--- /dev/null
+/*
+ * Copyright 2016 ZTE Corporation.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+// 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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Code Review / aai / esr-server.git / blobdiff