This package is SpiderMonkey wrapper for Go.
You can use this package to embed JavaScript into your Go program.
This package just newborn, use in production enviroment at your own risk!
You can found "go-v8" or "gomonkey" project on the github.
Thy have same purpose: Embed JavaScript into Golang program, make it more dynamic.
But I found all of existing projects are not powerful enough.
For example "go-v8" use JSON to pass data between Go and JavaScript, each callback has a significant performance cost.
So I make one by myself.
You need install SpiderMonkey first.
Mac OS X:
brew install spidermonkey
Ubuntu:
sudo apt-get install libmozjs185-dev
Or compile by yourself (reference).
And then install Monkey by "go get" command.
go get github.com/realint/monkey
All the example codes can be found in "examples" folder.
You can run all of the example codes like this:
go run examples/hello_world.go
The "hello_world.go" shows what Monkey can do.
package main
import "fmt"
import js "github.com/realint/monkey"
func main() {
// Create Script Runtime
runtime, err1 := js.NewRuntime()
if err1 != nil {
panic(err1)
}
// Evaluate Script
if value, err := runtime.Eval("'Hello ' + 'World!'"); err == nil {
println(value.ToString())
}
// Built-in Function
runtime.Eval("println('Hello Built-in Function!')")
// Compile Once, Run Many Times
if script, err := runtime.Compile(
"println('Hello Compiler!')",
"<no name>", 0,
); err == nil {
script.Execute()
script.Execute()
script.Execute()
}
// Define Function
if err := runtime.DefineFunction("add",
func(argv []js.Value) (js.Value, bool) {
if len(argv) != 2 {
return runtime.Null(), false
}
return runtime.Int(argv[0].Int() + argv[1].Int()), true
},
); err == nil {
if value, err := runtime.Eval("add(100, 200)"); err == nil {
println(value.Int())
}
}
// Error Handle
runtime.SetErrorReporter(func(report *js.ErrorReport) {
println(fmt.Sprintf(
"%s:%d: %s",
report.FileName, report.LineNum, report.Message,
))
if report.LineBuf != "" {
println("\t", report.LineBuf)
}
})
// Trigger An Error
runtime.Eval("abc()")
// Say Good Bye
runtime.Dispose()
}This code will output:
Hello World!
Hello Built-in Function!
Hello Compiler!
Hello Compiler!
Hello Compiler!
300
Eval():0: ReferenceError: abc is not defined
The "op_value.go" shows how to convert JS value to Go value.
package main
import js "github.com/realint/monkey"
func assert(c bool) bool {
if !c {
panic("assert failed")
}
return c
}
func main() {
// Create Script Runtime
runtime, err1 := js.NewRuntime()
if err1 != nil {
panic(err1)
}
// String
if value, err := runtime.Eval("'abc'"); assert(err == nil) {
assert(value.IsString())
assert(value.String() == "abc")
}
// Int
if value, err := runtime.Eval("123456789"); assert(err == nil) {
assert(value.IsInt())
assert(value.Int() == 123456789)
}
// Number
if value, err := runtime.Eval("12345.6789"); assert(err == nil) {
assert(value.IsNumber())
assert(value.Number() == 12345.6789)
}
runtime.Dispose()
}The "op_object.go" shows how to play with JS object.
package main
import js "github.com/realint/monkey"
func assert(c bool) bool {
if !c {
panic("assert failed")
}
return c
}
func main() {
// Create Script Runtime
runtime, err1 := js.NewRuntime()
if err1 != nil {
panic(err1)
}
// Return Object From JavaScript
if value, err := runtime.Eval("x={a:123}"); assert(err == nil) {
// Type Check
assert(value.IsObject())
obj := value.Object()
// Get Property
value1, ok1 := obj.GetProperty("a")
assert(ok1)
assert(value1.IsInt())
assert(value1.Int() == 123)
// Set Property
assert(obj.SetProperty("b", runtime.Int(456)))
value2, ok2 := obj.GetProperty("b")
assert(ok2)
assert(value2.IsInt())
assert(value2.Int() == 456)
}
// Return Object From Go
if err := runtime.DefineFunction("get_data",
func(argv []js.Value) (js.Value, bool) {
obj := runtime.NewObject()
obj.SetProperty("abc", runtime.Int(100))
obj.SetProperty("def", runtime.Int(200))
return obj.ToValue(), true
},
); err == nil {
if value, err := runtime.Eval("get_data()"); assert(err == nil) {
// Type Check
assert(value.IsObject())
obj := value.Object()
// Get Property 'abc'
value1, ok1 := obj.GetProperty("abc")
assert(ok1)
assert(value1.IsInt())
assert(value1.Int() == 100)
// Get Property 'def'
value2, ok2 := obj.GetProperty("def")
assert(ok2)
assert(value2.IsInt())
assert(value2.Int() == 200)
}
}
runtime.Dispose()
}The "op_array.go" shows how to play with JS array.
package main
import js "github.com/realint/monkey"
func assert(c bool) bool {
if !c {
panic("assert failed")
}
return c
}
func main() {
// Create Script Runtime
runtime, err1 := js.NewRuntime()
if err1 != nil {
panic(err1)
}
// Return Array From JavaScript
if value, err := runtime.Eval("[123, 456]"); assert(err == nil) {
// Type Check
assert(value.IsObject())
obj := value.Object()
assert(obj.IsArray())
assert(obj.GetArrayLength() == 2)
// Get First Item
value1, ok1 := obj.GetElement(0)
assert(ok1)
assert(value1.IsInt())
assert(value1.Int() == 123)
// Get Second Item
value2, ok2 := obj.GetElement(1)
assert(ok2)
assert(value2.IsInt())
assert(value2.Int() == 456)
// Set First Item
assert(obj.SetElement(0, runtime.Int(789)))
value3, ok3 := obj.GetElement(0)
assert(ok3)
assert(value3.IsInt())
assert(value3.Int() == 789)
// Grows
assert(obj.SetArrayLength(3))
assert(obj.GetArrayLength() == 3)
}
// Return Array From Go
if err := runtime.DefineFunction("get_data",
func(argv []js.Value) (js.Value, bool) {
array := runtime.NewArray()
array.SetElement(0, runtime.Int(100))
array.SetElement(1, runtime.Int(200))
return array.ToValue(), true
},
); err == nil {
if value, err := runtime.Eval("get_data()"); assert(err == nil) {
// Type Check
assert(value.IsObject())
obj := value.Object()
assert(obj.IsArray())
assert(obj.GetArrayLength() == 2)
// Get First Item
value1, ok1 := obj.GetElement(0)
assert(ok1)
assert(value1.IsInt())
assert(value1.Int() == 100)
// Get Second Item
value2, ok2 := obj.GetElement(1)
assert(ok2)
assert(value2.IsInt())
assert(value2.Int() == 200)
}
}
runtime.Dispose()
}The "op_func.go" shows how to play with JS function value.
package main
import js "github.com/realint/monkey"
func assert(c bool) bool {
if !c {
panic("assert failed")
}
return c
}
func main() {
// Create Script Runtime
runtime, err1 := js.NewRuntime()
if err1 != nil {
panic(err1)
}
// Function
if value, err := runtime.Eval("function(a,b){ return a+b; }"); assert(err == nil) {
// Type Check
assert(value.IsFunction())
// Call
value1, ok1 := value.Call([]js.Value{
runtime.Int(10),
runtime.Int(20),
})
// Result Check
assert(ok1)
assert(value1.IsNumber())
assert(value1.Int() == 30)
}
runtime.Dispose()
}The "many_many.go" shows Monkey is thread safe.
package main
import "sync"
import "runtime"
import js "github.com/realint/monkey"
func main() {
runtime.GOMAXPROCS(20)
// Create Script Runtime
runtime, err1 := js.NewRuntime()
if err1 != nil {
panic(err1)
}
wg := new(sync.WaitGroup)
// One Runtime Instance Used By Many Goroutines
for i := 0; i < 100; i++ {
wg.Add(1)
go func() {
for j := 0; j < 1000; j++ {
runtime.Eval("println('Hello World!')")
}
wg.Done()
}()
}
wg.Wait()
// Say Good Bye
runtime.Dispose()
}