feat: add GitHub Enterprise Server/Cloud support

Add support for GitHub Enterprise instances via --enterprise-url flag.
The enterprise URL is persisted to disk for reuse across sessions.

Changes:
- Add new url.ts with normalizeDomain, githubBaseUrl, githubApiBaseUrl
- Convert GITHUB_BASE_URL and GITHUB_API_BASE_URL to functions
- Update all GitHub API calls to use dynamic base URLs
- Add enterprise_url persistence in token.ts
- Pass enterprise URL to setupGitHubToken

Usage:
  --enterprise-url ghe.example.com

PR: ericc-ch#128

Author: jacks0n

README.md

@@ -167,6 +167,7 @@ The following command line options are available for the `start` command:
 | --show-token   | Show GitHub and Copilot tokens on fetch and refresh                           | false      | none  |
 | --proxy-env    | Initialize proxy from environment variables                                   | false      | none  |
 | --api-key      | API keys for authentication. Can be specified multiple times                  | none       | none  |
+| --enterprise-url | GitHub Enterprise host (eg. ghe.example.com)                                | none       | none  |
 
 #### Usage examples with --host
 

src/lib/api-config.ts

@@ -2,6 +2,9 @@ import { randomUUID } from "node:crypto"
 
 import type { State } from "./state"
 
+import { state } from "./state"
+import { githubApiBaseUrl, githubBaseUrl } from "./url"
+
 export const standardHeaders = () => ({
   "content-type": "application/json",
   accept: "application/json",
@@ -13,10 +16,15 @@ const USER_AGENT = `GitHubCopilotChat/${COPILOT_VERSION}`
 
 const API_VERSION = "2025-04-01"
 
-export const copilotBaseUrl = (state: State) =>
-  state.accountType === "individual" ?
-    "https://api.githubcopilot.com"
-  : `https://api.${state.accountType}.githubcopilot.com`
+export const copilotBaseUrl = (st: State) => {
+  if (st.enterpriseUrl) {
+    return `https://copilot-api.${st.enterpriseUrl}`
+  }
+
+  return st.accountType === "individual"
+    ? "https://api.githubcopilot.com"
+    : `https://api.${st.accountType}.githubcopilot.com`
+}
 export const copilotHeaders = (state: State, vision: boolean = false) => {
   const headers: Record<string, string> = {
     Authorization: `Bearer ${state.copilotToken}`,
@@ -36,7 +44,7 @@ export const copilotHeaders = (state: State, vision: boolean = false) => {
   return headers
 }
 
-export const GITHUB_API_BASE_URL = "https://api.github.com"
+export const GITHUB_API_BASE_URL = () => githubApiBaseUrl(state.enterpriseUrl)
 export const githubHeaders = (state: State) => ({
   ...standardHeaders(),
   authorization: `token ${state.githubToken}`,
@@ -47,6 +55,6 @@ export const githubHeaders = (state: State) => ({
   "x-vscode-user-agent-library-version": "electron-fetch",
 })
 
-export const GITHUB_BASE_URL = "https://github.com"
+export const GITHUB_BASE_URL = () => githubBaseUrl(state.enterpriseUrl)
 export const GITHUB_CLIENT_ID = "Iv1.b507a08c87ecfe98"
 export const GITHUB_APP_SCOPES = ["read:user"].join(" ")

src/lib/paths.ts

@@ -5,15 +5,18 @@ import path from "node:path"
 const APP_DIR = path.join(os.homedir(), ".local", "share", "copilot-api")
 
 const GITHUB_TOKEN_PATH = path.join(APP_DIR, "github_token")
+const ENTERPRISE_URL_PATH = path.join(APP_DIR, "enterprise_url")
 
 export const PATHS = {
   APP_DIR,
   GITHUB_TOKEN_PATH,
+  ENTERPRISE_URL_PATH,
 }
 
 export async function ensurePaths(): Promise<void> {
   await fs.mkdir(PATHS.APP_DIR, { recursive: true })
   await ensureFile(PATHS.GITHUB_TOKEN_PATH)
+  await ensureFile(PATHS.ENTERPRISE_URL_PATH)
 }
 
 async function ensureFile(filePath: string): Promise<void> {

src/lib/state.ts

@@ -3,6 +3,7 @@ import type { ModelsResponse } from "~/services/copilot/get-models"
 export interface State {
   githubToken?: string
   copilotToken?: string
+  enterpriseUrl?: string
 
   accountType: string
   models?: ModelsResponse
@@ -25,4 +26,5 @@ export const state: State = {
   manualApprove: false,
   rateLimitWait: false,
   showToken: false,
+  enterpriseUrl: undefined,
 }

src/lib/token.ts

@@ -15,6 +15,19 @@ const readGithubToken = () => fs.readFile(PATHS.GITHUB_TOKEN_PATH, "utf8")
 const writeGithubToken = (token: string) =>
   fs.writeFile(PATHS.GITHUB_TOKEN_PATH, token)
 
+const readEnterpriseUrl = async () => {
+  try {
+    const txt = await fs.readFile(PATHS.ENTERPRISE_URL_PATH, "utf8")
+    const trimmed = txt.trim()
+    return trimmed || undefined
+  } catch {
+    return undefined
+  }
+}
+
+const writeEnterpriseUrl = (url?: string) =>
+  fs.writeFile(PATHS.ENTERPRISE_URL_PATH, url || "")
+
 export const setupCopilotToken = async () => {
   const { token, refresh_in } = await getCopilotToken()
   state.copilotToken = token
@@ -44,13 +57,16 @@ export const setupCopilotToken = async () => {
 
 interface SetupGitHubTokenOptions {
   force?: boolean
+  enterpriseUrl?: string
 }
 
 export async function setupGitHubToken(
   options?: SetupGitHubTokenOptions,
 ): Promise<void> {
   try {
     const githubToken = await readGithubToken()
+    const persistedEnterprise = await readEnterpriseUrl()
+    if (persistedEnterprise) state.enterpriseUrl = persistedEnterprise
 
     if (githubToken && !options?.force) {
       state.githubToken = githubToken
@@ -63,6 +79,10 @@ export async function setupGitHubToken(
     }
 
     consola.info("Not logged in, getting new access token")
+
+    const enterpriseFromOptions = options?.enterpriseUrl
+    if (enterpriseFromOptions) state.enterpriseUrl = enterpriseFromOptions
+
     const response = await getDeviceCode()
     consola.debug("Device code response:", response)
 
@@ -72,6 +92,7 @@ export async function setupGitHubToken(
 
     const token = await pollAccessToken(response)
     await writeGithubToken(token)
+    await writeEnterpriseUrl(state.enterpriseUrl)
     state.githubToken = token
 
     if (state.showToken) {

src/lib/url.ts

@@ -0,0 +1,16 @@
+export function normalizeDomain(url: string | undefined): string | undefined {
+  if (!url) return undefined
+  return url.replace(/^https?:\/\//, "").replace(/\/+$/, "")
+}
+
+export function githubBaseUrl(enterprise?: string): string {
+  if (!enterprise) return "https://github.com"
+  const domain = normalizeDomain(enterprise)
+  return `https://${domain}`
+}
+
+export function githubApiBaseUrl(enterprise?: string): string {
+  if (!enterprise) return "https://api.github.com"
+  const domain = normalizeDomain(enterprise)
+  return `https://api.${domain}`
+}

src/services/github/get-copilot-token.ts

@@ -4,7 +4,7 @@ import { state } from "~/lib/state"
 
 export const getCopilotToken = async () => {
   const response = await fetch(
-    `${GITHUB_API_BASE_URL}/copilot_internal/v2/token`,
+    `${GITHUB_API_BASE_URL()}/copilot_internal/v2/token`,
     {
       headers: githubHeaders(state),
     },

src/services/github/get-copilot-usage.ts

@@ -3,9 +3,12 @@ import { HTTPError } from "~/lib/error"
 import { state } from "~/lib/state"
 
 export const getCopilotUsage = async (): Promise<CopilotUsageResponse> => {
-  const response = await fetch(`${GITHUB_API_BASE_URL}/copilot_internal/user`, {
-    headers: githubHeaders(state),
-  })
+  const response = await fetch(
+    `${GITHUB_API_BASE_URL()}/copilot_internal/user`,
+    {
+      headers: githubHeaders(state),
+    },
+  )
 
   if (!response.ok) {
     throw new HTTPError("Failed to get Copilot usage", response)

src/services/github/get-device-code.ts

@@ -7,7 +7,7 @@ import {
 import { HTTPError } from "~/lib/error"
 
 export async function getDeviceCode(): Promise<DeviceCodeResponse> {
-  const response = await fetch(`${GITHUB_BASE_URL}/login/device/code`, {
+  const response = await fetch(`${GITHUB_BASE_URL()}/login/device/code`, {
     method: "POST",
     headers: standardHeaders(),
     body: JSON.stringify({

src/services/github/get-user.ts

@@ -3,7 +3,7 @@ import { HTTPError } from "~/lib/error"
 import { state } from "~/lib/state"
 
 export async function getGitHubUser() {
-  const response = await fetch(`${GITHUB_API_BASE_URL}/user`, {
+  const response = await fetch(`${GITHUB_API_BASE_URL()}/user`, {
     headers: {
       authorization: `token ${state.githubToken}`,
       ...standardHeaders(),