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subscriber.cpp
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subscriber.cpp
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/*
Copyright (c) 2012-2014 The icomet Authors. All rights reserved.
Use of this source code is governed by a BSD-style license that can be
found in the LICENSE file.
*/
#include "subscriber.h"
#include "channel.h"
#include "server.h"
#include "util/log.h"
#include "server_config.h"
#include <http-internal.h>
static std::string iframe_header = "<html><head><meta http-equiv='Content-Type' content='text/html; charset=utf-8'><meta http-equiv='Cache-Control' content='no-store'><meta http-equiv='Cache-Control' content='no-cache'><meta http-equiv='Pragma' content='no-cache'><meta http-equiv=' Expires' content='Thu, 1 Jan 1970 00:00:00 GMT'><script type='text/javascript'>window.onError = null;try{document.domain = window.location.hostname.split('.').slice(-2).join('.');}catch(e){};</script></head><body>";
static std::string iframe_chunk_prefix = "<script>parent.icomet_cb(";
static std::string iframe_chunk_suffix = ");</script>";
Subscriber::Subscriber(){
req = NULL;
idle = 0;
}
Subscriber::~Subscriber(){
}
static void connection_closecb(struct evhttp_connection *evcon, void *arg){
Subscriber *sub = (Subscriber *)arg;
log_debug("subscriber disconnected");
sub->close();
}
static void add_http_header(int sub_type, struct evhttp_request *req){
evhttp_add_header(req->output_headers, "Expires", "0");
evhttp_add_header(req->output_headers, "Cache-Control", "no-cache");
if(sub_type == Subscriber::SSE){
evhttp_add_header(req->output_headers, "Content-Type", "text/event-stream; charset=utf-8");
// 允许客户端跨域请求
evhttp_add_header(req->output_headers, "Access-Control-Allow-Origin", "*");
}else{
evhttp_add_header(req->output_headers, "Content-Type", "application/json; charset=utf-8");
}
}
void Subscriber::start(){
log_debug("%s:%d sub %s, seq: %d, subs: %d",
req->remote_host, req->remote_port,
channel->name.c_str(), this->seq_next, channel->subs.size);
// 需要监控 EV_READ 事件，否则无法得知客户端主动关闭连接。
bufferevent_enable(req->evcon->bufev, EV_READ);
// evhttp_send_reply_start 与 evhttp_send_reply_end 必须成对出现, 否则内存泄露。
// 有两个地方需要调用 evhttp_send_reply_end(), 一是服务端主动关闭，二是客户端主动关闭
// 客户端主动关闭会触发 connection_closecb
evhttp_connection_set_closecb(req->evcon, connection_closecb, this);
add_http_header(this->type, req);
evhttp_add_header(req->output_headers, "Connection", "keep-alive");
evhttp_send_reply_start(req, HTTP_OK, "OK");
if(this->type == Subscriber::IFRAME){
struct evbuffer *buf = evhttp_request_get_output_buffer(req);
evbuffer_add_printf(buf, "%s\n", iframe_header.c_str());
evhttp_send_reply_chunk(req, buf);
}
if(this->seq_next == 0 || Channel::SEQ_GT(this->seq_next, channel->seq_next)){
this->seq_next = channel->seq_next;
if(this->seq_next != 0){
this->sync_next_seq();
}
}else{
// send buffered messages
if(!channel->msg_list.empty() && channel->seq_next != this->seq_next){
this->send_old_msgs();
}
}
}
void Subscriber::close(){
log_debug("%s:%d end %s, subs: %d,",
this->req->remote_host, this->req->remote_port,
channel->name.c_str(), channel->subs.size);
if(req->evcon){
// 记得清除 closecb
evhttp_connection_set_closecb(req->evcon, NULL, NULL);
}
evhttp_send_reply_end(req);
channel->serv->sub_end(this);
}
void Subscriber::send_old_msgs(){
std::vector<Message>::iterator it = channel->msg_list.begin();
while(1){
if(it == channel->msg_list.end()){
return;
}
const Message &msg = *it;
if(msg.seq >= this->seq_next){
log_debug("%s:%d send old msg [%d ~ %d]", req->remote_host, req->remote_port,
msg.seq, this->channel->seq_next-1);
break;
}
it ++;
}
if(this->type == POLL){
Subscriber::send_start(this->type, this->req, this->callback.c_str(), true);
for(int i=0; it != channel->msg_list.end(); i++, it++){
const Message &msg = *it;
int is_arr = (i != 0);
Subscriber::send_msg(this->req, msg.get_type_text(),
this->channel->name.c_str(), msg.seq, msg.content.c_str(), is_arr);
// 兼容老的客户端, 因为老的客户端遇到 broadcast 时没有将自己的 seq+1
if(msg.type == Message::BROADCAST){
Subscriber::send_msg(this->req, "next_seq",
this->channel->name.c_str(), msg.seq+1, "", true);
}
}
Subscriber::send_end(this->type, this->req, this->callback.c_str(), true);
this->close();
}else{
for(/**/; it != channel->msg_list.end(); it++){
const Message &msg = *it;
this->send_chunk(msg.seq, msg.get_type_text(), msg.content.c_str());
}
}
}
void Subscriber::noop(){
this->send_chunk(this->seq_noop, "noop", "");
this->seq_noop ++;
}
void Subscriber::sync_next_seq(){
log_debug("%s:%d send sync_next_seq: %d", req->remote_host, req->remote_port, seq_next);
this->send_chunk(seq_next, "next_seq", NULL);
}
void Subscriber::send_chunk(int seq, const char *type, const char *content){
this->idle = 0;
if(strcmp(type, "data") == 0 || strcmp(type, "broadcast") == 0){
this->seq_next = seq + 1;
}
if(this->type == POLL && strcmp(type, "broadcast") == 0){
Subscriber::send_start(this->type, this->req, this->callback.c_str(), true);
Subscriber::send_msg(this->req, type, this->channel->name.c_str(), seq, content);
// 兼容老的客户端, 因为老的客户端遇到 broadcast 时没有将自己的 seq+1
Subscriber::send_msg(this->req, "next_seq", this->channel->name.c_str(), this->seq_next, "", true);
Subscriber::send_end(this->type, this->req, this->callback.c_str(), true);
}else{
Subscriber::send_start(this->type, this->req, this->callback.c_str());
Subscriber::send_msg(this->req, type, this->channel->name.c_str(), seq, content);
Subscriber::send_end(this->type, this->req, this->callback.c_str());
// 兼容老的客户端, 因为老的客户端遇到 broadcast 时没有将自己的 seq+1
if(strcmp(type, "broadcast") == 0){
this->sync_next_seq();
}
}
if(this->type == POLL){
this->close();
}
}
void Subscriber::send_start(int sub_type, struct evhttp_request *req, const char *cb, bool is_arr){
struct evbuffer *buf = evhttp_request_get_output_buffer(req);
if(sub_type == POLL){
if(cb != NULL && cb[0] != '\0'){
evbuffer_add_printf(buf, "%s(", cb);
}
if(is_arr){
evbuffer_add_printf(buf, "[");
}
}else if(sub_type == IFRAME){
evbuffer_add_printf(buf, "%s", iframe_chunk_prefix.c_str());
}else if(sub_type == SSE){
evbuffer_add_printf(buf, "data: ");
}
}
void Subscriber::send_end(int sub_type, struct evhttp_request *req, const char *cb, bool is_arr){
struct evbuffer *buf = evhttp_request_get_output_buffer(req);
if(sub_type == POLL){
if(is_arr){
evbuffer_add_printf(buf, "]");
}
if(cb != NULL && cb[0] != '\0'){
evbuffer_add_printf(buf, ");");
}
}else if(sub_type == IFRAME){
evbuffer_add_printf(buf, "%s", iframe_chunk_suffix.c_str());
}else if(sub_type == SSE){
evbuffer_add_printf(buf, "\n");
}
evbuffer_add_printf(buf, "\n");
evhttp_send_reply_chunk(req, buf);
}
void Subscriber::send_msg(struct evhttp_request *req, const char *type, const std::string &cname, int seq, const char *content, bool is_arr){
struct evbuffer *buf = evhttp_request_get_output_buffer(req);
if(content == NULL){
content = "";
}
if(is_arr){
evbuffer_add(buf, ",", 1);
}
evbuffer_add_printf(buf,
"{\"type\":\"%s\",\"cname\":\"%s\",\"seq\":%d,\"content\":\"%s\"}",
type, cname.c_str(), seq, content);
}
void Subscriber::send_error_reply(int sub_type, struct evhttp_request *req, const char *cb, const std::string &cname, const char *type, const char *content){
add_http_header(sub_type, req);
evhttp_send_reply_start(req, HTTP_OK, "OK");
if(sub_type == Subscriber::IFRAME){
struct evbuffer *buf = evhttp_request_get_output_buffer(req);
evbuffer_add_printf(buf, "%s\n", iframe_header.c_str());
evhttp_send_reply_chunk(req, buf);
}
Subscriber::send_start(sub_type, req, cb);
Subscriber::send_msg(req, type, cname, 0, content);
Subscriber::send_end(sub_type, req, cb);
evhttp_send_reply_end(req);
}