public-server
v2.0.1
Published
let's a client talk to `hidden-server` via `public-server`
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public-server
let's a client talk to hidden-server via public-server
use case: e.g. access server sitting behind firewalls with unknown ip-address via reverse tunnel on demand.
the public-server is the counter part of hidden-server.
how it works
the hidden-server consists of three parts: client --command--> public <--ping-- hidden
hiddenthe hidden server or device that sits behind a firewall and does not have a fixed ip-address.publica publicly available server theclientcan connect to. tt acts as a reverse proxy.clientclient Machine that want's to access the hidden server.
it uses http POST with JSON content. the hidden server sends out ping messages to the publicServer at the given pingInterval.
in order to allow simultaneous user access, simultaneousPings are sent by the hidden server.
when the keepPingOpen option is true on the hidden and on the public server,
the pings are kept open until a command is received, or the next pingInterval kicks in. pingInterval is in seconds btw.
if the keepPingOpen option is false, the command request from the client will only be responded,
after the public server could respond to an incomming ping request from the hidden server.
when a command request by the client was successful, both ends (public and hidden) receive a command event.
ah and yes, you can have as many hidden servers as you like and connect them to a single public server.
the client can decide with wich hidden server it want's to talk.
scenarios
The following scenarios describe the combinations with the options: keepPingOpen and roundTripResponse
###Scenario: keepPingOpen and roundTripResponse
+Advantage: fast, deterministic command response time / feedback fromhidden-server-Disadvantage: many open ports onpublic-serverwith manyhidden-servers
+--------+ +--------+ +--------+
| Client | | Public | | Hidden |
+----+---+ +----+---+ +----+---+
| | Ping |
| | <--------------------------+ |
| | | |
| | | keepPingOpen |
| | | |
| | | Response |
| | v--------------------------> |
| | |
| | Ping |
| | <--------------------------+ |
| Command | | |
| +------------------------> | | Response |
| | | v--------------------------> | +---->
| | | | | handleRequest
| | | Ping | |
| Response | | <--------------------------+ | <----v
| <------------------------v | | |
| | | keepPingOpen |
| | | |
| | | Response |
| | v--------------------------> |
| | |
| | |
+ + +###Scenario: roundTripResponse
+Advantage: no open ports onpublic-server/ feedback fromhidden-server-Disadvantage: long, non deterministic command response time
+--------+ +--------+ +--------+
| Client | | Public | | Hidden |
+----+---+ +----+---+ +----+---+
| | Ping |
| | <--------------------------+ | +
| | v--------------------------> | |
| | Response | | pingInterval
| | | |
| | | |
| | Ping | v
| | <--------------------------+ |
| | v--------------------------> | +
| | Response | |
| Command | | | pingInterval
| +------------------------> | | |
| | | | |
| | | Ping | v
| | | <--------------------------+ |
| | | v--------------------------> | +---->
| | | Response | | handleRequest
| | | Ping | |
| | | <--------------------------+ | <----v
| Response | | v--------------------------> |
| <------------------------v | Response |
| | |
| | |
+ + +###Scenario: keepPingOpen
+Advantage: fast, deterministic command response time,-Disadvantage: no feedback from hidden-server / many open ports onpublic-serverwith manyhidden-servers
+--------+ +--------+ +--------+
| Client | | Public | | Hidden |
+----+---+ +----+---+ +----+---+
| | Ping |
| | <--------------------------+ |
| | | |
| | | keepPingOpen |
| | | |
| | | Response |
| | v--------------------------> |
| | |
| | Ping |
| | <--------------------------+ |
| | | |
| Command | | Response |
| +------------------------> | v--------------------------> |
| Response | | |
| <------------------------v | Ping |
| | <--------------------------+ |
| | | |
| | | keepPingOpen |
| | | |
| | | Response |
| | v--------------------------> |
| | |
| | |
+ + +###Scenario: no Options
+Advantage: not many... simple :-) ... no open ports onpublic-server-Disadvantage: long, non deterministic command response time / no feedback from hidden-server
+--------+ +--------+ +--------+
| Client | | Public | | Hidden |
+----+---+ +----+---+ +----+---+
| | Ping |
| | <--------------------------+ | +
| | v--------------------------> | |
| | Response | | pingInterval
| | | |
| | | v
| | Ping |
| | <--------------------------+ | +
| | v--------------------------> | |
| Command | Response | | pingInterval
| +------------------------> | | |
| | | | v
| | | Ping |
| Response | | <--------------------------+ | +
| <------------------------v | v--------------------------> | |
| | Response | | pingInterval
| | | |
| | | v
| | |
| | |
+ + +diagrams created with asciiflow
install
npm install public-servertest
npm install public-server -d
mocha##usage
hidden
var HiddenServer = require('hidden-server');
var hidden = new HiddenServer({
publicServer: 'http://localhost:3000',
pingUri: '/ping/:hiddenServerName',
simultaneousPings: 5,
pingInterval: 3,
keepPingOpen: true,
roundTripResponse: false,
hiddenServerName: 'server1'
}).start();
hidden.on('command', function(obj) {
console.log('command', obj);
});public
var PublicServer = require('public-server');
var public = PublicServer({
commandUri: '/command/:hiddenServerName',
pingUri: '/ping/:hiddenServerName',
pingInterval: 3,
keepPingOpen: true,
roundTripResponse: false
});
public.on('command', function(obj) {
console.log('command', obj);
});
public.listen(3000);client
curl -H "Content-Type: application/json" -d '{"command":"newCommand","additional":"parameter"}' localhost:3000/command/server1