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1---
2navhome: /docs
3next: true
4sort: 7
5title: Web
6---
8# Web
10<div class="row">
11<div class="col-md-8">
13Your Urbit runs its own webserver, `%eyre`, that handles all things HTTP. Here we'll cover the features of `%eyre` that most resemble a traditional web server.
15By default `%eyre` uses Tree, which is sort of like a combination of [Jekyll](https://jekyllrb.com/) or [Kirby](https://getkirby.com/) and Finder on OSX. Tree is a simple ui for browsing the contents of the filesystem, statically publishing a blog or any kind of content and for running single-page apps.
17Tree was built primarily to display both our documentation and the contents of `urbit.org`. We provide a few simple examples [here](#-examples) of how to publish using Tree. If you're interested in doing anything complex it's worth checking out the [docs source](https://github.com/urbit/docs) and the [urbit.org](https://github.com/urbit/urbit.org) source.
19We ship `tree` as compiled JavaScript on your Urbit, but the source lives in its own repo [here](https://github.com/urbit/tree).
21</div>
22</div>
24## Quickstart
26Your Urbit runs a web server and can be found at either `http://localhost:8080/` (or `8081` if you're running other processes that might be occupying `8080`, you can determine which port your urbit is on by looking at your boot sequence — it's specified there), or `http://your-urbit.urbit.org/`.
28<span class="red">
29(Make sure you have a desk mounted to unix, as covered in the
30[filesystem walkthrough](/docs/using/filesystem)).
31</span>
33To switch the desk you're serving from:
35 |serve %sandbox
37To host a file on the web try putting the following in `/home/web/test.md` (from Unix):
39 # Hello
41 This is a simple markdown file.
43Create the directory `/home/web/test/` and add two more markdown files in it.
45Now modify `/home/web/test.md` to list the children using the `<list/>` JSX:
47 # Hello
49 This is a simple markdown file.
51 <div><list /></div>
53To view your file as raw `md`:
55 http://localhost:8080/test.md
57To view your file as raw `html`:
59 http://localhost:8080/test.html
61You may have noticed that we just created both `test.md` and `test/`. In Urbit, there is no distinction between a directory and a file. So, if you're adding files directly from unix, simply `mkdir test` and Urbit will treat the file and directory as the same entity.
63You can use this feature to change your homepage at `your-urbit.urbit.org` with the page `/home/web.md`, where `home` is the current mounted desk. By default, `web.md` will display some info about your urbit, but you can customize it to your heart's content.
65## Examples
67We've created a few simple examples of how to get set up publishing content from your Urbit. Feel free to ask questions in the comments.
69<list/>
71## Manual
73## `/web`
75This is the equivalent of a `public_html` directory. Your Urbit looks in this directory to serve content to the world. You can change what desk you're serving from using `|serve`.
77Switch to the `%sandbox` desk:
79 |serve %sandbox
81Let's quickly step through the default contents of `web/`:
83- `404.hoon` - The default 404 page.
84- `dojo.hoon` - Page body that loads the `dojo` React module.
85- `lib/css/bootstrap.css` - The Urbit-flavored bootstrap
86- `lib/css/codemirror.css` - Syntax highlighting
87- `lib/css/fonts.css` - The Urbit custom fonts
88- `lib/js/hoon.js` - Hoon syntax highlighting
89- `lib/js/sole.js` - `dojo` operational transformation JS
90- `lib/js/urb.js` - Base Urbit JS library. Handles AJAX and polling.
91- `static.md` - Sample static file
92- `talk/` - Talk compiled JS / CSS
93- `talk.hoon` - Page body that loads the `talk` React module.
94- `tree/` - Tree compiled JS / CSS
95- `tree.hoon` - Page body that loads the `tree` React module.
97## Tree
99Tree is a simple publishing tool for files that live on your Urbit. You're probably reading this file using Tree right now. The main driving use-case for Tree has been for us to host our own documentation and the surrounding discussion. Tree remains a pretty simple and flexible tool for getting content online. We think it's pretty great.
101Tree is a simple static publishing tool and the basic UI for browsing the filesystem. We take it one step further and make it possible to write modules (tiny little apps), like Talk and Dojo, that can be run directly inside of Tree.
103In the browser Tree is a [React](https://facebook.github.io/react/) / [Flux](https://facebook.github.io/react/blog/2014/05/06/flux.html) app that uses a slightly modifed version of [Bootstrap](http://getbootstrap.com/). On your Urbit Tree is a renderer that translates data in `%clay`, our filesystem, into JSON / JSX that can be read by the client.
105Your Urbit comes with a pre-built copy of the tree (as a single `.js` file). If you're interested in helping to develop tree or learning about how it works, it has its own GitHub repo [here](https://github.com/urbit/tree). We have our own fork of Bootstrap, which lives [here](https://github.com/urbit/bootstrap).
107## `/web/pages`
109To render content without the Tree put it in `/web/pages`. Files in this directory aren't wrapped by Tree. For some examples check out [`web/` in the examples repo](https://github.com/urbit/examples/tree/master/web).
111## Publishing files
113Publishing files in Tree is simple. Try dropping a file in `/web` (as covered in the Quickstart) and navigating to it.
115The best example of more complicated usage of Tree is covered by the Urbit docs themselves. See anything while perusing the docs that you'd like to use yourself? The docs are all on GitHub [here](https://github.com/urbit/docs).
117## YAML
119We use [YAML](http://yaml.org/)-style frontmatter to do odds and ends like override the title. A YAML block looks something like this:
121```
122---
123next: true
124sort: 5
125title: Tree
126---
127```
129and appears at the top of a file. YAML values can't contain newlines but can contain spaces. Here are the fields we support:
131### `title`
133String. Example: `title: Tree manual`.
135This sets the title in the nav or in lists as distinct from the filename.
137### `next`
139Boolean. Example: `next: true`
141Adds a 'next' link at the bottom of the page that links to the next item as decided by the sort order.
143### `sort`
145Integer. Example: `sort: 7`
147User-defined sort. Indicates the sort order as distinct from alphabetical sort. These numbers should not be overlapping.
149### `hide`
151Boolean. Example: `hide: true`
153Whether or not to hide the item from the tree.
155### `date`
157Urbit date. Example: `~2016.2.22`
159Used for sorting posts by date.
161## Using components
163Tree is built using React with a small library of components that you can add to your pages using [JSX](https://facebook.github.io/jsx/) tags.
165If you don't know anything about JSX that's okay: basically we just give you a few custom HTML tags that you can use to create components on the page.
167For those familiar with React / Flux each JSX tag corresponds to a component in [the source](https://github.com/urbit/tree/tree/master/js/components).
169### `<list>`
171Example: `<list src="/posts" titlesOnly="true" />`
173Creates a list of children at a path. Defaults to the current path.
175Optional properties:
177- `src`: Path to load kids from.
178- `titlesOnly`: Only show the 'title' which is either the filename or the first h1.
179- `sortBy`: Can be `date` if items have a `date` YAML.
180- `className`: Class to be assigned to the container.
182### `<kids>`
184Example: `<kids src="/posts" />`
186Includes all the children at the specified path separated by `<hr>` tags.
188Optional properties:
190- `src`: Path to load kids from.
191- `className`: Class to be assigned to the container.
193### `<toc>`
195Example: `<toc noHeader="true" />`
197Creates a table of contents from the `h1` - `h6` tags on the page.
199Optional properties:
201- `match`: Tag name to match. If you wanted to only match `h2` tags it could be `match="h2"`
202- `noHeader`: By default we add a 'Table of Contents' header to the top. Remove it with `noHeader="true"`.
204## Implementation
206On the frontend Tree is mostly just a standard Flux app: components generate actions that get dispatched to stores which are picked up by components. If you're not familiar with Flux, [this overview](https://facebook.github.io/flux/docs/overview.html) is a good place to start.
208As a file browser Tree does a simple job: it fetches data and keeps a cache of what it has seen. To do this simple job we do three fancy things: `manx` to JSON encoding, the Async component and Modules.
210### `manx` to JSON format
212Since we want to use React to manage our DOM lifecycle we actually transfer the DOM structure of each page as JSON over the wire, and 'reactify' it on the client side.
214On the Urbit side we have a type for html: `++manx`. Our wire format for sending HTML as JSON is really similar to a `++manx`. If you're not interested here's what the json looks like:
216```
217"string" || {gn:"string", ga:{key:"string", [...]}, c:[...]}
218```
220To make this clearer let's look at some HTML and it's JSON representation:
222```
223<div class="blue">
224 <h1>Title</h1>
225</div>
226```
228```
229{gn:"div", ga:{className:"blue"}, [
230 {gn:"h1", ga:null, "Title"}
231]}
232```
234To see the mechanics of how this is handled on the frontend, checkout `components/Reactify.coffee` in the `urbit/tree` repo.
236### Async component
238Each of our components (even those we fetched from the server) can depend on data that may not exist in our stores, so we wrap our components in a general-purpose Async component. You can find the component in `components/Async.coffee` in the `urbit/tree` repo.
240When we say that we just fetch HTML as JSON it's actually slightly more complicated. When we fetch a node in the filesystem we might not want to fetch its entire contents. Sometimes we just get the title as a part of a list of children, sometimes we might get a snippet (in a list with previews), and sometimes we get the whole thing. On the Urbit side these results are provided by `ren/tree/json`.
242From the perspective of the frontend we just send queries on a path that obey a simple API. To see this in action, here's our `BodyComponent`:
244```
245query {
246 body:'r'
247 name:'t'
248 path:'t'
249 meta:'j'
250 sein:'t'
252```
254Here we're asking for the body, name, path, metadata and parent of the current path. When it loads that data gets passed to our component as props.
256### Module basics
258A module is a special component that can kind of 'take over' the page. It can change properties of the nav bar as well as load custom scripts / css.
260Talk, for example, looks like this:
262```
263<module nav_title="Talk" nav_no-dpad="" nav_no-sibs="" nav_subnav="talk-station">
264 <script src="/~~/~/at/lib/js/urb.js" />
265 <script src="/talk/main.js" />
266 <link href="/talk/main.css" rel="stylesheet" />
267 <talk />
268</module>
269```
271A module will first download all the scripts and styles that it specifies before trying to load any contained components. This means that you can define React components in external scripts and a module can be entirely self contained. The `<talk>` component isn't a part of Tree — it's loaded first before it's executed.
273If you're interested in seeing how a module works you can check out the source for Talk [here](https://github.com/urbit/talk). Dojo also ships on your Urbit, its source is [here](https://github.com/urbit/sole).
275## `urb.js`
277The most basic interface between your browser and your Urbit is `urb.js`. This small library provides the basic utilities for sending and receiving messages from an Urbit.
279### `window.urb.appl`
281Each JSON message sent to your Urbit needs an app endpoint. Can be set as a global `window.urb.appl` or set on a per-request basis in the payload to `send()`.
283### `window.urb.oryx`
285CSRF token. Written to the page by `%eyre`, our webserver, when logged in. Required part of any authenticated request and included by default.
287### `window.urb.req(method,url,params,json,cb)`
289Our basic request wrapper. You can see here how a request needs to be packaged to be properly understood by your Urbit.
291### `window.urb.subscribe({path:"string"})`
293Subscribe to an endpoint. Subscription data is returned through the continuous long poll.
295### `window.urb.unsubscribe({path:"string"})`
297Close subscription on specified path.
299### `window.urb.poll()`
301Mechanics of the continuous long poll. Used mostly internally.
303### `window.urb.util`
305Library of utility and helper functions.