Blog moving to blogspot

I’ve decided to move the blog to Google Blogspot. The new address is

nginx-rtmp.blogspot.com

It looks more consistent and much faster. Moreover wordpress.com is blocked by several major Russian ISPs.

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Multi-worker statistics and control with nginx “per-worker-listener” patch

Today I’ve written a small nginx patch providing a feature that solves many problems in RTMP-HTTP integration namely statistics and control. Statistics and control is known to work bad in multi-worker mode since HTTP request goes to a random worker. So the client receives random worker statistics or performs a control action with a worker that didn’t receive previous actions from user.

The patch is named per-worker-listener. It can be downloaded here. When applied to nginx it opens ports for connecting to the worker you want, not just a random worker. Each worker has its own port number so you can choose the port to connect. The new syntax extends listen directive with a new option per_worker. The port specified in listen directive becomes base port number for worker listeners.

listen 80; # usual listen directive
listen 9000 per_worker; # per-worker listener

With the above configuration 1st worker will listen to 9000 port, 2nd to 9001 port, 3rd to 9002 port etc. To make that work please turn off accept_mutex. Listeners with no per_worker work as usual.

events {
    worker_connections  1024;
    accept_mutex off;
}

The patch is especially useful with stat and control handlers of nginx-rtmp-module.

server {
    listen   9000 per_worker;
    location /stat {
        rtmp_stat all;
        rtmp_stat_stylesheet stat.xsl;
    }
    location /stat.xsl {
        root /tmp;
    }
    location /control {
        rtmp_control all;
    }
}

Now see 3rd worker stats at the location http://localhost:9002/stat.

Windows support in 1.0.1

I’ve updated the nginx-rtmp code to compile and run on MS Windows. The limitations are

• execs are not supported
• static pulls are not supported
• auto_push is not supported

Moreover the code is now much more portable so it can probably compile on uncommon platforms not supported earlier.

UPD: Nginx for Windows compilation guide
Add RTMP module with the usual option –add=module=PATH/TO/nginx-rtmp-module

UPD2: You can use Microsoft Visual C++ 2010 Express to compile nginx. It’s free. Download it from Microsoft web site.

Secure links in nginx-rtmp

Many people ask me for secure link support in nginx-rtmp similar to nginx http secure links. The truth is no special support is needed to have that in nginx-rtmp. You can set secure links on on_connect, on_play or on_plubish. I’ll show how to do that for on_play. on_publish is very much the same, on_connect has no name argument, only app.

http {
    server {
        listen 8080;
        server_name localhost;

        location /on_play {

            # set connection secure link
            secure_link $arg_st,$arg_e;
            secure_link_md5 mysecretkey$arg_app/$arg_name$arg_e;

            # bad hash
            if ($secure_link = "") {
                return 501;
            }

            # link expired
            if ($secure_link = "0") {
                return 502;
            }

            return 200;
        }
    }
}
rtmp {
    server {
        listen 1935;

        # protected application
        application myapp {
            live on;
            on_play http://localhost:8080/on_play;
        }
    }
}

With the above configuration you cannot play any stream from myapp application without providing the right secure link.

> ffplay 'rtmp://localhost/myapp/mystream'
ffplay version 1.0.6 Copyright (c) 2003-2013 the FFmpeg developers
...
rtmp://localhost/myapp/mystream: Unknown error occurred

In error.log we have this message

notify: HTTP retcode: 5xx

Now let’s construct valid secure RTMP link. Get current timestamp first and add 1 hour expire time to it.

> date +%s
1370777449
> echo $((1370777449+3600))
1370781049

Then construct the hash (watch config above for key)

> echo -n "mysecretkeymyapp/mystream1370781049" | openssl dgst -md5 -binary | 
         openssl enc -base64 | tr '+/' '-_' | tr -d '='
Mbjev5ld4mmCN00mwIqD7w

Now we have the hash. It’s easy to construct the valid secure RTMP url.

> ffplay 'rtmp://localhost/myapp/mystream?e=1370781049&st=Mbjev5ld4mmCN00mwIqD7w'

Fixed build in nginx-1.5.1

According to nginx 1.5.1 changelist the bug with ssl requiring nginx-http_ssl_module when adding nginx-rtmp-module is now fixed. So nginx with nginx-rtmp-module should now build as before without any additional options. The bug has been introduced in 1.3.14. Thanks to Maxim Dounin for that fix.