160 lines
4.9 KiB
Markdown
160 lines
4.9 KiB
Markdown
<h1 align="center">connect-history-api-fallback</h1>
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<p align="center">Middleware to proxy requests through a specified index page, useful for Single Page Applications that utilise the HTML5 History API.</p>
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<h2>Table of Contents</h2>
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<!-- TOC depthFrom:2 depthTo:6 withLinks:1 updateOnSave:1 orderedList:0 -->
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- [Introduction](#introduction)
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- [Usage](#usage)
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- [Options](#options)
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- [index](#index)
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- [rewrites](#rewrites)
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- [verbose](#verbose)
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- [htmlAcceptHeaders](#htmlacceptheaders)
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- [disableDotRule](#disabledotrule)
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<!-- /TOC -->
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## Introduction
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Single Page Applications (SPA) typically only utilise one index file that is
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accessible by web browsers: usually `index.html`. Navigation in the application
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is then commonly handled using JavaScript with the help of the
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[HTML5 History API](http://www.w3.org/html/wg/drafts/html/master/single-page.html#the-history-interface).
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This results in issues when the user hits the refresh button or is directly
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accessing a page other than the landing page, e.g. `/help` or `/help/online`
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as the web server bypasses the index file to locate the file at this location.
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As your application is a SPA, the web server will fail trying to retrieve the file and return a *404 - Not Found*
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message to the user.
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This tiny middleware addresses some of the issues. Specifically, it will change
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the requested location to the index you specify (default being `/index.html`)
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whenever there is a request which fulfills the following criteria:
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1. The request is a `GET` or `HEAD` request
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2. which accepts `text/html`,
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3. is not a direct file request, i.e. the requested path does not contain a
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`.` (DOT) character and
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4. does not match a pattern provided in options.rewrites (see options below)
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## Usage
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The middleware is available through NPM and can easily be added.
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```
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npm install --save connect-history-api-fallback
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```
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Import the library
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```javascript
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var history = require('connect-history-api-fallback');
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```
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Now you only need to add the middleware to your application like so
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```javascript
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var connect = require('connect');
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var app = connect()
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.use(history())
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.listen(3000);
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```
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Of course you can also use this piece of middleware with express:
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```javascript
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var express = require('express');
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var app = express();
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app.use(history());
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```
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## Options
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You can optionally pass options to the library when obtaining the middleware
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```javascript
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var middleware = history({});
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```
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### index
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Override the index (default `/index.html`). This is the request path that will be used when the middleware identifies that the request path needs to be rewritten.
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This is not the path to a file on disk. Instead it is the HTTP request path. Downstream connect/express middleware is responsible to turn this rewritten HTTP request path into actual responses, e.g. by reading a file from disk.
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```javascript
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history({
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index: '/default.html'
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});
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```
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### rewrites
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Override the index when the request url matches a regex pattern. You can either rewrite to a static string or use a function to transform the incoming request.
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The following will rewrite a request that matches the `/\/soccer/` pattern to `/soccer.html`.
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```javascript
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history({
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rewrites: [
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{ from: /\/soccer/, to: '/soccer.html'}
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]
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});
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```
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Alternatively functions can be used to have more control over the rewrite process. For instance, the following listing shows how requests to `/libs/jquery/jquery.1.12.0.min.js` and the like can be routed to `./bower_components/libs/jquery/jquery.1.12.0.min.js`. You can also make use of this if you have an API version in the URL path.
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```javascript
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history({
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rewrites: [
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{
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from: /^\/libs\/.*$/,
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to: function(context) {
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return '/bower_components' + context.parsedUrl.pathname;
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}
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}
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]
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});
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```
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The function will always be called with a context object that has the following properties:
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- **parsedUrl**: Information about the URL as provided by the [URL module's](https://nodejs.org/api/url.html#url_url_parse_urlstr_parsequerystring_slashesdenotehost) `url.parse`.
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- **match**: An Array of matched results as provided by `String.match(...)`.
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- **request**: The HTTP request object.
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### verbose
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This middleware does not log any information by default. If you wish to activate logging, then you can do so via the `verbose` option or by specifying a logger function.
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```javascript
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history({
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verbose: true
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});
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```
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Alternatively use your own logger
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```javascript
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history({
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logger: console.log.bind(console)
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});
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```
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### htmlAcceptHeaders
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Override the default `Accepts:` headers that are queried when matching HTML content requests (Default: `['text/html', '*/*']`).
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```javascript
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history({
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htmlAcceptHeaders: ['text/html', 'application/xhtml+xml']
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})
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```
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### disableDotRule
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Disables the dot rule mentioned above:
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> […] is not a direct file request, i.e. the requested path does not contain a `.` (DOT) character […]
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```javascript
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history({
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disableDotRule: true
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})
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```
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