Official Go implementation of the Ethereum protocol
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go-ethereum/docs/_doc/URL-Scheme.md

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---
title: URL Scheme
---
# URLs in DAPP browsers
URLs should contain all allowable urls in browsers and _all_ `http(s)` urls that resolve in a usual browser must resolve the same way.
All urls not conforming to the existing urls scheme must still resemble the current urls scheme.
```
<protocol>://<source>/<path>
```
Irrespective of the main protocol, `<source>` should be resolved with our version of DNS (`NameReg` (ename registration contract on ethereum) and/or via swarm signed version stream.
In the special case of the bzz protocol, `<source>` must resolve to a Swarm hash of the content (in other words, the root key of the content). This content is assumed to be of mime type `application/bzz-sitemap+json` the only mime-type directly handled by Swarm.
# Swarm manifests
A Swarm manifest is a json formatted description of url routing.
The swarm manifest allows swarm documents to act as file systems or webservers.
Their mime type is `application/bzz-sitemap+json`
Manifest has the following attributes:
- `entries`: an array of route configurations
- `host`: eth host name registered (or to register) with NameReg
- `number`: position index (increasing integers) of manifest within channel,
- `auth`: devp2p cryptohandshake public key(s), signed number
- `first`: root key of initial state of the stream
- `previous`: previous state of stream
A route descriptor manifest entry json object has the following attributes:
- `path`: a path relative to the url that resolved to the manifest (_optional, with empty default_)
- `hash`: key of the content to be looked up by swarm (_optional_)
- `link`: relative path or external link (_optional_)
- `contentType`: mime type of the content (_optional, `application/bzz-server` by default_)
- `status`: optional http status code to pass back to the server (_optional, 200 by default_)
- `cache`: cache entry, etag? and other header options (_optional_)
- `www`: alternative old web address that the route replicates: e.g., `http://eth:bzz@google.com` (_optional_)
If `path` is an empty string or is missing, the path matches the _document-root_ of the DAPP.
If `contentType` is empty or missing, manifest if assumed by default.
(NOTE: Unclear. When no path matches and there is no fallback path e.g. a root `/` path with hash specified, it should return a simple 404 status code)
# Url resolution
Given
```
bzz://<source>/<path>
```
in the browser, the following steps need to happen:
- the browser sees that its bzz protocol `<source>/<path>` is passed to the *bzz protocol handler*,
- the handler checks if `<source>` is a hash. If not it resolves to a hash via NameReg and signed version table, see below
- the bzz protocol handler first retrieves the content for the hash (with integrity check) which it interprets as a manifest file (`application/bzz-sitemap+json`),
- this manifest file is then parsed, read and the json array element with the longest prefix `p` of `<path>` is looked up. I.e., `p` is the longest prefix such that `<path> == p'/p''`. (If the longest prefix is 0 length, the row with `<path> == ""` (or left out) is chosen.)
- as a special case, trailing forward slashes are ignored so all variants will match the directory,
- the protocol then looks up content for `p'` and serves it to the browser together with the status code and content type.
- if content is of type manifest, bzz retrieves it and repeats the steps using `p''` to match the manifest's `<path>` values against,
- the url relative path is set to `p''`
- if the url looked up is an old-world http site, then a standard http client call is sufficient.
### Example 1
```js
{
entries: [
{
"path": "cv.pdf",
"contentType": "document/pdf",
"hash": "sdfhsd76ftsd86ft76sdgf78h7tg",
}
]
}
```
where the hash is the hash of the actual file `cv.pdf`.
If this manifest hashes to `dafghjfgsdgfjfgsdjfgsd`, then `bzz://dafghjfgsdgfjfgsdjfgsd/cv.pdf` will serve `cv.pdf`
Now you can register the manifest hash with NameReg to resolve `my-website` the file as follows:
```
http://my-website/cv.pdf
```
serves `cv.pdf`
### Example 2
Imagine you have a DAPP called _chat_ and host it under
your local directory `<dir>` looks like this:
```
index.html
img/logo.gif
img/avatars/fefe.jpg
img/avatars/index.html
```
the webserver has the following routing rules:
```
-> <dir>/index.html
<unkwown> -> <dir>/index.html # where <unknown> != index.html
img/logo.gif -> <dir>/img/logo.gif
img/avatars -> <dir>img/avatars/index.html
img/avatars/fefe.jpg -> <dir>/img/avatars/fefe.jpg
img/avatars/<unknown>.jpg <dir>/img/avatars/index.html # where <unknown> != fefe.jpg
```
Now you can alternatively host your app in Swarm by creating the following manifest:
```js
{
"entries": [
{ "hash": HASH(<dir>/index.html) },
{ "path": "index.html", "hash": HASH(<dir>/index.html) },
{ "path": "img/logo.gif", "hash": HASH(<dir>/img/logo.gif) },
{ "path": "img/avatars/", "hash": HASH(<dir>/img/avatars/index.html) },
{ "path": "img/avatars/fefe.jpg", "hash": HASH(img/avatars/fefe.jpg) }
]
}
```
# Swarm webservers
Swarm webservers are simply bzz site manifest files routing relative paths to static assets.
Manifest route entries specify metadata: http header values, etag, redirects, links, etc.
In a typical scenario, the developer has a website within a working copy directory on their dev environment and they want to create a decentralised version of their site.
They then register the host domain with ethereum NameReg or swarm signed version stream, upload all desired static assets to swarm, and produce a site manifest.
In order to facilitate the creation of the manifest file for existing web projects, a native API and a command line utility are provided to automatically generate manifest files from a directory.
## ArcHive API
A native API and a command line utility are provided to automatically swarmify document collections.
constructor parameters:
- `template`: manifest template: the entries found in the directory scan are merged into this template to yield the resulting site-map. Note that this template can be considered a config file to the archiver.
The archiver can be called multiple times scanning multiple directories.
runtime parameters:
- `path`: path to directory relative routes in the template matched against directory paths under `path` (_optional_, '.' by default).
- `not-found`: errorchange to be used when asset is not found: for 404, (_optional_, `index.html`)
- `register-names` use eth NameReg to register public key and this version is pushed to swarm mutable store (_optional_, _false_)
- `without-scan` only consider paths given in template (_optional_, by default _false_: in template, scan directory and add/merge all readable content to manifest)
- `without-upload`: files are not uploaded, only hashes are calculated and manifest is created (_optional_, _false_, upload every asset to swarm)
If both `without-scan` and `without-upload` are omitted then `path` is used to associate files, extend the manifest entries, and upload content.
if `register-names` is set all named nodes.
### Examples
```js
{
"entries": [
{
"path": "chat",
"hash": "sdfhsd76ftsd86ft76sdgf78h7tg",
"status": 200,
"contentType": "document/pdf"
},
...
]
}
```
## Without swarm, the zip fallback
namereg resolution:
`contentOf('eth/wallet') -> 324234kj23h4kj2h3kj423kj4h23`
This name reg has also a `urlOf` where it can find the file (e.g. from a raw pastebin)
It then downloads the file, extracts it and resolves all relative/absolute paths, based on the manifest it finds in it.
For the developer, the upload mechanism in mix will be the same, as he chooses a folder and can provide a `serverconfig.json` (or manfiest)
The only difference is the lookup and where it gets the files from.
```
swarm -> content hashes
before swarm -> zip file content
```
And both are resolved through the same manifest scheme
## Server config examples:
URL: bzz://dsf32f3cdsfsd/somefolder/other
Same as: eth://myname.reggae/somefolder/other
We should also map folder with and without "/" so that the path lookup for path: "/something/myfolder" is the same as "/something/myfolder/"
```js
{
previous: 'jgjgj67576576576567ytjy',
first: 'ds564rh5656hhfghfg',
entries:[{
// Custom error page
path: '/i18n/',
file: '/errorpages/404.html',
// parses "file" when processing the folder and add: hash: '7685trgdrreewr34f34', contentType: 'text/html'
status: 404
},{
// custom fallback file for this folder: "/images/sdffsdfds/"
path: '/images/sdffsdfds/',
file: '/index.html',
// parses "file" when processing the folder and add: hash: '345678678678678678tryrty', contentType: 'text/html'
},{
// custom fallback file with custom header.
path: '/',
file: '/index.html',
// parses "file" when processing the folder and add: hash: '434534534f34k234234hrkj34hkjrh34', contentType: 'text/html'
status: 500
},{
// redirect (changing url after?)
path: '/somefolder/',
redirect: 'http://google.com'
},{
// linking?
path: '/somefolder/other/',
link: 'bzz://43greg45gerg5t45gerge/chat/' // hash to another manifest
},{
// downloading a file by pointing to a folder
path: '/somefolder/other/',
file: '/mybook.pdf',
// parses "file" when processing the folder and add: hash: '645325ytrhfgdge4tgre43f34', BUT no contentType, as its already present
contentType: 'application/octet-stream' // trigger a download in the browser for this link)
},{
// downloading
path: '/test.html',
file: '/test.html',
// parses "file" when processing the folder and add: hash: '645325ytrhfgdge4tgre43f34', BUT no contentType, as its already present
contentType: 'application/octet-stream' // trigger a download in the browser for this link)
// automatic generated files
},{
path: '/i18n/app.en.json',
hash: '456yrtgfds43534t45',
contentType: 'text/json',
},{
path: '/somefolder/other/image.png',
hash: '434534534f34khrkj34hkjrh34',
contentType: 'image/png',
},{
path: '/somefolder/other/343242.png',
hash: '434534534f34k234234hrkj34hkjrh34',
contentType: 'image/png',
},{
path: '/somefold/frau.png',
hash: 'sdfsdfsdfsdfsdfsdfsd',
contentType: 'image/png',
}]
}
```