A tiny cross-platform webview library for C/C++/Golang.
It uses Cocoa/WebKit on macOS, gtk-webkit on Linux and good old MSHTML on Windows.
WebView library prrovides C API. For Go API please see godoc.
For the most simple use cases there is only one function:
// C (#include "webview.h")
int webview(const char *title, const char *url, int width, int height, int resizable);
// Go (package github.com/zserge/webview)
func Open(title, url string, w, h int, resizable bool) error
The following URL schemes are supported:
http:https://andhttps://, no surprises here.file:https:///can be useful if you want to unpack HTML/CSS assets to some temporary directory and point a webview to open index.html from there.data:text/html,<html>...</html>allows to pass short HTML data inline without using a web server or pulluting the file system. Furhter modifications of the webview contents can be done via JavaScript bindings.
If you write in C/C++ and have choosen a regular http URL scheme, you can use Mongoose or any other web server/framework you like.
You may also use Go web server running on a random port:
ln, err := net.Listen("tcp", "127.0.0.1:0")
if err != nil {
log.Fatal(err)
}
defer ln.Close()
go func() {
// Set up your http server here
log.Fatal(http.Serve(ln, nil))
}()
webview.Open("Hello", "http:https://"+ln.Addr().String(), 400, 300, false)If you want to have more control over the app you can use the following functions:
struct webview webview = {
.title = title,
.url = url,
.width = w,
.height = h,
.resizable = resizable,
};
/* Create webview window using the provided options */
webview_init(&webview);
/* Main app loop, can be either blocking or non-blocking */
while (webview_loop(&webview, blocking) == 0);
/* Destroy webview window, often exits the app */
webview_exit(&webview);
/* To change window title later: */
webview_set_title(&webview, "New title");
/* To terminate the webview main loop: */
webview_terminate(&webview);To evaluate arbitrary javascript code use the following C function:
webview_eval(&webview, "alert('hello, world');");There is also a special callback (webview.external_invoke_cb) that can be invoked from javascript:
// C
void my_cb(struct webview *w, const char *arg) {
...
}
// JS (note the trailing underscore)
window.external.invoke_('some arg');
// Exactly one string argument must be provided, to pass more complex objects
// serialize them to JSON and parse it in C. To pass binary data consider using
// base64.
window.external.invoke_(JSON.stringify({fn: 'sum', x: 5, y: 3}));In Go you can reduce the boilerplate by using WebView.Bind() method. It binds
an existing Go struct or struct pointer so that it appears under the same name
in JS, all its methods and fields are accessible directly from JS. Bind()
also returns a function that may be used to update the JS "mirrored" object
when you have asynchronously modified Go struct.
You may find a counter-go example that shows how to bind a Go "controller"
and use it from the various JavaScript UI frameworks, such as Vue.js, Preact or
Picodom.
Webview library is meant to be used from a single UI thread only. So if you
want to call webview_eval or webview_terminate from some background thread
- you have to use
webview_dispatchto post some arbitrary function with some context to be executed inside the main UI thread:
// This function will be executed on the UI thread
void render(struct webview *w, void *arg) {
webview_eval(w, ......);
}
// Dispatch render() function from another thread:
webview_dispatch(w, render, some_arg);Code is distributed under MIT license, feel free to use it in your proprietary projects as well.
Execution on OpenBSD requires wxallowed mount(8) option.