├── .gitignore
├── CHANGELOG.md
├── LICENSE
├── README.md
├── client-script.go
├── client.go
├── clientOps.go
├── doc.go
├── examples
├── groups
│ ├── index.html
│ └── main.go
├── shape-move
│ ├── index.html
│ └── main.go
└── time-push
│ ├── index.html
│ └── main.go
├── exchange.go
├── groupOps.go
├── longpoll-transport.go
├── operation.go
├── relay.go
├── transport.go
├── util.go
└── websocket-transport.go
/.gitignore:
--------------------------------------------------------------------------------
1 | *.swp
2 |
--------------------------------------------------------------------------------
/CHANGELOG.md:
--------------------------------------------------------------------------------
1 | ## RelayR changelog
2 |
3 | #### v0.2.1 - v0.3.0
4 |
5 | * FEATURE: Added Long Polling transport - allowing all browsers that support AJAX requests to work with RelayR. RelayR will test
6 | for WebSocket support and if not found, will fall back to Long Polling.
7 | * BUGFIX: Removed renegotiation bug.
8 | * BUGFIX: Stop `RelayRConnection.ready` being called more than once.
9 |
10 | ----------------
11 |
12 | #### v0.2.0 - v0.2.1
13 |
14 | * Added `clientScript` caching variable, which allows the RelayR client-side script to be cached in a `[]byte` slice and served each time.
15 | * Added `DisableScriptCache()` package-level function to disable the above functionality and regenerate the script each page refresh (mostly for debug purposes).
16 |
17 | ----------------
18 |
19 | #### v0.1.0 - v0.2.0
20 |
21 | There are are four necessary breaking changes in the update from 0.1.0 to 0.2.0 to make it more "Go-like" and consumer friendly.
22 |
23 | * The package name now has a lowercase r; "relayr" instead of "relayR". This was one of the only gripes from the community about this package.
24 | * You no longer need to embed `*relayr.Relay` .. but you now need to have all of your relay methods accept a `*relayr.Relay` as their first argument.
25 | * Groups are now an object in themselves and no longer "hang off" of the `Clients` property of a Relay. The examples have been updated to reflect this.
26 | * relayr.Exchange now implements `ServeHTTP`, which means it can now handle a route directly, instead of using `relayr.Handle` .. you can use `http.Handle`.
27 |
28 | The rest should _mostly_ work as it did. I have completely re-written most of the underlying code for easier maintenance and better documentation. The public API now has better documentation and should make a lot more sense.
29 |
30 |
--------------------------------------------------------------------------------
/LICENSE:
--------------------------------------------------------------------------------
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2 | Version 2.0, January 2004
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/README.md:
--------------------------------------------------------------------------------
1 | ## RelayR
2 |
3 | RelayR is a Go package that provides easy-to-use real time communication APIs for Go web applications.
4 |
5 | #### Current version: 0.3.0
6 |
7 | Please see CHANGELOG.md for details about the changes between versions.
8 |
9 | ### Installation
10 |
11 | #### IMPORTANT:
12 |
13 | RelayR relies on the [Gorilla WebSocket package](https://github.com/gorilla/websocket) for WebSocket support. Please head over to that repository, give it a star, and ``go get` it into your `GOPATH`.
14 |
15 | RelayR itself however, will fall back to Long Polling for any browsers that do not support Web Sockets (you just need the above package so that your server supports Web Sockets).
16 |
17 | #### Installing RelayR
18 |
19 | After you have installed the [Gorilla WebSocket package](https://github.com/gorilla/websocket), you can run the following:
20 |
21 | go get -u github.com/simon-whitehead/relayr
22 |
23 | ### Examples
24 |
25 | The `/examples` directory contains three examples.
26 |
27 | The first one is a simple Server -> Client timestamp push. The server will push the current time down to all connected clients every second.
28 |
29 | It looks like this:
30 |
31 | 
32 |
33 | The second one is a replica of the famous SignalR sample, "High-Frequency Realtime with SignalR" where a shape can be dragged around a browser and broadcast to all clients.
34 |
35 | It looks like this:
36 |
37 | 
38 |
39 | The third one demonstrates Groups and membership. It allows clients to subscribe to groups and receive notifications that are pushed to groups they are subscribed to.
40 |
41 | ### Project status
42 |
43 | This is very much a work in progress - some might say, pre-alpha. The code is horrible .. but it works. I am opening it up to the world early for feedback and contributions (in any form).
44 |
45 | ### Contributing
46 |
47 | Please! Fork away .. improve it .. create a PR .. whatever you want to do. I am open to any and all help.
48 |
49 | ### Licence
50 |
51 | This code is released under the Apache 2.0 licence.
52 |
--------------------------------------------------------------------------------
/client-script.go:
--------------------------------------------------------------------------------
1 | /*
2 | *
3 | * This file contains client side Javascript that is rendered
4 | * when a client hits the RelayR route with a GET request.
5 | *
6 | */
7 |
8 | package relayr
9 |
10 | const connectionClassScript = `
11 |
12 | var RelayRConnection = {};
13 |
14 | RelayRConnection = (function() {
15 | var readyCalled = false;
16 | var web, transport;
17 | var route = '%v';
18 | transport = {
19 | websocket: {
20 | connect: function(c) {
21 | var s = this;
22 | s.socket = new WebSocket("ws://" + window.location.host + route + "/ws?connectionId=" + transport.ConnectionId);
23 | s.socket.onclose = function(evt) {
24 | setTimeout(function() {
25 | web.n(); // renegotiate
26 | }, 2000);
27 | };
28 |
29 | s.socket.onmessage = function(evt) {
30 | c(evt.data);
31 | };
32 |
33 | s.socket.onerror = function(evt) {
34 | setTimeout(function() {
35 | s.connect(cId, c);
36 | });
37 | };
38 |
39 | s.socket.onopen = function(evt) {
40 | if (!readyCalled) {
41 | RelayRConnection.r();
42 | readyCalled = true;
43 | }
44 | };
45 | },
46 | send: function(data) {
47 | var s = this;
48 | s.socket.send(data);
49 | }
50 | },
51 | longpoll: {
52 | connect: function(c) {
53 | if (!readyCalled) {
54 | RelayRConnection.r();
55 | readyCalled = true;
56 | }
57 | var retry;
58 | retry = function() {
59 | web.gj(route + '/longpoll?connectionId=' + transport.ConnectionId + '&_=' + new Date().getTime(), function(data) {
60 | if (data.responseText) {
61 | var reconn = JSON.parse(data.responseText);
62 | if (reconn.Z) {
63 | web.n();
64 | } else {
65 | c(data);
66 | retry();
67 | }
68 | } else {
69 | web.n();
70 | }
71 | });
72 | };
73 |
74 | retry();
75 | },
76 | send: function(data) {
77 | var s = this;
78 | web.p(route + '/call?connectionId=' + transport.ConnectionId + '&_=' + new Date().getTime(), data, null, "json", null);
79 | }
80 | }
81 | };
82 | web = (function() {
83 | return {
84 | x: function() {
85 | var xd;
86 |
87 | if (window.XMLHttpRequest) {
88 | xd = new XMLHttpRequest();
89 | }
90 | else {
91 | xd = new ActiveXObject("Microsoft.XMLHTTP");
92 | }
93 |
94 | return xd;
95 | },
96 | g: function(u, c) {
97 | var s = this;
98 |
99 | var xd = s.x();
100 |
101 | xd.open('GET', u, true);
102 |
103 | xd.onreadystatechange = function() {
104 | if (xd.readyState === 4 && xd.status === 200) {
105 | c(xd);
106 | }
107 | };
108 |
109 | xd.send();
110 | },
111 | gj: function(u, c) {
112 | var s = this;
113 |
114 | var xd = s.x();
115 |
116 | xd.open('GET', u, true);
117 | xd.setRequestHeader("Content-type", "application/json");
118 |
119 | xd.onreadystatechange = function() {
120 | if (xd.readyState === 4) {
121 | if (xd.status === 200) {
122 | c(xd);
123 | }
124 | }
125 | };
126 |
127 | xd.send();
128 | },
129 | p: function(u, d, c, t, e) {
130 | var s = this;
131 |
132 | var xd = s.x();
133 |
134 | xd.open('POST', u, true);
135 | xd.setRequestHeader("Content-type", "application/" + t);
136 |
137 | xd.onreadystatechange = function() {
138 | if (xd.readyState === 4) {
139 | if (xd.status === 200) {
140 | if (c) {
141 | c(xd);
142 | }
143 | }
144 | }
145 | };
146 |
147 | xd.onerror = function() {
148 | if (e) {
149 | e(xd);
150 | }
151 | };
152 |
153 | xd.send(d);
154 |
155 | window.onbeforeunload = function() {
156 | delete xd;
157 | xd = null;
158 | };
159 | },
160 | t: function() {
161 | if (!!window.WebSocket) {
162 | return "websocket";
163 | } else {
164 | return "longpoll";
165 | }
166 |
167 | // TODO: Implement SSE Circuit
168 | /*if (typeof EventSource !== 'undefined') {
169 | return "SSE";
170 | }*/
171 | },
172 | n: function() {
173 | var s = this;
174 | var t = s.t();
175 | web.p(route + "/negotiate?_=" + new Date().getTime(), JSON.stringify({ t: t }), function(result) {
176 | var obj = JSON.parse(result.responseText);
177 | transport.ConnectionId = obj.ConnectionID;
178 | setTimeout(function() {
179 | transport[t].connect(function(data) {
180 | var cobj;
181 | if (data.responseText && data.status && data.responseXML) {
182 | cobj = JSON.parse(data.responseText);
183 | } else {
184 | if (data.responseText == "") return;
185 | cobj = JSON.parse(data);
186 | }
187 | var lobj = RelayR[cobj.R].client;
188 | var args = [];
189 | for (var i = 0; i < cobj.A.length; i++) {
190 | args.push(cobj.A[i]);
191 | }
192 | lobj[cobj.M].apply(lobj||window, args);
193 | });
194 | }, 0);
195 | }, "json",
196 | function(result) {
197 | // error .. try again
198 | setTimeout(function() {
199 | s.n();
200 | }, 2000);
201 | });
202 | }
203 | };
204 | })();
205 |
206 | return {
207 | ready: function(r) {
208 | RelayRConnection.r = r;
209 |
210 | web.n();
211 | },
212 | callServer: function(r, f, a) {
213 | transport[web.t()].send(JSON.stringify({ S: true, C: transport.ConnectionId, R: r, M: f, A: a}));
214 | }
215 | };
216 | })();
217 |
218 | `
219 |
220 | const relayClassBegin = `
221 |
222 | var RelayR = (function() {
223 | return {
224 |
225 | `
226 |
227 | const relayBegin = `
228 |
229 | %v: {
230 |
231 | client: {},
232 |
233 | server: {
234 |
235 | `
236 |
237 | // {0} == function name
238 | // {1} == Relay name
239 | // {2} == function name
240 | const relayMethod = `
241 |
242 | %v: function() {
243 | RelayRConnection.callServer('%v', '%v', Array.prototype.slice.call(arguments));
244 | },
245 |
246 | `
247 |
248 | const relayEnd = `
249 |
250 | },
251 |
252 | },
253 |
254 | `
255 |
256 | const relayClassEnd = `
257 |
258 | };
259 | })();
260 |
261 | `
262 |
--------------------------------------------------------------------------------
/client.go:
--------------------------------------------------------------------------------
1 | package relayr
2 |
3 | type client struct {
4 | ConnectionID string
5 | exchange *Exchange
6 | transport Transport
7 | }
8 |
9 | type clientMessage struct {
10 | Relay string `json:"R"`
11 | Function string `json:"F"`
12 | Arguments string `json:"A"`
13 | }
14 |
--------------------------------------------------------------------------------
/clientOps.go:
--------------------------------------------------------------------------------
1 | package relayr
2 |
3 | // ClientOperations provides helper methods for
4 | // interacting with Clients connected to a Relay.
5 | type ClientOperations struct {
6 | e *Exchange
7 | relay *Relay
8 | }
9 |
10 | // All invokes a client side method on all clients for the
11 | // given relay.
12 | func (c *ClientOperations) All(fn string, args ...interface{}) {
13 | c.e.callGroupMethod(c.relay, "Global", fn, args...)
14 | }
15 |
16 | // Others invokes a client side method on all clients except the
17 | // one who calls it.
18 | func (c *ClientOperations) Others(fn string, args ...interface{}) {
19 | c.e.callGroupMethodExcept(c.relay, "Global", fn, args...)
20 | }
21 |
--------------------------------------------------------------------------------
/doc.go:
--------------------------------------------------------------------------------
1 | // Package relayr provides high level functionality for
2 | // real-time web communication. It allows communication
3 | // between front-end clients and back-end servers via
4 | // easy-to-use constructs.
5 | package relayr
6 |
--------------------------------------------------------------------------------
/examples/groups/index.html:
--------------------------------------------------------------------------------
1 |
2 |
3 |
4 |
5 | Groups
6 |
7 |
8 |
9 |
10 |
35 |
36 |
37 |
38 | Select a group below to toggle membership
39 |
40 |
41 |
42 |
43 |
44 |
45 |
46 |
--------------------------------------------------------------------------------
/examples/groups/main.go:
--------------------------------------------------------------------------------
1 | package main
2 |
3 | import (
4 | "fmt"
5 | "net/http"
6 | "time"
7 |
8 | "github.com/simon-whitehead/relayR"
9 | )
10 |
11 | var group int = 1
12 |
13 | type NotificationRelay struct {
14 | }
15 |
16 | func (nr NotificationRelay) SendNotification(relay *relayr.Relay, g string) {
17 | relay.Groups(g).Call("notificationReceive", "Notification for group "+g)
18 | }
19 |
20 | func (nr NotificationRelay) Subscribe(relay *relayr.Relay, g string) {
21 | relay.Groups(g).Add(relay.ConnectionID)
22 | }
23 |
24 | func (nr NotificationRelay) Unsubscribe(relay *relayr.Relay, g string) {
25 | relay.Groups(g).Remove(relay.ConnectionID)
26 | }
27 |
28 | func main() {
29 | exchange := relayr.NewExchange()
30 | exchange.RegisterRelay(NotificationRelay{})
31 |
32 | go func() {
33 | for {
34 | select {
35 | case <-time.After(time.Second * 2):
36 | exchange.Relay(NotificationRelay{}).Call("SendNotification", fmt.Sprintf("Group %d", group))
37 | if group == 1 {
38 | group = 2
39 | } else {
40 | group = 1
41 | }
42 | }
43 | }
44 | }()
45 |
46 | http.Handle("/relayr/", exchange)
47 | http.Handle("/", http.FileServer(http.Dir(".")))
48 |
49 | http.ListenAndServe(":8080", nil)
50 | }
51 |
--------------------------------------------------------------------------------
/examples/shape-move/index.html:
--------------------------------------------------------------------------------
1 |
2 |
3 |
4 |
5 | Shape move
6 |
14 |
15 |
16 |
17 |
42 |
43 |
44 |
45 |
46 |
47 |
--------------------------------------------------------------------------------
/examples/shape-move/main.go:
--------------------------------------------------------------------------------
1 | package main
2 |
3 | import (
4 | "net/http"
5 |
6 | "github.com/simon-whitehead/relayR"
7 | )
8 |
9 | type ShapeRelay struct {
10 | }
11 |
12 | func (sr ShapeRelay) UpdateShape(relay *relayr.Relay, s map[string]interface{}) {
13 | relay.Clients.Others("shapeUpdated", s) // Only send to other clients
14 | }
15 |
16 | func main() {
17 | exchange := relayr.NewExchange()
18 | exchange.RegisterRelay(ShapeRelay{})
19 |
20 | http.Handle("/relayr/", exchange)
21 | http.Handle("/", http.FileServer(http.Dir(".")))
22 |
23 | http.ListenAndServe(":8080", nil)
24 | }
25 |
--------------------------------------------------------------------------------
/examples/time-push/index.html:
--------------------------------------------------------------------------------
1 |
2 |
3 |
4 |
5 | Time Push
6 |
7 |
14 |
15 |
16 |
17 |
18 |
19 |
--------------------------------------------------------------------------------
/examples/time-push/main.go:
--------------------------------------------------------------------------------
1 | package main
2 |
3 | import (
4 | "net/http"
5 | "time"
6 |
7 | "github.com/simon-whitehead/relayR"
8 | )
9 |
10 | type TimeRelay struct {
11 | }
12 |
13 | func (tr TimeRelay) PushTime(relay *relayr.Relay) {
14 | relay.Clients.All("timeUpdated", time.Now().Local().Format("Mon Jan 2 2006 03:04:05 PM"))
15 | }
16 |
17 | func main() {
18 | exchange := relayr.NewExchange()
19 | exchange.RegisterRelay(TimeRelay{})
20 |
21 | go func() {
22 | for {
23 | select {
24 | case <-time.After(time.Second * 1):
25 | exchange.Relay(TimeRelay{}).Call("PushTime")
26 | }
27 | }
28 | }()
29 |
30 | http.Handle("/relayr/", exchange)
31 | http.Handle("/", http.FileServer(http.Dir(".")))
32 | http.ListenAndServe(":8080", nil)
33 | }
34 |
--------------------------------------------------------------------------------
/exchange.go:
--------------------------------------------------------------------------------
1 | package relayr
2 |
3 | import (
4 | "bytes"
5 | "encoding/json"
6 | "fmt"
7 | "io"
8 | "net/http"
9 | "reflect"
10 | "strings"
11 |
12 | "github.com/gorilla/websocket"
13 | )
14 |
15 | // ClientScriptFunc is a callback for altering the client side
16 | // generated Javascript. This can be used to minify/alter the
17 | // generated client-side RelayR library before it gets to the browser.
18 | var ClientScriptFunc func([]byte) []byte
19 |
20 | // A cache for the client script to avoid regenerating it every
21 | // single page load
22 | var clientScript []byte
23 | var cacheEnabled = true
24 |
25 | // DisableScriptCache forces the RelayR client-side script to
26 | // be regenerated on each request, rather than serving it from
27 | // an internal cache.
28 | func DisableScriptCache() {
29 | cacheEnabled = false
30 | }
31 |
32 | var upgrader = &websocket.Upgrader{ReadBufferSize: 1024, WriteBufferSize: 1024}
33 |
34 | type longPollServerCall struct {
35 | Server bool `json:"S"`
36 | Relay string `json:"R"`
37 | Method string `json:"M"`
38 | Arguments []interface{} `json:"A"`
39 | ConnectionID string `json:"C"`
40 | }
41 |
42 | // Exchange represents a hub where clients exchange information
43 | // via Relays. Relays registered with the Exchange expose methods
44 | // that can be invoked by clients.
45 | type Exchange struct {
46 | relays []Relay
47 | groups map[string][]*client
48 | transports map[string]Transport
49 | }
50 |
51 | type negotiation struct {
52 | T string // the transport that the client is comfortable using (e.g, websockets)
53 | }
54 |
55 | type negotiationResponse struct {
56 | ConnectionID string
57 | }
58 |
59 | // NewExchange initializes and returns a new Exchange
60 | func NewExchange() *Exchange {
61 | e := &Exchange{}
62 | e.groups = make(map[string][]*client)
63 | e.transports = map[string]Transport{
64 | "websocket": newWebSocketTransport(e),
65 | "longpoll": newLongPollTransport(e),
66 | }
67 |
68 | return e
69 | }
70 |
71 | func (e *Exchange) ServeHTTP(w http.ResponseWriter, r *http.Request) {
72 | route := extractRouteFromURL(r)
73 | op := extractOperationFromURL(r)
74 |
75 | switch op {
76 | case opWebSocket:
77 | e.upgradeWebSocket(w, r)
78 | case opNegotiate:
79 | e.negotiateConnection(w, r)
80 | case opLongPoll:
81 | e.awaitLongPoll(w, r)
82 | case opCallServer:
83 | e.callServer(w, r)
84 | default:
85 | e.writeClientScript(w, route)
86 | }
87 | }
88 |
89 | func extractRouteFromURL(r *http.Request) string {
90 | lastSlash := strings.LastIndex(r.URL.Path, "/")
91 | return r.URL.Path[:lastSlash]
92 | }
93 |
94 | func extractOperationFromURL(r *http.Request) string {
95 | lastSlash := strings.LastIndex(r.URL.Path, "/")
96 | return r.URL.Path[lastSlash+1:]
97 | }
98 |
99 | func (e *Exchange) upgradeWebSocket(w http.ResponseWriter, r *http.Request) {
100 | ws, err := upgrader.Upgrade(w, r, nil)
101 | if err != nil {
102 | return
103 | }
104 | c := &connection{e: e, out: make(chan []byte, 256), ws: ws, c: e.transports["websocket"].(*webSocketTransport), id: r.URL.Query()["connectionId"][0]}
105 | c.c.connected <- c
106 | defer func() { c.c.disconnected <- c }()
107 | go c.write()
108 | c.read()
109 | }
110 |
111 | func (e *Exchange) negotiateConnection(w http.ResponseWriter, r *http.Request) {
112 | jsonResponse(w)
113 | decoder := json.NewDecoder(r.Body)
114 |
115 | var neg negotiation
116 |
117 | decoder.Decode(&neg)
118 |
119 | encoder := json.NewEncoder(w)
120 | encoder.Encode(negotiationResponse{ConnectionID: e.addClient(neg.T)})
121 | }
122 |
123 | func (e *Exchange) awaitLongPoll(w http.ResponseWriter, r *http.Request) {
124 | jsonResponse(w)
125 | cid := e.extractConnectionIDFromURL(r)
126 | longPoll := e.transports["longpoll"].(*longPollTransport)
127 | longPoll.wait(w, cid)
128 | }
129 |
130 | func (e *Exchange) callServer(w http.ResponseWriter, r *http.Request) {
131 | var msg longPollServerCall
132 | decoder := json.NewDecoder(r.Body)
133 | decoder.Decode(&msg)
134 | cid := e.extractConnectionIDFromURL(r)
135 | relay := e.getRelayByName(msg.Relay, cid)
136 | go e.callRelayMethod(relay, msg.Method, msg.Arguments...)
137 | }
138 |
139 | func (e *Exchange) extractConnectionIDFromURL(r *http.Request) string {
140 | return r.URL.Query()["connectionId"][0]
141 | }
142 |
143 | func (e *Exchange) addClient(t string) string {
144 | cID := generateConnectionID()
145 | e.groups["Global"] = append(e.groups["Global"], &client{ConnectionID: cID, exchange: e, transport: e.transports[t]})
146 | return cID
147 | }
148 |
149 | func (e *Exchange) writeClientScript(w http.ResponseWriter, route string) {
150 | if len(clientScript) > 0 && cacheEnabled {
151 | io.Copy(w, bytes.NewBuffer(clientScript))
152 | } else {
153 | resultBuff := bytes.Buffer{}
154 | buff := bytes.Buffer{}
155 |
156 | buff.WriteString(fmt.Sprintf(connectionClassScript, route))
157 |
158 | buff.WriteString(relayClassBegin)
159 |
160 | for _, relay := range e.relays {
161 | buff.WriteString(fmt.Sprintf(relayBegin, relay.Name))
162 |
163 | for _, method := range relay.methods {
164 | buff.WriteString(fmt.Sprintf(relayMethod, lowerFirst(method), relay.Name, method))
165 |
166 | }
167 | buff.WriteString(relayEnd)
168 | }
169 |
170 | buff.WriteString(relayClassEnd)
171 |
172 | if ClientScriptFunc != nil {
173 | resultBuff.Write(ClientScriptFunc(buff.Bytes()))
174 | } else {
175 | resultBuff.Write(buff.Bytes())
176 | }
177 |
178 | if cacheEnabled {
179 | clientScript = resultBuff.Bytes()
180 | }
181 |
182 | io.Copy(w, &resultBuff)
183 | }
184 | }
185 |
186 | // RegisterRelay registers a struct as a Relay with the Exchange. This allows clients
187 | // to invoke server methods on a Relay and allows the Exchange to invoke
188 | // methods on a Relay on the server side.
189 | func (e *Exchange) RegisterRelay(x interface{}) {
190 | t := reflect.TypeOf(x)
191 |
192 | methods := e.getMethodsForType(t)
193 |
194 | e.relays = append(e.relays, Relay{Name: t.Name(), t: t, methods: methods, exchange: e})
195 | }
196 |
197 | func (e *Exchange) getMethodsForType(t reflect.Type) []string {
198 | r := []string{}
199 | for i := 0; i < t.NumMethod(); i++ {
200 | r = append(r, t.Method(i).Name)
201 | }
202 |
203 | return r
204 | }
205 |
206 | func (e *Exchange) getRelayByName(name string, cID string) *Relay {
207 | // Create an instance of Relay
208 | for _, r := range e.relays {
209 | if r.Name == name {
210 | relay := &Relay{
211 | Name: name,
212 | ConnectionID: cID,
213 | t: r.t,
214 | exchange: e,
215 | }
216 |
217 | relay.Clients = &ClientOperations{
218 | e: e,
219 | relay: relay,
220 | }
221 |
222 | return relay
223 | }
224 | }
225 |
226 | return nil
227 | }
228 |
229 | func (e *Exchange) callRelayMethod(relay *Relay, fn string, args ...interface{}) error {
230 | newInstance := reflect.New(relay.t)
231 | method := newInstance.MethodByName(fn)
232 | empty := reflect.Value{}
233 | if method == empty {
234 | return fmt.Errorf("Method '%v' does not exist on relay '%v'", fn, relay.Name)
235 | }
236 | method.Call(buildArgValues(relay, args...))
237 |
238 | return nil
239 | }
240 |
241 | func buildArgValues(relay *Relay, args ...interface{}) []reflect.Value {
242 | r := []reflect.Value{reflect.ValueOf(relay)}
243 | for _, a := range args {
244 | r = append(r, reflect.ValueOf(a))
245 | }
246 |
247 | return r
248 | }
249 |
250 | // Relay generates an instance of a Relay, allowing calls to be made to
251 | // it on the server side. It is generated a random ConnectionID for the duration
252 | // of the call and it does not represent an actual client.
253 | func (e *Exchange) Relay(x interface{}) *Relay {
254 | return e.getRelayByName(reflect.TypeOf(x).Name(), generateConnectionID())
255 | }
256 |
257 | func (e *Exchange) callClientMethod(r *Relay, fn string, args ...interface{}) {
258 | if r.ConnectionID == "" {
259 | e.callGroupMethod(r, "Global", fn, args...)
260 | return
261 | }
262 |
263 | c := e.getClientByConnectionID(r.ConnectionID)
264 | if c != nil {
265 | c.transport.CallClientFunction(r, fn, args...)
266 | }
267 | }
268 |
269 | func (e *Exchange) callGroupMethod(relay *Relay, group, fn string, args ...interface{}) {
270 | if _, ok := e.groups[group]; ok {
271 | for _, c := range e.groups[group] {
272 | r := e.getRelayByName(relay.Name, c.ConnectionID)
273 | c.transport.CallClientFunction(r, fn, args...)
274 | }
275 | }
276 | }
277 |
278 | func (e *Exchange) callGroupMethodExcept(relay *Relay, group, fn string, args ...interface{}) {
279 | for _, c := range e.groups[group] {
280 | if c.ConnectionID == relay.ConnectionID {
281 | continue
282 | }
283 | r := e.getRelayByName(relay.Name, c.ConnectionID)
284 | c.transport.CallClientFunction(r, fn, args...)
285 | }
286 | }
287 |
288 | func (e *Exchange) getClientByConnectionID(cID string) *client {
289 | for _, c := range e.groups["Global"] {
290 | if c.ConnectionID == cID {
291 | return c
292 | }
293 | }
294 | return nil
295 | }
296 |
297 | func (e *Exchange) removeFromAllGroups(id string) {
298 | for group := range e.groups {
299 | e.removeFromGroupByID(group, id)
300 | }
301 | }
302 |
303 | func (e *Exchange) removeFromGroupByID(g, id string) {
304 | if i := e.getClientIndexInGroup(g, id); i > -1 {
305 | group := e.groups[g]
306 | group[i] = nil
307 | e.groups[g] = append(group[:i], group[i+1:]...)
308 |
309 | // clean up the group if it is empty
310 | if len(e.groups[g]) == 0 {
311 | delete(e.groups, g)
312 | }
313 | }
314 | }
315 |
316 | func (e *Exchange) getClientIndexInGroup(g, id string) int {
317 | for i, c := range e.groups[g] {
318 | if c.ConnectionID == id {
319 | return i
320 | }
321 | }
322 |
323 | return -1
324 | }
325 |
326 | func (e *Exchange) addToGroup(group, connectionID string) {
327 | // only add them if they aren't currently in the group
328 | if e.getClientIndexInGroup(group, connectionID) == -1 {
329 | e.groups[group] = append(e.groups[group], e.getClientByConnectionID(connectionID))
330 | }
331 | }
332 |
--------------------------------------------------------------------------------
/groupOps.go:
--------------------------------------------------------------------------------
1 | package relayr
2 |
3 | // GroupOperations provides helper methods for communicating
4 | // with clients in groups. Clients must be added to a group
5 | // to be considered a member of a group.
6 | type GroupOperations struct {
7 | relay *Relay
8 | group string
9 | e *Exchange
10 | }
11 |
12 | // Add adds a client to a group via its ConnectionID. It
13 | // is a member of the group for the remainder of its
14 | // connection. At that point, the client must re-negotiate
15 | // its place within the group to be considered a member of it.
16 | func (g *GroupOperations) Add(connectionID string) {
17 | g.e.addToGroup(g.group, connectionID)
18 | }
19 |
20 | // Remove removes a client from a group via its ConnectionID.
21 | func (g *GroupOperations) Remove(connectionID string) {
22 | g.e.removeFromGroupByID(g.group, connectionID)
23 | }
24 |
25 | // Call invokes a client-side method across a Group of clients,
26 | // passing args to them.
27 | func (g *GroupOperations) Call(fn string, args ...interface{}) {
28 | g.e.callGroupMethod(g.relay, g.group, fn, args...)
29 | }
30 |
--------------------------------------------------------------------------------
/longpoll-transport.go:
--------------------------------------------------------------------------------
1 | package relayr
2 |
3 | import (
4 | "bytes"
5 | "encoding/json"
6 | "io"
7 | "net/http"
8 | "sync"
9 | "time"
10 | )
11 |
12 | type longPollConnection struct {
13 | e *Exchange
14 | result chan []byte
15 | timeoutChan chan struct{}
16 | t *time.Timer
17 | ConnectionID string
18 | }
19 |
20 | type longPollTransport struct {
21 | e *Exchange
22 | connections map[string]longPollConnection
23 | clock *sync.RWMutex
24 | }
25 |
26 | func (t *longPollTransport) clientInConnections(cid string) bool {
27 | _, exists := t.connections[cid]
28 |
29 | return exists
30 | }
31 |
32 | func (t *longPollTransport) addConnection(cid string) longPollConnection {
33 | lp := longPollConnection{
34 | e: t.e,
35 | result: make(chan []byte, 100),
36 | timeoutChan: make(chan struct{}, 10),
37 | ConnectionID: cid,
38 | }
39 |
40 | t.connections[cid] = lp
41 |
42 | return lp
43 | }
44 |
45 | func (t *longPollTransport) withClient(cid string, fn func(c longPollConnection)) {
46 | if t.clientInConnections(cid) {
47 | fn(t.connections[cid])
48 | }
49 | }
50 |
51 | func newLongPollTransport(e *Exchange) *longPollTransport {
52 | lp := &longPollTransport{
53 | e: e,
54 | connections: make(map[string]longPollConnection),
55 | clock: &sync.RWMutex{},
56 | }
57 |
58 | return lp
59 | }
60 |
61 | func (t *longPollTransport) CallClientFunction(relay *Relay, fn string, args ...interface{}) {
62 | buff := &bytes.Buffer{}
63 | encoder := json.NewEncoder(buff)
64 |
65 | encoder.Encode(struct {
66 | R string
67 | M string
68 | A []interface{}
69 | }{
70 | relay.Name,
71 | fn,
72 | args,
73 | })
74 |
75 | go t.withClient(relay.ConnectionID, func(c longPollConnection) {
76 | // force a timeout if we block on sending too long..
77 | go func() {
78 | <-time.After(time.Second * 30)
79 | c.timeoutChan <- struct{}{}
80 | }()
81 | c.result <- buff.Bytes()
82 | })
83 | }
84 |
85 | func (t *longPollTransport) removeConnection(cid string) {
86 | delete(t.connections, cid)
87 | }
88 |
89 | func (t *longPollTransport) wait(w http.ResponseWriter, cid string) {
90 | var conn longPollConnection
91 | if !t.clientInConnections(cid) {
92 | conn = t.addConnection(cid)
93 | } else {
94 | conn = t.connections[cid]
95 | }
96 |
97 | select {
98 | case m := <-conn.result:
99 | io.Copy(w, bytes.NewBuffer(m))
100 | case <-conn.timeoutChan:
101 | buff := &bytes.Buffer{}
102 | encoder := json.NewEncoder(buff)
103 | encoder.Encode(struct {
104 | Z string
105 | }{
106 | "RECONNECT",
107 | })
108 | io.WriteString(w, buff.String())
109 | t.removeConnection(cid)
110 | t.e.removeFromAllGroups(cid)
111 | }
112 | }
113 |
--------------------------------------------------------------------------------
/operation.go:
--------------------------------------------------------------------------------
1 | package relayr
2 |
3 | const (
4 | opNegotiate = "negotiate"
5 | opConnect = "connect"
6 | opWebSocket = "ws"
7 | opLongPoll = "longpoll"
8 | opCallServer = "call"
9 | )
10 |
--------------------------------------------------------------------------------
/relay.go:
--------------------------------------------------------------------------------
1 | package relayr
2 |
3 | import "reflect"
4 |
5 | // Relay encapsulates a connection with a client
6 | // during an interaction with the server. It provides methods
7 | // for interacting with clients and groups.
8 | type Relay struct {
9 | Name string // The name of the relay it is associated with
10 | ConnectionID string // The connectionID of the client that this Relay interacts with
11 | Clients *ClientOperations // An abstraction over clients currently connected to this Relay
12 |
13 | methods []string
14 | t reflect.Type
15 | exchange *Exchange
16 | }
17 |
18 | // Call will execute a function on another server-side Relay,
19 | // passing along the details of the currently connected client.
20 | func (r *Relay) Call(fn string, args ...interface{}) {
21 | r.exchange.callRelayMethod(r, fn, args...)
22 | }
23 |
24 | // Groups returns a GroupOperations object, which offers helper
25 | // methods for communicating with and grouping clients.
26 | func (r *Relay) Groups(group string) *GroupOperations {
27 | return &GroupOperations{
28 | group: group,
29 | e: r.exchange,
30 | relay: r,
31 | }
32 | }
33 |
--------------------------------------------------------------------------------
/transport.go:
--------------------------------------------------------------------------------
1 | package relayr
2 |
3 | // Transport represents a communication mechanism between
4 | // a Relay and a client.
5 | type Transport interface {
6 | CallClientFunction(relay *Relay, fn string, args ...interface{})
7 | }
8 |
--------------------------------------------------------------------------------
/util.go:
--------------------------------------------------------------------------------
1 | package relayr
2 |
3 | import (
4 | "crypto/rand"
5 | "encoding/base64"
6 | "net/http"
7 | "unicode"
8 | "unicode/utf8"
9 | )
10 |
11 | func jsonResponse(w http.ResponseWriter) {
12 | w.Header().Set("Content-type", "application/json")
13 | }
14 |
15 | func generateConnectionID() string {
16 | rb := make([]byte, 32)
17 | rand.Read(rb)
18 | rs := base64.URLEncoding.EncodeToString(rb)
19 | return rs
20 | }
21 |
22 | func lowerFirst(s string) string {
23 | if s == "" {
24 | return ""
25 | }
26 | r, n := utf8.DecodeRuneInString(s)
27 | return string(unicode.ToLower(r)) + s[n:]
28 | }
29 |
30 | func upperFirst(s string) string {
31 | if s == "" {
32 | return ""
33 | }
34 | r, n := utf8.DecodeRuneInString(s)
35 | return string(unicode.ToUpper(r)) + s[n:]
36 | }
37 |
--------------------------------------------------------------------------------
/websocket-transport.go:
--------------------------------------------------------------------------------
1 | package relayr
2 |
3 | import (
4 | "bytes"
5 | "encoding/json"
6 | "fmt"
7 |
8 | "github.com/gorilla/websocket"
9 | )
10 |
11 | type connection struct {
12 | ws *websocket.Conn
13 | out chan []byte
14 | c *webSocketTransport
15 | id string
16 | e *Exchange
17 | }
18 |
19 | type webSocketTransport struct {
20 | connections map[string]*connection
21 | connected chan *connection
22 | disconnected chan *connection
23 | e *Exchange
24 | }
25 |
26 | type webSocketClientMessage struct {
27 | Server bool `json:"S"`
28 | Relay string `json:"R"`
29 | Method string `json:"M"`
30 | Arguments []interface{} `json:"A"`
31 | ConnectionID string `json:"C"`
32 | }
33 |
34 | func newWebSocketTransport(e *Exchange) *webSocketTransport {
35 | c := &webSocketTransport{
36 | connected: make(chan *connection),
37 | disconnected: make(chan *connection),
38 | connections: make(map[string]*connection),
39 | e: e,
40 | }
41 |
42 | go c.listen()
43 |
44 | return c
45 | }
46 |
47 | func (c *webSocketTransport) listen() {
48 | for {
49 | select {
50 | case conn := <-c.connected:
51 | c.connections[conn.id] = conn
52 | case conn := <-c.disconnected:
53 | if _, ok := c.connections[conn.id]; ok {
54 | c.e.removeFromAllGroups(conn.id)
55 | delete(c.connections, conn.id)
56 | close(conn.out)
57 | }
58 | }
59 | }
60 | }
61 |
62 | func (c *webSocketTransport) CallClientFunction(relay *Relay, fn string, args ...interface{}) {
63 | buff := &bytes.Buffer{}
64 | encoder := json.NewEncoder(buff)
65 |
66 | encoder.Encode(struct {
67 | R string
68 | M string
69 | A []interface{}
70 | }{
71 | relay.Name,
72 | fn,
73 | args,
74 | })
75 |
76 | o := c.connections[relay.ConnectionID]
77 |
78 | if o != nil {
79 | o.out <- buff.Bytes()
80 | }
81 | }
82 |
83 | func (c *connection) read() {
84 | for {
85 | _, message, err := c.ws.ReadMessage()
86 | if err != nil {
87 | break
88 | }
89 | var m webSocketClientMessage
90 | err = json.Unmarshal(message, &m)
91 | if err != nil {
92 | fmt.Println("ERR:", err)
93 | continue
94 | }
95 |
96 | relay := c.e.getRelayByName(m.Relay, m.ConnectionID)
97 |
98 | if m.Server {
99 | err := c.e.callRelayMethod(relay, m.Method, m.Arguments...)
100 | if err != nil {
101 | fmt.Println("ERR:", err)
102 | }
103 | } else {
104 | c.c.CallClientFunction(relay, m.Method, m.Arguments)
105 | }
106 | }
107 | c.ws.Close()
108 | }
109 |
110 | func (c *connection) write() {
111 | for message := range c.out {
112 | err := c.ws.WriteMessage(websocket.TextMessage, message)
113 | if err != nil {
114 | break
115 | }
116 | }
117 | c.ws.Close()
118 | }
119 |
--------------------------------------------------------------------------------