server

Demo httprc server

This is a demo server for passing commands to httprc clients. Commands can be scheduled for execution by using integrated admin web UI.

Internally this application starts two independent web servers. One HTTP/HTTPS server communicates with httprc clients (devices on which commands can be executed remotely), by default it is started on tcp port 8989. Second server is used for admin web IU and by default it is started on 127.0.0.1:8889. Admin web interface is not protected by any authentication mechanism and by default accessible only from localhost.

Basic server architecture:

+-------------+
| Client #001 |<-\
+-------------+   \        ++---------------++
                   \------>||               ||
+-------------+    HTTP/S  ||               ||   HTTP   +-------------------+
| Client #002 |<---------->|| httprc server ||<-------->| Admin web browser |
+-------------+            ||               ||          +-------------------+
   .                 /---->||               ||
   .                /      ++---------------++
   .               /       ^                 ^
+-------------+   /        |                 |
| Client #999 |<-/   (client backend)   (admin web UI)
+-------------+        0.0.0.0:8989     127.0.0.1:8889

For near real-time command execution this server is using long-polling in the client backend server and SSE in admin web UI.

Building

Install golang tools by following official golang installation instructions.

Download dependencies:

$ go get    # download application dependencies
$ go build  # compile the application

Usage

Server can be started in different security level modes.

Plain-text mode

In this mode server is waiting for clients to connect using plain-text HTTP. Clients must provide client identifier in the request url.

Starting server in plain text mode requires no additional arguments:

./server

In this mode clients should use backend URL http://server.example.net:8989/httprc/{clientID}.

HTTPS without client authentication

Server is waiting for clients to connect using HTTPS and does not require client certificate. Clients must provide client identifier in the request url.

To start server in HTTPS mode without client authentication server certificate and private key must be provided:

./server --server-cert ../ca/server.pem  --server-key ../ca/server.key

In this mode clients should use backend URL https://server.example.net:8989/httprc/{clientID}.

HTTPS with client authentication mode

Server is waiting for clients to connect using HTTPS, and only accepts the connection if client provides a valid certificate signed by the CA the server trusts. In this mode client certificate Common Name field is used as client identifier.

To use client authentication server must be provided with CA certificate:

./server --client-ca ../ca/ca.pem  --server-cert ../ca/server.pem  --server-key ../ca/server.key

In this mode clients are identified by the client certificate and can use backend URL without clientID part https://server.example.net:8989/httprc.

Startup arguments summary