学习nginx-rtmp:replay push代码流程

1, 如何触发connect到push上游服务器的

h = ngx_array_push(&cmcf->events[NGX_RTMP_HANDSHAKE_DONE]);

*h = ngx_rtmp_relay_handshake_done;

在服务器有流push上来后，也就是NGX_RTMP_HANDSHAKE_DONE事件后，触发ngx_rtmp_relay_handshake_done，完成向上游的rtmp connect。

ngx_rtmp_relay_handshake_done---->ngx_rtmp_relay_send_connect--------->ngx_rtmp_send_chunk_size,ngx_rtmp_send_ack_size, ngx_rtmp_send_amf(connect)

2, 如何完成后续rtmp create, push的收发的

cmcf = ngx_rtmp_conf_get_module_main_conf(cf, ngx_rtmp_core_module);

ch = ngx_array_push(&cmcf->amf);

ngx_str_set(&ch->name, "_result");

ch->handler = ngx_rtmp_relay_on_result;//注册了与上游rtmp服务器的协议处理函数

在ngx_rtmp_relay_on_result函数中，处理了协议回调：

static ngx_int_t

ngx_rtmp_relay_on_result(ngx_rtmp_session_t *s, ngx_rtmp_header_t *h, ngx_chain_t *in){

......

switch ((ngx_int_t)v.trans) {

case NGX_RTMP_RELAY_CONNECT_TRANS://如果rtmp connect返回后，立马发送create_stream

return ngx_rtmp_relay_send_create_stream(s);

case NGX_RTMP_RELAY_CREATE_STREAM_TRANS://如果create_stream返回后，立马发送rtmp_publish

if (ctx->publish != ctx && !s->static_relay) {

if (ngx_rtmp_relay_send_publish(s) != NGX_OK) {

return NGX_ERROR;

}

//这个ngx_rtmp_relay_play_local函数比较有意思，就是从本地拉流一份。

//其实就是把对上游rtmp的session作为订阅者，放入这个application stream的订阅者列表中。

//然后本地的会在发送给所有订阅者列表循环中，把rtmp流发送给上游rtmp服务器

return ngx_rtmp_relay_play_local(s);

} else {

if (ngx_rtmp_relay_send_play(s) != NGX_OK) {

return NGX_ERROR;

}

return ngx_rtmp_relay_publish_local(s);

}

default:

return NGX_OK;

}

}

在函数ngx_rtmp_relay_play_local中，调用ngx_rtmp_play

static ngx_int_t ngx_rtmp_relay_play_local(ngx_rtmp_session_t *s)

{

......

return ngx_rtmp_play(s, &v);//这里的指针指向：ngx_rtmp_relay_play

}

static ngx_int_tngx_rtmp_relay_play(ngx_rtmp_session_t *s, ngx_rtmp_play_t *v)

{

ngx_rtmp_relay_ctx_t *ctx;

ctx = ngx_rtmp_get_module_ctx(s, ngx_rtmp_relay_module);

if (ctx && s->relay) {

goto next;//条件满足，其实意思就是，这个play不是去pull别人，是pull自己的流给上游，直接到next_play中去

}

next:

return next_play(s, v);//这里的next_play = ngx_rtmp_live_play

}

static ngx_int_t ngx_rtmp_live_play(ngx_rtmp_session_t *s, ngx_rtmp_play_t *v){

........

/* join stream as subscriber */

ngx_rtmp_live_join(s, v->name, 0);//把上游rtmp服务器的session加入到这个流的订阅者中去

........

}

------------------------------------------------------------------------------------------------

关键数据结构：

typedef struct {

ngx_array_t pulls; /* ngx_rtmp_relay_target_t * */

ngx_array_t pushes; /* ngx_rtmp_relay_target_t * */

ngx_array_t static_pulls; /* ngx_rtmp_relay_target_t * */

ngx_array_t static_events; /* ngx_event_t * */

ngx_log_t *log;

ngx_uint_t nbuckets;

ngx_msec_t buflen;

ngx_flag_t session_relay;

ngx_msec_t push_reconnect;

ngx_msec_t pull_reconnect;

ngx_rtmp_relay_ctx_t **ctx;

} ngx_rtmp_relay_app_conf_t;//application下push和pull的配置信息

pulls, pushes: 成员就是ngx_rtmp_relay_target_t，主要保存url等信息

typedef struct {

ngx_url_t url;

ngx_str_t app;

ngx_str_t name;

ngx_str_t tc_url;

ngx_str_t page_url;

ngx_str_t swf_url;

ngx_str_t flash_ver;

ngx_str_t play_path;

ngx_int_t live;

ngx_int_t start;

ngx_int_t stop;

void *tag; /* usually module reference */

void *data; /* module-specific data */

ngx_uint_t counter; /* mutable connection counter */

} ngx_rtmp_relay_target_t;//目的url(push或pull)的相关信息

typedef structngx_rtmp_relay_ctx_s ngx_rtmp_relay_ctx_t;

struct ngx_rtmp_relay_ctx_s {//这个module的ctx信息，包含session

ngx_str_t name;

ngx_str_t url;

ngx_log_t log;

ngx_rtmp_session_t *session;

ngx_rtmp_relay_ctx_t *publish;

ngx_rtmp_relay_ctx_t *play;

ngx_rtmp_relay_ctx_t *next;

ngx_str_t app;

ngx_str_t tc_url;

ngx_str_t page_url;

ngx_str_t swf_url;

ngx_str_t flash_ver;

ngx_str_t play_path;

ngx_int_t live;

ngx_int_t start;

ngx_int_t stop;

ngx_event_t push_evt;

ngx_event_t *static_evt;

void *tag;

void *data;

};

typedef struct {//ngx_rtmp_session_t, 顾名思义，就是连接上游的session信息

uint32_t signature; /* "RTMP" */ /* <-- FIXME wtf */

ngx_event_t close;

void **ctx;

void **main_conf;

void **srv_conf;

void **app_conf;

ngx_str_t *addr_text;

int connected;

#if (nginx_version >= 1007005)

ngx_queue_t posted_dry_events;

#else

ngx_event_t *posted_dry_events;

#endif

/* client buffer time in msec */

uint32_t buflen;

uint32_t ack_size;

/* connection parameters */

ngx_str_t app;

ngx_str_t args;

ngx_str_t flashver;

ngx_str_t swf_url;

ngx_str_t tc_url;

uint32_t acodecs;

uint32_t vcodecs;

ngx_str_t page_url;

/* handshake data */

ngx_buf_t *hs_buf;

u_char *hs_digest;

unsigned hs_old:1;

ngx_uint_t hs_stage;

/* connection timestamps */

ngx_msec_t epoch;

ngx_msec_t peer_epoch;

ngx_msec_t base_time;

uint32_t current_time;

/* ping */

ngx_event_t ping_evt;

unsigned ping_active:1;

unsigned ping_reset:1;

/* auto-pushed? */

unsigned auto_pushed:1;

unsigned relay:1;

unsigned static_relay:1;

/* input stream 0 (reserved by RTMP spec)

* is used as free chain link */

ngx_rtmp_stream_t *in_streams;

uint32_t in_csid;

ngx_uint_t in_chunk_size;

ngx_pool_t *in_pool;

uint32_t in_bytes;

uint32_t in_last_ack;

ngx_pool_t *in_old_pool;

ngx_int_t in_chunk_size_changing;

ngx_connection_t *connection;

/* circular buffer of RTMP message pointers */

ngx_msec_t timeout;

uint32_t out_bytes;

size_t out_pos, out_last;

ngx_chain_t *out_chain;

u_char *out_bpos;

unsigned out_buffer:1;

size_t out_queue;

size_t out_cork;

ngx_chain_t *out[0];

} ngx_rtmp_session_t;