static ngx_http_push_channel_t * ngx_http_push_store_find_channel(ngx_str_t *id, time_t channel_timeout, ngx_log_t *log) {
//get the channel and check channel authorization while we're at it.
ngx_http_push_channel_t *channel;
ngx_shmtx_lock(&ngx_http_push_shpool->mutex);
channel = ngx_http_push_find_channel(id, channel_timeout, log);
ngx_shmtx_unlock(&ngx_http_push_shpool->mutex);
return channel;
}
static void ngx_http_push_publisher_body_handler(ngx_http_request_t * r) {
ngx_str_t *id;
ngx_http_push_loc_conf_t *cf = ngx_http_get_module_loc_conf(r, ngx_http_push_module);
ngx_slab_pool_t *shpool = (ngx_slab_pool_t *) ngx_http_push_shm_zone->shm.addr;
ngx_buf_t *buf = NULL, *buf_copy;
ngx_http_push_channel_t *channel;
ngx_uint_t method = r->method;
time_t last_seen = 0;
ngx_uint_t subscribers = 0;
ngx_uint_t messages = 0;
if((id = ngx_http_push_get_channel_id(r, cf))==NULL) {
ngx_http_finalize_request(r, r->headers_out.status ? NGX_OK : NGX_HTTP_INTERNAL_SERVER_ERROR);
return;
}
ngx_shmtx_lock(&shpool->mutex);
//POST requests will need a channel created if it doesn't yet exist.
if(method==NGX_HTTP_POST || method==NGX_HTTP_PUT) {
channel = ngx_http_push_get_channel(id, &((ngx_http_push_shm_data_t *) ngx_http_push_shm_zone->data)->tree, shpool, r->connection->log);
NGX_HTTP_PUSH_PUBLISHER_CHECK_LOCKED(channel, NULL, r, "push module: unable to allocate memory for new channel", shpool);
}
//no other request method needs that.
else{
//just find the channel. if it's not there, NULL.
channel = ngx_http_push_find_channel(id, &((ngx_http_push_shm_data_t *) ngx_http_push_shm_zone->data)->tree, shpool, r->connection->log);
}
if(channel!=NULL) {
subscribers = channel->subscribers;
last_seen = channel->last_seen;
messages = channel->messages;
}
else {
//404!
ngx_shmtx_unlock(&shpool->mutex);
r->headers_out.status=NGX_HTTP_NOT_FOUND;
//just the headers, please. we don't care to describe the situation or
//respond with an html page
r->headers_out.content_length_n=0;
r->header_only = 1;
ngx_http_finalize_request(r, ngx_http_send_header(r));
return;
}
ngx_shmtx_unlock(&shpool->mutex);
switch(method) {
ngx_http_push_msg_t *msg, *previous_msg;
size_t content_type_len;
ngx_uint_t received;
ngx_http_push_msg_t *sentinel;
case NGX_HTTP_POST:
//first off, we'll want to extract the body buffer
//note: this works mostly because of r->request_body_in_single_buf = 1;
//which, i suppose, makes this module a little slower than it could be.
//this block is a little hacky. might be a thorn for forward-compatibility.
if(r->headers_in.content_length_n == -1 || r->headers_in.content_length_n == 0) {
buf = ngx_create_temp_buf(r->pool, 0);
//this buffer will get copied to shared memory in a few lines,
//so it does't matter what pool we make it in.
}
else if(r->request_body->temp_file==NULL) { //everything in the first buffer, please
//no file
buf=r->request_body->bufs->buf;
}
else { //(r->request_body->bufs->next!=NULL)
//there's probably a file
buf=r->request_body->bufs->next->buf;
}
NGX_HTTP_PUSH_PUBLISHER_CHECK(buf, NULL, r, "push module: can't find or allocate publisher request body buffer");
content_type_len = (r->headers_in.content_type!=NULL ? r->headers_in.content_type->value.len : 0);
ngx_shmtx_lock(&shpool->mutex);
//create a buffer copy in shared mem
msg = ngx_slab_alloc_locked(shpool, sizeof(*msg) + content_type_len);
NGX_HTTP_PUSH_PUBLISHER_CHECK_LOCKED(msg, NULL, r, "push module: unable to allocate message in shared memory", shpool);
previous_msg=ngx_http_push_get_latest_message_locked(channel); //need this for entity-tags generation
NGX_HTTP_PUSH_CREATE_BUF_COPY(buf, buf_copy, shpool, ngx_slab_alloc_locked);
NGX_HTTP_PUSH_PUBLISHER_CHECK_LOCKED(buf_copy, NULL, r, "push module: unable to allocate buffer in shared memory", shpool);
msg->buf=buf_copy;
if(cf->store_messages) {
ngx_queue_insert_tail(&channel->message_queue->queue, &msg->queue);
channel->messages++;
}
//Stamp the new message with entity tags
msg->message_time=ngx_time(); //ESSENTIAL TODO: make sure this ends up producing GMT time
msg->message_tag=(previous_msg!=NULL && msg->message_time == previous_msg->message_time) ? (previous_msg->message_tag + 1) : 0;
//store the content-type
if(content_type_len>0) {
msg->content_type.len=r->headers_in.content_type->value.len;
msg->content_type.data=(u_char *) (msg+1); //we had reserved a contiguous chunk, myes?
ngx_memcpy(msg->content_type.data, r->headers_in.content_type->value.data, msg->content_type.len);
}
else {
msg->content_type.len=0;
msg->content_type.data=NULL;
}
//set message expiration time
time_t message_timeout = cf->buffer_timeout;
msg->expires = (message_timeout==0 ? 0 : (ngx_time() + message_timeout));
//FMI (For My Information): shm is still locked.
switch(ngx_http_push_broadcast_message_locked(channel, msg, r->connection->log, shpool)) {
case NGX_HTTP_PUSH_MESSAGE_QUEUED:
//message was queued successfully, but there were no
//subscribers to receive it.
r->headers_out.status = NGX_HTTP_ACCEPTED;
r->headers_out.status_line.len =sizeof("202 Accepted")- 1;
r->headers_out.status_line.data=(u_char *) "202 Accepted";
break;
case NGX_HTTP_PUSH_MESSAGE_RECEIVED:
//message was queued successfully, and it was already sent
//to at least one subscriber
r->headers_out.status = NGX_HTTP_CREATED;
r->headers_out.status_line.len =sizeof("201 Created")- 1;
r->headers_out.status_line.data=(u_char *) "201 Created";
//update the number of times the message was received.
//in the interest of premature optimization, I assume all
//current subscribers have received the message successfully.
received = msg->received;
//nasty overflow check
msg->received = (received + subscribers < received) ? NGX_MAX_UINT32_VALUE : (received + subscribers);
break;
case NGX_ERROR:
//WTF?
ngx_shmtx_unlock(&shpool->mutex);
ngx_log_error(NGX_LOG_ERR, r->connection->log, 0, "push module: error broadcasting message to workers");
ngx_http_finalize_request(r, NGX_HTTP_INTERNAL_SERVER_ERROR);
return;
default:
//for debugging, mostly. I don't expect this branch to be
//hit during regular operation
ngx_shmtx_unlock(&shpool->mutex);
ngx_log_error(NGX_LOG_ERR, r->connection->log, 0, "push module: TOTALLY UNEXPECTED error broadcasting message to workers");
ngx_http_finalize_request(r, NGX_HTTP_INTERNAL_SERVER_ERROR);
return;
}
//shm is still locked I hope.
if(buf->file!=NULL) {
//future subscribers won't be able to use this file descriptor --
//it will be closed once the publisher request is finalized.
//(That's about to happen a handful of lines below.)
msg->buf->file->fd=NGX_INVALID_FILE;
}
//now see if the queue is too big
if(channel->messages > (ngx_uint_t) cf->max_messages) {
//exceeeds max queue size. force-delete oldest message
ngx_http_push_force_delete_message_locked(channel, ngx_http_push_get_oldest_message_locked(channel), shpool);
}
if(channel->messages > (ngx_uint_t) cf->min_messages) {
//exceeeds min queue size. maybe delete the oldest message
ngx_http_push_msg_t *oldest_msg = ngx_http_push_get_oldest_message_locked(channel);
NGX_HTTP_PUSH_PUBLISHER_CHECK_LOCKED(oldest_msg, NULL, r, "push module: oldest message not found", shpool);
if(oldest_msg->received >= (ngx_uint_t) cf->min_message_recipients) {
//received more than min_message_recipients times
ngx_http_push_delete_message_locked(channel, oldest_msg, shpool);
}
}
messages = channel->messages;
ngx_shmtx_unlock(&shpool->mutex);
ngx_http_finalize_request(r, ngx_http_push_channel_info(r, messages, subscribers, last_seen));
return;
case NGX_HTTP_PUT:
case NGX_HTTP_GET:
r->headers_out.status = NGX_HTTP_OK;
ngx_http_finalize_request(r, ngx_http_push_channel_info(r, messages, subscribers, last_seen));
return;
case NGX_HTTP_DELETE:
ngx_shmtx_lock(&shpool->mutex);
sentinel = channel->message_queue;
msg = sentinel;
while((msg=(ngx_http_push_msg_t *)ngx_queue_next(&msg->queue))!=sentinel) {
//force-delete all the messages
ngx_http_push_force_delete_message_locked(NULL, msg, shpool);
}
channel->messages=0;
//410 gone
NGX_HTTP_PUSH_PUBLISHER_CHECK_LOCKED(ngx_http_push_broadcast_status_locked(channel, NGX_HTTP_GONE, &NGX_HTTP_PUSH_HTTP_STATUS_410, r->connection->log, shpool), NGX_ERROR, r, "push module: unable to send current subscribers a 410 Gone response", shpool);
ngx_http_push_delete_node_locked(&((ngx_http_push_shm_data_t *) ngx_http_push_shm_zone->data)->tree, (ngx_rbtree_node_t *) channel, shpool);
ngx_shmtx_unlock(&shpool->mutex);
//done.
r->headers_out.status=NGX_HTTP_OK;
ngx_http_finalize_request(r, ngx_http_push_channel_info(r, messages, subscribers, last_seen));
return;
default:
//some other weird request method
ngx_http_push_add_response_header(r, &NGX_HTTP_PUSH_HEADER_ALLOW, &NGX_HTTP_PUSH_ALLOW_GET_POST_PUT_DELETE);
ngx_http_finalize_request(r, NGX_HTTP_NOT_ALLOWED);
return;
}
}
static ngx_int_t ngx_http_push_subscriber_handler(ngx_http_request_t *r) {
ngx_http_push_loc_conf_t *cf = ngx_http_get_module_loc_conf(r, ngx_http_push_module);
ngx_slab_pool_t *shpool = (ngx_slab_pool_t *)ngx_http_push_shm_zone->shm.addr;
ngx_str_t *id;
ngx_http_push_channel_t *channel;
ngx_http_push_msg_t *msg;
ngx_int_t msg_search_outcome;
ngx_str_t *content_type=NULL;
ngx_str_t *etag;
if (r->method == NGX_HTTP_OPTIONS) {
ngx_buf_t *buf = ngx_create_temp_buf(r->pool, sizeof(NGX_HTTP_PUSH_OPTIONS_OK_MESSAGE));
ngx_chain_t *chain;
buf->pos=(u_char *)NGX_HTTP_PUSH_OPTIONS_OK_MESSAGE;
buf->last=buf->pos + sizeof(NGX_HTTP_PUSH_OPTIONS_OK_MESSAGE)-1;
chain = ngx_http_push_create_output_chain(buf, r->pool, r->connection->log);
buf->last_buf=1;
r->headers_out.content_length_n=ngx_buf_size(buf);
r->headers_out.status=NGX_HTTP_OK;
ngx_http_send_header(r);
ngx_http_output_filter(r, chain);
return NGX_OK;
}
if (r->method != NGX_HTTP_GET) {
ngx_http_push_add_response_header(r, &NGX_HTTP_PUSH_HEADER_ALLOW, &NGX_HTTP_PUSH_ALLOW_GET); //valid HTTP for the win
return NGX_HTTP_NOT_ALLOWED;
}
if((id=ngx_http_push_get_channel_id(r, cf)) == NULL) {
return r->headers_out.status ? NGX_OK : NGX_HTTP_INTERNAL_SERVER_ERROR;
}
//get the channel and check channel authorization while we're at it.
ngx_shmtx_lock(&shpool->mutex);
if (cf->authorize_channel==1) {
channel = ngx_http_push_find_channel(id, r->connection->log);
}else{
channel = ngx_http_push_get_channel(id, r->connection->log, cf->channel_timeout);
}
if (channel==NULL) {
//unable to allocate channel OR channel not found
ngx_shmtx_unlock(&shpool->mutex);
if(cf->authorize_channel) {
return NGX_HTTP_FORBIDDEN;
}
else {
ngx_log_error(NGX_LOG_ERR, r->connection->log, 0, "push module: unable to allocate shared memory for channel");
return NGX_HTTP_INTERNAL_SERVER_ERROR;
}
}
msg = ngx_http_push_find_message_locked(channel, r, &msg_search_outcome);
channel->last_seen = ngx_time();
channel->expires = ngx_time() + cf->channel_timeout;
ngx_shmtx_unlock(&shpool->mutex);
if (cf->ignore_queue_on_no_cache && !ngx_http_push_allow_caching(r)) {
msg_search_outcome = NGX_HTTP_PUSH_MESSAGE_EXPECTED;
msg = NULL;
}
switch(ngx_http_push_handle_subscriber_concurrency(r, channel, cf)) {
case NGX_DECLINED: //this request was declined for some reason.
//status codes and whatnot should have already been written. just get out of here quickly.
return NGX_OK;
case NGX_ERROR:
ngx_log_error(NGX_LOG_ERR, r->connection->log, 0, "push module: error handling subscriber concurrency setting");
return NGX_ERROR;
}
switch(msg_search_outcome) {
//for message-found:
ngx_chain_t *chain;
time_t last_modified;
size_t content_type_len;
case NGX_HTTP_PUSH_MESSAGE_EXPECTED:
// ♫ It's gonna be the future soon ♫
switch(cf->subscriber_poll_mechanism) {
//for NGX_HTTP_PUSH_MECHANISM_LONGPOLL
ngx_http_push_pid_queue_t *sentinel, *cur, *found;
ngx_http_push_subscriber_t *subscriber;
ngx_http_push_subscriber_t *subscriber_sentinel;
case NGX_HTTP_PUSH_MECHANISM_LONGPOLL:
//long-polling subscriber. wait for a message.
//subscribers are queued up in a local pool. Queue sentinels are separate and also local, but not in the pool.
ngx_shmtx_lock(&shpool->mutex);
sentinel = &channel->workers_with_subscribers;
cur = (ngx_http_push_pid_queue_t *)ngx_queue_head(&sentinel->queue);
found = NULL;
ngx_http_push_subscriber_cleanup_t *clndata;
ngx_pool_cleanup_t *cln;
while(cur!=sentinel) {
if(cur->pid==ngx_pid) {
found = cur;
break;
}
cur = (ngx_http_push_pid_queue_t *)ngx_queue_next(&cur->queue);
}
if(found == NULL) { //found nothing
if((found=ngx_http_push_slab_alloc_locked(sizeof(*found)))==NULL) {
ngx_shmtx_unlock(&shpool->mutex);
ngx_log_error(NGX_LOG_ERR, r->connection->log, 0, "push module: unable to allocate worker subscriber queue marker in shared memory");
return NGX_HTTP_INTERNAL_SERVER_ERROR;
}
//initialize
ngx_queue_insert_tail(&sentinel->queue, &found->queue);
found->pid=ngx_pid;
found->slot=ngx_process_slot;
found->subscriber_sentinel=NULL;
}
ngx_shmtx_unlock(&shpool->mutex);
if((subscriber = ngx_palloc(ngx_http_push_pool, sizeof(*subscriber)))==NULL) { //unable to allocate request queue element
return NGX_ERROR;
}
//attach a cleaner to remove the request from the channel.
if ((cln=ngx_pool_cleanup_add(r->pool, sizeof(*clndata))) == NULL) { //make sure we can.
return NGX_ERROR;
}
cln->handler = (ngx_pool_cleanup_pt) ngx_http_push_subscriber_cleanup;
clndata = (ngx_http_push_subscriber_cleanup_t *) cln->data;
clndata->channel=channel;
clndata->subscriber=subscriber;
subscriber->request = r;
subscriber->clndata=clndata;
ngx_shmtx_lock(&shpool->mutex);
channel->subscribers++; // do this only when we know everything went okay.
//figure out the subscriber sentinel
subscriber_sentinel = ((ngx_http_push_pid_queue_t *)found)->subscriber_sentinel;
if(subscriber_sentinel==NULL) {
//it's perfectly nornal for the sentinel to be NULL.
if((subscriber_sentinel=ngx_palloc(ngx_http_push_pool, sizeof(*subscriber_sentinel)))==NULL) {
ngx_log_error(NGX_LOG_ERR, r->connection->log, 0, "push module: unable to allocate channel subscriber sentinel");
return NGX_HTTP_INTERNAL_SERVER_ERROR;
}
ngx_queue_init(&subscriber_sentinel->queue);
((ngx_http_push_pid_queue_t *)found)->subscriber_sentinel=subscriber_sentinel;
}
ngx_shmtx_unlock(&shpool->mutex);
ngx_queue_insert_tail(&subscriber_sentinel->queue, &subscriber->queue);
ngx_memzero(&subscriber->event, sizeof(subscriber->event));
if (cf->subscriber_timeout > 0) {
subscriber->event.handler = ngx_http_push_clean_timeouted_subscriber;
subscriber->event.data = subscriber;
subscriber->event.log = r->connection->log;
ngx_add_timer(&subscriber->event, cf->subscriber_timeout * 1000);
}
//r->read_event_handler = ngx_http_test_reading;
//r->write_event_handler = ngx_http_request_empty_handler;
r->discard_body = 1;
//r->keepalive = 1; //stayin' alive!!
return NGX_DONE;
case NGX_HTTP_PUSH_MECHANISM_INTERVALPOLL:
//interval-polling subscriber requests get a 304 with their entity tags preserved.
if (r->headers_in.if_modified_since != NULL) {
r->headers_out.last_modified_time=ngx_http_parse_time(r->headers_in.if_modified_since->value.data, r->headers_in.if_modified_since->value.len);
}
if ((etag=ngx_http_push_subscriber_get_etag(r)) != NULL) {
r->headers_out.etag=ngx_http_push_add_response_header(r, &NGX_HTTP_PUSH_HEADER_ETAG, etag);
}
return NGX_HTTP_NOT_MODIFIED;
default:
//if this ever happens, there's a bug somewhere else. probably config stuff.
return NGX_HTTP_INTERNAL_SERVER_ERROR;
}
case NGX_HTTP_PUSH_MESSAGE_EXPIRED:
//subscriber wants an expired message
//TODO: maybe respond with entity-identifiers for oldest available message?
return NGX_HTTP_NO_CONTENT;
case NGX_HTTP_PUSH_MESSAGE_FOUND:
//found the message
ngx_shmtx_lock(&shpool->mutex);
ngx_http_push_reserve_message_locked(channel, msg);
NGX_HTTP_PUSH_MAKE_ETAG(msg->message_tag, etag, ngx_palloc, r->pool);
if(etag==NULL) {
//oh, nevermind...
ngx_shmtx_unlock(&shpool->mutex);
ngx_log_error(NGX_LOG_ERR, r->connection->log, 0, "push module: unable to allocate memory for Etag header");
return NGX_ERROR;
}
content_type_len = msg->content_type.len;
if(content_type_len>0) {
NGX_HTTP_PUSH_MAKE_CONTENT_TYPE(content_type, content_type_len, msg, r->pool);
if(content_type==NULL) {
ngx_log_error(NGX_LOG_ERR, r->connection->log, 0, "push module: unable to allocate memory for content-type header while responding to subscriber request");
ngx_shmtx_unlock(&shpool->mutex);
return NGX_ERROR;
}
}
//preallocate output chain. yes, same one for every waiting subscriber
if((chain = ngx_http_push_create_output_chain_locked(msg->buf, r->pool, r->connection->log, shpool))==NULL) {
ngx_log_error(NGX_LOG_ERR, r->connection->log, 0, "push module: unable to allocate buffer chain while responding to subscriber request");
ngx_shmtx_unlock(&shpool->mutex);
return NGX_ERROR;
}
last_modified = msg->message_time;
//is the message still needed?
ngx_http_push_release_message_locked(channel, msg);
ngx_shmtx_unlock(&shpool->mutex);
if(chain->buf->file!=NULL) {
//close file when we're done with it
ngx_pool_cleanup_t *cln;
ngx_pool_cleanup_file_t *clnf;
if((cln = ngx_pool_cleanup_add(r->pool, sizeof(ngx_pool_cleanup_file_t)))==NULL) {
return NGX_HTTP_INTERNAL_SERVER_ERROR;
}
cln->handler = ngx_pool_cleanup_file;
clnf = cln->data;
clnf->fd = chain->buf->file->fd;
clnf->name = chain->buf->file->name.data;
clnf->log = r->pool->log;
}
return ngx_http_push_prepare_response_to_subscriber_request(r, chain, content_type, etag, last_modified);
default: //we shouldn't be here.
return NGX_HTTP_INTERNAL_SERVER_ERROR;
}
}