1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
|
// The purpose of the `Content` object is to abstract away the data conversions
// to and from raw content entities as strings. For example, you want to be able
// to pass in a Javascript object and have it be automatically converted into a
// JSON string if the `content-type` is set to a JSON-based media type.
// Conversely, you want to be able to transparently get back a Javascript object
// in the response if the `content-type` is a JSON-based media-type.
// One limitation of the current implementation is that it [assumes the `charset` is UTF-8](https://github.com/spire-io/shred/issues/5).
// The `Content` constructor takes an options object, which *must* have either a
// `body` or `data` property and *may* have a `type` property indicating the
// media type. If there is no `type` attribute, a default will be inferred.
var Content = function(options) {
this.body = options.body;
this.data = options.data;
this.type = options.type;
};
Content.prototype = {
// Treat `toString()` as asking for the `content.body`. That is, the raw content entity.
//
// toString: function() { return this.body; }
//
// Commented out, but I've forgotten why. :/
};
// `Content` objects have the following attributes:
Object.defineProperties(Content.prototype,{
// - **type**. Typically accessed as `content.type`, reflects the `content-type`
// header associated with the request or response. If not passed as an options
// to the constructor or set explicitly, it will infer the type the `data`
// attribute, if possible, and, failing that, will default to `text/plain`.
type: {
get: function() {
if (this._type) {
return this._type;
} else {
if (this._data) {
switch(typeof this._data) {
case "string": return "text/plain";
case "object": return "application/json";
}
}
}
return "text/plain";
},
set: function(value) {
this._type = value;
return this;
},
enumerable: true
},
// - **data**. Typically accessed as `content.data`, reflects the content entity
// converted into Javascript data. This can be a string, if the `type` is, say,
// `text/plain`, but can also be a Javascript object. The conversion applied is
// based on the `processor` attribute. The `data` attribute can also be set
// directly, in which case the conversion will be done the other way, to infer
// the `body` attribute.
data: {
get: function() {
if (this._body) {
return this.processor.parser(this._body);
} else {
return this._data;
}
},
set: function(data) {
if (this._body&&data) Errors.setDataWithBody(this);
this._data = data;
return this;
},
enumerable: true
},
// - **body**. Typically accessed as `content.body`, reflects the content entity
// as a UTF-8 string. It is the mirror of the `data` attribute. If you set the
// `data` attribute, the `body` attribute will be inferred and vice-versa. If
// you attempt to set both, an exception is raised.
body: {
get: function() {
if (this._data) {
return this.processor.stringify(this._data);
} else {
return this._body.toString();
}
},
set: function(body) {
if (this._data&&body) Errors.setBodyWithData(this);
this._body = body;
return this;
},
enumerable: true
},
// - **processor**. The functions that will be used to convert to/from `data` and
// `body` attributes. You can add processors. The two that are built-in are for
// `text/plain`, which is basically an identity transformation and
// `application/json` and other JSON-based media types (including custom media
// types with `+json`). You can add your own processors. See below.
processor: {
get: function() {
var processor = Content.processors[this.type];
if (processor) {
return processor;
} else {
// Return the first processor that matches any part of the
// content type. ex: application/vnd.foobar.baz+json will match json.
var main = this.type.split(";")[0];
var parts = main.split(/\+|\//);
for (var i=0, l=parts.length; i < l; i++) {
processor = Content.processors[parts[i]]
}
return processor || {parser:identity,stringify:toString};
}
},
enumerable: true
},
// - **length**. Typically accessed as `content.length`, returns the length in
// bytes of the raw content entity.
length: {
get: function() {
if (typeof Buffer !== 'undefined') {
return Buffer.byteLength(this.body);
}
return this.body.length;
}
}
});
Content.processors = {};
// The `registerProcessor` function allows you to add your own processors to
// convert content entities. Each processor consists of a Javascript object with
// two properties:
// - **parser**. The function used to parse a raw content entity and convert it
// into a Javascript data type.
// - **stringify**. The function used to convert a Javascript data type into a
// raw content entity.
Content.registerProcessor = function(types,processor) {
// You can pass an array of types that will trigger this processor, or just one.
// We determine the array via duck-typing here.
if (types.forEach) {
types.forEach(function(type) {
Content.processors[type] = processor;
});
} else {
// If you didn't pass an array, we just use what you pass in.
Content.processors[types] = processor;
}
};
// Register the identity processor, which is used for text-based media types.
var identity = function(x) { return x; }
, toString = function(x) { return x.toString(); }
Content.registerProcessor(
["text/html","text/plain","text"],
{ parser: identity, stringify: toString });
// Register the JSON processor, which is used for JSON-based media types.
Content.registerProcessor(
["application/json; charset=utf-8","application/json","json"],
{
parser: function(string) {
return JSON.parse(string);
},
stringify: function(data) {
return JSON.stringify(data); }});
var qs = require('querystring');
// Register the post processor, which is used for JSON-based media types.
Content.registerProcessor(
["application/x-www-form-urlencoded"],
{ parser : qs.parse, stringify : qs.stringify });
// Error functions are defined separately here in an attempt to make the code
// easier to read.
var Errors = {
setDataWithBody: function(object) {
throw new Error("Attempt to set data attribute of a content object " +
"when the body attributes was already set.");
},
setBodyWithData: function(object) {
throw new Error("Attempt to set body attribute of a content object " +
"when the data attributes was already set.");
}
}
module.exports = Content;
|
