CODEWITHSUNDEEP
gowebassembly
emranio
emranio

Reputation: 448

How to bundle Go and its asset files into WASM?

I have a Go program that uses some json files (like 15) for data. I want to compile it into a WebAssembly file.

How can I do this?

Note: I know I can just pass those json values from my JS code to WASM, but I don't want that if I can effectively bundle them with WASM.

EDIT: lastly we tried https://pkg.go.dev/embed as NobbyNobbs mentioned, and it's working perfectly.

Upvotes: 3

Views: 1180

Answers (1)

sk shahriar ahmed raka
sk shahriar ahmed raka

Reputation: 1179

if you want to bundle any type of file/directory with compiled code (like binary/wasm) , there is a awesome Golang library packr . It's easy to use and when you compile the source code to binary or webassembly packr loads the file/directory and works the same way as before.

here i am using main.go in the root directory of the project. and a directory to store json data (like /jsondata/mydata.json)

main.go

package main

import (
    "fmt"

    "github.com/gobuffalo/packr/v2"
)

func main() {
    box := packr.New("myBox", "./jsondata")

    s, err := box.FindString("mydata.json")
    if err != nil {
        fmt.Println("🚀 ~ file: main.go ~ line 14 ~ funcmain ~ err : ", err)
    }
    fmt.Println(s)

}

/jsondata/mydata.json

{
    "glossary": {
        "title": "example glossary",
        "GlossDiv": {
        "title": "S"
        }
    }
}

than run the code using go run main.go. if you compiled it to the binary the json file ships with the binary code go build main.go

if you compiled it to the wasm , the folder will behave the same way GOOS=js GOARCH=wasm go build -o main.wasm main.go

Second method (Using "embed")

use embed library from standard library .

here i am using main.go in the root directory of the project. and creating a file in same directory (like /sample.json)

main.go

package main

import (
  "embed"
)

//go:embed sample.json
var f embed.FS

func main(){
data, _ := f.ReadFile("sample.json")
print(string(data))

}

/sample.json

{
    "glossary": {
        "title": "example glossary",
        "GlossDiv": {
        "title": "S"
        }
    }
}

than run the code using go run main.go. if you compiled it to the binary the json file ships with the binary code go build main.go

if you compiled it to the wasm , the folder will behave the same way GOOS=js GOARCH=wasm go build -o main.wasm main.go

Upvotes: 1

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