12 KiB
vweb - the V Web Server
A simple yet powerful web server with built-in routing, parameter handling, templating, and other features. The gitly site is based on vweb.
Some features may not be complete, and have some bugs.
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.
And others like:
- vweb_orm_jwt (back-end)
- vorum (front-end)
- gitly (full-stack)
Front-end getting start example
src/main.v
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()
}
$vweb.html() compiles an HTML template into V during compilation, and embeds the resulting code
into the current action.
That means that the template automatically has access to that action's entire environment.
src/templates/page/home.html
<html>
<header>
<title>${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
<div>This is a component</div>
src/templates/page/home.css
h1.title {
font-family: Arial, Helvetica, sans-serif;
color: #3b7bbf;
}
V suport some Template directives 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:
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:
// 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:
[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 direcly 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:
vvvv
['/hello/:user'] vvvv
fn (mut app App) hello_user(user string) vweb.Result {
return app.text('Hello $user')
}
You have access to the raw request data such as headers
or the request body by accessing app (which is vweb.Context).
If you want to read the request body, you can do that by calling app.req.data.
To read the request headers, you just call app.req.header and access the
header you want, e.g. app.req.header.get(.content_type). See struct Header
for all available methods (v doc net.http Header).
Middleware
V haven't a well defined middleware.
For now, you can use before_request(). This method called before every request.
Probably you can use it for check user session cookie or add header
Example:
pub fn (mut app App) before_request() {
app.user_id = app.get_cookie('id') or { '0' }
}
Redirect
Used when you want be redirected to an url Examples:
pub fn (mut app App) before_request() {
app.user_id = app.get_cookie('id') or { app.redirect('/') }
}
['/articles'; get]
pub fn (mut app App) articles() vweb.Result {
if !app.token {
app.redirect('/login')
}
return app.text("patatoes")
}
Responses
- set_status
Sets the response status Example:
['/user/get_all'; get]
pub fn (mut app App) controller_get_all_user() vweb.Result {
token := app.get_header('token')
if !token {
app.set_status(401, '')
return app.text('Not valid token')
}
response := app.service_get_all_user() or {
app.set_status(400, '')
return app.text('$err')
}
return app.json(response)
}
- html
Response HTTP_OK with payload with content-type text/html
Example:
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:
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:
['/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)
}
['/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:
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:
['/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:
fn (mut app App) sse() vweb.Result {
return app.server_error(501)
}
- not_found
Response HTTP_NOT_FOUND with payload Example:
['/: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: $repository')
}
Requests
- get_header
Returns the header data from the key Example:
['/user/get_all'; get]
pub fn (mut app App) controller_get_all_user() vweb.Result {
token := app.get_header('token')
return app.text(token)
}
- get_cookie
Sets a cookie Example:
pub fn (mut app App) before_request() {
app.user_id = app.get_cookie('id') or { '0' }
}
- add_header
Adds an header to the response with key and val Example:
['/upload'; post]
pub fn (mut app App) upload() vweb.Result {
fdata := app.files['upfile']
data_rows := fdata[0].data.split('\n')
mut output_data := ''
for elem in data_rows {
delim_row := elem.split('\t')
output_data += '${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 $vweb.html()
}
- set_cookie
Sets a cookie Example:
pub fn (mut app App) cookie() vweb.Result {
app.set_cookie(name: 'cookie', value: 'test')
return app.text('Response Headers\n$app.header')
}
- set_cookie_with_expire_date
Sets a cookie with a expire_data
Example:
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:
['/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:
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:
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:
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:
pub fn (mut app App) error() vweb.Result {
app.error('here as an error')
println(app.form_error) //'vweb error: here as an error'
}