js-sdk: Add support for proxy environment variables like HTTPS_PROXY

This adds support for the following proxy environment variables:

- https_proxy
- HTTPS_PROXY
- http_proxy
- HTTP_PROXY
- all_proxy
- ALL_PROXY

Lowercase version takes precedence as that seems to be standard across
cURL, Python, and wget -- yes, I agree -- it is nuts!

For a reference on the used environment variables and their
precedence see: https://superuser.com/a/1690537

Author: malthejorgensen

packages/js-sdk/src/api/index.ts

@@ -5,6 +5,7 @@ import { defaultHeaders } from './metadata'
 import { ConnectionConfig } from '../connectionConfig'
 import { AuthenticationError, RateLimitError, SandboxError } from '../errors'
 import { createApiLogger } from '../logs'
+import { getProxyFetch } from '../proxy'
 
 export function handleApiError(
   response: FetchResponse<any, any, any>,
@@ -74,6 +75,7 @@ class ApiClient {
 
     this.api = createClient<paths>({
       baseUrl: config.apiUrl,
+      fetch: getProxyFetch(),
       // In HTTP 1.1, all connections are considered persistent unless declared otherwise
       // keepalive: true,
       headers: {

packages/js-sdk/src/envd/api.ts

@@ -3,6 +3,7 @@ import createClient from 'openapi-fetch'
 import type { components, paths } from './schema.gen'
 import { ConnectionConfig } from '../connectionConfig'
 import { createApiLogger } from '../logs'
+import { getProxyFetch } from '../proxy'
 import {
   SandboxError,
   InvalidArgumentError,
@@ -130,7 +131,7 @@ class EnvdApiClient {
   ) {
     this.api = createClient({
       baseUrl: config.apiUrl,
-      fetch: config?.fetch,
+      fetch: config?.fetch ?? getProxyFetch(),
       headers: config?.headers,
       // In HTTP 1.1, all connections are considered persistent unless declared otherwise
       // keepalive: true,

packages/js-sdk/src/proxy.ts

@@ -0,0 +1,46 @@
+import { getEnvVar } from './api/metadata'
+import { runtime } from './utils'
+
+function getProxyUrl(): string | undefined {
+  return (
+    getEnvVar('HTTPS_PROXY') ||
+    getEnvVar('https_proxy') ||
+    getEnvVar('HTTP_PROXY') ||
+    getEnvVar('http_proxy') ||
+    getEnvVar('ALL_PROXY') ||
+    getEnvVar('all_proxy') ||
+    undefined
+  )
+}
+
+let cachedProxyFetch: typeof fetch | null = null
+let proxyResolved = false
+
+/**
+ * Returns a proxy-aware fetch function if HTTPS_PROXY/HTTP_PROXY/ALL_PROXY
+ * env vars are set. In browser environments, returns undefined (browsers
+ * handle proxies natively via OS settings).
+ *
+ * Uses undici's ProxyAgent, which is built into Node.js 20+.
+ */
+export function getProxyFetch(): typeof fetch | undefined {
+  if (proxyResolved) return cachedProxyFetch ?? undefined
+  proxyResolved = true
+
+  if (runtime === 'browser') return undefined
+
+  const proxyUrl = getProxyUrl()
+  if (!proxyUrl) return undefined
+
+  try {
+    // eslint-disable-next-line @typescript-eslint/no-var-requires
+    const { ProxyAgent } = require('undici')
+    const agent = new ProxyAgent(proxyUrl)
+    cachedProxyFetch = ((input: any, init?: any) =>
+      fetch(input, { ...init, dispatcher: agent })) as typeof fetch
+    return cachedProxyFetch
+  } catch {
+    // undici not available (e.g. edge runtimes, older Node.js) — fall back to default fetch
+    return undefined
+  }
+}

packages/js-sdk/src/sandbox/index.ts

@@ -9,6 +9,7 @@ import {
 } from '../connectionConfig'
 import { EnvdApiClient, handleEnvdApiError } from '../envd/api'
 import { createRpcLogger } from '../logs'
+import { getProxyFetch } from '../proxy'
 import { Commands, Pty } from './commands'
 import { Filesystem } from './filesystem'
 import { Git } from './git'
@@ -150,6 +151,7 @@ export class Sandbox extends SandboxApi {
       'E2b-Sandbox-Port': this.envdPort.toString(),
     }
 
+    const proxyFetch = getProxyFetch() ?? fetch
     const rpcTransport = createConnectTransport({
       baseUrl: this.envdApiUrl,
       useBinaryFormat: false,
@@ -178,7 +180,7 @@ export class Sandbox extends SandboxApi {
           redirect: 'follow',
         }
 
-        return fetch(url, options)
+        return proxyFetch(url, options)
       },
     })
 

packages/js-sdk/src/volume/client.ts

@@ -3,6 +3,7 @@ import createClient from 'openapi-fetch'
 import type { components, paths } from './schema.gen'
 import { defaultHeaders, getEnvVar } from '../api/metadata'
 import { createApiLogger, Logger } from '../logs'
+import { getProxyFetch } from '../proxy'
 import type { Volume } from './index'
 
 const FILE_TIMEOUT_MS = 3_600_000 // 1 hour
@@ -99,6 +100,7 @@ class VolumeApiClient {
   constructor(config: VolumeConnectionConfig) {
     this.api = createClient<paths>({
       baseUrl: config.apiUrl,
+      fetch: getProxyFetch(),
       headers: {
         ...defaultHeaders,
         ...(config.token && { Authorization: `Bearer ${config.token}` }),