Website Structure

Frontend-Learner/node_modules/koa/lib/response.js

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+
+'use strict';
+
+/**
+ * Module dependencies.
+ */
+
+const contentDisposition = require('content-disposition');
+const getType = require('cache-content-type');
+const onFinish = require('on-finished');
+const escape = require('escape-html');
+const typeis = require('type-is').is;
+const statuses = require('statuses');
+const destroy = require('destroy');
+const assert = require('assert');
+const extname = require('path').extname;
+const vary = require('vary');
+const only = require('only');
+const util = require('util');
+const encodeUrl = require('encodeurl');
+const Stream = require('stream');
+const URL = require('url').URL;
+
+/**
+ * Prototype.
+ */
+
+module.exports = {
+
+  /**
+   * Return the request socket.
+   *
+   * @return {Connection}
+   * @api public
+   */
+
+  get socket() {
+    return this.res.socket;
+  },
+
+  /**
+   * Return response header.
+   *
+   * @return {Object}
+   * @api public
+   */
+
+  get header() {
+    const { res } = this;
+    return typeof res.getHeaders === 'function'
+      ? res.getHeaders()
+      : res._headers || {}; // Node < 7.7
+  },
+
+  /**
+   * Return response header, alias as response.header
+   *
+   * @return {Object}
+   * @api public
+   */
+
+  get headers() {
+    return this.header;
+  },
+
+  /**
+   * Get response status code.
+   *
+   * @return {Number}
+   * @api public
+   */
+
+  get status() {
+    return this.res.statusCode;
+  },
+
+  /**
+   * Set response status code.
+   *
+   * @param {Number} code
+   * @api public
+   */
+
+  set status(code) {
+    if (this.headerSent) return;
+
+    assert(Number.isInteger(code), 'status code must be a number');
+    assert(code >= 100 && code <= 999, `invalid status code: ${code}`);
+    this._explicitStatus = true;
+    this.res.statusCode = code;
+    if (this.req.httpVersionMajor < 2) this.res.statusMessage = statuses[code];
+    if (this.body && statuses.empty[code]) this.body = null;
+  },
+
+  /**
+   * Get response status message
+   *
+   * @return {String}
+   * @api public
+   */
+
+  get message() {
+    return this.res.statusMessage || statuses[this.status];
+  },
+
+  /**
+   * Set response status message
+   *
+   * @param {String} msg
+   * @api public
+   */
+
+  set message(msg) {
+    this.res.statusMessage = msg;
+  },
+
+  /**
+   * Get response body.
+   *
+   * @return {Mixed}
+   * @api public
+   */
+
+  get body() {
+    return this._body;
+  },
+
+  /**
+   * Set response body.
+   *
+   * @param {String|Buffer|Object|Stream} val
+   * @api public
+   */
+
+  set body(val) {
+    const original = this._body;
+    this._body = val;
+
+    // no content
+    if (null == val) {
+      if (!statuses.empty[this.status]) this.status = 204;
+      if (val === null) this._explicitNullBody = true;
+      this.remove('Content-Type');
+      this.remove('Content-Length');
+      this.remove('Transfer-Encoding');
+      return;
+    }
+
+    // set the status
+    if (!this._explicitStatus) this.status = 200;
+
+    // set the content-type only if not yet set
+    const setType = !this.has('Content-Type');
+
+    // string
+    if ('string' === typeof val) {
+      if (setType) this.type = /^\s*</.test(val) ? 'html' : 'text';
+      this.length = Buffer.byteLength(val);
+      return;
+    }
+
+    // buffer
+    if (Buffer.isBuffer(val)) {
+      if (setType) this.type = 'bin';
+      this.length = val.length;
+      return;
+    }
+
+    // stream
+    if (val instanceof Stream) {
+      onFinish(this.res, destroy.bind(null, val));
+      if (original != val) {
+        val.once('error', err => this.ctx.onerror(err));
+        // overwriting
+        if (null != original) this.remove('Content-Length');
+      }
+
+      if (setType) this.type = 'bin';
+      return;
+    }
+
+    // json
+    this.remove('Content-Length');
+    this.type = 'json';
+  },
+
+  /**
+   * Set Content-Length field to `n`.
+   *
+   * @param {Number} n
+   * @api public
+   */
+
+  set length(n) {
+    if (!this.has('Transfer-Encoding')) {
+      this.set('Content-Length', n);
+    }
+  },
+
+  /**
+   * Return parsed response Content-Length when present.
+   *
+   * @return {Number}
+   * @api public
+   */
+
+  get length() {
+    if (this.has('Content-Length')) {
+      return parseInt(this.get('Content-Length'), 10) || 0;
+    }
+
+    const { body } = this;
+    if (!body || body instanceof Stream) return undefined;
+    if ('string' === typeof body) return Buffer.byteLength(body);
+    if (Buffer.isBuffer(body)) return body.length;
+    return Buffer.byteLength(JSON.stringify(body));
+  },
+
+  /**
+   * Check if a header has been written to the socket.
+   *
+   * @return {Boolean}
+   * @api public
+   */
+
+  get headerSent() {
+    return this.res.headersSent;
+  },
+
+  /**
+   * Vary on `field`.
+   *
+   * @param {String} field
+   * @api public
+   */
+
+  vary(field) {
+    if (this.headerSent) return;
+
+    vary(this.res, field);
+  },
+
+  _getBackReferrer() {
+    const referrer = this.ctx.get('Referrer');
+    if (referrer) {
+      // referrer is an absolute URL, check if it's the same origin
+      const url = new URL(referrer, this.ctx.href);
+      if (url.host === this.ctx.host) {
+        return referrer;
+      }
+    }
+  },
+
+  /**
+   * Perform a 302 redirect to `url`.
+   *
+   * The string "back" is special-cased
+   * to provide Referrer support, when Referrer
+   * is not present `alt` or "/" is used.
+   *
+   * Examples:
+   *
+   *    this.redirect('back');
+   *    this.redirect('back', '/index.html');
+   *    this.redirect('/login');
+   *    this.redirect('http://google.com');
+   *
+   * @param {String} url
+   * @param {String} [alt]
+   * @api public
+   */
+
+  redirect(url, alt) {
+    // location
+    if ('back' === url) {
+      url = this._getBackReferrer() || alt || '/';
+    }
+
+    if (/^https?:\/\//i.test(url)) {
+      // formatting url again avoid security escapes
+      url = new URL(url).toString();
+    }
+    this.set('Location', encodeUrl(url));
+
+    // status
+    if (!statuses.redirect[this.status]) this.status = 302;
+
+    // html
+    if (this.ctx.accepts('html')) {
+      url = escape(url);
+      this.type = 'text/html; charset=utf-8';
+      this.body = `Redirecting to ${url}.`;
+      return;
+    }
+
+    // text
+    this.type = 'text/plain; charset=utf-8';
+    this.body = `Redirecting to ${url}.`;
+  },
+
+  /**
+   * Set Content-Disposition header to "attachment" with optional `filename`.
+   *
+   * @param {String} filename
+   * @api public
+   */
+
+  attachment(filename, options) {
+    if (filename) this.type = extname(filename);
+    this.set('Content-Disposition', contentDisposition(filename, options));
+  },
+
+  /**
+   * Set Content-Type response header with `type` through `mime.lookup()`
+   * when it does not contain a charset.
+   *
+   * Examples:
+   *
+   *     this.type = '.html';
+   *     this.type = 'html';
+   *     this.type = 'json';
+   *     this.type = 'application/json';
+   *     this.type = 'png';
+   *
+   * @param {String} type
+   * @api public
+   */
+
+  set type(type) {
+    type = getType(type);
+    if (type) {
+      this.set('Content-Type', type);
+    } else {
+      this.remove('Content-Type');
+    }
+  },
+
+  /**
+   * Set the Last-Modified date using a string or a Date.
+   *
+   *     this.response.lastModified = new Date();
+   *     this.response.lastModified = '2013-09-13';
+   *
+   * @param {String|Date} type
+   * @api public
+   */
+
+  set lastModified(val) {
+    if ('string' === typeof val) val = new Date(val);
+    this.set('Last-Modified', val.toUTCString());
+  },
+
+  /**
+   * Get the Last-Modified date in Date form, if it exists.
+   *
+   * @return {Date}
+   * @api public
+   */
+
+  get lastModified() {
+    const date = this.get('last-modified');
+    if (date) return new Date(date);
+  },
+
+  /**
+   * Set the ETag of a response.
+   * This will normalize the quotes if necessary.
+   *
+   *     this.response.etag = 'md5hashsum';
+   *     this.response.etag = '"md5hashsum"';
+   *     this.response.etag = 'W/"123456789"';
+   *
+   * @param {String} etag
+   * @api public
+   */
+
+  set etag(val) {
+    if (!/^(W\/)?"/.test(val)) val = `"${val}"`;
+    this.set('ETag', val);
+  },
+
+  /**
+   * Get the ETag of a response.
+   *
+   * @return {String}
+   * @api public
+   */
+
+  get etag() {
+    return this.get('ETag');
+  },
+
+  /**
+   * Return the response mime type void of
+   * parameters such as "charset".
+   *
+   * @return {String}
+   * @api public
+   */
+
+  get type() {
+    const type = this.get('Content-Type');
+    if (!type) return '';
+    return type.split(';', 1)[0];
+  },
+
+  /**
+   * Check whether the response is one of the listed types.
+   * Pretty much the same as `this.request.is()`.
+   *
+   * @param {String|String[]} [type]
+   * @param {String[]} [types]
+   * @return {String|false}
+   * @api public
+   */
+
+  is(type, ...types) {
+    return typeis(this.type, type, ...types);
+  },
+
+  /**
+   * Return response header.
+   *
+   * Examples:
+   *
+   *     this.get('Content-Type');
+   *     // => "text/plain"
+   *
+   *     this.get('content-type');
+   *     // => "text/plain"
+   *
+   * @param {String} field
+   * @return {String}
+   * @api public
+   */
+
+  get(field) {
+    return this.header[field.toLowerCase()] || '';
+  },
+
+  /**
+   * Returns true if the header identified by name is currently set in the outgoing headers.
+   * The header name matching is case-insensitive.
+   *
+   * Examples:
+   *
+   *     this.has('Content-Type');
+   *     // => true
+   *
+   *     this.get('content-type');
+   *     // => true
+   *
+   * @param {String} field
+   * @return {boolean}
+   * @api public
+   */
+
+  has(field) {
+    return typeof this.res.hasHeader === 'function'
+      ? this.res.hasHeader(field)
+      // Node < 7.7
+      : field.toLowerCase() in this.headers;
+  },
+
+  /**
+   * Set header `field` to `val` or pass
+   * an object of header fields.
+   *
+   * Examples:
+   *
+   *    this.set('Foo', ['bar', 'baz']);
+   *    this.set('Accept', 'application/json');
+   *    this.set({ Accept: 'text/plain', 'X-API-Key': 'tobi' });
+   *
+   * @param {String|Object|Array} field
+   * @param {String} val
+   * @api public
+   */
+
+  set(field, val) {
+    if (this.headerSent) return;
+
+    if (2 === arguments.length) {
+      if (Array.isArray(val)) val = val.map(v => typeof v === 'string' ? v : String(v));
+      else if (typeof val !== 'string') val = String(val);
+      this.res.setHeader(field, val);
+    } else {
+      for (const key in field) {
+        this.set(key, field[key]);
+      }
+    }
+  },
+
+  /**
+   * Append additional header `field` with value `val`.
+   *
+   * Examples:
+   *
+   * ```
+   * this.append('Link', ['<http://localhost/>', '<http://localhost:3000/>']);
+   * this.append('Set-Cookie', 'foo=bar; Path=/; HttpOnly');
+   * this.append('Warning', '199 Miscellaneous warning');
+   * ```
+   *
+   * @param {String} field
+   * @param {String|Array} val
+   * @api public
+   */
+
+  append(field, val) {
+    const prev = this.get(field);
+
+    if (prev) {
+      val = Array.isArray(prev)
+        ? prev.concat(val)
+        : [prev].concat(val);
+    }
+
+    return this.set(field, val);
+  },
+
+  /**
+   * Remove header `field`.
+   *
+   * @param {String} name
+   * @api public
+   */
+
+  remove(field) {
+    if (this.headerSent) return;
+
+    this.res.removeHeader(field);
+  },
+
+  /**
+   * Checks if the request is writable.
+   * Tests for the existence of the socket
+   * as node sometimes does not set it.
+   *
+   * @return {Boolean}
+   * @api private
+   */
+
+  get writable() {
+    // can't write any more after response finished
+    // response.writableEnded is available since Node > 12.9
+    // https://nodejs.org/api/http.html#http_response_writableended
+    // response.finished is undocumented feature of previous Node versions
+    // https://stackoverflow.com/questions/16254385/undocumented-response-finished-in-node-js
+    if (this.res.writableEnded || this.res.finished) return false;
+
+    const socket = this.res.socket;
+    // There are already pending outgoing res, but still writable
+    // https://github.com/nodejs/node/blob/v4.4.7/lib/_http_server.js#L486
+    if (!socket) return true;
+    return socket.writable;
+  },
+
+  /**
+   * Inspect implementation.
+   *
+   * @return {Object}
+   * @api public
+   */
+
+  inspect() {
+    if (!this.res) return;
+    const o = this.toJSON();
+    o.body = this.body;
+    return o;
+  },
+
+  /**
+   * Return JSON representation.
+   *
+   * @return {Object}
+   * @api public
+   */
+
+  toJSON() {
+    return only(this, [
+      'status',
+      'message',
+      'header'
+    ]);
+  },
+
+  /**
+   * Flush any set headers and begin the body
+   */
+
+  flushHeaders() {
+    this.res.flushHeaders();
+  }
+};
+
+/**
+ * Custom inspection implementation for node 6+.
+ *
+ * @return {Object}
+ * @api public
+ */
+
+/* istanbul ignore else */
+if (util.inspect.custom) {
+  module.exports[util.inspect.custom] = module.exports.inspect;
+}