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sse.js
根目录 / static / sse.js
1 function SSE(url, options) {
2 this.INITIALIZING = -1;
3 this.CONNECTING = 0;
4 this.OPEN = 1;
5 this.CLOSED = 2;
6
7 this.url = url;
8
9 options = options || {};
10 this.headers = options.headers || {};
11 this.payload = options.payload !== undefined ? options.payload : '';
12 this.method = options.method || (this.payload && 'POST') || 'GET';
13 this.withCredentials = !!options.withCredentials;
14
15 this.FIELD_SEPARATOR = ':';
16 this.listeners = {};
17
18 this.xhr = null;
19 this.readyState = this.INITIALIZING;
20 this.progress = 0;
21 this.chunk = '';
22
23 this.addEventListener = function (type, listener) {
24 if (this.listeners[type] === undefined) {
25 this.listeners[type] = [];
26 }
27
28 if (this.listeners[type].indexOf(listener) === -1) {
29 this.listeners[type].push(listener);
30 }
31 };
32
33 this.removeEventListener = function (type, listener) {
34 if (this.listeners[type] === undefined) {
35 return;
36 }
37
38 var filtered = [];
39 this.listeners[type].forEach(function (element) {
40 if (element !== listener) {
41 filtered.push(element);
42 }
43 });
44 if (filtered.length === 0) {
45 delete this.listeners[type];
46 } else {
47 this.listeners[type] = filtered;
48 }
49 };
50
51 this.dispatchEvent = function (e) {
52 if (!e) {
53 return true;
54 }
55
56 e.source = this;
57
58 var onHandler = 'on' + e.type;
59 if (this.hasOwnProperty(onHandler)) {
60 this[onHandler].call(this, e);
61 if (e.defaultPrevented) {
62 return false;
63 }
64 }
65
66 if (this.listeners[e.type]) {
67 return this.listeners[e.type].every(function (callback) {
68 callback(e);
69 return !e.defaultPrevented;
70 });
71 }
72
73 return true;
74 };
75
76 this._setReadyState = function (state) {
77 var event = new CustomEvent('readystatechange');
78 event.readyState = state;
79 this.readyState = state;
80 this.dispatchEvent(event);
81 };
82
83 this._onStreamFailure = function (e) {
84 var event = new CustomEvent('error');
85 event.data = e.currentTarget.response;
86 this.dispatchEvent(event);
87 this.close();
88 };
89
90 this._onStreamAbort = function (e) {
91 this.dispatchEvent(new CustomEvent('abort'));
92 this.close();
93 };
94
95 this._onStreamProgress = function (e) {
96 if (!this.xhr) {
97 return;
98 }
99
100 if (this.xhr.status !== 200) {
101 this._onStreamFailure(e);
102 return;
103 }
104
105 if (this.readyState == this.CONNECTING) {
106 this.dispatchEvent(new CustomEvent('open'));
107 this._setReadyState(this.OPEN);
108 }
109
110 var data = this.xhr.responseText.substring(this.progress);
111 this.progress += data.length;
112 data.split(/(\r\n|\r|\n){2}/g).forEach(
113 function (part) {
114 if (part.trim().length === 0) {
115 this.dispatchEvent(this._parseEventChunk(this.chunk.trim()));
116 this.chunk = '';
117 } else {
118 this.chunk += part;
119 }
120 }.bind(this),
121 );
122 };
123
124 this._onStreamLoaded = function (e) {
125 this._onStreamProgress(e);
126
127 // Parse the last chunk.
128 this.dispatchEvent(this._parseEventChunk(this.chunk));
129 this.chunk = '';
130 };
131
132 /**
133 * Parse a received SSE event chunk into a constructed event object.
134 */
135 this._parseEventChunk = function (chunk) {
136 if (!chunk || chunk.length === 0) {
137 return null;
138 }
139
140 var e = { id: null, retry: null, data: '', event: 'message' };
141 chunk.split(/\n|\r\n|\r/).forEach(
142 function (line) {
143 line = line.trimRight();
144 var index = line.indexOf(this.FIELD_SEPARATOR);
145 if (index <= 0) {
146 // Line was either empty, or started with a separator and is a comment.
147 // Either way, ignore.
148 return;
149 }
150
151 var field = line.substring(0, index);
152 if (!(field in e)) {
153 return;
154 }
155
156 var value = line.substring(index + 1).trimLeft();
157 if (field === 'data') {
158 e[field] += value;
159 } else {
160 e[field] = value;
161 }
162 }.bind(this),
163 );
164
165 var event = new CustomEvent(e.event);
166 event.data = e.data;
167 event.id = e.id;
168 return event;
169 };
170
171 this._checkStreamClosed = function () {
172 if (!this.xhr) {
173 return;
174 }
175
176 if (this.xhr.readyState === XMLHttpRequest.DONE) {
177 this._setReadyState(this.CLOSED);
178 var event = new CustomEvent('end');
179 event.data = this.xhr.responseText;
180 this.dispatchEvent(event);
181 }
182 };
183
184 this.stream = function () {
185 this._setReadyState(this.CONNECTING);
186
187 this.xhr = new XMLHttpRequest();
188 this.xhr.addEventListener('progress', this._onStreamProgress.bind(this));
189 this.xhr.addEventListener('load', this._onStreamLoaded.bind(this));
190 this.xhr.addEventListener('readystatechange', this._checkStreamClosed.bind(this));
191 this.xhr.addEventListener('error', this._onStreamFailure.bind(this));
192 this.xhr.addEventListener('abort', this._onStreamAbort.bind(this));
193 this.xhr.open(this.method, this.url);
194 for (var header in this.headers) {
195 this.xhr.setRequestHeader(header, this.headers[header]);
196 }
197 this.xhr.withCredentials = this.withCredentials;
198 this.xhr.send(this.payload);
199 };
200
201 this.close = function () {
202 if (this.readyState === this.CLOSED) {
203 return;
204 }
205
206 this.xhr.abort();
207 this.xhr = null;
208 this._setReadyState(this.CLOSED);
209 };
210 };
211
212 // export { SSE }
213
214 /*
215 const url = 'https://xxx/chat';
216 var source = new SSE(url, {
217 method: 'POST',
218 // withCredentials: true,
219 headers: {
220 'Content-Type': 'application/json',
221 'Cache-Control': 'no-cache'
222 },
223 payload: JSON.stringify({ prompt: 'xxx' }),
224 });
225 source.onmessage = function (data) {
226 console.log('chunk => ' + data.data)
227 };
228 source.onend = function (data) {
229 console.log('结束');
230 };
231 source.onerror = function (err) {
232 console.error('异常', err);
233 };
234 source.stream();
235 */
235 lines JAVASCRIPT