document
// 2 - @@ TODO: document
//
// While uint8 is more than enough, use uint16 for the ease of printing.
//
std::uint16_t verb_ {0};
template <class F> static void level1 (const F& f) {if (verb_ >= 1) f ();}
template <class F> static void level2 (const F& f) {if (verb_ >= 2) f ();}
struct trace_mark_base: basic_mark_base
{
trace_mark_base (const module* this_, const char* name)
: basic_mark_base (severity::trace, this_->log_writer_, name) {}
};
using trace_mark = diag_mark<trace_mark_base>;
using tracer = trace_mark;
// Implementation details.
//
protected:
module ();
virtual void
handle (request&, response&, log&);
// Diagnostics implementation details.
//
private:
log* log_ {nullptr}; // Diagnostics backend provided by the web server.
void
log_write (diag_data&&) const;
const diag_epilogue log_writer_;
};
}
#endif // BREP_MODULE
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