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v/vlib/vweb/README.md
2023-03-26 00:57:42 +01:00

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# vweb - the V Web Server
A simple yet powerful web server with built-in routing, parameter handling, templating, and other
features.
The [gitly](https://gitly.org/) site is based on vweb.
**_Some features may not be complete, and have some bugs._**
## Getting start
Just run **`v new <name> web`** in your terminal
## Features
- **Very fast** performance of C on the web.
- **Small binary** hello world website is <100 KB.
- **Easy to deploy** just one binary file that also includes all templates. No need to install any
dependencies.
- **Templates are precompiled** all errors are visible at compilation time, not at runtime.
### Examples
There are some examples
that can be explored [here](https://github.com/vlang/v/tree/master/examples/vweb).
And others like:
- [vweb_orm_jwt](https://github.com/vlang/v/tree/master/examples/vweb_orm_jwt) (back-end)
- [vorum](https://github.com/vlang/vorum) (front-end)
- [gitly](https://github.com/vlang/gitly) (full-stack)
**Front-end getting start example**
`src/main.v`
```v ignore
module main
import vweb
import os
struct App {
vweb.Context
}
struct Object {
title string
description string
}
fn main() {
vweb.run_at(new_app(), vweb.RunParams{
port: 8081
}) or { panic(err) }
}
fn new_app() &App {
mut app := &App{}
// makes all static files available.
app.mount_static_folder_at(os.resource_abs_path('.'), '/')
return app
}
['/']
pub fn (mut app App) page_home() vweb.Result {
// all this constants can be accessed by src/templates/page/home.html file.
page_title := 'V is the new V'
v_url := 'https://github.com/vlang/v'
list_of_object := [
Object{
title: 'One good title'
description: 'this is the first'
},
Object{
title: 'Other good title'
description: 'more one'
},
]
// $vweb.html() in `<folder>_<name> vweb.Result ()` like this
// render the `<name>.html` in folder `./templates/<folder>`
return $vweb.html()
}
```
`$vweb.html()` compiles an HTML template into V during compilation, and embeds the resulting code
into the current action.
That means that the template automatically has access to that action's entire environment.
`src/templates/page/home.html`
```html
<html>
<header>
<title>${page_title}</title>
@css 'src/templates/page/home.css'
</header>
<body>
<h1 class="title">Hello, Vs.</h1>
@for var in list_of_object
<div>
<a href="${v_url}">${var.title}</a>
<span>${var.description}</span>
</div>
@end
<div>@include 'component.html'</div>
</body>
</html>
```
`src/templates/page/component.html`
```html
<div>This is a component</div>
```
`src/templates/page/home.css`
```css
h1.title {
font-family: Arial, Helvetica, sans-serif;
color: #3b7bbf;
}
```
V supports [Template directives](/vlib/v/TEMPLATES.md) like
`@css`, `@js` for static files in \<path\>
`@if`, `@for` for conditional and loop
and
`@include` to include html components.
## Deploying vweb apps
Everything, including HTML templates, is in one binary file. That's all you need to deploy.
## Getting Started
To start with vweb, you have to import the module `vweb` and define a struct to hold vweb.Context
(and any other variables your program will need).
The web server can be started by calling `vweb.run(&App{}, port)` or `vweb.run(&App{}, RunParams)`
**Example:**
```v ignore
import vweb
struct App {
vweb.Context
}
fn main() {
vweb.run(&App{}, 8080)
// // or
// vweb.run_at(new_app(), vweb.RunParams{
// host: 'localhost'
// port: 8099
// family: .ip
// }) or { panic(err) }
}
```
### Defining endpoints
To add endpoints to your web server, you have to extend the `App` struct.
For routing you can either use auto-mapping of function names or specify the path as an attribute.
The function expects a response of the type `vweb.Result`.
**Example:**
```v ignore
// This endpoint can be accessed via http://localhost:port/hello
fn (mut app App) hello() vweb.Result {
return app.text('Hello')
}
// This endpoint can be accessed via http://localhost:port/foo
["/foo"]
fn (mut app App) world() vweb.Result {
return app.text('World')
}
```
#### - HTTP verbs
To use any HTTP verbs (or methods, as they are properly called),
such as `[post]`, `[get]`, `[put]`, `[patch]` or `[delete]`
you can simply add the attribute before the function definition.
**Example:**
```v ignore
[post]
fn (mut app App) world() vweb.Result {
return app.text('World')
}
['/product/create'; post]
fn (mut app App) create_product() vweb.Result {
return app.text('product')
}
```
#### - Parameters
Parameters are passed directly in endpoint route using colon sign `:` and received using the same
name at function
To pass a parameter to an endpoint, you simply define it inside an attribute, e. g.
`['/hello/:user]`.
After it is defined in the attribute, you have to add it as a function parameter.
**Example:**
```v ignore
vvvv
['/hello/:user'] vvvv
fn (mut app App) hello_user(user string) vweb.Result {
return app.text('Hello $user')
}
```
You have access to the raw request data such as headers
or the request body by accessing `app` (which is `vweb.Context`).
If you want to read the request body, you can do that by calling `app.req.data`.
To read the request headers, you just call `app.req.header` and access the
header you want example. `app.req.header.get(.content_type)`. See `struct Header`
for all available methods (`v doc net.http Header`).
It has, too, fields for the `query`, `form`, `files`.
#### - Query
To handle the query context, you just need use the `query` field
**Example:**
```v
module main
import vweb
struct App {
vweb.Context
}
fn main() {
vweb.run(&App{}, 8081)
}
['/user'; get]
pub fn (mut app App) controller_get_user_by_id() vweb.Result {
// http://localhost:3000/user?q=vpm&order_by=desc => { 'q': 'vpm', 'order_by': 'desc' }
return app.text(app.query.str())
}
```
### Middleware
Vweb has different kinds of middleware.
The `before_request()` method is always called before every request before any
other middleware is processed. You could use it to check user session cookies or to add a header.
**Example:**
```v ignore
pub fn (mut app App) before_request() {
app.user_id = app.get_cookie('id') or { '0' }
}
```
Middleware functions can be passed directly when creating an App instance and is
executed when the url starts with the defined key.
In the following example, if a user navigates to `/path/to/test` the middleware
is executed in the following order: `middleware_func`, `other_func`, `global_middleware`.
The middleware is executed in the same order as they are defined and if any function in
the chain returns `false` the propogation is stopped.
**Example:**
```v
module main
import vweb
struct App {
vweb.Context
middlewares map[string][]vweb.Middleware
}
fn new_app() &App {
mut app := &App{
middlewares: {
// chaining is allowed, middleware will be evaluated in order
'/path/to/': [middleware_func, other_func]
'/': [global_middleware]
}
}
// do stuff with app
// ...
return app
}
fn middleware_func(mut ctx vweb.Context) bool {
// ...
return true
}
fn other_func(mut ctx vweb.Context) bool {
// ...
return true
}
fn global_middleware(mut ctx vweb.Context) bool {
// ...
return true
}
```
Middleware functions will be of type `vweb.Middleware` and are not methods of App,
so they could also be imported from other modules.
```v ignore
pub type Middleware = fn (mut Context) bool
```
Middleware can also be added to route specific functions via attributes.
**Example:**
```v ignore
[middleware: check_auth]
['/admin/data']
pub fn (mut app App) admin() vweb.Result {
// ...
}
// check_auth is a method of App, so we don't need to pass the context as parameter.
pub fn (mut app App) check_auth () bool {
// ...
return true
}
```
For now you can only add 1 middleware to a route specific function via attributes.
### Redirect
Used when you want be redirected to an url
**Examples:**
```v ignore
pub fn (mut app App) before_request() {
app.user_id = app.get_cookie('id') or { app.redirect('/') }
}
```
```v ignore
['/articles'; get]
pub fn (mut app App) articles() vweb.Result {
if !app.token {
app.redirect('/login')
}
return app.text('patatoes')
}
```
You can also combine middleware and redirect.
**Example:**
```v ignore
[middleware: with_auth]
['/admin/secret']
pub fn (mut app App) admin_secret() vweb.Result {
// this code should never be reached
return app.text('secret')
}
['/redirect']
pub fn (mut app App) with_auth() bool {
app.redirect('/auth/login')
return false
}
```
### Responses
#### - set_status
Sets the response status
**Example:**
```v ignore
['/user/get_all'; get]
pub fn (mut app App) controller_get_all_user() vweb.Result {
token := app.get_header('token')
if !token {
app.set_status(401, '')
return app.text('Not valid token')
}
response := app.service_get_all_user() or {
app.set_status(400, '')
return app.text('$err')
}
return app.json(response)
}
```
#### - html
Response HTTP_OK with payload with content-type `text/html`
**Example:**
```v ignore
pub fn (mut app App) html_page() vweb.Result {
return app.html('<h1>ok</h1>')
}
```
#### - text
Response HTTP_OK with payload with content-type `text/plain`
**Example:**
```v ignore
pub fn (mut app App) simple() vweb.Result {
return app.text('A simple result')
}
```
#### - json
Response HTTP_OK with payload with content-type `application/json`
**Examples:**
```v ignore
['/articles'; get]
pub fn (mut app App) articles() vweb.Result {
articles := app.find_all_articles()
json_result := json.encode(articles)
return app.json(json_result)
}
```
```v ignore
['/user/create'; post]
pub fn (mut app App) controller_create_user() vweb.Result {
body := json.decode(User, app.req.data) or {
app.set_status(400, '')
return app.text('Failed to decode json, error: $err')
}
response := app.service_add_user(body.username, body.password) or {
app.set_status(400, '')
return app.text('error: $err')
}
return app.json(response)
}
```
#### - json_pretty
Response HTTP_OK with a pretty-printed JSON result
**Example:**
```v ignore
fn (mut app App) time_json_pretty() {
app.json_pretty({
'time': time.now().format()
})
}
```
#### - file
Response HTTP_OK with file as payload
#### - ok
Response HTTP_OK with payload
**Example:**
```v ignore
['/form_echo'; post]
pub fn (mut app App) form_echo() vweb.Result {
app.set_content_type(app.req.header.get(.content_type) or { '' })
return app.ok(app.form['foo'])
}
```
#### - server_error
Response a server error
**Example:**
```v ignore
fn (mut app App) sse() vweb.Result {
return app.server_error(501)
}
```
#### - not_found
Response HTTP_NOT_FOUND with payload
**Example:**
```v ignore
['/:user/:repo/settings']
pub fn (mut app App) user_repo_settings(username string, repository string) vweb.Result {
if username !in known_users {
return app.not_found()
}
return app.html('username: $username | repository: $repository')
}
```
### Requests
#### - get_header
Returns the header data from the key
**Example:**
```v ignore
['/user/get_all'; get]
pub fn (mut app App) controller_get_all_user() vweb.Result {
token := app.get_header('token')
return app.text(token)
}
```
#### - get_cookie
Sets a cookie
**Example:**
```v ignore
pub fn (mut app App) before_request() {
app.user_id = app.get_cookie('id') or { '0' }
}
```
#### - add_header
Adds an header to the response with key and val
**Example:**
```v ignore
['/upload'; post]
pub fn (mut app App) upload() vweb.Result {
fdata := app.files['upfile']
data_rows := fdata[0].data.split('\n')
mut output_data := ''
for elem in data_rows {
delim_row := elem.split('\t')
output_data += '${delim_row[0]}\t${delim_row[1]}\t'
output_data += '${delim_row[0].int() + delim_row[1].int()}\n'
}
output_data = output_data.all_before_last('\n')
app.add_header('Content-Disposition', 'attachment; filename=results.txt')
app.send_response_to_client('application/octet-stream', output_data)
return $vweb.html()
}
```
#### - set_cookie
Sets a cookie
**Example:**
```v ignore
pub fn (mut app App) cookie() vweb.Result {
app.set_cookie(name: 'cookie', value: 'test')
return app.text('Response Headers\n$app.header')
}
```
#### - set_cookie_with_expire_date
Sets a cookie with a `expire_data`
**Example:**
```v ignore
pub fn (mut app App) cookie() vweb.Result {
key := 'cookie'
value := 'test'
duration := time.Duration(2 * time.minute ) // add 2 minutes
expire_date := time.now().add(duration)
app.set_cookie_with_expire_date(key, value, expire_date)
return app.text('Response Headers\n$app.header')
}
```
#### - set_content_type
Sets the response content type
**Example:**
```v ignore
['/form_echo'; post]
pub fn (mut app App) form_echo() vweb.Result {
app.set_content_type(app.req.header.get(.content_type) or { '' })
return app.ok(app.form['foo'])
}
```
### Template
#### -handle_static
handle_static is used to mark a folder (relative to the current working folder) as one that
contains only static resources (css files, images etc).
If `root` is set the mount path for the dir will be in '/'
**Example:**
```v ignore
fn main() {
mut app := &App{}
app.serve_static('/favicon.ico', 'favicon.ico')
// Automatically make available known static mime types found in given directory.
os.chdir(os.dir(os.executable()))?
app.handle_static('assets', true)
vweb.run(app, port)
}
```
#### -mount_static_folder_at
makes all static files in `directory_path` and inside it, available at http://server/mount_path.
For example: suppose you have called .mount_static_folder_at('/var/share/myassets', '/assets'),
and you have a file /var/share/myassets/main.css .
=> That file will be available at URL: http://server/assets/main.css .
#### -serve_static
Serves a file static.
`url` is the access path on the site, `file_path` is the real path to the file, `mime_type` is the
file type
**Example:**
```v ignore
fn main() {
mut app := &App{}
app.serve_static('/favicon.ico', 'favicon.ico')
app.mount_static_folder_at(os.resource_abs_path('.'), '/')
vweb.run(app, 8081)
}
```
### Others
#### -ip
Returns the ip address from the current user
**Example:**
```v ignore
pub fn (mut app App) ip() vweb.Result {
ip := app.ip()
return app.text('ip: $ip')
}
```
#### -error
Set a string to the form error
**Example:**
```v ignore
pub fn (mut app App) error() vweb.Result {
app.error('here as an error')
println(app.form_error) //'vweb error: here as an error'
}
```
# Cross-Site Request Forgery (CSRF) protection
## Provides protection against Cross-Site Request Forgery
## Usage
When building a csrf-protected service, first of all create a `struct`that implements `csrf.App`
```v ignore
module main
import vweb
import vweb.csrf
// embeds the csrf.App struct in order to empower the struct to protect against CSRF
struct App {
csrf.App
}
```
Start a server e.g. in the main function.
```v ignore
fn main() {
vweb.run_at(&App{}, vweb.RunParams{
port: 8080
}) or { panic(err) }
}
```
### Enable CSRF-protection
Then add a handler-function to define on which route or on which site the CSRF-Token shall be set.
```v ignore
fn (mut app App) index() vweb.Result {
// Set a Csrf-Cookie (Token will be generated automatically)
app.set_csrf_cookie()
// Get the token-value from the csrf-cookie that was just set
token := app.get_csrf_token() or { panic(err) }
return app.text("Csrf-Token set! It's value is: $token")
}
```
If you want to set the cookies's HttpOnly-status to false in order to make it
accessible to scripts on your site, you can do it like this:
`app.set_csrf_cookie(csrf.HttpOnly{false})`
If no argument is passed the value will be set to true by default.
### Protect against CSRF
If you want to protect a route or a site against CSRF just add
`app.csrf_protect()` at the beginning of the handler-function.
```v ignore
fn (mut app App) foo() vweb.Result {
// Protect this handler-function against CSRF
app.csrf_protect()
return app.text("Checked and passed csrf-guard")
}
```