ext_net

The ext_net crate provides HTTP fetch and network operations for Forge applications through the runtime:net module.

Overview

ext_net handles:

• HTTP fetch - GET, POST, PUT, DELETE, etc.
• Request configuration - Headers, body, timeout
• Response handling - JSON, text, bytes
• Capability-based security - URL-based permission checks

Module: runtime:net

import {
  fetchJson,
  fetchText,
  fetchBytes
} from "runtime:net";

Key Types

Error Types

enum NetErrorCode {
    Io = 1000,
    PermissionDenied = 1001,
    InvalidUrl = 1002,
    Timeout = 1003,
    ConnectionFailed = 1004,
    RequestFailed = 1005,
}

struct NetError {
    code: NetErrorCode,
    message: String,
}

Request/Response Types

struct FetchOpts {
    method: Option<String>,
    headers: Option<HashMap<String, String>>,
    body: Option<String>,
    timeout_ms: Option<u64>,
}

struct FetchResponse {
    status: u16,
    headers: HashMap<String, String>,
    body: String,
}

struct FetchBytesResponse {
    status: u16,
    headers: HashMap<String, String>,
    body: Vec<u8>,
}

Capability Types

struct NetCapabilities {
    allowed_hosts: Vec<String>,
    denied_hosts: Vec<String>,
}

trait NetCapabilityChecker {
    fn check_url(&self, url: &str) -> bool;
}

Operations

Op	TypeScript	Description
op_net_fetch	fetch(url, opts?)	HTTP fetch returning text
op_net_fetch_json	fetchJson(url, opts?)	HTTP fetch parsing JSON
op_net_fetch_bytes	fetchBytes(url, opts?)	HTTP fetch returning bytes

File Structure

crates/ext_net/
├── src/
│   └── lib.rs        # Extension implementation
├── ts/
│   └── init.ts       # TypeScript module shim
├── build.rs          # forge-weld build configuration
└── Cargo.toml

Rust Implementation

Operations are annotated with forge-weld macros for automatic TypeScript binding generation:

src/lib.rs

use deno_core::{op2, Extension, OpState};
use forge_weld_macro::{weld_op, weld_struct};
use serde::{Deserialize, Serialize};

#[weld_struct]
#[derive(Debug, Serialize)]
pub struct FetchResponse {
    pub status: u16,
    pub headers: HashMap<String, String>,
    pub body: String,
}

#[weld_op(async)]
#[op2(async)]
#[serde]
pub async fn op_net_fetch(
    state: Rc<RefCell<OpState>>,
    #[string] url: String,
    #[serde] opts: Option<FetchOpts>,
) -> Result<FetchResponse, NetError> {
    // implementation
}

Build Configuration

build.rs

use forge_weld::ExtensionBuilder;

fn main() {
    ExtensionBuilder::new("runtime_net", "runtime:net")
        .ts_path("ts/init.ts")
        .ops(&["op_net_fetch", "op_net_fetch_json", "op_net_fetch_bytes"])
        .generate_sdk_module("sdk")
        .use_inventory_types()
        .build()
        .expect("Failed to build runtime_net extension");
}

Dependencies

Dependency	Purpose
deno_core	Op definitions
reqwest	HTTP client
url	URL parsing
tokio	Async runtime
serde	JSON serialization
tracing	Logging
forge-weld	Build-time code generation
forge-weld-macro	#[weld_op], #[weld_struct] macros
linkme	Compile-time symbol collection

Related

• runtime:net API - TypeScript API documentation
• forge-weld - Code generation library