# 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._** ## Quick Start Just run **`v new web`** in your terminal. Run your vweb app with a live reload via `v -d vweb_livereload watch run .` Now modifying any file in your web app (whether it's a .v file with the backend logic or a compiled .html template file) will result in an instant refresh of your app in the browser. No need to quit the app, rebuild it, and refresh the page in the browser! ## 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. - **Multithreaded** by default ### 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 `_ vweb.Result ()` like this // render the `.html` in folder `./templates/` 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 ${page_title} @css 'src/templates/page/home.css'

Hello, Vs.

@for var in list_of_object

${var.title} ${var.description}

@end

@include 'component.html'

``` `src/templates/page/component.html` ```html

This is a component

``` `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 \ `@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 $user') } ``` You have access to the raw request data such as headers or the request body by accessing `app` (which is `vweb.Context`). If you want to read the request body, you can do that by calling `app.req.data`. To read the request headers, you just call `app.req.header` and access the header you want example. `app.req.header.get(.content_type)`. See `struct Header` for all available methods (`v doc net.http Header`). It has, too, fields for the `query`, `form`, `files`. #### - Parameter Arrays If you want multiple parameters in your route and if you want to parse the parameters yourself, or you want a wildcard route, you can add `...` after the `:` and name, e.g. `['/:path...']`. This will match all routes after `'/'`. For example the url `/path/to/test` would give `path = '/path/to/test'`. ```v ignore vvv ['/:path...'] vvvv fn (mut app App) wildcard(path string) vweb.Result { return app.text('URL path = "${path}"') } ``` #### - 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()) } ``` #### - Host To restrict an endpoint to a specific host, you can use the `host` attribute followed by a colon `:` and the host name. You can test the Host feature locally by adding a host to the "hosts" file of your device. **Example:** ```v ignore ['/'; host: 'example.com'] pub fn (mut app App) hello_web() vweb.Result { return app.text('Hello World') } ['/'; host: 'api.example.org'] pub fn (mut app App) hello_api() vweb.Result { return app.text('Hello API') } // define the handler without a host attribute last if you have conflicting paths. ['/'] pub fn (mut app App) hello_others() vweb.Result { return app.text('Hello Others') } ``` You can also [create a controller](#hosts) to handle all requests from a specific host in one app. ### 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 } ``` You can only add 1 middleware to a route specific function via attributes. #### Middleware evaluation order The middleware is executed in the following order: 1. `before_request` 2. The middleware in `app.middlewares` 3. The middleware in the `[middleware]` attribute If any function of step 2 or 3 returns `false` the middleware functions that would come after it are not executed and the app handler will also not be executed. You can think of it as a chain. ### Context values You can store a value pair in vweb's context. It is especially useful for passing variables from a middleware function to the route handler. **Example**: ```v oksyntax module main import vweb struct App { vweb.Context middlewares map[string][]vweb.Middleware } pub fn (mut app App) index() vweb.Result { // get the user or return HTTP 401 user := app.get_value[User]('user') or { app.set_status(401, '') return app.text('HTTP 401: Unauthorized') } return app.text('welcome ${user.name}') } fn main() { vweb.run(&App{ middlewares: { '/': [get_session] } }, 8080) } struct User { session_id string name string } fn get_session(mut ctx vweb.Context) bool { // impelement your own logic to get the user user := User{ session_id: '123456' name: 'Vweb' } // set the user ctx.set_value('user', user) return true } ``` When you visit the index page the middleware function `get_session` will run first This function sets a `User` value to a key `'user'`. We get this key in `index` and display it to the user if the `'user'` key exists. #### Changing Context values By default context values are immutable when retrieved with `get_value`. If you want to change the value later you have to set it again with `set_value`. **Example:** ```v ignore fn change_user(mut ctx vweb.Context) bool { user := User{ session_id: '654321' name: 'tester' } // set the user ctx.set_value('user', user) return true } ``` ### 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 } ``` ### Custom not found page You can implement a `not_found` route that is called when a request is made and no matching route is found to replace the default HTTP 404 not found page. **Example:** ``` v ignore pub fn (mut app App) not_found() vweb.Result { app.set_status(404, 'Not Found') return app.html('

Page not found

') } ``` ### Databases The `db` field in a vweb app is reserved for database connections. The connection is copied to each new request. **Example:** ```v module main import vweb import db.sqlite struct App { vweb.Context mut: db sqlite.DB } fn main() { // create the database connection mut db := sqlite.connect('db')! vweb.run(&App{ db: db }, 8080) } ``` ### Multithreading By default, a vweb app is multithreaded, that means that multiple requests can be handled in parallel by using multiple CPU's: a worker pool. You can change the number of workers (maximum allowed threads) by altering the `nr_workers` option. The default behaviour is to use the maximum number of jobs (cores in most cases). **Example:** ```v ignore fn main() { // assign a maximum of 4 workers vweb.run_at(&App{}, nr_workers: 4) } ``` #### Database Pool A single connection database works fine if you run your app with 1 worker, of if you access a file-based database like a sqlite file. This approach will fail when using a non-file based database connection like a mysql connection to another server somewhere on the internet. Multiple threads would need to access the same connection at the same time. To resolve this issue, you can use the vweb's built-in database pool. The database pool will keep a number of connections open when the app is started and each worker is assigned its own connection. Let's look how we can improve our previous example with database pooling and using a postgresql server instead. **Example:** ```v module main import vweb import db.pg struct App { vweb.Context db_handle vweb.DatabasePool[pg.DB] mut: db pg.DB } fn get_database_connection() pg.DB { // insert your own credentials return pg.connect(user: 'user', password: 'password', dbname: 'database') or { panic(err) } } fn main() { // create the database pool and pass our `get_database_connection` function as handler pool := vweb.database_pool(handler: get_database_connection) // no need to set the `db` field vweb.run(&App{ db_handle: pool }, 8080) } ``` If you don't use the default number of workers (`nr_workers`) you have to change it to the same number in `vweb.run_at` as in `vweb.database_pool` ### Extending the App struct with `[vweb_global]` You can change your `App` struct however you like, but there are some things you have to keep in mind. Under the hood at each request a new instance of `App` is constructed, and all fields are re-initialized with their default type values, except for the `db` field. This behaviour ensures that each request is treated equally and in the same context, but problems arise when we want to provide more context than just the default `vweb.Context`. Let's view the following example where we want to provide a secret token to our app: ```v module main import vweb struct App { vweb.Context secret string } fn main() { vweb.run(&App{ secret: 'my secret' }, 8080) } fn (mut app App) index() vweb.Result { return app.text('My secret is: ${app.secret}') } ``` When you visit `localhost:8080/` you would expect to see the text `"My secret is: my secret"`, but instead there is only the text `"My secret is: "`. This is because of the way vweb works. We can override the default behaviour by adding the attribute `[vweb_global]` to the `secret` field. **Example:** ```v ignore struct App { vweb.Context secret string [vweb_global] } ``` Now if you visit `localhost:8080/` you see the text `"My secret is: my secret"`. > **Note**: the value of `secret` gets initialized with the provided value when creating > `App`. If you would modify `secret` in one request the value won't be changed in the > next request. You can use shared fields for this. ### Shared Objects across requests We saw in the previous section that we can persist data across multiple requests, but what if we want to be able to mutate the data? Since vweb works with threads, we have to use `shared` fields. Let's see how we can add a visitor counter to our `App`. **Example:** ```v module main import vweb struct Counter { pub mut: count int } struct App { vweb.Context mut: counter shared Counter // shared fields can only be structs, arrays or maps. } fn main() { // initialize the shared object shared counter := Counter{ count: 0 } vweb.run(&App{ counter: counter }, 8080) } fn (mut app App) index() vweb.Result { mut count := 0 // lock the counter so we can modify it lock app.counter { app.counter.count += 1 count = app.counter.count } return app.text('Total visitors: ${count}') } ``` #### Drawback of Shared Objects The drawback of using shared objects is that it affects performance. In the previous example `App.counter` needs to be locked each time the page is loaded if there are simultaneous requests the next requests will have to wait for the lock to be released. It is best practice to limit the use of shared objects as much as possible. ### Controllers Controllers can be used to split up app logic so you are able to have one struct per `"/"`. E.g. a struct `Admin` for urls starting with `"/admin"` and a struct `Foo` for urls starting with `"/foo"` **Example:** ```v module main import vweb struct App { vweb.Context vweb.Controller } struct Admin { vweb.Context } struct Foo { vweb.Context } fn main() { mut app := &App{ controllers: [ vweb.controller('/admin', &Admin{}), vweb.controller('/foo', &Foo{}), ] } vweb.run(app, 8080) } ``` You can do everything with a controller struct as with a regular `App` struct. The only difference being is that only the main app that is being passed to `vweb.run` is able to have controllers. If you add `vweb.Controller` on a controller struct it will simply be ignored. #### Routing Any route inside a controller struct is treated as a relative route to its controller namespace. ```v ignore ['/path'] pub fn (mut app Admin) path vweb.Result { return app.text('Admin') } ``` When we created the controller with `vweb.controller('/admin', &Admin{})` we told vweb that the namespace of that controller is `"/admin"` so in this example we would see the text `"Admin"` if we navigate to the url `"/admin/path"`. Vweb doesn't support fallback routes or duplicate routes, so if we add the following route to the example the code will produce an error. ```v ignore ['/admin/path'] pub fn (mut app App) admin_path vweb.Result { return app.text('Admin overwrite') } ``` There will be an error, because the controller `Admin` handles all routes starting with `"/admin"`; the method `admin_path` is unreachable. #### Hosts You can also set a host for a controller. All requests coming from that host will be handled by the controller. **Example:** ```v module main import vweb struct App { vweb.Context vweb.Controller } pub fn (mut app App) index() vweb.Result { return app.text('App') } struct Example { vweb.Context } // You can only access this route at example.com: http://example.com/ pub fn (mut app Example) index() vweb.Result { return app.text('Example') } fn main() { vweb.run(&App{ controllers: [ vweb.controller_host('example.com', '/', &Example{}), ] }, 8080) } ``` #### Databases and `[vweb_global]` in controllers Fields with `[vweb_global]` have to passed to each controller individually. The `db` field is unique and will be treated as a `vweb_global` field at all times. **Example:** ```v module main import vweb import db.sqlite struct App { vweb.Context vweb.Controller mut: db sqlite.DB } struct Admin { vweb.Context mut: db sqlite.DB } fn main() { mut db := sqlite.connect('db')! mut app := &App{ db: db controllers: [ vweb.controller('/admin', &Admin{ db: db }), ] } } ``` #### Using a database pool **Example:** ```v module main import vweb import db.pg struct App { vweb.Context vweb.Controller db_handle vweb.DatabasePool[pg.DB] mut: db pg.DB } struct Admin { vweb.Context db_handle vweb.DatabasePool[pg.DB] mut: db pg.DB } fn get_database_connection() pg.DB { // insert your own credentials return pg.connect(user: 'user', password: 'password', dbname: 'database') or { panic(err) } } fn main() { // create the database pool and pass our `get_database_connection` function as handler pool := vweb.database_pool(handler: get_database_connection) mut app := &App{ db_handle: pool controllers: [ vweb.controller('/admin', &Admin{ db_handle: pool }), ] } } ``` ### 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('

ok

') } ``` #### - 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).\ host_handle_static can be used to limit the static resources to a specific host. 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') // app.host_serve_static('localhost', '/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 . mount_static_folder_at can be used to limit the static resources to a specific host. #### -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 host_serve_static can be used to limit the static resources to a specific host. **Example:** ```v ignore fn main() { mut app := &App{} app.serve_static('/favicon.ico', 'favicon.ico') // app.host_serve_static('localhost', /favicon.ico', 'favicon.ico') app.mount_static_folder_at(os.resource_abs_path('.'), '/') vweb.run(app, 8081) } ``` ### Others #### -user_agent Returns the user-agent from the current user **Example:** ```v ignore pub fn (mut app App) user_agent() vweb.Result { ua := app.user_agent() return app.text('User-Agent: $ua') } ``` #### -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 Vweb has built-in csrf protection. Go to the [csrf module](csrf/) to learn how you can protect your app against CSRF.