swagger.lib.shred.content.js Maven / Gradle / Ivy
// 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;© 2015 - 2024 Weber Informatics LLC | Privacy Policy