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Figuring out how to close the connection

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Přemysl Eric Janouch 2015-03-06 19:49:33 +01:00
parent 0b0d64124b
commit 2733ead30f
1 changed files with 112 additions and 92 deletions
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196
demo-json-rpc-server.c
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@ -68,30 +68,6 @@ msg_unpacker_u32 (struct msg_unpacker *self, uint32_t *value)
// --- libev helpers ----------------------------------------------------------- // --- libev helpers -----------------------------------------------------------
static bool
read_loop (EV_P_ ev_io *watcher,
bool (*cb) (EV_P_ ev_io *, const void *, ssize_t))
{
char buf[8192];
while (true)
{
ssize_t n_read = recv (watcher->fd, buf, sizeof buf, 0);
if (n_read < 0)
{
if (errno == EAGAIN)
break;
if (errno == EINTR)
continue;
}
// The callback is called on EOF as well
if (n_read < 0 || !cb (EV_A_ watcher, buf, n_read))
return false;
if (!n_read)
return false;
}
return true;
}
static bool static bool
flush_queue (write_queue_t *queue, ev_io *watcher) flush_queue (write_queue_t *queue, ev_io *watcher)
{ {
@ -504,11 +480,13 @@ struct scgi_parser
struct str name; ///< Header name so far struct str name; ///< Header name so far
struct str value; ///< Header value so far struct str value; ///< Header value so far
/// Finished parsing request headers /// Finished parsing request headers.
void (*on_headers_read) (void *user_data); /// Return false to abort further processing of input.
bool (*on_headers_read) (void *user_data);
/// Content available; len == 0 means end of file /// Content available; len == 0 means end of file.
void (*on_content) (void *user_data, const void *data, size_t len); /// Return false to abort further processing of input.
bool (*on_content) (void *user_data, const void *data, size_t len);
void *user_data; ///< User data passed to callbacks void *user_data; ///< User data passed to callbacks
}; };
@ -545,15 +523,15 @@ scgi_parser_push (struct scgi_parser *self,
} }
// Indicate end of file // Indicate end of file
self->on_content (self->user_data, NULL, 0); return self->on_content (self->user_data, NULL, 0);
return true;
} }
// Notice that this madness is significantly harder to parse than FastCGI; // Notice that this madness is significantly harder to parse than FastCGI;
// this procedure could also be optimized significantly // this procedure could also be optimized significantly
str_append_data (&self->input, data, len); str_append_data (&self->input, data, len);
while (true) bool keep_running = true;
while (keep_running)
switch (self->state) switch (self->state)
{ {
case SCGI_READING_NETSTRING_LENGTH: case SCGI_READING_NETSTRING_LENGTH:
@ -601,7 +579,7 @@ scgi_parser_push (struct scgi_parser *self,
return false; return false;
} }
self->state = SCGI_READING_CONTENT; self->state = SCGI_READING_CONTENT;
// TODO: a "on_headers_read" callback? keep_running = self->on_headers_read (self->user_data);
} }
else if (c != '\0') else if (c != '\0')
str_append_c (&self->name, c); str_append_c (&self->name, c);
@ -641,10 +619,12 @@ scgi_parser_push (struct scgi_parser *self,
break; break;
} }
case SCGI_READING_CONTENT: case SCGI_READING_CONTENT:
self->on_content (self->user_data, self->input.str, self->input.len); keep_running = self->on_content
(self->user_data, self->input.str, self->input.len);
str_remove_slice (&self->input, 0, self->input.len); str_remove_slice (&self->input, 0, self->input.len);
return true; return keep_running;
} }
return false;
} }
// --- Server ------------------------------------------------------------------ // --- Server ------------------------------------------------------------------
@ -703,6 +683,9 @@ server_context_free (struct server_context *self)
// returns back a JSON reply. This function may get called multiple times if // returns back a JSON reply. This function may get called multiple times if
// the user sends a batch request. // the user sends a batch request.
// TODO: a function that queues up a ping over IRC: this has to be owned by the
// server context as a background job that removes itself upon completion.
static bool static bool
try_advance (const char **p, const char *text) try_advance (const char **p, const char *text)
{ {
@ -747,9 +730,6 @@ validate_json_rpc_content_type (const char *type)
// --- Requests ---------------------------------------------------------------- // --- Requests ----------------------------------------------------------------
// TODO: something to read in the headers and decide what to do with the request
// e.g. whether to reject it with a 404, or do JSON-RPC, or ignore it with 200
struct request struct request
{ {
// TODO *ctx // TODO *ctx
@ -759,7 +739,8 @@ struct request
/// Callback to write some CGI response data to the output /// Callback to write some CGI response data to the output
void (*write_cb) (void *user_data, const void *data, size_t len); void (*write_cb) (void *user_data, const void *data, size_t len);
/// Callback to close the connection /// Callback to close the connection.
/// CALLING THIS MAY CAUSE THE REQUEST TO BE DESTROYED.
void (*close_cb) (void *user_data); void (*close_cb) (void *user_data);
struct request_handler *handler; ///< Current request handler struct request_handler *handler; ///< Current request handler
@ -771,8 +752,9 @@ struct request_handler
/// Install ourselves as the handler for the request if applicable /// Install ourselves as the handler for the request if applicable
bool (*try_handle) (struct request *request, struct str_map *headers); bool (*try_handle) (struct request *request, struct str_map *headers);
/// Handle incoming data /// Handle incoming data.
void (*push_cb) (struct request *request, const void *data, size_t len); /// Return false if further processing should be stopped.
bool (*push_cb) (struct request *request, const void *data, size_t len);
/// Destroy the handler /// Destroy the handler
void (*destroy_cb) (struct request *request); void (*destroy_cb) (struct request *request);
@ -787,16 +769,27 @@ request_init (struct request *self)
static void static void
request_free (struct request *self) request_free (struct request *self)
{ {
// TODO: destroy the handler? if (self->handler)
self->handler->destroy_cb (self);
} }
/// This function is only intended to be run from asynchronous event handlers
/// such as timers, not as a direct result of starting the request or receiving
/// request data. CALLING THIS MAY CAUSE THE REQUEST TO BE DESTROYED.
static void static void
request_finish (struct request *self)
{
self->close_cb (self->user_data);
}
static bool
request_start (struct request *self, struct str_map *headers) request_start (struct request *self, struct str_map *headers)
{ {
bool handled = false; bool handled = false;
// TODO: try request handlers registered in self->ctx // TODO: try request handlers registered in self->ctx
if (handled) if (handled)
return; // TODO: can also be false
return true;
// Unable to serve the request // Unable to serve the request
struct str response; struct str response;
@ -804,16 +797,17 @@ request_start (struct request *self, struct str_map *headers)
str_append (&response, "404 Not Found\r\n\r\n"); str_append (&response, "404 Not Found\r\n\r\n");
self->write_cb (self->user_data, response.str, response.len); self->write_cb (self->user_data, response.str, response.len);
str_free (&response); str_free (&response);
return false;
// XXX: how will the clients behave when this happens?
self->close_cb (self->user_data);
} }
static void static bool
request_push (struct request *self, const void *data, size_t len) request_push (struct request *self, const void *data, size_t len)
{ {
if (soft_assert (self->handler)) if (soft_assert (self->handler))
self->handler->push_cb (self, data, len); return self->handler->push_cb (self, data, len);
// No handler, nothing to do with any data
return false;
} }
// --- Requests handlers ------------------------------------------------------- // --- Requests handlers -------------------------------------------------------
@ -833,12 +827,13 @@ request_handler_json_rpc_try_handle
return true; return true;
} }
static void static bool
request_handler_json_rpc_push request_handler_json_rpc_push
(struct request *request, const void *data, size_t len) (struct request *request, const void *data, size_t len)
{ {
// TODO: append to a buffer // TODO: append to a buffer
// TODO: len == 0: process the request // TODO: len == 0: process the request
return true;
} }
static void static void
@ -883,7 +878,7 @@ struct client_impl
void (*destroy) (struct client *client); void (*destroy) (struct client *client);
/// Process incoming data; "len == 0" means EOF /// Process incoming data; "len == 0" means EOF
bool (*on_data) (struct client *client, const void *data, size_t len); bool (*push) (struct client *client, const void *data, size_t len);
}; };
static void static void
@ -910,6 +905,24 @@ client_write (struct client *client, const void *data, size_t len)
ev_io_start (EV_DEFAULT_ &client->write_watcher); ev_io_start (EV_DEFAULT_ &client->write_watcher);
} }
static void
client_remove (struct client *client)
{
struct server_context *ctx = client->ctx;
LIST_UNLINK (ctx->clients, client);
ctx->n_clients--;
// First uninitialize the higher-level implementation
client->impl->destroy (client);
ev_io_stop (EV_DEFAULT_ &client->read_watcher);
ev_io_stop (EV_DEFAULT_ &client->write_watcher);
xclose (client->socket_fd);
client_free (client);
free (client);
}
// - - FastCGI - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - // - - FastCGI - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
struct client_fcgi struct client_fcgi
@ -938,7 +951,7 @@ client_fcgi_destroy (struct client *client)
} }
static bool static bool
client_fcgi_on_data (struct client *client, const void *data, size_t len) client_fcgi_push (struct client *client, const void *data, size_t len)
{ {
struct client_fcgi *self = client->impl_data; struct client_fcgi *self = client->impl_data;
fcgi_parser_push (&self->parser, data, len); fcgi_parser_push (&self->parser, data, len);
@ -949,7 +962,7 @@ static struct client_impl g_client_fcgi =
{ {
.init = client_fcgi_init, .init = client_fcgi_init,
.destroy = client_fcgi_destroy, .destroy = client_fcgi_destroy,
.on_data = client_fcgi_on_data, .push = client_fcgi_push,
}; };
// - - SCGI - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - // - - SCGI - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@ -957,7 +970,7 @@ static struct client_impl g_client_fcgi =
struct client_scgi struct client_scgi
{ {
struct scgi_parser parser; ///< SCGI stream parser struct scgi_parser parser; ///< SCGI stream parser
struct request request; ///< Request struct request request; ///< Request (only one per connection)
}; };
static void static void
@ -970,29 +983,29 @@ client_scgi_write (void *user_data, const void *data, size_t len)
static void static void
client_scgi_close (void *user_data) client_scgi_close (void *user_data)
{ {
// XXX: this rather really means "close me [the request]"
struct client *client = user_data; struct client *client = user_data;
struct client_scgi *self = client->impl_data; client_remove (client);
// TODO
} }
static void static bool
client_scgi_on_headers_read (void *user_data) client_scgi_on_headers_read (void *user_data)
{ {
struct client *client = user_data; struct client *client = user_data;
struct client_scgi *self = client->impl_data; struct client_scgi *self = client->impl_data;
return request_start (&self->request, &self->parser.headers);
request_start (&self->request, &self->parser.headers);
} }
static void static bool
client_scgi_on_content (void *user_data, const void *data, size_t len) client_scgi_on_content (void *user_data, const void *data, size_t len)
{ {
struct client *client = user_data; struct client *client = user_data;
struct client_scgi *self = client->impl_data; struct client_scgi *self = client->impl_data;
// XXX: make sure this is understood as EOF // XXX: do we have to count CONTENT_LENGTH and supply our own EOF?
request_push (&self->request, data, len); // If we do produce our own EOF, we should probably make sure we don't
// send it twice in a row.
return request_push (&self->request, data, len);
} }
static void static void
@ -1018,23 +1031,24 @@ client_scgi_destroy (struct client *client)
struct client_scgi *self = client->impl_data; struct client_scgi *self = client->impl_data;
client->impl_data = NULL; client->impl_data = NULL;
// TODO: do something more to abort the request?
request_free (&self->request); request_free (&self->request);
scgi_parser_free (&self->parser); scgi_parser_free (&self->parser);
free (self); free (self);
} }
static bool static bool
client_scgi_on_data (struct client *client, const void *data, size_t len) client_scgi_push (struct client *client, const void *data, size_t len)
{ {
struct client_scgi *self = client->impl_data; struct client_scgi *self = client->impl_data;
struct error *e = NULL; struct error *e = NULL;
if (scgi_parser_push (&self->parser, data, len, &e)) if (scgi_parser_push (&self->parser, data, len, &e))
return true; return true;
if (e != NULL)
{
print_debug ("SCGI parser failed: %s", e->message); print_debug ("SCGI parser failed: %s", e->message);
error_free (e); error_free (e);
}
return false; return false;
} }
@ -1042,7 +1056,7 @@ static struct client_impl g_client_scgi =
{ {
.init = client_scgi_init, .init = client_scgi_init,
.destroy = client_scgi_destroy, .destroy = client_scgi_destroy,
.on_data = client_scgi_on_data, .push = client_scgi_push,
}; };
// --- Basic server stuff ------------------------------------------------------ // --- Basic server stuff ------------------------------------------------------
@ -1054,41 +1068,45 @@ struct listener
struct client_impl *impl; ///< Client behaviour struct client_impl *impl; ///< Client behaviour
}; };
static void static bool
remove_client (struct server_context *ctx, struct client *client) client_read_loop (EV_P_ struct client *client, ev_io *watcher)
{ {
LIST_UNLINK (ctx->clients, client); char buf[8192];
ctx->n_clients--; while (true)
{
ssize_t n_read = recv (watcher->fd, buf, sizeof buf, 0);
if (n_read < 0)
{
if (errno == EAGAIN)
break;
if (errno == EINTR)
continue;
// First uninitialize the higher-level implementation return false;
client->impl->destroy (client);
ev_io_stop (EV_DEFAULT_ &client->read_watcher);
ev_io_stop (EV_DEFAULT_ &client->write_watcher);
xclose (client->socket_fd);
client_free (client);
free (client);
} }
static bool if (!client->impl->push (client, buf, n_read))
on_client_data (EV_P_ ev_io *watcher, const void *buf, ssize_t n_read) return false;
{
(void) loop;
struct client *client = watcher->data; if (!n_read)
return client->impl->on_data (client, buf, n_read); {
// Don't receive the EOF condition repeatedly
ev_io_stop (EV_A_ watcher);
// We can probably still write, so let's just return
return true;
}
}
return true;
} }
static void static void
on_client_ready (EV_P_ ev_io *watcher, int revents) on_client_ready (EV_P_ ev_io *watcher, int revents)
{ {
struct server_context *ctx = ev_userdata (loop);
struct client *client = watcher->data; struct client *client = watcher->data;
// FIXME: don't close the connection on EOF; we need to be able to keep
// the connection open and respond in an asynchronous manner
if (revents & EV_READ) if (revents & EV_READ)
if (!read_loop (EV_A_ watcher, on_client_data)) if (!client_read_loop (EV_A_ client, watcher))
goto error; goto error;
if (revents & EV_WRITE) if (revents & EV_WRITE)
if (!flush_queue (&client->write_queue, watcher)) if (!flush_queue (&client->write_queue, watcher))
@ -1096,7 +1114,9 @@ on_client_ready (EV_P_ ev_io *watcher, int revents)
return; return;
error: error:
remove_client (ctx, client); // The callback also could have just told us to stop reading,
// this is not necessarily an error condition
client_remove (client);
} }
static void static void