http-wagi-as

AssemblyScript example of making an HTTP Request from WAGI using wasi-experimental-http

WAGI is the easiest way to get started doing cloud-side WASM web apps. wasi_experimental_http provides a temporary workaround to enable HTTP requests from WASM modules until the capability is available via the WASI networking API

WARNING: This is experimental code . It is not considered production-grade by its developers, neither is it "supported" software.

What It Does

This is an example of WAGI. It is written in AssemblyScript, a WebAssembly-oriented dialect of TypeScript/JavaScript.

This example makes an HTTP POST request to https://postman-echo.com/ using WAGI and wasi-experimental-http.

Building

• Clone this repo to http-wagi-as and enter that directory.
• Use npm i to install all dependencies.
• Use npm run asbuild to build a WASM binary.

Configuring and Running

You can run this module using either the WAGI server or [wagi-dotnet] (https://github.com/deislabs/wagi-dotnet).

wagi-dotnet

The simplehttp example contains a sample that runs this module.

WAGI server

In your modules.toml for the WAGI server, add the following:

[[module]]
route = "/test"
module = "/path/to/http-wagi-as/build/optimized.wasm"

Substitute the correct module path for wherever you cloned this repo.

At that point, you should be able to access this program at http://localhost:3000/test (Possibly substituting in your own domain and port, depending on the WAGI server).

You can use curl to test:

curl -d "Test" http://localhost:3000/test -v
*   Trying 127.0.0.1...
* TCP_NODELAY set
* Connected to localhost (127.0.0.1) port 3000 (#0)
> POST /test HTTP/1.1
> Host: localhost:3000
> User-Agent: curl/7.58.0
> Accept: */*
> Content-Length: 4
> Content-Type: application/x-www-form-urlencoded
>
* upload completely sent off: 4 out of 4 bytes
< HTTP/1.1 200 OK
< Date: Thu, 10 Jun 2021 19:12:12 GMT
< Content-Type: application/json; charset=utf-8
< Server: Kestrel
< Transfer-Encoding: chunked
<
{"args":{},"data":"Test","files":{},"form":{},"headers":{"x-forwarded-proto":"https","x-forwarded-port":"443","host":"postman-echo.com","x-amzn-trace-id":"Root=1-60c2640c-58ffc97501ccd62c5f254dd0","content-length":"4","traceparent":"00-4671ab1d04d2e84c9ec1b5bd77d2fcef-062c6c2ca34ccc41-00","cookie":"sails.sid=s%3AiRsZ3Qzq2GsNrTQQxi3AhEELcyW7Hn6w.yRzXCs2iaMdX4LAyOafZ9QfhJyQp1Liu%2FJx3kllNjs8","content-type":"text/plain"},"json":null,"url":"https://postman-echo.com/post"}