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-
- // 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;
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