try the various xhr loading techniques
[OpenSRF.git] / src / javascript / opensrf_xhr.js
1 /* -----------------------------------------------------------------------
2  * Copyright (C) 2008  Georgia Public Library Service
3  * Bill Erickson <erickson@esilibrary.com>
4  *  
5  * This program is free software; you can redistribute it and/or
6  * modify it under the terms of the GNU General Public License
7  * as published by the Free Software Foundation; either version 2
8  * of the License, or (at your option) any later version.
9  * 
10  * This program is distributed in the hope that it will be useful,
11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
13  * GNU General Public License for more details.
14  * ----------------------------------------------------------------------- */
15
16 var OSRF_HTTP_HEADER_TO = 'X-OpenSRF-to';
17 var OSRF_HTTP_HEADER_XID = 'X-OpenSRF-xid';
18 var OSRF_HTTP_HEADER_FROM = 'X-OpenSRF-from';
19 var OSRF_HTTP_HEADER_THREAD = 'X-OpenSRF-thread';
20 var OSRF_HTTP_HEADER_TIMEOUT = 'X-OpenSRF-timeout';
21 var OSRF_HTTP_HEADER_SERVICE = 'X-OpenSRF-service';
22 var OSRF_HTTP_HEADER_MULTIPART = 'X-OpenSRF-multipart';
23 var OSRF_HTTP_TRANSLATOR = '/osrf-http-translator'; /* XXX config */
24 var OSRF_POST_CONTENT_TYPE = 'application/x-www-form-urlencoded';
25
26
27 OpenSRF.XHRequest = function(osrf_msg, args) {
28     this.message = osrf_msg;
29     this.args = args;
30     try {
31             this.xreq =  new XMLHttpRequest();
32     } catch(e) {
33             try { 
34                     this.xreq = new ActiveXObject("Msxml2.XMLHTTP"); 
35             } catch (e2) {
36                         this.xreq = new ActiveXObject("Microsoft.XMLHTTP"); 
37             }
38     }
39
40 }
41
42 OpenSRF.XHRequest.prototype.send = function() {
43     var xhr_req = this;
44     var xreq = this.xreq
45     
46     if(this.args.timeout) {
47         /* this is a standard blocking (non-multipart) call */
48         xreq.open('POST', OSRF_HTTP_TRANSLATOR, false);
49
50     } else {
51
52         if(!navigator.userAgent.match(/mozilla/i)) {
53
54             /* standard asynchronous call */
55             xreq.onreadystatechange = function() {
56                 if(xreq.readyState == 4)
57                     xhr_req.core_handler();
58             }
59             xreq.open('POST', OSRF_HTTP_TRANSLATOR, true);
60
61         } else {
62
63             /* asynchronous multipart call */
64             xreq.multipart = true;
65             xreq.onload = function(evt) {xhr_req.core_handler();}
66             xreq.open('POST', OSRF_HTTP_TRANSLATOR, true);
67             xreq.setRequestHeader(OSRF_HTTP_HEADER_MULTIPART, 'true');
68
69             /* multipart requests do not pass the status info to the onload if there 
70                is no new data to load.  Capture the status on the readystate handler */
71             xreq.onreadystatechange = function() {
72                 if(xreq.readyState == 4 && xreq.status >= 400)
73                     xhr_req.transport_error_handler();
74             }
75         }
76     }
77
78     xreq.setRequestHeader('Content-Type', OSRF_POST_CONTENT_TYPE);
79     xreq.setRequestHeader(OSRF_HTTP_HEADER_THREAD, this.args.thread);
80     if(this.args.rcpt)
81         xreq.setRequestHeader(OSRF_HTTP_HEADER_TO, this.args.rcpt);
82     else
83         xreq.setRequestHeader(OSRF_HTTP_HEADER_SERVICE, this.args.rcpt_service);
84
85     var post = 'osrf-msg=' + encodeURIComponent(js2JSON([this.message.serialize()]));
86     xreq.send(post);
87
88     if(this.args.timeout) /* this was a blocking call, manually run the handler */
89         this.core_handler()
90
91     return this;
92 }
93
94 OpenSRF.XHRequest.prototype.core_handler = function() {
95     sender = this.xreq.getResponseHeader(OSRF_HTTP_HEADER_FROM);
96     thread = this.xreq.getResponseHeader(OSRF_HTTP_HEADER_THREAD);
97     json = this.xreq.responseText;
98     stat = this.xreq.status;
99
100     if(stat >= 400) 
101         return this.transport_error_handler();
102
103     OpenSRF.Stack.push(
104         new OpenSRF.NetMessage(null, sender, thread, json),
105         {
106             onresponse : this.args.onresponse,
107             oncomplete : this.args.oncomplete,
108             onerror : this.args.onerror,
109             onmethoderror : this.method_error_handler()
110         }
111     );
112 }
113
114
115 OpenSRF.XHRequest.prototype.method_error_handler = function() {
116     var xhr = this;
117     return function(req, status, status_text) {
118         if(xhr.args.onmethoderror) 
119             xhr.args.onmethoderror(req, status, status_text);
120         if(xhr.args.onerror)  
121             xhr.args.onerror(xhr.message, xhr.args.rcpt || xhr.args.rcpt_service, xhr.args.thread);
122     }
123 }
124
125 OpenSRF.XHRequest.prototype.transport_error_handler = function() {
126     if(this.args.ontransporterror) 
127         this.args.ontransporterror(this.xreq);
128     if(this.args.onerror) 
129         this.args.onerror(this.message, this.args.rcpt || this.args.rcpt_service, this.args.thread);
130 }
131
132